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Here we present a novel approach that combines soil micromorphology with the analysis of magnetically oriented samples to improve the interpretation of archaeomagnetic results. The aim is to test whether irregular archaeomagnetic data can be examined with micromorphological soil analysis in a single sample methodology, allowing said archaeomagnetic data to contribute to more meaningful archaeological interpretation. Experimental work included reusing oriented magnetic samples previously treated with sodium silicate resin, which were then re-impregnated with polyester or epoxy resins to produce thin sections. Initial experimentation was conducted to understand the potential effects of sodium silicate treatment on the optical and mechanical qualities of the thin sections. When no significant optical anomalies were identified, the methodology was tested using samples gathered from hearths at level X (ca. 52 ky BP) at the Middle Palaeolithic site of El Salt, Spain. Thin section analysis was conducted on archaeological hearth samples to identify syn- and post-depositional processes influencing the magnetic data. Micromorphological analysis of magnetic samples can identify the causes of anomalous magnetic direction, attributing them to specific sedimentary features rather than sampling or measurement errors. Discrepancies in magnetic signatures are linked to the presence or absence of certain combustion layers, such as black and white layers, as well as the impact of bioturbation and mechanical deformation. This integrative approach improves the interpretive potential of archaeomagnetic studies by not only validating the magnetic data as representative of the deposit but also providing a visual understanding of the sedimentary structure creating the magnetic signature. Our findings advocate for the routine inclusion of thin section inspection in archaeomagnetic research, particularly when dealing with complex sedimentary sequences and ambiguous magnetic data. [ABSTRACT FROM AUTHOR]

The geological structure of the goaf overlying rock is complex, a consequence of coal mining that has modified the original stratified structure of the sedimentary strata. To enhance the accuracy of microseismic source location in such intricate geological formations, a wave velocity model for the "three zones" goaf was constructed based on natural divisions within the strata using Snell's law and assuming a homogeneous medium. The model took into account the effects of rock deformation and fracture development, enabling the derivation of formulas for microseismic wave propagation path and travel time calculation. Additionally, the concept of equivalent wave velocity was defined. An indoor simulation test using similar materials was conducted to establish a geological model of the goaf. By comparing the errors between the theoretical and measured values of equivalent wave velocity, assessing the locating effects before and after implementing the wave velocity model of the goaf, and verifying the feasibility of the model, it was demonstrated that establishing a wave velocity model based on the characteristics of the strata structure was crucial for improving the accuracy of the microseismic source location. Notably, as the propagation path of microseismic waves in the goaf increased, the equivalent wave velocity decreased. The wave velocity structure in the goaf exhibited nonuniformity, with the relative error between the theoretical and measured values of equivalent wave velocity being limited to 10 %. The incorporation of this established wave velocity model into the location method resulted in a substantial 58.57 % increase in locating accuracy. • Using the goaf overlying rock strata morphology to construct a wave velocity model. • The propagation path and travel time of waves passing through the arc interfaces. • The interface and intralayer diffraction path increments in the goaf. • The location method with the goaf overlying rock strata wave velocity model. [ABSTRACT FROM AUTHOR]

Shelf mud patches represent major sinks for fine-grained particles on continental shelves, as well as for carbon and contaminants of continental origin. The West Gironde Mud Patch (WGMP) is an interesting example of such offshore marine systems as it is an active mud deposition area located offshore the Gironde estuarine mouth (France) at depths between 30 and 70 m. It is known to be the trap of fine particles coming from the estuary, but the contribution of this material to the total mass of the depocenter is poorly quantified. In addition, despite the economic and ecological issues at stake, the response of such subtidal sedimentary structure to the combination of tidal currents, waves, and river supply remain poorly understood. Thus, using a realistic 3-D hydrodynamic and mixed (mud/sand) sediment transport model, this study aims at investigating the sediment dynamics of the WGMP under different hydrometeorological conditions. The analysis of the residual fluxes at the estuarine mouth exhibited large discrepancies between the different sediment classes as well as for contrasted hydro-and meteorological conditions induced by different dominant transport mechanisms. During winter, the reinforced density gradients drive strong up-estuary baroclinic circulation at the bottom that dominates the sediment dynamics over the barotropic export of mud particles. The model also reproduced the signature of a subtidal mud accumulation area over the continental shelf around 30–40 m water depth, on the proximal side of the observed WGMP. On average over two years, 26% of the mud mass accumulating on the simulated subtidal mudflat comes from the estuary. The trapping efficiency of this mud patch is negatively correlated with the significant wave height. Moreover, due to the estuarine turbid plume being more concentrated and developed at the surface during high river discharge, the trapping efficiency of the mud body is enhanced compared to lower discharge. This study highlights the sensitivity of mud and sand fluxes to vertical and horizontal residual circulation, and points out the uncertainties associated with the simulation of short-term (i.e., years) fine particle deposits compared to long-term (i.e., centuries) sediment accumulation trends. In addition, these results show the primordial effects of both wave action and riverine sediment supply on the dynamics of such subtidal muddy structures, which raises concern about their fate facing climate change and human activities in the future. • A process-based model simulated mud/sand fluxes along an estuary-shelf continuum. • Density gradients drive up-estuary sand fluxes at the estuarine mouth. • The formation and dynamics of an active shelf mud deposition area are reproduced. • The trapping efficiency of the mudflat is modulated by waves and river turbid plume. • About 26% of the mud mass accumulated on the mudflat originates from the estuary. [ABSTRACT FROM AUTHOR]

Exploring the interdependence between watermass conditions and climate change in marginal marine regions is essential for gaining insights into contemporary environmental challenges arising from global warming. Salinity, a key parameter of watermass conditions in coastal areas, plays a crucial role in influencing nutrient availability, stratification, and the spatial-temporal distribution of redox conditions. Here, we focus on the cyclostratigraphic analysis of gamma-ray (GR) data obtained from Eocene strata in the Luo-69 drillcore from the Bohai Bay Basin (NE China). This analysis establishes a high-resolution astronomical time scale (ATS) for the lower third member of the Shahejie Formation (Es3l), spanning 39.04 Ma to 41.46 million years ago (Ma). Various proxies for watermass conditions, such as salinity, sedimentary structures, mineral content, total organic carbon (TOC), organic carbon isotopes and nitrogen isotopes (δ13C org and δ15N), exhibit a strong correlation with 405-kyr long orbital eccentricity climate forcing. Notably, spectral analysis of salinity data (represented by the Sr/Ba proxy) reveals a clear astronomical control, with 405-kyr eccentricity cycles that align closely with variations in the GR data. Peaks in paleosalinity, as indicated by Sr/Ba (as well as B/Ga and S/TOC), correspond with maxima in 405-kyr long orbital eccentricity cycles in the GR data. As such, we infer that astronomical forcing regulated long-term changes in watermass conditions, likely through mediation of the East Asia monsoon system. Specifically, during eccentricity maxima, the basin would have experienced a warm and humid climate with pronounced seasonality and a robust summer monsoon. During such periods, increased continental runoff would lead to a rise in lake-levels, facilitating better connections with the ocean, and hence increased salinity. By contrast, during eccentricity minima, cooler and more arid conditions with weaker seasonality would result in lower lake levels which together with a global eustatic lowstand would result in as weakened connection with the open ocean restricting the ingress of seawater into the basin lowering salinity. Our dataset spans the Middle Eocene Climatic Optimum (MECO, ∼40.60–40.10 Ma), identified by elevated GR values and a conspicuous negative excursion in oxygen isotopes. This interval is characterized by a significant decline in salinity, likely attributed to enhanced freshwater runoff driven by an extremely warm and humid climate. The paleosalinity fluctuation recorded by the proxies B/Ga, Sr/Ba, and S/TOC in Bohai Bay Basin demonstrate the sensitivity of marginal-marine environment to subtle changes in climate driven by astronomical forcing. Our results provide new insights into how elemental salinity proxies can be utilized in paleoenvironmental reconstruction studies. [ABSTRACT FROM AUTHOR]

Fossils of the Ediacara Biota preserve the oldest indisputable evidence of macroscopic animal life. Although new finds continue to expand the near global distribution of such organisms, relatively abundant and diverse populations of these primarily soft-bodied taxa are known from just a handful of localities. More commonly, reports of late Precambrian fossils consist of comparably lower diversity assemblages (less than ∼10 genera), with a limited number of total specimens (less than ∼1000 reported macrofossils over a broad geographic area). Determining the factors responsible for such differences can help to fully appreciate preserved patterns of Ediacaran biodiversity. The lower member of the Wood Canyon Formation in the Death Valley region of the southern Great Basin, USA contains fossils of the Ediacara Biota. Here we redescribe previously recovered specimens based on new data from 3D surface scans and report several new finds from this unit. Although this allows the addition of two Ediacara taxa (Pteridinium and Charnia ?) to the known diversity in the region, most potential macrofauna consist of amorphous, irregular forms with minimal preserved structures wherein an abiotic origin cannot be ruled out. A combination of factors – including variable taphonomic conditions, difficulty of identification and an original depauperate community – contribute to the observed diversity of this assemblage. Many biases that impact this record are either common (e.g., age, preservation requirements, difficulty of recognition) or comparable (e.g., paleoenvironmental and taphonomic controls) to known occurrences of Ediacara macrofauana. Thus, we argue this fossil record at least partially reflects the original community composition, suggesting that fossils of the lower Wood Canyon record a signal of relatively low diversity of the Ediacara Biota in the lead up to the Ediacaran-Cambrian boundary. • Latest Ediacaran fossils of the Great Basin are rare and poorly preserved. • Taphonomy, transport and identification all contribute to this record. • Many potential macrofauna cannot be distinguished from other structures. • Despite limitations, current data support a global extinction prior to the Cambrian. [ABSTRACT FROM AUTHOR]

The present study attempts to explore the efficacy of self-organizing maps (SOMs) in understanding the pattern of seismic reflections and analyze their implications for revealing the subsurface tectono-depositional environment prevailing within the Oligocene-Miocene intervals of the Upper Assam foreland basin, NE India. A series of seismic attributes including geometrical, spectral, amplitude, and GLCM-textures are extracted using high-resolution three-dimensional seismic data acquired from the upper shelf of the basin. These attributes are amalgamated into two different cases to compute the SOM models with an aim to highlight the subsurface structures and reveal sedimentary deposits engulfed within these structures. It is observed that the model SOM Case 1 highlights subsurface fault networks that structurally control the Oligocene-Miocene intervals. However, the model SOM Case 2 not only hints at the presence of these structures but also illuminates different patterns of seismic reflections and geomorphic features associated with sediment entrapped within the fault-bounded structures. Through this research, we envisage that for the SOMs to be optimal, geologically meaningful sets of seismic attributes should be used as an input such that attributes assisting seismic interpreters could successfully identify relations or patterns within the data. The method presented in this study can be applied to similar geologic settings to aid subsurface interpretation. • Elucidates the usage of attribute-assisted unsupervised machine learning approach. • Designed SOM models using a set of suitable seismic attributes tuned to geologic targets. • Highlighted the efficacy of using SOMs for interpreting subsurface tectono-depositional environment. [ABSTRACT FROM AUTHOR]

An integrated analysis of ichnological and sedimentological features in ancient successions provides a robust dataset of high-resolution interpretations of environmental parameters, encompassing both depositional and ecological aspects. By characterising discrete and recurring bioturbation patterns in the Puerto Madryn Formation (Late Miocene, Argentine Patagonia), we arrive at key knowledge about predominant environmental stresses within transgressive phase shallow marine and estuarine systems, shedding light on their palaeoenvironmental implications. Given the inherent complexities of coastal settings, including the challenges posed by omission/erosion surfaces, it becomes imperative to consider the intricate interplay of multiple depositional processes and environmental factors. Through a detailed integration of sedimentological and ichnological approaches, we discern the establishment of a wave-dominated system overlain by a tide-dominated estuarine system. The wave-dominated marine system involves tabular bodies extending laterally over tens of kilometres, with upward fining and coarsening successions from the mid- to lower-shoreface to offshore-shelf environments. The influence of waves and tides on these systems is discussed in the absence of physical sedimentary structures and the need to find elements that bring us closer to elucidating whether waves or tidal processes influence shoreface to offshore systems. The ichnological assemblages allow for the characterisation of Cruziana ichnofacies with proximal (Taenidium and Thalassinoides), archetypal (Asterosoma , Chondrites , Cylindrichnus , Ophiomorpha , ? Rhizocorallium , Rosselia , Scolicia , Sinusichnus , Siphonichnus , Teichichnus , and Thalassinoides), and distal expressions (Chondrites , Helicodromites , Phycodes , Thalassinoides , and ? Zoophycos) in the lower shoreface to lower offshore and transitional settings with the shelf. However, the transition from these deposits to Chondrites -dominated beds associated with lower offshore to shelf environments—determined by changes in oxygenation, nutrients, and energy conditions—impedes assignment of all the successions to a particular ichnofacies. The tide-dominated estuarine system features wide, channel-shaped bodies filled with sandy to heterolithic facies, interpreted as intertidal and subtidal deposits. To differentiate between estuary mouths and other settings, the analysis involved characterisation of transgressive and regressive surfaces, ichnological assemblages, and facies distribution, determining net sediment movement—whether landwards or seawards—and its influence on system classification. The ichnological assemblages could be assigned to the Skolithos (Arenicolites , Gyrolithes , Maiakarichnus , Ophiomorpha , Schaubcylindrichnus , Skolithos , and Thalassinoides) and Cruziana ichnofacies (Ophiomorpha , Rosselia , Scolicia , and Siphonichnus). Variations in diversity and abundance often help to determine certain stressful conditions, although the transition to more open areas is discussed, addressing how it could modify the typical models linked with a direct relationship between abundance/diversity and physico-chemical stress. • Ichnological analysis as indicators of physico-chemical stresses • Ecosystem evolution from wave-dominated to tide-dominated environments • Non-tidal shorefaces in transgressive phase • Tide-dominated estuarine system in regressive phase • Physico-chemical stressors challenge traditional ichnofacies analysis. [ABSTRACT FROM AUTHOR]

• There are 2.1 Ga tropical storm deposits of coastal to shallow-marine environments in the Hutuo Group in North China Craton. • The storm deposits lasted for over 40 Myr, indicating a high-temperature greenhouse climate after Huronian glaciation. • Greenhouse climate is evident by extensive carbonate, evaporite, and black shale above glacial diamictite in multi-cratons. The Hutuo Group was deposited from 2.14 to 2.0 Ga in Wutai Mountain, North China Craton. This group is composed of the Doucun and Dongye subgroups, which are likely contemporaneous heterotopic facies. The Hutuo Group displays well-known positive to negative drifts of inorganic carbon isotopes, large-scale stromatolitic carbonates, and red beds in epigenetic environments. Twelve storm-deposited lithofacies were identified in the Dongye Subgroup, which changes from sandstones, siltstones, and mudstones of the Qingshicun and lower Wenshan formations to carbonates of the upper Wenshan, Hebiancun, Jian'ancun, Daguanshan, Huaiyincun, Beidaxing, and Tianpengnao formations from bottom to top. The above sedimentary sequence transformation indicates a gradual transformation from terrigenous storm deposits in the Qingshicun and Wenshan formations to endogenous or mixed-source storm deposits in the Hebiancun, Jian'ancun, Daguanshan, and Huaiyincun formations. Additionally, coastal and shallow-marine storm deposits are revealed from sedimentary structures, including hummocky cross-stratification, intraclasts or boulder clays exhibiting radial or chrysanthemum-shaped stacking, and sinuous or torn stromatolites. These storm deposits, occurring with oolitic and stromatolitic carbonates of mid-low latitudes or tropical-subtropical zones, are characterized as tropical storm deposits. Based on reported ages, we propose that such tropical storms started from ca. 2.1 Ga and lasted for over 40 Myr. The long-term storm deposits indicate high temperatures and intense water circulation during the greenhouse climate. A climate change from icehouse to greenhouse is also evident by the extensive distribution of carbonates, evaporates, and organic-rich shales above the glacial diamictites in multi-cratons, and was probably driven by the transformative evolution of the atmosphere. [ABSTRACT FROM AUTHOR]

Some new tridactyl footprints have been recorded in the Malhada Vermelha farm locality, municipality of Fortaleza dos Nogueiras, state of Maranhão, northern Brazil, from the Sambaíba Formation, Parnaíba Sedimentary Basin. The specimens are fifteen isolated, in situ, mesaxonic tridactyl tracks preserved in six sandstone slabs as concave epireliefs. Abundant MISS evidence is preserved in the track-bearing blocks. The footprints are referred to as Grallator isp., linking them with an theropodian origin. The footprint-bearing levels were accumulated in shallow environments influenced by a tidal flat. The occurrence and interpretation of these findings bring a new approach to sedimentary subenvironments in the Sambaíba Formation. • Ichnofossils consisting of tridactyl footprints were found in the Sambaíba Formation, attributed to sedimentation in an arid climate. • All the track-bearing surfaces in the slabs or blocks have abundant evidence of microbially induced sedimentary structures. • The general features of the tracks presented herein allow to link their producer with Theropoda. • The analysis of the Sambaíba Sandstone outcropping in the study area allows us to consider the occurrence of marine incursions in that region of the basin during the late Triassic and early Jurassic. [ABSTRACT FROM AUTHOR]

Megaripple stripes (MRS) are enigmatic aeolian bedform patterns which are composed of crosswind alternating, wind-parallel megaripple corridors (MRCs) and smaller bedform corridors (SBCs). Compared to SBCs, MRCs have taller bedforms, longer wavelengths, and coarser surface sediments. However, their morphology, grain size, and internal structure are poorly understood. Numerous MRS have been identified in the central-southern edge of the Qaidam Basin. Unmanned Aerial Vehicle (UAV) images and 3D cloud point data were used to explore the morphological properties of MRS, and sediment samples were collected for grain size analysis. The sedimentary characteristics were analyzed through sections of MRC, transition zone between MRC and SBC, and SBC. The results show that the downwind and crosswind wavelengths of MRCs, along with the downwind wavelength of SBCs, decrease in the downwind direction. Conversely, the crosswind wavelength of SBCs displays an increasing trend. The crestline of MRS becomes progressively curved along the downwind direction. The average wavelength of MRCs is 8.51 m, with a height of 0.46 m. The average wavelength and height of SBCs are 1.69 m and 0.07 m, respectively. SBCs are smaller and more densely distributed than MRCs. Most values of the Ripple Index (RI) of MRS clustered between 11 and 60. MRCs exhibit a relatively symmetrical cross-sectional profile, while SBCs exhibit comparatively poor symmetry. MRCs are mainly composed of gravel and very fine sand, with accounting for 63.67 % of content in total. In SBCs, the prevalent grain sizes are very coarse sand and fine sand, accounting for 48.42 % of content in total. MRS display poor sorting, presenting a predominantly positive skewness and wide to very wide peaks. The thickness and inclination of laminae in middle layer 1 gradually decrease from MRCs to SBCs. The sedimentary structure of MRS provides insights into the grain migration in downwind and crosswind directions during their formation. • Morphological parameters of megaripple stripes were measured based on high-resolution imagery. • Massive samples were collected for sediment grain size distribution of megaripple stripes. • Sections were excavated in the field to investigate the internal structure of megaripple stripes. [ABSTRACT FROM AUTHOR]

Microbialites are microbial sedimentary structures that constitute some of the oldest traces of life on Earth. By their deposition in a wide range of sedimentary environments and their presence throughout most of geological time, the sedimentological and geochemical signatures they preserve represent important paleoenvironmental archives for understanding Earth's biological and geochemical co-evolution. Here we present a large microbialite collection containing >1370 curated specimens, covering all continents except Antarctica and spanning >3.5 Ga of Earth history, that is accessible to the international scientific community for examination and sampling at the Muséum National d'Histoire Naturelle (MNHN) in Paris, France. After cataloguing and evaluating the samples for their lithology, biogenicity, and inferred depositional environments, we characterized the collection for selected geochemical parameters, notably carbonate stable carbon and oxygen isotope ratios, as well as major, trace, and rare earth element compositions. Finally, we explore the different geochemical proxies analyzed with regards to their utility for reconstructing evolving Earth surface environments and/or microbial metabolisms via comparison of geochemical data from the MNHN Microbialite Collection to a compilation of similar proxy data for carbonates worldwide. We demonstrate that certain temporal trends previously recognized in carbonates worldwide (e.g., with respect to variations in C and O stable isotope compositions and redox sensitive trace element enrichments) are well reflected in this collection. Our findings highlight the utility of the MNHN Microbialite Collection and microbialites more generally for reconstructing the conditions associated with habitable environments in deep time and for tracing the response of microbial communities to the geochemical evolution of Earth's surface. • we present the MNHN Microbialite Collection. • a curated public sample archive with associated metadata. • carbonate C and O isotope data show trends comparable to carbonates in literature. • REE and redox-sensitive tracers also comparable to carbonates in literature. • carbonate microbialites may indeed record paleoenvironmental signatures. [ABSTRACT FROM AUTHOR]

The present study focuses on the morphosedimentary organization and sediment infilling stratigraphy of one of the largest estuaries of southern Patagonia in Argentina. With a tidal range up to 12 m, the area is subject to extreme tidal conditions, combined with moderate offshore wave climate, strong and constant westerly winds, and contrasted water and sediment discharges from the two tributaries of the estuary, the Santa Cruz and Chico rivers. The estuarine valley is entrenched in the Patagonian coastal plateau due to significant uplift. On the basis of sediment facies (sedimentary structures, grain size, geochemistry, mineralogy), meiofauna (foraminifera and testate amoebae), morphological changes and shallow geophysics (high-resolution seismic reflection, ground-penetrating radar) data, the Santa Cruz–Chico River system is defined as a hybrid system comprising a tide-influenced fluvial mouth (the Santa Cruz River) and a tide-dominated estuary (the Chico River estuary), both converging toward an elongated subtidal ria-type estuarine basin. River-supplied sands and muds by-pass the estuarine basin and are exported offshore where they settle and form an ebb-tidal delta. Sediments in the Santa Cruz–Chico River valley mainly consist of Pleistocene lowstand fluvial gravels resting on the regional Miocene substrate, and thin early Holocene transgressive deposits, deeply incised by a tidal ravinement surface that developed during the highest Holocene sea-level at ca 7500 y. BP. After the maximum stillstand, relative sea level fell and a competition occurred between erosion, promoted by water depth decrease, and deposition, favored by tidal prism reduction. At present, sediment by-passing and offshore sediment export are the dominant processes. The very large size of the ebb-tidal delta, which expands on the continental shelf, suggests that this situation has prevailed for a very long time. [ABSTRACT FROM AUTHOR]

In this study, we delve into an in-depth analysis of crustal mobility within the broken foreland of the Southern Central Andes, specifically focusing on the proximal area between 31°S and 32°S. This region presently stands as one of the most dynamically evolving and seismically active zones in the extensive Andean retroarc area. To achieve our goal, we employed a multidisciplinary approach encompassing the analysis of gravity data and GNSS measurements. Here, we discuss previous GNSS data and present new measurements, collected from a high-precision geodetic network established along the proximal broken foreland at 31°S latitude. To enhance our findings, we complemented this data with measurements of temporal gravity variations, primarily of tectonic origin, and conducted geophysical modeling of basement structures in the foreland area. Our geophysical model of the upper crust unveiled that deformation is closely associated with basement structures marked by faulted blocks and transverse lineaments identified in previous surface studies. The GNSS data analysis revealed complex crustal mobility patterns that are not easily explained. In general, the integrated analysis highlights varied responses observed in vectors and gravitational changes across distinct crustal domains in the study area that seem to conform to the characteristics of a fragmented or broken foreland setting. This structural configuration allows, to a certain degree, independent movement of crustal blocks. However, it appears that a substantial portion of the fractured foreland exhibits a relatively cohesive behavior, serving as coherent domains that facilitate elastic deformation linked to the underlying deep structures beneath the Eastern Precordillera. Therefore, this study provides further insights into the crustal mobility of broken foreland systems, where far-field tectonic stress interacts with complex basement block structures and intermontane sedimentary depocenters. These findings are of paramount significance in the context of intraplate earthquakes in the Andean broken foreland near San Juan City. Below is a brief description of our study: This investigation conducts an extensive analysis of crustal mobility within the fractured foreland of the Southern Central Andes, focusing specifically on the proximal region between 31°S and 32°S. Positioned within one of the most dynamically evolving and seismically active zones in the extensive Andean retroarc area, the study employs a multidisciplinary approach, integrating gravity data and GNSS measurements. The analysis incorporates both existing GNSS data and new measurements obtained from 2013 to 2015, establishing a high-precision geodetic network along the proximal broken foreland Andean deformational front at 31°S latitude. Augmenting this dataset, temporal gravity variations of tectonic origin are measured, and geophysical modeling of basement structures in the foreland area is conducted. The geophysical model of the upper crust reveals deformation closely linked to basement structures characterized by faulted blocks and transverse lineaments identified in previous surface studies. The GNSS data analysis unveils complex crustal mobility patterns, showcasing varied responses in vectors and gravitational changes across distinct crustal domains in the study area, indicative of a fragmented or broken foreland setting. While allowing for some degree of independent movement of crustal blocks, a substantial portion of the fractured foreland displays relatively cohesive behavior, serving as coherent domains that facilitate elastic deformation associated with deep structures beneath the Eastern Precordillera. In summary, this study significantly contributes to understanding crustal mobility in broken foreland systems, elucidating the interaction between far-field tectonic stress and complex basement block structures within intermontane sedimentary depocenters. These insights are particularly relevant in the context of intraplate earthquakes in the Andean broken foreland near San Juan City. [ABSTRACT FROM AUTHOR]

Trogu, D.; Simeone, S.; Usai, A.; Porta, M., and De Muro, S., 2024. On the role of wood and seagrass rests in coastal flooding events in Mediterranean microtidal beaches. In: Phillips, M.R.; Al-Naemi, S., and Duarte, C.M. (eds.), Coastlines under Global Change: Proceedings from the International Coastal Symposium (ICS) 2024 (Doha, Qatar). Journal of Coastal Research, Special Issue No. 113, pp. 115-119. Charlotte (North Carolina), ISSN 0749-0208. In December 2019, following intense rainfall, the riverbeds of the rivers flowing into the Gulf of Cagliari (Sardinia, Italy, western Mediterranean Sea) dumped a large quantity of river reeds attributed to the species Arundo donax (Poaceae) into the sea. The concomitance of a sea storm event acting in the waters of the Gulf of Cagliari transported and allowed the deposition and sedimentation of reeds and other seagrass rests (mostly P. oceanica) on the Poetto beach (an urban microtidal beach located in the Gulf of Cagliari), for an estimated mass of over 85 tonnes. The subsequent lock-down given by the Covid-19 pandemic, and thus the absence of anthropogenic interferences, allowed the almost undisturbed interaction of beach processes with these wood and seagrass rests. This paper will describe the sedimentary structures formed on the berm, generated by the interaction between reeds, Posidonia and sediment. Subsequently, it will be analysed how these sedimentary structures protected the beach from coastal flooding during storm events which were characterised by wave parameters (significant wave height and wave peak period) with greater values than those recorded during other storm events that led to beach inundation. In detail, analyses were carried out comparing the wave data with images acquired by a coastal video monitoring system. However, this storm event caused the reeds to redistribute along the emerged beach, generating new sedimentary structures that, as a result of successive storm events from different directions, became stratified in the beach increasing its permeability. Although the beach cleaning operations often carried out with a removal of vegetal berms, the results of this study highlighted that the non-removal strategies along the foreshore and the backshore can increase the whole beach system resilience and protect the anthropic structures built in and behind the beach. [ABSTRACT FROM AUTHOR]

Strong-motion records of earthquakes are used not only to evaluate the source rupture process, seismic wave propagation and strong ground motion characteristics, but also to provide valuable data for earthquake disaster mitigation. The Kathmandu Valley, Nepal, which is characterised by having soft sediments that have been deposited in an earthquake-prone zone, has experienced numerous earthquakes. We have operated four strong-motion stations in the Kathmandu Valley since 2011. These stations recorded the 2015 magnitude 7.8 Gorkha Nepal earthquake that occurred in the Himalayan continental collision zone. For several months after the mainshock, we deployed four additional temporary stations. Here, we describe the seismic data for 18 earthquakes over magnitude 5.0 collected by this array, including the 2015 magnitude 7.3 Dolakha earthquake of maximum aftershock and three large aftershocks of magnitude 6-class. These data are essential for validating the sedimentary structure of the basin and for evaluating the hazard and risk of future earthquakes in the Kathmandu Valley. Measurement(s) Strong ground motion Technology Type(s) Accelerometer Sample Characteristic - Location Kathmandu Valley • Nepal [ABSTRACT FROM AUTHOR]

The present field and petrographic investigations of the Tortonian to Gelasian Siwalik Group in the core of the Hazara-Kashmir Syntaxis have been carried out to comprehend the middle stage Himalayan orogeny that resulted from the collision of Indian and Asian plates. The Chinji, Nagri, Dhok Pathan, and Soan Formations of the Siwalik Group were deposited by river meandering flood plains, braided rivers, and alluvial fan systems, respectively. The Siwalik Group is classified into seven major facies and many minor facies based on sedimentological properties. According to the petrographic analysis, the Siwalik Group sandstone is classified as litharenite and feldspathic litharenite petrofacies. The sandstone of the Siwalik Group is texturally mature, but compositionally it is immature. The data shown on the tectonic discrimination diagrams point to a recycled orogen provenance field for the Siwalik sandstone. In addition to quartz and feldspar, the sandstone includes clasts of volcanic, metamorphic, and sedimentary rock types. The igneous and metamorphic rock clasts were derived from the Lesser and Higher Himalayas. The sedimentary lithic fragments, on the other hand, are derived from both the earlier molasse and pre-molasse rocks. The presence of lithic fragments of the earlier molasse sandstone in the Siwalik sandstone indicates that the Siwalik Group sandstones were deposited during the Middle Stage of the Himalayan orogeny. The paleoclimatic conditions were semi-arid to semi-humid during the Siwalik Group's deposition. The presence of clay minerals in the shale reveals the intense chemical weathering processes that occurred during their deposition on the flood plains of the river meandering system. [ABSTRACT FROM AUTHOR]

The Transcarpathian Basin, consisting of the Prešov and Trebišov sub-basins, is situated at the border of the Western and Eastern Carpathians. Hydrocarbon exploration in this basin has been ongoing for more than 60 years and reserves of economic importance are located in the E to NE part of the basin. The Trebišov sub-basin was analysed to characterize and predict lower Badenian (Langhian) reservoir rocks. To achieve this aim, new sedimentary facies, seismic facies, petrographic and paleontological analyses were performed, combined with original total porosity and permeability measurements. Based on the planktic foraminifera and calcareous nannoplankton zonation, the lower Badenian sequence in the Trebišov sub-basin was divided into a lower and an upper interval. The presence of very well sorted sandstone layers, glauconite grains, albitization, selective alteration of tuffs into zeolites as well as the fossil assemblages reinforce the volcanic influenced marine environments. Documented sedimentary structures indicate subaqueous density flows preceded by the newly observed fluvial and deltaic facies. The total sandstone porosity measurements indicate a gradual porosity decrease with depth marked by a value of 13.21 % at the surface decreasing down to 6.41 % at ~3 km below the surface. These numbers correspond to reservoirs with low to reduced porosity. Diagenetic products such as illite, chlorite and feldspar cement together with compaction effects, and variations in the crystallinity in siliceous cement led to the modification of initial porosity. The potential lower Badenian reservoir sandstones are frequently deformed by strike-slip faults responsible for the large pull-apart basin complex (seen as horsetail structures on reflection seismic sections) forming various fault-bounded structural traps. The lower Badenian sandstones present at the top of two anticlinal structures in the central part of the basin, display very strong reflection amplitudes on newly merged 3D reflection seismic data underlining the additional exploration potential in the basin. [ABSTRACT FROM AUTHOR]

Joint analysis of the receiver and autocorrelation functions was performed to estimate the structure of the P- and S-wave velocities VP and VSas well as the depth to the seismic bedrock using strong motion records obtained in Narita, Kanto basin, Japan. From data of over 1000 P-waves and their coda induced by local seismic events, the autocorrelation revealed a clear reflection in the sedimentary layer, and the receiver function revealed clear Ps and PpPs converted phases at the seismic bedrock. The sediment thickness and VS were measured from the H–κ stack of the vertical and transverse components of the autocorrelation and the Ps and PpPs phases in the receiver function. The previous VS structure model obtained with only the transverse autocorrelation in Narita was found to be appropriately evaluated, whereas the corresponding VP structure model must be improved. Because the H–κ stack requires an assumed VP value, an appropriate value of VP is crucial for accurate estimation of VS and the thickness of the sediment. Thus, the frequency analysis of the H–κ–VP stack was performed to estimate VP, VS, and the thickness of the sedimentary structure. From the results of this analysis, VS was determined to have been estimated appropriately for the present case in Narita. However, VP had been estimated to be lower than the value estimated by this study. It is clear that an appropriate assumption of VP is important to capture the Ps and PpPs phases in the receiver function. [ABSTRACT FROM AUTHOR]

Ediacaran cap dolostone atop Marinoan glacial deposits contains complex sedimentary structures with extremely negative δ13Ccarb values in close association with oscillations in palaeoclimatic and oceanographic proxy records. However, the precise geological, geochronological and geochemical context of the cap dolostone is not clarified, which hampers us from correctly interpreting the extremely negative δ13Ccarb values and their causal relationships with the Snowball Earth hypothesis. In this study, we conducted detailed in situ geochronological and geochemical analyses on the calcite within the cap dolostone from the Ediacaran Doushantuo Formation in South China in order to define its formation and relationship to the Snowball Earth hypothesis. Petrographic observations show that formation of dolomite pre-dates precipitation of calcite and pyrite, which pre-dates quartz cementation in the basal cap carbonate. Calcite cement within the cap dolostone yielded a U–Pb age of 636.5 ± 7.4/17.8 Ma (2σ, MSWD = 1.6, n = 36/40), which is within uncertainty of a published dolomite U–Pb age of 632 ± 17 Ma (recalculated as 629.3 ± 16.7/22.9 Ma). These age constraints negate the possibility that the calcite cement was formed by late Ediacaran or Cambrian hydrothermal activity. The rare earth element distribution patterns suggest a dominant seawater origin overprinted by subsequent early Ediacaran hydrothermal activity. The combined age, petrographic and geochemical data suggest oxidization of methane clathrates in response to complicated interplay between eustasy and isostatic rebound and hydrothermal fluids. [ABSTRACT FROM AUTHOR]

Analysis of the sedimentary environment during the clastic formation process is of great significance for reservoir evaluation and desert prediction. This paper focused on the Paleocene in the West Lishui Sag, East China Sea Basin. XRF fluorescence diffraction and carbon and oxygen isotope tests were carried out on core samples from four wells. Based on the geochemical characteristics of the samples and the changes in the elemental ratios, combined with the lithologic characteristics and sedimentary structure of the samples, the paleoclimate, paleosalinity, paleobathymetric, paleoredox, paleotemperature, and other paleoenvironmental characteristics were analyzed. The results show that the characteristics of major and trace elements were similar in the lower Mingyuefeng Formation (E1m2), Upper Lingfeng Formation (E1l1), Lower Lingfing Formation (E1l2), and Yueguifeng Formation (E1y). The Paleocene in the West Lishui Sag was mainly in the reducing environment of brackish-salt water with weak water stratification. The water depth showed a trend of becoming deeper, then shallower, and then deeper. The paleoclimate in the West Lishui Sag was warm on the whole. However, the content of Sr became smaller after later deposition, so the calculated paleowater temperature was higher. In addition, oxygen isotopes were affected by diagenesis, resulting in a negative oxygen isotope value. The paleoproductivity was low, and the hydrocarbon generation potential was poor. The content of nutrient elements mainly came from terrigenous input rather than biological origin, and terrigenous intrusion characteristics gradually increased from E1y to E1m2. The study also shows that paleoproductivity was affected by the paleoclimate and paleowater depth. Warm and humid climate and deep water body were conducive to the accumulation of paleoproductivity. [ABSTRACT FROM AUTHOR]

Sediment transport modeling (STM) is a potentially effective tool for estimating the magnitude of tsunamis and earthquakes without historical records. However, the application of STM to prehistorical tsunamis is challenging because of multiple uncertainties in topography and roughness. Along the coast of Hidaka, Hokkaido, Japan, there is potential to conduct STM even in the absence of historical records because comprehensive geological data for the coastal evolution during the Holocene are available here. The tsunami deposits in Hokkaido indicate the presence of events on a larger scale than historical tsunamis; in particular, the seventeenth‐century tsunami had multiple potential wave sources other than a Kuril Trench earthquake, inhibiting its magnitude estimation. In this study, we applied STM to paleotsunamis for the coast of Hidaka, where comprehensive geological data are available, although the wave source is unknown. The modeling parameters—paleotopography, roughness, grain size, initial sand source, sea level, and beach ridge height—were estimated using data obtained from geological surveys and sensitivity tests. The modeling of a tsunami induced by a Kuril Trench earthquake reproduced the sediment distributions and sedimentary structures of the observed sand layers better than that of extreme storms and volcanic tsunamis. Because the conventional fault model is reasonably suitable in the western area from the Kuril Trench, a much wider rupture zone is less likely. Parameters such as sand source area, roughness, ridge height, and paleo sea level are important for geologists and modelers when applying STM to paleotsunamis. Plain Language Summary: Sediment transport modeling (STM) can correctly reproduce extreme waves caused by tsunamis and storms based on sedimentary evidence. However, applying STM to prehistorical periods is challenging because of uncertainties in paleotopography. The coast of Hidaka, Hokkaido, Japan, is suitable area for STM because of the comprehensive geological data available here. These data reveal the coastal evolution during the Holocene, in addition to tsunami sediment surveys. In this study, we established realistic computational parameters for STM based on detailed geological data and estimated wave sources for the sand layers formed by extreme waves. By comparing the observed sediment distribution or sedimentary structures and those estimated from the transport processes by the modeling of tsunami and extreme storm models, most sand layers were reported to be tsunami deposits. This result allowed us to estimate the extent of the largest class of rupture zones in the Kuril Trench. Moreover, sensitivity tests for computational parameters with large uncertainties in the prehistoric period provide geologists and modelers important information that should be considered when applying STM to paleotsunamis. Key Points: Sediment transport is modeled in prehistoric periods by obtaining parameters such as paleogeography and roughness from geological dataA tsunami induced by a Kuril Trench earthquake reproduced the distribution and sedimentary structure of prehistoric sand layersSensitivity tests demonstrated parameters that significantly affect sediment transport modeling in prehistoric periods [ABSTRACT FROM AUTHOR]

The deep ocean is Earth's largest habitable space inhabited by diverse benthic organisms. Infauna play crucial roles in shaping sedimentary structures, relocating organic matter, porewater chemistry, and hence biogeochemical cycles. However, the visualization and quantification of infauna in situ inside deep-sea sediment has been challenging, due to their sparse distribution and that deep-sea cameras do not visualize animals living below the sediment surface. Here, we newly developed a 3D acoustic "coring" system and applied it to visualize and detect burrowing bivalves in deep-sea sediments. The in situ acoustic observation was conducted at a dense colony of vesicomyid clams in a hydrocarbon seep in Sagami Bay, Japan, focusing on a patch of juvenile clams with a completely infaunal life style. We clearly observed strong backscatters from the top and lower edges of animals in our 3D acoustic data. At least 17 reflectors were identified in the survey area (625 cm2), interpreted to correspond to living clams. The estimated depths of the lower edge of clams ranged between 41 and 98 mm. The acoustic system presented here is effective for detecting and monitoring infauna with calcified exoskeletons. This novel tool will help us better assess and understand the distribution of deep-sea infauna, particularly those groups with hard exoskeletons, as well as biogeochemical cycles. [ABSTRACT FROM AUTHOR]

Understanding the frequency of high energy storm and tsunami events is crucial for apprehending the vulnerability of coastal communities. Identifying and dating sedimentary evidence deposited by such high energy events can assist in the planning and installation of suitable protection measurements. The Andaman Sea coast of Thailand is particularly vulnerable to such events as illustrated by the 2004 Indian Ocean Tsunami. Here, three shore-perpendicular transects and ten sediment cores along a beach ridge in the northern part of Lam Son National Park, Ranong Province, Andaman Sea coast are investigated with respect to high energy deposits. A multi-proxy analysis was conducted including stratigraphical correlations between cores, detailed description of physical characteristics, sedimentary structure, grain size, organic matter and carbonate content as well as identification of the remains of marine organisms. Optically stimulated luminescence (OSL) dating was applied for determining the age of the sediments on this beach ridge plain. The stratigraphy and sediment characteristics, in particular composition, of the sands in the study area clearly allow us to distinguish between high energy deposits and normal beach sediments. Two high energy deposits were identified and attributed to result from the 2004 Indian Ocean Tsunami as well as a past storm, which, based on OSL dating occurred more than 340 ± 20 years ago. [ABSTRACT FROM AUTHOR]

The Luchedu rock avalanche (LRA) that occurred in 1935 at the junction of Sichuan and Yunnan in Southwest China is a disaster chain of the rock slide, debris avalanche, and river blocking induced by heavy rainfall. The rock slide originated from the wedge formed by sheet metamorphic rocks on the fault zone on the left bank of the Jinsha River. After breaking away from the slope, the wedge disintegrated and cracked rapidly, forming debris and causing them to flow in fluidization along a 7.3 km path. After the obvious entrainment process and curve superelevation in the proximal area, the deposition reached 50.5 × 10 6 m3 in the distal area. The sedimentary structure of clasts has typical stratification characteristics. The types of sedimentary facies include carapace facies, body facies, and mixed facies. Inside the sedimentary structure, dense shear zones, liquefied intercalations, jigsaw structures, and directional arrangement of particles are observed. Through a detailed geological survey and DEM spatial analysis, the avalanche entrainment rate of LRA was determined as 1.2. The morphological fluctuation of basement lithology and gully path plays an important role in the long-distance movement. The rock fragments formed by metamorphic rocks with a primary schistosity structure can effectively reduce the energy loss in the internal shear process and significantly promote the laminar flow movement in the distal region of the avalanche. Therefore, as a giant rock avalanche formed by the evolution of specific metamorphic rocks, LRA results from the combination of macrohydrodynamics and microrock failure properties. [ABSTRACT FROM AUTHOR]

A Messinian and lithified horizon enriched in volcanic particles with thicknesses of 170–180 cm crops in the Camporotondo (CR) section (Marche, Italy). This volcanic-rich layer (VRL) was investigated by field plus mesoscopic observations, X-ray powder diffraction (XRPD), scanning electron microscopy (SEM), bulk composition methods and electron-microprobe analysis (EMPA). The quantitative textural features of volcanic and sedimentary components were determined by 2D image analysis. The lowermost massive 70–80 cm portion is free of sedimentary structure or characterised only by plane-parallel ones, whereas the uppermost one is undulated and cross-laminated. The XRPD and SEM outcomes unveil that the VRL of CR is mainly composed of glassy shards (≥80 area%), a variable amount of sedimentary minerals (<20 area%) and a very low content of magmatic minerals (few area%). The bulk and micro-chemical attributes of volcanic and glassy materials are rhyolitic and almost identical to previous VRLs dated at 5.5 Ma (VRL-5.5). The signatures of immobile elements and the high amount of H2O present in the glass fraction suggest a provenance from a convergent geodynamic setting. The 2D image analysis on SEM observations show that the VRL-5.5 of CR is composed of very fine and sorted (averages of MZ of 5,72 and σi of 0,70), scarcely vesicular, glass shards, with similar long and short size dimensions, shape and roundness. The VRL-5.5 of CR is free of large minerals and fossils. The coupling of mesoscopic and microscopic determinations indicates that the lowermost interval was deposited such as a primary tephra, i.e., fallout pyroclasts sinking in seawater. Instead, the uppermost interval derives from local, low-energy and sin-depositional remobilisation of the same VRL-5.5. The textural attributes of the volcanic fractions, the sedimentological features and the thickness of the VRL at CR correspond to the westward deposit of a still unknown eruption likely occurred at 5.5 Ma. [ABSTRACT FROM AUTHOR]

Partially exposed bedrock beneath Pleistocene glacial till in Erie County (north-central Ohio) displays unusual structural deformation in the Devonian Berea Sandstone, Bedford Shale, and Ohio Shale. These folded and faulted units are exposed in creeks as anticlines and synclines. Past studies of this area proposed Pleistocene ice movement and soft-sediment deformation during the Late Paleozoic as the deformation mechanisms, but these hypotheses cannot explain the extent of layer displacement or the contradiction between the southwest travel direction of the ice sheet and the structural sense of motion on the folded units. A new interpretation using field data and constructing geologic profiles explains the development of these structures. This study investigated 17 anticlines that trend in different directions. Four of these anticlines are tightly folded with steep or overturned flanks and thrust-faulted Ohio Shale in their cores. Structural analysis of these folds shows that the incompetent shaly units of the Plum Brook--Ohio--Bedford and competent Berea Sandstone were folded above the Delaware--Niagara carbonates as a result of the compressional stress during the Late Paleozoic. Development of these tight or overturned folds, and change in trend of the anticlines, is caused by unusual stratigraphic thickness variations in the Berea and Bedford units. Preserved and undeformed fine sedimentary structures, and sharply faulted beds, in the Berea and Bedford indicate that soft-sediment deformation was not the cause of the regional structural deformation. Finally, the absence of physical features of glacially deformed bedrock demonstrates that Pleistocene glacial ice shove was not the cause of deformed bedrock units in the study area. [ABSTRACT FROM AUTHOR]

In the Ediacaran marine succession of the Cerro Negro Formation (Tandilia System, NE Argentina), abundant microbially induced sedimentary structures indicate general conditions of substrate biostabilization. Numerous discoidal structures in this succession were previously interpreted as moulds of soft-tissue holdfasts of sessile organisms, within the form genus Aspidella. In this study, we performed a detailed re-analysis of some of these features and discuss two alternative hypotheses to explain their genesis: (1) as the result of soft-sediment deformation and fluid injection structures; and (2) as structures of active animal–sediment interaction (i.e. trace fossils). We show that the dome-shaped discs are internally laminated, with a cylindrical to a funnel-shaped vertical tube at their central region. The presence of these downwards vertical extensions and other intricate internal arrangements cannot be explained under the taphonomic spectrum of discoidal fossils, but shows striking similarities to Intrites-like structures and other sand-volcano-like pseudofossils (e.g. Astropolithon). However, some structures are hard to distinguish from vertical dwelling burrows with funnel-shaped apertures and thick-lined walls, commonly produced by suspension- and detritus-feeding invertebrates (e.g. Skolithos isp., Monocraterion isp. and, less likely, Rosselia isp.). Since reliable age constraints are unavailable, and further investigation concerning other palaeobiological indicators is needed, the most parsimonious hypothesis is that of a structure derived from fluid-escape processes. Our study demonstrates the importance of detailed investigation on discoidal structures in either upper Ediacaran or lower Cambrian strata. [ABSTRACT FROM AUTHOR]

The Lower Cretaceous Tuxen (lower Hauterivian - upper Barremian) and Sola (upper Barremian - Albian) Formations in the Danish Central Graben (North Sea) constitute one of the oldest chalk successions recorded globally, but have received little attention with regards to sedimentary facies and depositional processes. This study presents the first comprehensive carbonate facies analysis of the succession, retrieved from seven drill cores from the Valdemar and Adda Fields. A total of 50 facies are identified, based on a continuum of six lithologies ranging from chalk to marlstone and tuffaceous siltstone to sandstone that display eight different sedimentary structures or fabrics, and two redox-associated lithological color variations (green and red) in the Adda Field. The eight sedimentary structures record: (i) comprehensive bioturbation of homogeneous sediment during fully oxygenated benthic conditions and low sedimentation rates; (ii) a similar bioturbation process but in heterogeneous sediment with lithological contrasts permitting visible burrows to form, perhaps due to rhythmic alternation between pelagic (clay-poor) and hemipelagic (clay-rich) sedimentation; (iii) pelagic to hemipelagic suspension settling in dysoxic to anoxic bottom-water conditions; (iv) patchy cementation of the shallow sea bed during incipient hardground formation; (v) reworking of bioclasts and chalk intraclasts by bottom or wave-induced currents and cohesive debris flows; (vi) pressure solution during late burial diagenesis; (vii) shear deformation by intense plastic deformation of unlithified sediment from limited lateral displacement; and (viii) silicification during burial diagenesis. The facies distribution indicates that active tectonism took place prior to the onset of anoxia that resulted in deposition of the Munk Marl Bed, which in the Valdemar Field was followed by tectonic waning and repeated anoxia. The Valdemar Field constituted a basinal depocenter and was flanked to the east by an early inversion high in the Adda Field characterized by condensation and bypass. The Fischschiefer Member represents a return to prevailing anoxia, consistent with global records of the early Aptian Oceanic Anoxic Event 1a (OAE-1a). [ABSTRACT FROM AUTHOR]

During the Late Ordovician-Early Silurian period, Gondwanan glaciation has affected around the world. To infer the geologic record of the glaciation across the Ordovician-Silurian transition in South China, we measured the petrological and geochemical characteristics of 60 samples of Wufeng-Longmaxi Formations taken from four sections and Huadi no. 1 well in the Sichuan Basin. Petrologically, the Guanyinqiao Formation is composed of argillaceous sandstone, argillaceous siltstone, silty bioclastic limestone and silty limestone, combing with their sedimentary structures and fossils, which verifies a shallow water environment between the two sets of black shales in the Wufeng and Longmaxi Formations. Geochemically, the Chemical Index of Alteration (CIA) and Sr/Cu ratios indicate that palaeoclimate transformed from warm to cold and then to warm again during the Late Ordovician-Early Silurian period. The low CIA values of Guanyinqiao Formation, suggesting a short-cold climate which is consistent with Gondwana glaciation in Hirnantian period. In addition, the fluctuations of V/(V + Ni), V/Cr, V/Sc, Sr/Ba and Zr/Rb ratios from Wufeng-Longmaxi Formations implied that sea water had experienced an anoxic-oxic-anoxic process, the paleosalinity changed from sea water to brackish-marine and then to sea water, and the hydrodynamic condition had shown low-high-low characteristic. All these results indicate that because of the end Ordovician Glaciation, the area of the ice sheet increased, the climate changed and sea level fell during the Hirnantian period. [ABSTRACT FROM AUTHOR]

Sedimentary rocks record the ancient climate of Mars through changes between subaqueous and eolian depositional environments, recognized by their stratal geometries and suites of sedimentary structures. Orbiter‐ and rover‐image‐based geologic mapping show a dynamic evolution of the 5‐km‐thick sedimentary sequence exposed along the flanks of Aeolis Mons (informally, Mt. Sharp) in Gale crater, Mars, by deposition of subaqueous strata followed by exhumation via eolian erosion and then deposition of overlying, onlapping strata of inferred eolian origin. This interpretation suggests that a significant unconformity should occur at the base of the onlapping strata, thus predicting lateral variations in elevation along the contact between the underlying Mt. Sharp group and overlying Stimson formation. Curiosity rover and high‐resolution orbital image data quantify paleotopographic variability associated with the contact; ∼140 m of net elevation change and a slope closely aligned with the modern topography is expressed along the regional contact. These results support the interpretation of an erosional unconformity between these strata and that it was likely formed as a result of eolian erosion within the crater, indicative of a transition from wet to dry climate and providing insight into the stratigraphic context, geologic history, and habitability within Gale crater. Plain Language Summary: The discovery of sedimentary rocks on Mars is relatively recent. On a planet that apparently lacked plate tectonics, one important question is whether or not there is a rock cycle in which sediments become rocks that then are exhumed and recycled back into the crust through renewed burial. Rover missions have confirmed the existence of the first part of this cycle—erosion, transport, deposition, and burial. However, the second half of the cycle, which begins with exhumation, is poorly constrained. The work presented here demonstrates the presence of ancient surfaces of erosion—unconformities—that mark past exhumation events at Gale crater. Furthermore, the ancient erosion surface is then overlain by a younger series of sedimentary rocks, which demonstrates burial of that unconformity surface and the completion of the rock cycle. On Earth, exhumation is driven by tectonic uplift, followed by erosion via rainfall and fluvial processes; on Mars, exhumation was driven entirely by eolian erosion and deflation. Understanding the sedimentary rock cycle is especially significant in the search for ancient biosignatures on Mars as virtually all remnants of Earth's earliest biosphere are preserved in sedimentary rocks that were formed in this fashion. Key Points: Paleotopographic mapping is consistent with an erosional unconformity between the Mt. Sharp group and Stimson formationLateral variations in paleorelief are regionally present along the contact at the base of the Stimson formationErosion and exhumation were likely driven by eolian processes and a transition from wet to dry climate transition [ABSTRACT FROM AUTHOR]

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The k-nearest neighbors (KNN) algorithm is a non-parametric supervised machine learning classifier; which uses proximity and similarity to make classifications or predictions about the grouping of an individual data point. This ability makes the KNN algorithm ideal for classifying datasets of geological variables and parameters prior to 3D visualization. This paper introduces a machine learning KNN algorithm and Python libraries for visualizing the 3D stratigraphic architecture of sedimentary porous media in the Quaternary onshore Llobregat River Delta (LRD) in northeastern Spain. A first HTML model showed a consecutive 5 m-equispaced set of horizontal sections of the granulometry classes created with the KNN algorithm from 0 to 120 m below sea level in the onshore LRD. A second HTML model showed the 3D mapping of the main Quaternary gravel and coarse sand sedimentary bodies (lithosomes) and the basement (Pliocene and older rocks) top surface created with Python libraries. These results reproduce well the complex sedimentary structure of the LRD reported in recent scientific publications and proves the suitability of the KNN algorithm and Python libraries for visualizing the 3D stratigraphic structure of sedimentary porous media, which is a crucial stage in making decisions in different environmental and economic geology disciplines. [ABSTRACT FROM AUTHOR]

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Copyright of Oil Drilling & Production Technology / Shiyou Zuancai Gongyi is the property of Shiyou Zuancai Gongyi Bianjibu and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The geomorphology of river basin is complex, and its soil sedimentary characteristics are poorly defined. To study the spatial variability of soil structure in different sedimentary environments at the basin scale, 356 sets of soil samples were collected from five typical sedimentary environments in the Yellow River Basin and the Haihe River Basin, including the upper and lower reaches of the rivers, mountain-front plains, central alluvial plains and eastern coastal plains. The particle size distribution (PSD) of the soil samples was obtained using a laser particle size analyzer, and the fractal dimension (D) of the soil structure was derived by applying fractal theory. The PSD, D and the correlation between them were analyzed by the Pearson correlation method for typical sedimentary environments in two basins. The results show that: (1) The main soil types in the typical geological environments in the basin are sand, loamy sand, sandy loam, silty loam, and silty soil. The soil particle size in the upper and lower reaches of the rivers was higher than that in the plain areas. (2) In the plane, The D value descended in different regions in the following order: the mountain-front plain > the eastern coastal plain > the upper Yellow River > the central alluvial plain > the lower Yellow River. In the vertical direction for both rivers, the D value showed a decreasing trend with increasing burial depth. (3) The model results showed a cubic polynomial correlation between D values and PSD, which was closely related to the non-uniformity of particle size during sorting and deposition. The soil PSD and fractal characteristics are effective tools for the quantitative evaluation of soil structure in various sedimentary environments in the basin. [ABSTRACT FROM AUTHOR]

The S-wave velocity (Vs) structure of sediments and the uppermost crust in the landward slope of a subduction zone are important for determining the dynamics of the overriding plate. Although distributed acoustic sensing (DAS) measurements have improved the horizontal resolution of Vs structure in marine areas, the estimations have been limited to the uppermost sedimentary layers. In the present study, we applied seismic interferometry to DAS data of 13 h duration to image the sedimentary and crustal structure offshore of Sanriku, Japan with a spatial horizontal resolution of 2.5 km and > 3.0 km depth. We grouped the DAS data into 10 km long subarrays with 75% overlaps. We first applied a frequency-wavenumber filter to the DAS data to remove DAS instrumental noise and to allow effective extraction of surface waves from short-time records. We then applied a seismic interferometry method and estimated the phase velocities at each subarray. The estimated phase velocities of the fundamental-mode and first higher-mode Rayleigh waves were then used to determine one-dimensional Vs structures for each subarray. The resultant 2-D Vs structure was interpreted as representing sediments and crust. The upper sedimentary layers thicken seaward, while the entire sedimentary unit shows complex lateral variations in depth. The boundary between the sedimentary layers and the uppermost crust varies in depth from 1.8 to 6.8 km and is the deepest in the middle of the profile. Combining this result with the P-wave velocity (Vp) structure along the nearest survey line, determined in previous studies, allowed us to estimate Vp/Vs = 3.12, on average, for the lower sedimentary layers. Our method of applying seismic interferometry to marine DAS data broadens the techniques for estimating Vs and Vp/Vs structure of sedimentary layers and the upper crust across subduction zones. These results show that application of the frequency-wavenumber filtering and seismic interferometry to marine DAS data can estimate the Vs structure and the Vp/Vs structure, together with standard marine geophysical surveys of sedimentary layers and the upper crust across subduction zones. [ABSTRACT FROM AUTHOR]

This paper introduces a Python application for visualizing the 3D stratigraphic architecture of porous sedimentary media. The application uses the parameter granulometry deduced from borehole lithological records to create interactive 3D HTML models of essential stratigraphic elements. On the basis of the high density of boreholes and the subsequent geological knowledge gained during the last six decades, the Quaternary onshore Llobregat River Delta (LRD) in northeastern Spain was selected to show the application. The public granulometry dataset produced by the Water Authority of Catalonia from 433 boreholes in this strategic coastal groundwater body was clustered into the clay–silt, coarse sand, and gravel classes. Three interactive 3D HTML models were created. The first shows the location of the boreholes granulometry. The second includes the main gravel and coarse sand sedimentary bodies (lithosomes) associated with the identified three stratigraphic intervals, called lower (>50 m b.s.l.) in the distal LRD sector, middle (20–50 m b.s.l.) in the central LRD, and upper (<20 m b.s.l.) spread over the entire LRD. The third deals with the basement (Pliocene and older rocks) top surface, which shows an overall steeped shape deepening toward the marine platform and local horsts, probably due to faulting. The modeled stratigraphic elements match well with the sedimentary structures reported in recent scientific publications. This proves the good performance of this incipient Python application for visualizing the 3D stratigraphic architecture, which is a crucial stage for groundwater management and governance. [ABSTRACT FROM AUTHOR]

The thick fine‐grained sedimentary rocks in the second member of the Kongdian Formation (Ek2) in the Cangdong sag, Bohai Bay Basin, eastern China, are typical lacustrine source rocks and have recently been regarded as the main target for shale oil exploration. Compared with marine shales, the strong heterogeneity in the mineral composition, structure feature, and vertical association pattern of the Ek2 lacustrine fine‐grained sedimentary rocks in the Cangdong sag is significantly influenced by frequent variations in the sedimentary environment and depositional process. Based on the detailed core and thin‐section description analyses as well as the two‐dimensional X‐ray fluorescence (2D‐XRF) analysis, the Ek2 fine‐grained sedimentary rocks in the Cangdong sag can be classified into six types of lithofacies by employing the content of three main mineral compositions together with structure features, among which five types are mainly deposited, including laminated felsic fine‐grained sedimentary rocks, laminated and massive carbonate fine‐grained sedimentary rocks, and laminated and massive mixed fine‐grained sedimentary rocks. The sedimentary environment during the sedimentary period of the Ek2 in the Cangdong sag was reconstructed by several indexes (including salinity, water depth, redox condition, climate, and detrital input) using the element geochemical parameters. The variations of detrital input and lake physicochemical characteristics driven by climate were vertically divided into four phases, indicating that the lake gradually changed from the transgression to the highstand period. In addition, the water column stratification led to the overall dysoxic–anoxic condition. The depositional process can be interpreted by correlating the lithofacies and the sedimentary environment. The results indicate that the mineral composition is controlled by the detrital input and carbonate production driven by climate and that structural features are mainly affected by the water column stratification. The Ek2 fine‐grained sedimentary rocks in the Cangdong sag present the vertical distribution of lithofacies that matches with the evolution phases of the sedimentary environment. This study's results enhance the understanding of the formation mechanism of lacustrine fine‐grained sedimentary rocks and provide basic geological knowledge for shale oil exploration in the study area. [ABSTRACT FROM AUTHOR]

Shorebirds produce a range of biogenic sedimentary structures related to their feeding behaviors, the most common of which are probing behaviors that result in morphologically simple impressions or indentations on the surface of a sedimentary substrate. Here we describe an unusual biodeformational structure made by a feeding gull (Larus sp.) produced as the tracemaker kneaded the sediment by moving its feet back and forth in place. This process liquified the sediment making it easier to catch invertebrate prey — the most common of which is the varnish clam (Nuttallia obscurata) — that are advected to the top of the liquified sediment. The bird retreated slowly backward as the sediment was liquified, an effort that is interpreted to represent continued and ongoing feeding in the sediment of prey-rich substrates. The resulting structure comprises a series of nested, concavo-convex sediment mounds and a terminal bowl-shaped impression. The aim of this paper is to document the trace–tracemaker association and provide a means of comparison with similar structures. Most notably, the structure bears similarities to Piscichnus, which represents ray feeding traces produced by hydraulic jetting (fodichnia) or nesting behaviors (calichnia) in fish. Piscichnus, however, lacks the nested mounds that result from the tracemaker systematically moving backward as it searches for food. [ABSTRACT FROM AUTHOR]

Fluvial deposits of the uppermost Stockton Formation (Late Triassic), west-central New Jersey have yielded the trace fossils Cruziana tenella and Helminthopsis isp. The ichnotaxa belong to the Scoyenia ichnofacies. On the basis of stratification and primary sedimentary structures, the beds are interpreted as deposits in a meandering stream environment. Worm-like forms, nematodes, notostracans, myriapods, and arthropods are probably responsible for most of the animal traces in moist or wet channel and point bar sediments subject to aerial exposure. [ABSTRACT FROM AUTHOR]

The Silurian Sharawra Member (middle to late Llandoverian) in Saudi Arabia exhibits unique surface traces with exceptional preservation: Seven small, wing-shaped traces occur on a sandstone slab showing well-defined hummocky cross-stratification having a few decimeters wavelength being covered by a thin mud layer. These traces are preserved as concave epirelief along with elongated internal striae and surrounded by slightly elevated levees. Preservation of these delicate, 10–20 mm long and ∼10 mm wide traces suggests that they were formed after a storm event when mud had already settled to the sediment surface. The lack of wave-generated sedimentary structures implies deposition between fair-weather and storm-wave base probably preventing further rapid reworking by waves. Based on their geometry, internal pattern, and spatial distribution, these wing-shaped traces are interpreted to have been produced by relatively stationary bottom-feeding fish, morphologically similar to ancestors of Gobiidae, probably in the Actinopterygii class. The majority of fish-made trace fossils record feeding and locomotion behaviour, whereas the wing-shaped traces are interpreted to represent resting structures made by fish that pressed their fins downward on the muddy sediment surface and hence, represent undertracks. These traces are possibly the oldest fish-made structure documented thus far. These wing-shaped traces are described as Pisquiesichnus dashtgardi igen. et isp. nov. in this study. [ABSTRACT FROM AUTHOR]

The sandstone of the lithologic reservoir in Songliao Basin is characterized by thin vertical thickness and rapid lateral pinch outs, which make it difficult to identify and describe the sandstone due to insufficient resolution of existing seismic data. To solve this problem, a method based on S-transform and modified variational mode decomposition is proposed to improve the resolution in the time–frequency domain by cepstrum deconvolution. Firstly, the time–frequency spectrum of seismic records is obtained by generalized S-transform; then it is transformed into cepstrum; and the wavelet amplitude spectrum is extracted by modified variational mode decomposition with permutation entropy, to realize the time–frequency domain deconvolution of cepstrum. After improving the resolution of seismic data in the study area, the frequency band of the data is broadened by more than 20%. After frequency expansion, the seismic reflection structure reflects the sedimentary characteristics of the actual sandstone in the area. The seismic reflection has a good correspondence with the well point sandstone, and the thin sandstone is clearly depicted. It is fully verified that this method can effectively improve the resolution of seismic data and has the characteristics of relative amplitude preservation. [ABSTRACT FROM AUTHOR]

Fault relay ramps are important sediment delivery points along rift margins and often provide persistent flow pathways in deepwater sedimentary basins. They form as tilted rock volumes between en‐echelon fault segments, which become modified through progressive deformation, and may develop through‐going faults that 'breach' the relay ramp. It is well established that hinterland drainage (fluvial/alluvial systems) is greatly affected by the presence of relay ramps at basin margins. However, the impact on deepwater (deep‐marine/lacustrine) subaqueous sediment gravity flow processes, particularly by breached relay ramps, is less well documented. To better evaluate the complex geology of breached relay settings, this study examines a suite of high‐quality subsurface data from the Early Cretaceous deep‐lacustrine North Falkland Basin (NFB). The Isobel Embayment breached relay‐ramp, an ideal example, formed during the syn‐rift and was later covered by a thick transitional and early post‐rift succession. Major transitional and early post‐rift fan systems are observed to have consistently entered the basin at the breached relay location, directed through a significant palaeo‐bathymetric low associated with the lower, abandoned ramp of the structure. More minor systems also entered the basin across the structure‐bounding fault to the north. Reactivation of basin‐bounding faults is shown by the introduction of new point sources along its extent. This study shows the prolonged influence of margin‐located relay ramps on sedimentary systems from syn‐rift, transitional and into the early post‐rift phase. It suggests that these structures can become reactivated during post‐rift times, providing continued control on deposition and sourcing of overlying sedimentary systems. Importantly, breached relays exert control on fan distribution, characterised by laterally extensive lobes sourced by widespread feeder systems, and hanging walls settings by small‐scale lobes, with small, often line‐sourced feeders. Further characterising the likely sandstone distribution in these structurally complex settings is important as these systems often form attractive hydrocarbon reservoirs. [ABSTRACT FROM AUTHOR]

Sand ridges are present in modern storm‐dominated and tide‐dominated shallow‐marine environments worldwide, but the number of published ancient examples is limited. The role of ocean currents in the formation of sand ridges is also poorly understood. This study investigated the lithofacies architecture of a lenticular sandstone body (ca 70 m thick and ca 30 km long) in the upper Mandano Formation (ca 0.6 Ma) on the Boso Peninsula, Japan, to establish criteria for identifying sand ridge deposits built by storm and ocean currents. The sandstone body is unconformably underlain by coastal and valley‐fill deposits and fines upward to outer‐shelf muddy deposits. It consists mainly of medium‐grained to very coarse‐grained sandstones and pebbly sandstones that are moderately to intensely bioturbated and are represented by three‐dimensional compound dune deposits. The body consists of six 10 to 20 m thick units (units 1 to 6 in ascending order), which are each defined by an erosional base and locally capped by storm‐induced fluid mud deposits. Each unit also contains low‐angle (ca 5°) large stratification inclined obliquely to palaeocurrents, indicating lateral accretion surfaces. Units 1 and 2 are characterized by south‐eastward migration (locally north‐westward), smaller dune deposits, storm‐induced sedimentary structures and cold‐water molluscs indicating a palaeowater depth of up to 50 m. The other units are represented by east/north‐eastward migration, larger dune deposits, warm‐water molluscs indicating a palaeowater depth of up to 200 m, and a general lack of storm‐induced sedimentary structures. Temporal changes in the migration directions and lithofacies features of the units indicate that sand ridge formation was initially controlled by storm‐induced currents that were subsequently replaced by the northward or north‐eastward intruding palaeo‐Kuroshio Current in response to the expansion of the shelf during an overall transgression. The initiation and development of the sand ridges may have been supported by the supply of clastic sediments eroded from the underlying coastal and valley‐fill deposits. [ABSTRACT FROM AUTHOR]

Extensive research into the evolution of wave‐dominated estuaries has been documented since the 1960s. However, there has only been limited research on the prograding bay‐head deltas that are the primary drivers for the rate and stage of estuary evolution. This paper presents the findings of a high‐resolution spatial study into the evolution of the Macquarie Rivulet bayhead delta in the Lake Illawarra barrier estuary. The delta's evolution has been established based on sedimentological analysis of 74 cores, two 14C ages and 45 amino acid racemization ages. This study intersected two Pleistocene and 10 Holocene sedimentary facies associations representing both the retrogradational and progradational phases of delta development. The distribution of bayhead delta facies associations in shallow barrier estuaries is initially controlled by the antecedent morphology, but, in contrast to deeper estuaries, this influence decreases as sedimentation proceeds. Changing relative sea level also has a major control on facies distribution with transgressive facies deposited as relative sea‐level rises being replaced by prograding deltaic facies during the highstand and subsequent minor relative sea‐level fall. Fluvial sediment supply and river flood events affect the rate of delta progradation, and produce low and high flow sediment deposits within the overall deltaic sequence. The low tidal flux in barrier estuaries, the muddy cohesive nature of the sediments and the prevalence of bioturbation means that primary sedimentary structures are rarely preserved in these bayhead delta facies. The depositional model of bayhead delta evolution shown by the Macquarie Rivulet delta would be widely applicable to other similar barrier estuary settings. [ABSTRACT FROM AUTHOR]

Interplay of deep‐water sedimentary processes is responsible for building a myriad of features and deposits across mixed turbidite–contourite systems, from <5 cm beds to >200 km long sedimentary drifts. Investigations of the spatial and temporal variability of their sedimentary facies and facies associations is crucial to reveal the dynamics between along‐slope bottom currents and down‐slope turbidity currents, as well as their impact on drift construction and channel erosion. This study focuses on extensive modern mixed (turbidite–contourite) systems, developed across the continental rise of the Pacific margin of the Antarctic Peninsula. Nine sediment cores were sampled and analysed, through grain size and geochemical methods, to study the sedimentary facies at high‐resolution (ca 1 to 20 cm). Three main facies associations have been identified across distinct morphological features (i.e. mounded drifts and trunk channels), comprising intercalations of hemipelagites, bottom current reworked sands (which include fine to coarse‐grained contourites) and gravitational facies (turbidites and mass‐transport deposits). These facies associations reflect fluctuations of the background sedimentation, oscillations of the bottom‐current velocity and of the frequency of gravity‐driven currents. The sedimentary record features cyclic alternations during the Late Quaternary (>99 kyr), suggesting that variations between along‐slope bottom currents and down‐slope turbidity currents are strongly linked to glacial–interglacial cycles during Marine Isotope Stages 1 to 6. Sedimentary records affected by bottom currents on polar margins, such as those of the Antarctic Peninsula, are essential to decipher the facies and facies sequences of bottom‐current deposits, as the low degree of bioturbation throughout most of the sediments allows us to observe the original sedimentary structures, which are poorly preserved in similar deposits from other continental margins. [ABSTRACT FROM AUTHOR]

Geological processes alter pore spaces over time, and their analysis can shed light on the dynamic fractal structure and fluid flow of rocks over time. This study presents experimental evidence to illustrate that the pore fractal structure evolves with sedimentation, carbonate cementation, clay growth, and dissolution. It examines, describes and characterizes a suite of core samples from the Gaotaizi oil layer of the second and third members of the Qingshankou Formation, Songliao Basin, China. The effects of mechanical compaction and other diagenesis effects on fractal pore structure on sedimentary rocks are discussed. A schematic diagram is proposed that describes the impacts of these diagenetic processes on fractal pore structure at the microscopic scale in sedimentary rocks. This work links the state of diagenetic alteration and fractal pore structure, which can guide practical applications such as predicting the permeability of sedimentary rocks. Plain Language Summary: Mechanical compaction or chemical alteration process will change the pore space of the rock, including pore size and grain‐pore interface properties. We present the evidence that geological processes alter the "roughness" amplitude of grain‐pore interface (fractal pore structure) in sedimentary rock, and discuss the evolutionary mechanism of the "roughness" amplitude of grain‐pore interface. This work links the state of diagenetic alteration and fractal properties of rocks, which can guide practical applications such as predicting permeability of sedimentary rocks for any historical period. Key Points: Evolution of fractal dimension with diagenesis was revealedEffects of diagenesis on fractal upper and lower limits were discussedEffect mechanism of fractal pore structure was revealed in sedimentary rocks [ABSTRACT FROM AUTHOR]

The sedimentary structure of tailings is of high significance to the engineering design and safety management of tailings dams. However, due to a lack of accurate measurement techniques for the flow field and hydrodynamic conditions of tailings reservoirs, it is challenging to study the complicated sedimentary structure of tailings dams from the perspective of fluid mechanics. This study focuses on developing a large-scale particle image velocimetry (LSPIV) system in a 20 m long and 2 m wide deposition model flume to measure the flow field characteristics during the ore-drawing process accurately. According to the surface flow field characteristics measured by LSPIV, the tailings in the flume can be divided into three zones, namely the fan-shaped zone, channel zone, and laminar flow zone. Then, a simple method for estimating the flow rate of the slurry was proposed using the surface velocities measured by LSPIV. The flow rate of iron tailings slurry in the flume displays a decreasing trend along the flow direction. The variation of the flow rate of tailings slurry can be described by an exponential function. After the deposition of tailings slurry, the sedimentary characteristics of tailings are investigated, and the distribution of iron tailings particles is discussed in combination with the flow field of the tailings slurry. The LSPIV system can be applied to further deposition model tests of different slurry concentrations, discharge flow rates, and tailings compositions to investigate the effects of these factors on the tailings flow and deposition. [ABSTRACT FROM AUTHOR]

The offshore rifted margins of the North Atlantic have a spatially complex crustal structure comprised of variable crustal morphologies, continental blocks, and inherited structures. Recently, deformable plate tectonic models have permitted the interplay of plate kinematics and deformation to be assessed throughout the North Atlantic, and elsewhere. In particular, the ability to calculate temporal variations in crustal thickness has provided insight into the kinematic role of continental blocks and their interplay with large and micro‐tectonic plates during the formation of the North Atlantic offshore rifted margins. In this study, the deformable plate modeling workflow introduced in the companion contribution of this study (Part 1) is used to investigate previously published and newly presented deformable plate models of the Newfoundland, Irish, and West Iberian margins. This approach permits the deformation and subsequent crustal thickness evolution within previously recognized continental blocks and sedimentary basins throughout the southern North Atlantic Ocean to be visualized and assessed from 200 Ma to present day. The segmentation of early rift crustal thicknesses calculated by deformable plate models demonstrate strong correlations with the offshore extension of Appalachian and Caledonian terrane boundaries. Thus, our observations suggest that inherited orogenic boundaries potentially play a key role in the early rift crustal structure of sedimentary basins and the partitioning of deformation around and within continental blocks. Plain Language Summary: The Earth is made up of large and small tectonic plates that are actively moving and can have variable thicknesses and morphologies. Over the last 200 million years, the gradual separation between the North American and Eurasian plates has led to the formation of the southern North Atlantic Ocean. Consequently, its present day form represents a natural playground for geoscientists to study the formation of oceans and plate tectonic processes through the interplay of data acquisition, interpretation, and modelling studies. In this work, we use an innovative and open‐source modelling workflow to study the evolution of large and small tectonic plates by reconstructing their present day template and thicknesses back through time. The results of our study reveal the influential role of smaller tectonic plates and their necessity for accurately restoring the southern North Atlantic Ocean back through time. In addition, this study highlights the potential impact of approximately 300–500 million year old geological structures that are inherited from the closure of earlier oceans that were re‐activated during the creation of the southern North Atlantic Ocean. Key Points: Continental blocks had a large impact on pre‐rift crustal thicknesses calculated within sedimentary basins throughout the North AtlanticThe Flemish Cap, Porcupine Bank, and Rockall‐Hatton Bank played a key role during rift related deformation throughout the North AtlanticAppalachian and Caledonian terrane boundaries were very influential on pre‐rift templates calculated throughout the North Atlantic [ABSTRACT FROM AUTHOR]