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The structure and origin of the Pleistocene (Marine Isotope Stage [MIS] 5) coastal Barrier III in southern Brazil were investigated through analysis of lithofacies, numerical ages, and ground-penetrating radar (GPR) data obtained in outcrops and subsurface deposits. The stratigraphic succession is characteristic of transgressive barriers, with muddy lagoon bottom facies unconformably overlying an older unit (Barrier II) and overlain by landward-dipping lagoon margin and aeolian facies. The back-barrier lagoon was filled with sediments and shells transferred from the foreshore through overwash and/or inlets during the MIS 5e transgressive-high-stand phase, with a higher sea level that reached about +6 to +7 m relative to the present. Marine sediments and shells on the seaward side of the barrier dated to ~100–106 ka indicate another high stand at +4 to +5.1 m during MIS 5c. One shell dated to ~87 ka and aeolian deposits dated to ~82 and ~85 ka suggest a third high stand during MIS 5a that reached at least −2 m relative to the present. The two (possibly three) juxtaposed marine deposits show that Barrier III is a more complex unit than previously recognized, built by successive orbitally forced eustatic sea-level oscillations also recorded in other deposits along the Brazilian coast and worldwide. [ABSTRACT FROM AUTHOR]

The Qom Formation is the most important hydrocarbon reservoir target in Central Iran. The Qom platform developed in a back‐arc basin during the Oligo–Miocene due to the closing of the Tethyan Seaway. This formation consists of a variety of carbonate and non‐carbonate facies deposited on a platform ranging from supratidal to basin. A combination of tectonic and eustatic events led to some lateral and vertical facies variations in the study area. Six third‐order depositional sequences and related surfaces were identified regarding vertical facies changes in the studied sections of this Oligo–Miocene succession. According to all results and data, this succession was initially deposited during the Chattian upon a distally steepened ramp of siliciclastic‐carbonate composition, including the Bouma sequence. Then, from the late Chattian to the Aquitanian, the platform changed into a homoclinal carbonate ramp with a gentle profile. With respect to tectonic activity, this phase was a calm period during the deposition of the Qom Formation. Finally, a drowned carbonate platform and a rimmed shelf emerged during the Burdigalian, terminated by the continental deposits of the Upper Red Formation. Regarding all geological characteristics, three main tectono‐eustatic evolutionary phases have been recognized in the Qom back‐arc basin. [ABSTRACT FROM AUTHOR]

The isolation of the eustatic signal from the sedimentary record is a challenging task, and accordingly, there is no consensus on the magnitude and pace (rate) of eustatic events in the geological record. Here we critically assess various published short-term Cretaceous eustatic curves using insights from forward stratigraphic modelling. We generate a range of simulations with varying eustatic rates and sediment supply against a background of constant subsidence. From these, we generate statistics on the accommodation change associated with the various systems tracts for different sediment supply. We quantify the minimum rate needed to generate transgressive systems tracts (TST). Using this threshold and average subsidence rates for passive margins and intracratonic basins, we document some key challenges with a range of Cretaceous eustatic curves. While it is possible to complexify, this approach through the inclusion of other parameters, our results provide a framework for evaluating eustatic (or relative sea level) curves in terms of the implied rate of change of accommodation. Given these caveats, we also show that many estimates of the magnitude of short-term transgressions are of insufficient rate to generate observable TST. Further, our work places an upper limit on the time frame over which aquifer and thermo-eustasy can have observable impacts on the rock record, providing support for the action of glacio-eustasy during the Cretaceous. [ABSTRACT FROM AUTHOR]

Based on a new deep drilling on southern Gotland (Sweden), this study is the first to document the carbon isotope chemostratigraphy of the Upper Ordovician through lowermost Silurian sedimentary record from the central parts of the Baltic Sea subsurface. The lithological record of the Stora Sutarve core has similarities with adjacent successions in both the Viki core in the East Baltic area and the Borenshult core in the Swedish mainland. The core includes the Kahula (including 13 bentonites in the "Kinnekulle K-bentonite complex"), Hirmuse(?), Rägavere, Paekna, Jonstorp, Loka, Motala and Kallholn formations. Several of the internationally recognized upper Ordovician δ13C excursions have been identified in the core, including the Guttenberg Isotope Carbon Excursion (GICE), Moe excursion, Hirnantian Isotope Carbon Excursion (HICE), and an undefined early Silurian carbon isotope excursion, presumably the Early Aeronian Carbon Isotope Excursion (EACIE). We particularly address the microstratigraphy of the Hirnantian Stage and the finer details of the HICE, which is not fully complete and entirely confined to the 2.09-m-thick Loka Formation. This formation yields abundant, but low-richness brachiopod faunas characteristic of the Hirnantian Stage and is, based on erosional-depositional surfaces and facies, interpreted as reflecting interglacial warming and eustatic transgression related to ice-sheet contraction in Gondwana. Based on very dense carbon isotope sampling we identify four clusters of δ13C values that aid to define significant changes in the preserved record of the HICE and which may facilitate global correlation of the succession and the herein interpreted sea-level record. [ABSTRACT FROM AUTHOR]

Lower Permian marine strata in the American Southwest (Arizona, New Mexico and Texas, USA) identify three extensive marine seaways, one of Wolfcampian age and the other two of Leonardian age. These are strata deposited on the Mogollon shelf and in the Holbrook basin of Arizona, the Pedregosa basin of Arizona-New Mexico and northern Mexico, the Orogrande basin of New Mexico, the Delaware basin of New Mexico-Texas and the Midland basin of Texas. Age control of these strata, based primarily on fusulinids and conodonts, including new conodont data presented here, correlates Wolfcampian (mostly Asselian to Sakmarian) marine strata from the Pedregosa basin to the Midland basin, lower to middle Leonardian (upper Artinskian to mid-Kungurian) marine strata that extend from the Mogollon shelf to the Delaware basin and upper Leonardian to lower Guadalupian (upper Kungurian to lower Roadian) marine strata that extend from the Mogollon shelf to the Midland basin. Active regional Ancestral Rocky Mountain tectonism affected Wolfcampian marine deposition by providing accommodation in which to preserve both non-marine and marine facies within multiple transgressive-regressive sequences associated with the most extensive part of the late Paleozoic ice age, when global sea level would have been low. In contrast, two Leonardian seaways were likely driven by global tectono-eustatic events. Identification of the three Early Permian seaways in the American Southwest underscores the need for more precise correlations as well as integrated sequence stratigraphic interpretations of the deposits of these seaways from Arizona to Texas. • Reconstructs the seaways present in the American Southwest, 274–299 million years ago. • Reviews stratigraphy, depositional environments and correlations. • Presents new data on conodonts from the Early Permian strata. • Underscores the need for integrated study of the seaways. [ABSTRACT FROM AUTHOR]

[Display omitted] • Phanerozoic sea level is reconstructed from plate tectonic activity and continental glaciation estimates. • Long-term and medium-term glacio-eustatic effects lead to eustatic sea level changes of up to ∼220 m. • Our Tectono-Glacio-Eustatic curve correlates well with other curves in the Mesozoic-Cenozoic, but a large spread remains in the Paleozoic. Global mean sea level is a key component within the fields of climate and oceanographic modelling in the Anthropocene. Hence, an improved understanding of eustatic sea level in deep time aids in our understanding of Earth's paleoclimate and may help predict future climatological and sea level changes. However, long-term eustatic sea level reconstructions are hampered because of ambiguity in stratigraphic interpretations of the rock record and limitations in plate tectonic modelling. Hence the amplitude and timescales of Phanerozoic eustasy remains poorly constrained. A novel, independent method from stratigraphic or plate modelling methods, based on estimating the effect of plate tectonics (i.e., mid-ocean ridge spreading) from the 87Sr/86Sr record led to a long-term eustatic sea level curve, but did not include glacio-eustatic drivers. Here, we incorporate changes in sea level resulting from variations in seawater volume from continental glaciations at time steps of 1 Myr. Based on a recent compilation of global average paleotemperature derived from δ18O data, paleo-Köppen zones and paleogeographic reconstructions, we estimate ice distribution on land and continental shelf margins. Ice thickness is calibrated with a recent paleoclimate model for the late Cenozoic icehouse, yielding an average ∼1.4 km thickness for land ice, ultimately providing global ice volume estimates. Eustatic sea level variations associated with long-term glaciations (>1 Myr) reach up to ∼90 m, similar to, and is at times dominant in amplitude over plate tectonic-derived eustasy. We superimpose the long-term sea level effects of land ice on the plate tectonically driven sea level record. This results in a Tectono-Glacio-Eustatic (TGE) curvefor which we describe the main long-term (>50 Myr) and residual trends in detail. [ABSTRACT FROM AUTHOR]

Deciphering the facies and architecture of alluvial successions provides invaluable insights into the interplay of tectonics, climate, eustasy, and autogenic processes affecting terrestrial sedimentary systems. The stratigraphic response of fluvial systems to variations in discharge and sediment-supply regimes is now well-understood and is tied to changes in climate, precipitation patterns, or sediment sources. The uraniferous Chu-Sarysu Basin in south Kazakhstan occupies the tectonically stable Turan Platform on the eastern margin of the Peri-Tethys, and the study of its Palaeocene–Eocene sedimentary fill offers an opportunity to unravel eustatic and climatic controls that drove the architecture of reservoirs hosting economically important deposits. The stratigraphic succession comprises two multistorey, laterally extensive, sheet-like sandstone bodies floored by prominent erosion surfaces and interpreted as the deposits of channel belts. These packages are interstratified with floodplain, coastal-wetland, and marine-embayment complexes reflecting major extra-channel belt avulsions and marginal-marine incursions on the low-gradient alluvial plain. The stratal architecture was controlled by changes in accommodation likely induced by well-documented sea-level changes in the Peri-Tethys during the Palaeogene, which permitted the development of a chronostratigraphic framework. Eustatic variations culminated in the widespread flooding of the Turan Platform in the middle Eocene, reflected by transgressive lags above a wave ravinement surface capping terrestrial and marginal-marine deposits. Marked changes in fluvial facies, floodplain styles, and inferred channel planforms between Palaeocene and Eocene strata suggest a climatic overprint on river discharge and sedimentation. Upper Palaeocene meandering channel deposits encased in well-drained floodplain strata are indicative of perennial discharge under a semi-arid climate, whereas lower Eocene low-sinuosity channel fills, displaying evidence for transcritical flows and abundant in-situ vegetation, point to intermittent runoff patterns consistent with a humid and seasonal climate. An evolution in atmospheric moisture at the Palaeocene–Eocene boundary from arid to humid conditions has been reported across the Tethys region, and linked to global climatic perturbations of the Palaeocene–Eocene Thermal Maximum. [ABSTRACT FROM AUTHOR]

The middle‐upper Jurassic successions (Sargelu, Najmah, and Gotnia formations) of the NW sector of the Zagros Mountain belt are studied to generate a sequence stratigraphic model that helps to understand the Jurassic tectono‐depositional processes and palaeogeographic reconstructions of the northeastern passive margin of the Arabian Plate. The major geological structures observed in northwestern Iran indicate the predominance of an extensional deformation during the Toarcian to Aalenian owing to the eastern Mediterranean rifting. This extensional regime reached its maximum from the Early to Middle Jurassic, causing the fragmentation/drowning of the long‐lived Triassic to Early Jurassic carbonate platform and the development of the Hawraman intrashelf basin (HIB). Associated changes in marine current dynamics, trophic conditions, and degree of substrate oxygenation led to the bloom of oligotypical biota (Bositra limestones) creating unfavourable conditions for the development of other benthic communities (Sargelu Formation). Later, from the Callovian to Oxfordian, changes in carbonate production types (switch from the Bositra filament facies to the stromatolitic‐thrombolitic boundstones) remarkably decreased the dip angle of the depositional profile (Najmah Formation). A second‐order tectono‐eustatic cycle (a major long‐term transgressive/regressive [T/R] cycle) including six minor short‐term T/R facies cycles (TR1–TR6) is identified in the study area. The development of the T/R facies cycles during the Middle Jurassic (TR1–TR3; give‐up sequences; Sargelu Formation) as a result of combined global eustatic transgression and linear subsidence resulted in drowning and backstepping of the platform. In contrast, the short‐term cycles that developed in the upper Jurassic (TR4–TR6; keep‐up sequences; Najmah and Gotnia formations), following a sea‐level fall, resulted in progressive shallowing of the carbonate platform. This study suggests that extensional deformation of the area reached its peak in the transition of the Early to Middle Jurassic, leading to the creation of HIB, but either decreased or played a subordinate role to eustatic sea‐level variations during the deposition of the TR1–TR3 facies cycles (Bajocian‐Callovian). Changes in tectonic regime from an extensional deformation (Early Jurassic) to cooling subsidence (Middle Jurassic), accompanied by a long‐term transgressive sea‐level trend during the Middle Jurassic, were important factors in the development of anoxic trough environments with the deposition of organic‐rich intervals, represented by the TR1–TR3 facies cycles. Tectonic instability (tectonic uplift plus considerable differential subsidence due to the reactivation of faults) in the eastern margin of the Arabian platform during the Late Jurassic led to the development of the TR4–TR6 facies cycles. [ABSTRACT FROM AUTHOR]

The timing of tectonic deformation in the Zagros foreland basin provides important information about the tectonic propagation process driven by the Arabia‐Eurasia convergence. The chronology of growth strata is one of the most important methods to delimit the history of folding and thrusting within the foreland basin. In this study, we report integrated analyses of sedimentology, magnetostratigraphy, and biostratigraphy of Miocene strata in the Dezful Embayment in the SW Zagros foreland basin. The new results indicate that deposition of the northern limb of the Gach‐e Moh Anticline was between 14.6 and 8.6 Ma; that includes the Upper Gachsaran Formation (14.6–13.8 Ma), the Mishan Formation (13.8–12.8 Ma), and the Agha Jari Formation (12.8–8.6 Ma). Based on magnetostratigraphic and sedimentary evidence, the transition from marine to non‐marine was at ∼12.8 Ma. Analysis of temporal lithofacies‐stacked patterns shows there were seventeen transgression‐regression cycles during the Middle Miocene Climatic Transition with a ∼100‐Kyr Earth eccentricity cycle, suggesting that the cyclic marine transgressions and regressions were mainly driven by eustatic sea level fluctuations; but tectonic‐induced basin subsidence also contributed marine transgressions in the Upper Mishan Formation. The final seawater retreat was at 12.8 Ma driven by both the global eustatic sea level drop and the enhanced south‐westward progradation of sediments eroded from the High Zagros. The base of the growth strata in the footwall of the Mountain Front Fault was at ∼11 Ma, suggesting that tectonic deformation caused by the Arabia‐Eurasia collision had propagated to the Dezful Embayment by that time. Key Points: Magnetostratigraphic chronology in the Dezful Embayment yields an age range of ∼15–9 Ma in the Zagros forelandTectonic deformation propagated to the Dezful Embayment at 11 Ma driven by the onset of thrusting from the Mountain Front FaultFinal seawater retreat in the Dezful Embayment was at 12.8 Ma, and the marine transgressions/regressions had a quasi‐cycle of 100‐Kyr [ABSTRACT FROM AUTHOR]

An almost continuous layer of Upper Cretaceous deposits up to 1000 m thick was probably deposited across much of SW England. Phases of uplift in the late Cretaceous and early Cenozoic, each of which was followed by extensive erosion and dissolution, resulted in the removal of all except a few outliers of Chalk Group that crop out in east Devon and south Somerset. Those on the Devon coast between Sidmouth and Lyme Regis are some of the best exposed Cenomanian to early Coniacian successions in NW Europe and include the most westerly chalks preserved onshore in England. They form an integral part of the Dorset and East Devon World Heritage Site. In contrast to the Chalk of much of southern England, the older formations in Devon, the Beer Head Limestone, Holywell Nodular Chalk and New Pit Chalk, show marked lateral lithological variations that result from a combination of penecontemporaneous movements on local faults and relatively shallow-water environments close to the western edge of the Chalk depositional basin. The younger parts of the succession, the Lewes Nodular Chalk and Seaford Chalk Formations, comprise chalks that do not appear to have been greatly affected by penecontemporaneous fault movements. These formations include lithological marker beds that have been correlated with marker beds in the Sussex type area. The principal sedimentary breaks in the Devon succession cannot be correlated with confidence with eustatic changes in sea level. [ABSTRACT FROM AUTHOR]

This paper provides insight into the Late Ordovician to earliest Silurian evolution of sedimentary environments in the southern Holy Cross Mountains (SE Poland), which at that time were a part of the SW periphery of Baltica. The facies layout in this area was influenced by the basement block faulting, which differentiated the basin bathymetry into submarine horst and grabens, controlling facies distribution. However, the local tectonism was insufficient to fully mask the global eustatic events. Therefore, it is possible to correlate some facies changes in the Upper Ordovician and lower Llandovery sedimentary record of the southern Holy Cross Mountains with eustatic and palaeoceanographic changes reported worldwide. The most noticeable influence of eustasy on the sedimentary record in the studied area occurs at the Ordovician/Silurian boundary. It is manifested by Hirnantian regressive coarse-grained clastic sediments overlain by a post-glacial anoxic/dysoxic interval represented by the Rhuddanian transgressive black cherts and shales. It is noteworthy that the pre- and post-Hirnantian sedimentary environments in the southern Holy Cross Mountains were affected by upwelling induced by the SE trade winds. [ABSTRACT FROM AUTHOR]

The Yangtze River is known as the 'mother river of China' because it flows through the country's most densely populated and historically wealthiest regions. However, the evolution of the Yangtze River and its controls remain unclear. In this study we dated samples extracted from five bedrock-penetrated boreholes in Anqing, in the lower Yangtze River Valley. The resultant optically stimulated luminescence (OSL) and radiocarbon (14C) dates would suggest that fluvial sediments accumulated during the ∼33–44 ka and ∼11-0.2 ka periods, with extensive erosion during the >44 ka and 33-11 ka timeframes. We also reviewed data from 13 OSL and 14C dated boreholes located between the middle reaches of the Yangtze River and its estuary. The results would suggest that most of the fluvial sediments were deposited during Marine Isotope Stages (MIS) 3 and 1, with a clear erosion hiatus during the Last Glacial Maximum (LGM). Glacial-interglacial cycle-driven eustasy was the main driver of the Yangtze River's incision-aggradation process. The eustatic forcing during the glacial-interglacial cycle influenced the changes in the landscape of the Yangtze River Valley as far inland as ∼1200 km from the present-day shoreline. • Five boreholes were drilled in Anqing city, the lower Yangtze River Valley. • Most of the fluvial sediments were deposited during MIS 3 and 1. • Intensive incision occurred during the LGM and MIS 4. • Eustasy was the main driver of the Yangtze River's incision-aggradation process. • Eustatic forcing influenced fluvial landscape change as far inland as ∼1200 km. [ABSTRACT FROM AUTHOR]

Available reconstructions of Jurassic global sea level changes differ and are in need of an update. New stratigraphical charts and palaeogeographical developments for a number of large continental blocks or their portions of these (e.g., Germany, India, northeast Africa, northwest Australia, the Russian Platform and western Siberia) reveal regional long-term shoreline shifts (i.e., transgressions and regressions) during the Bajocian Stage (168.3–170.3 Ma). A comparison of these allows to document only a single coherent feature, namely the earliest Bajocian transgression, in the majority of the continental blocks considered. Undoubtedly, this event was triggered by a eustatic rise. However, long-term shoreline shifts were either weak to absent or differed between the blocks during almost the entire Bajocian, thus providing evidence of the apparent stability of global sea level and the importance of regional tectonic activity as a control mechanism on particular transgressions and regressions. Interestingly, it appears that the earliest Bajocian eustatic rise was a constituent of a long-term eustatic pattern; the nature of this event has yet to be fully understood. Generally, the findings presented here are in better agreement with Anthony Hallam’s view of Jurassic eustasy and question some other global sea level reconstructions.

The uppermost Albian–Turonian interval has been studied in the south of the Izeh Zone (SW Iran) to investigate the depositional history of the Sarvak Formation in this area. This interval in the Middle East is characterized by the presence of very large shallow water carbonate platforms, surrounding the intra-shelf basins. The expansion of up to 90% hemipelagic strata throughout the studied outcrop proposes that it has been deposited in an intra-shelf basin. Three Cenomanian and one Turonian depositional sequences were distinguished in the studied interval based on the alternation of three microfacies associations including oligosteginid-dominated, oligosteginid-free, and platform-top microfacies. The biostratigraphical calibration by means of the planktic foraminifera indicates that these sequences can be well correlated on a global scale. The simultaneous influence of eustatic, tectonic, and environmental factors on the depositional sequences in the Lar Anticline section makes it difficult to identify the dominance of one over the others. The ability to correlate the sequence boundaries in the studied section with the global events suggests the effect of eustasy on the deposition of this interval. However, the tectonic control by the creation of a paleo-depression, subsidence (during the TST of Sequence 3), and uplift (at the Cenomanian/Turonian boundary (SB4) and mid-Turonian (SB5)) overprinted the eustatic factor. The influx of clay and the black shale formation during OAE2 conditions are the environmental factors that cannot be ignored in the deposition of sequence 1 and sequence 3, respectively. [ABSTRACT FROM AUTHOR]

The Rhaetic facies, as developed in the Southern Alpine region of Italy, were deposited in a strongly subsiding, fault-dissected trough (the Lombardian Basin) bounded by carbonate platforms. The main part of the Rhaetic succession consists of decametric scale, stacked asymmetric cycles, each divided into three parts: a lower shale portion, a central rhytmic portion consisting of repeated marl-limestone couplets, the limestone part of which gradually thickens upward, and a wholly carbonate upper unit. A study of the diagenetic history demonstrates that these marl-limestone alternations are fundamentally depositional in origin. This decametric cyclicity is identified as deriving from the superposition of a lower frequency (period of about 100,000 years) asymmetric carbonate mud signal with a high frequency sinusoidal argillaceous mud signal. Evidence is produced indicating that the basinal carbonate mud is predominantly allochthonous in origin, having been derived from the adjacent carbonate platforms. The associated asymmetric carbonate signal was a response to eustatic fluctuations which affected the characteristics of the subtidal "carbonate factory" in the platformal areas. These fluctuations are indicated by the repeated direct subaerial exposure of subtidal muds in shallow areas. The basinward exportation of carbonate muds was negligible in the deepening phase, increased during the shallowing evolution and was finally stopped by the emersion of large platformal flats. In contrast, the higher frequency argillaceous mud signal was probably climatically modulated; fluctuations of a higher frequency than those defined in Milankovitch theory affected hinterland precipitation and run off. The rapid subsidence and depositional rates allowed the preservation of this effect.

The mechanisms involved in the formation of 1- to 2-Myr-long third-order stratigraphic sequences through the Phanerozoic have been extensively debated, but the main underlying forcings remain uncertain. In this study, we investigated third-order sequences of Paleocene-Eocene age in the East China Sea Shelf Basin, identifying a prominent ∼1.2-Myr periodicity in the 405-kyr-tuned gamma ray profile of the WP-1 borehole. We infer that this ∼1.2-Myr cycle, which corresponds to long-period amplitude modulation of obliquity, was the main driver of third-order sea-level changes and sequence development. This modulation entails variation in the range of obliquity amplitude between a maximum of 2.4° (i.e. 24.5°–22.1°) and a minimum of 0.3° (i.e. 23.3°–23.0°) as a result of interactions among the three primary parameters of Earth's orbit (i.e., eccentricity, obliquity, and precession). We anchored our floating astronomical time scale (ATS) to the T42 seismic horizon, a major sequence boundary between the Lin Feng and Mingyuefeng formations that corresponds to the top of Nannofossil Zone NP8 (reported age of 57.7 Ma). This yields a fixed ATS for the late Paleocene-to-middle Eocene interval spanning 60.84 to 48.71 Ma. Finally, we evaluated our findings relative to the third-order sequence stratigraphy of the East China Sea Shelf Basin and to records of early Cenozoic eustasy and global events. • Third-order sequences and sea-level change can be generated by using cyclostratigraphic method. • ∼1.2- and ∼2.4-Myr Astronomical control on sediment accumulation rate. • T42 seismic horizon in East China Sea is adjusted to 57.7 Ma correspond to Th4 Sequence Boundary. • ∼1.2-Myr amplitude modulation of obliquity dominated sea-level change. • Astronomical Time Scale spanning from 48.71 Ma to 60.84 Ma. [ABSTRACT FROM AUTHOR]

Abstract The Kamura section, located in the Chichibu Belt of Kyushu Island in southern Japan, contains a succession of uppermost Permian to Upper Triassic shallow-marine atoll sediments from the mid-Panthalassic Ocean. In the present study, carbonate microfacies, conodont biostratigraphy, and carbonate carbon isotopes were analyzed, making it possible to construct a detailed biochronological framework for the Triassic of the central Panthalassic region. A total of 14 conodont zones are recognized from the uppermost Changhsingian to the upper Norian. The Lower Triassic contains the Hindeodus parvus , Isarcicella isarcica , and H. postparvus zones (Griesbachian), the Neospathodus dieneri Zone (Dienerian), and the Novispathodus ex gr. waageni - Parachirognathus Zone (Smithian), while no evidence of the upper Lower Triassic Spathian substage was recovered at Kamura. The overlying Middle Triassic section consists of the Chiosella ex gr. timorensis-Cratognathus , ' Paragondolella ' ex gr. alpina - Pg. ex gr. excelsa , Budurovignathus hungaricus , and B. mungoensis zones, followed in the Upper Triassic by the Quadralella tadpole - Gladigondolella malayensis , Q. lobata - Q. carpathica , Primatella cf. orchardi - Pr. permica , Epigondolella rigoi -' Pg. ' hallstattensis , and E. ex gr. bidentata - Norigondolella steinbergensis zones. The exact stratigraphic intervals present at Kamura were refined through intercalibration of the conodont biozonation data with its δ13C carb profile, which shows a characteristic series of negative and positive excursions that correspond to well-established global reference profiles. The Permian–Triassic boundary is placed 0.20 m above the Mitai-Kamura formation contact (a reference datum corresponding to the end-Permian extinction horizon, = 0 m) based on the first appearance of H. parvus , and the Olenekian–Anisian boundary is placed 17.60 m above the reference datum based on the first appearance of Ch. ex gr. timorensis. Kamura carbonates were assigned to six fabric types and 17 microfacies. The microfacies succession records a deepening immediately following the end-Permian mass extinction, a strong shallowing during the mid to late Smithian, development of an unconformity spanning the entire Spathian, and minor sea-level fluctuations during the Middle and Late Triassic. The Spathian unconformity is attributed to a eustatic fall related to a sharp cooling event at or close to the Smithian–Spathian boundary that exposed the Kamura atoll. The subsequent resumption of shallow-marine sedimentation in the earliest Middle Triassic was probably due to continued thermal subsidence of the oceanic crustal basement beneath the atoll. The present work is the most complete analysis to date of the conodont biostratigraphic, carbon isotope chemostratigraphic, and eustatic records of the Triassic System in the central Panthalassic Ocean and should serve as a regional reference standard in the future. Graphical abstract Image 2 Highlights • The Lower Triassic at Kamura, Japan provides a unique mid-Panthalassic Ocean record. • 14 conodont zones established from basal Triassic (Griesbachian) to Upper Triassic (Norian). • The Griesbachian to Smithian interval is complete, showing well-known global δ13C carb excursions. • Microfacies document semi-restricted atoll lagoon sedimentation and multiple sea-level fluctuations • A Spathian unconformity developed due to eustatic fall possibly related to global cooling at the SSB. [ABSTRACT FROM AUTHOR]

Abstract High-frequency depositional cycles are often used for long-distance correlations within sedimentary basins and constructing high-resolution chronostratigraphic scales calibrated to the orbital clock. Such an approach has been used for the tropical, epicontinental Muschelkalk Sea covering most of Europe in the Middle Triassic. This paper aims at establishing the spatial extent and internal architecture of shallow-marine Muschelkalk cycles within a small (120 by 50 km) area of the Germanic Basin, to identify their local vs. regional distribution and cycle-forming mechanisms. Three groups of cycles are distinguished: 1) peritidal cycles representing a tidal flat-lagoon system which experienced longer periods of emersion; 2) shallow subtidal cycles formed around the fair-weather wave base; and 3) deep subtidal cycles developed around the storm wave base. The three cycle types differ markedly in the composition, facies homogeneity, sedimentary trends, hierarchical organization, continuity, and degree of lateral changeability and complexity, which collectively translates into the ease of cycle recognition. Despite the differences, the defined cycles do not extend laterally beyond the studied area and have laterally variable facies heterogeneities, sedimentary trends, and thicknesses. This variability resulted from more or less mosaic infilling of accommodation space, reflecting local bathymetry, physicochemical conditions, and carbonate production and accumulation rates on the platform. Accommodation space evolved by the interplay of eustatic sea-level fluctuations regional subsidence, and synsedimentary tectonic-block movements, but the contribution of these factors changed over time and was to varying degrees masked for each of the three cycle types by intrinsic sedimentary processes. The study shows that Middle Triassic cycles of the Germanic Basin have a local to sub-regional distribution and thereby are inappropriate for basin-wide correlations and chronostratigraphic inferences. It also strengthens the opinion of several workers that correlation of idealized cycles is unrealistic without checking the horizontal continuity of facies and key surfaces directly in the field. [ABSTRACT FROM AUTHOR]

• Sea-level change paced by 400-kyr eccentricity in the peak Cretaceous greenhouse. • Continental water storage favored by increasing seasonality variation/extremes. • Phasing of greenhouse eustasy incompatible with glacioeustatic forcing. • Possible low-latitude water storage combined with steric effects. Climate-controlled changes in eustatic sea level (ESL) are linked to transfers of water between ocean and land, thus offering a rare insight into the past hydrological cycle. In this study, we examine the timing and phase of Milankovitch-scale ESL cycles in the peak Cretaceous greenhouse, the early Turonian (∼93–94 million years, Myr, ago). A high-resolution astronomical framework established for the Bohemian Cretaceous Basin (central Europe) suggests a ∼400-kyr pace and a distinct asymmetry of interpreted ESL cycles. The rising limbs of ESL change constitute only 20–30 % of the cycle, and are encased entirely within the falling phase of the 405-kyr eccentricity; the intervening ESL falls (≤6 m in magnitude) are more protracted, starting within 70 kyr prior to the eccentricity minima and culminating ∼60 kyr after the 405-kyr eccentricity maxima. Despite similarities to the sawtooth shape of ∼100-kyr glacioeustatic oscillations of the Late Pleistocene, the time scales and phasing are unparalleled in the Pleistocene icehouse. A similar, 405-kyr pace is found in ice-volume variations of the early Miocene, but the timing of glacioeustatic change relative to eccentricity forcing is incompatible with the phase of greenhouse sea-level oscillations. The phasing points to major differences in the geographic location and insolation sensitivity of the key hydrological reservoirs under icehouse and greenhouse regimes. The inferred structure of greenhouse eustasy points to low- or middle-latitude water storage, likely aquifers, that charge (expand) with rising seasonality variations and discharge (contract) with declining seasonality amplitudes on the 405-kyr scale. The net volume of water transferred on these time scales is within 2.2 × 106 km3, equivalent to ≤10 % of the present-day storage in the uppermost 2 km of continental crust; potential additive interference with steric eustasy, proportionally relevant during greenhouse regimes, could reduce the volumes required for continental storage. [ABSTRACT FROM AUTHOR]

The suggestion by Xu et al. (2023) that aquifer-eustasy is the dominant driver of early Aptian sea-level change is refuted. Misconceptions on the out-of-phase nature of aquifer-eustasy and its plausible magnitudes are corrected. Care is needed when interpreting carbonate platform facies during the time of global anoxic events and more research is required into the interplay between palaeoclimate, sea-level, and facies. • Aquifer-eustasy as the primary driver for early Aptian eustasy is refuted. • Aquifer-eustasy works in phase with glacio- and thermo-eustasy. • Magnitudes of observed sea-level change require appeal to processes additional to aquifer-eustasy. • Interpretation of sea-level change requires care, especially during times of ocean anoxic events. [ABSTRACT FROM AUTHOR]

The analyses of structural, seismostratigraphic patterns and seismic anomalies were conducted using borehole and two-dimensional (2-D) seismic data to reconstruct the geodynamic evolution of offshore eastern Tunisia from the Cretaceous to the Paleogene times. Thirteen third-order sequences (S1 to S13) were identified, and several hiatuses were recognized, which were most likely related to the tectonic event associated with the convergence between Eurasian and African plates. Aptian buildups have also been recognized in the outer platform margin. The growth and distribution of these reefs are controlled by the uplift of fault blocks responsible for the relative sea-level fall which led to sub-aerial exposure and the development of a karstified carbonate platform. The structural features and the major tectonic events as well as the stratigraphic pattern, recognized in offshore eastern Tunisia, are related to the geodynamic evolution of the North African and western Mediterranean basins. The identification of several undrilled reef buildups with significant hydrocarbon potential could replenish the operators' portfolio. • Geodynamic evolution of offshore eastern Tunisia from Cretaceous to Paleogene times • Identification and modeling of geological hiatuses and seismic anomalies • Hydrocarbon potential [ABSTRACT FROM AUTHOR]

Sea-level changes exert an important control on oceanic circulation and climate evolution. Researchers have proposed that sea-level rise favored accumulation of sediments enriched in organic carbon during oceanic anoxic events (OAEs), although high-frequency sea-level changes and their controlling mechanism have remained poorly constrained. Here we present a detailed sedimentological and geochemical study on Aptian (Lower Cretaceous) shallow-water carbonates of the Dariyan Formation exposed in the Zagros fold belt of southern Iran. Microfacies analysis reveals that a regression occurred during carbon isotopic stages C3-C4, followed by a transgression during stages C6-C7. Frequency analysis of carbonate allochems indicates a transition from rudists and other skeletal grains to microbial grains with reduced bioturbation during regression at late C3-C5 stages, whereas the opposite occurred during transgression at stages C6-C7. In the transition interval (C3-C5) nutrients (P, Ba) and redox indicators (Ce anomaly and U concentration) document low nutrient levels and oxygen-rich sea waters, suggesting sea-level changes, rather than by seawater chemistry control. Worldwide correlation of relative sea-level changes across Tethyan, Northern Atlantic, Pacific and Arctic areas is consistent with regression followed by transgression during OAE1a. The regression and transgression occurred at a period of climatic warming and cooling respectively, suggesting that aquifer-eustasy rather than thermo-eustasy or glacio-eustasy may have represented the main cause of eustatic changes. • Carbonate microfacies evaluation for sea-level history. • Sea level did not rise continuously but first fell and then rose during OAE1a. • Eustatic changes mainly driven by aquifer charge and discharge during OAE1a. [ABSTRACT FROM AUTHOR]

Abstract The late Viséan to early Bashkirian shallow-water carbonate Valdediezma Platform in the Picos de Europa Province of the Cantabrian Zone, has been subdivided into eight microbiotic intervals by means of similarity clusters (using the Morisita coefficient). The most complete Viséan-Bashkirian interval is represented in the Valdediezma Valley – Jitu l'Escarandi –road to Tresviso, where only the Steshevian to lower part of the Protvian (middle Serpukhovian) is missing. This interval is better represented in the Pompedrei Bridge to La Hermida composite section, and also in the deeper water section at Vegas de Sotres. These intervals contain a succession from the Mikhailovian (upper Viséan) up to the Krasnopolyanian (lower Bashkirian). The assemblages of the Valdediezma Limestone show, comparatively, low similarity indices with the neighbouring basins in the collisional front in the western extremity of the Palaeotethys during the progression of the Variscan Orogeny. In this mobile belt, two domains are recognized; a western domain composed of outcrops in south-western Spain and in the Moroccan Meseta, and an eastern domain comprising basins located in southern France. Some basins, such as the Betic Cordillera, initially had more influence from the western domain, but later, during the late Serpukhovian, it is considered as being part of the eastern domain. The Valdediezma Platform foraminiferal and algal content is coincident with its location as an isolated platform, surrounded by deep-water seas, and with higher similarities with the eastern domain. Regional tectonic events are recognized from the late Viséan onward, and they are mostly masked by the overprint of latest Pennsylvanian events. Facies changes are commonly observed, particularly at the base of the intervals, suggesting that facies control is the most important factor controlling the assemblages. It is considered that eustatic sea-level changes exerted a certain control on the assemblages. Highlights • Record of late Viséan–early Bashkirian foraminifers, algae and Algospongia • Palaeobiogeographic comparison of the western Palaeotethys • Palaeobiogeographic areas controlled by the progression of the Variscan Orogeny • Combined facies, eustatic and tectonic control on the assemblages [ABSTRACT FROM AUTHOR]

Abstract The lower Cambrian Lalun Formation of the Tabas Block, Central Iran, allows to generate a sequence stratigraphic model which characterises the sedimentary evolution and improves palaeoenvironmental interpretation of sedimentary successions along the northern margin of the Prototethys. This formation provides a key for understanding processes that took place during the late early Cambrian in Iran and is the best representative for the complex mosaic of mixed siliciclastic-carbonate systems which illustrate the development and evolution of fluvial and tide-dominated estuarine systems adjacent to an open coast during this interval in the region. Detailed facies analysis allows to differentiate five vertically-stacked groups of facies associations (fluvial facies associations; estuarine facies association; open coast tidal flat facies association; carbonate ramp facies association; and delta facies association) in the uppermost interval of the Lalun Formation. The conceptual depositional models for the siliciclastic-carbonate successions of the Lalun Formation are summarised in a sequence stratigraphic framework, including three third-order depositional sequences (braided fluvial systems; incised-valley fill; and carbonate ramp and tide-influenced delta systems). The data suggest that the Central Iranian Microcontinent broke up during latest Neoproterozoic–early Cambrian times, resulting in the Proto-/Palaeotethys rifting, with considerable differential subsidence recognizable from the reactivation of faults in the early Cambrian which led to new syn-rift successions. The mosaic pattern of deposition observed among the studied sections suggests a compartmentalization of the depositional setting as a result of the interplay between tectonics, sediment supply, and eustasy. Abrupt lateral changes in facies and thickness within the sequences depositional sequences suggest that deposition was controlled by repeated tectonic downdrop and uplift as a consequence of local syndepositional, extensional fault movements. Tectonic activities in the studied region controlled sedimentation and accommodation as well as the position of depocentres within the basin, and the stratal geometries within the sequences. However, the stratigraphic architectural style of the depositional sequences and the asymmetrical trend of the transgressive and regressive second-order sequences imply that the deposition of the late early Cambrian successions is at least partly a result of eustatic sea level changes and cannot be linked exclusively to differential subsidence due to fault movements. Our study indicates that stratigraphic relationship between carbonate and siliciclastic facies in the depositional sequences was also controlled by subsidence/uplift in the hinterland and the areas of siliciclastic input rather than climatic changes. The late early Cambrian depositional environments evolved from braided rivers and an incised valley system (lowstand) to transgressive incised-valley-fill successions which are capped by transgressive open coast tidal flat and carbonate open marine facies. Depositional history of the formation terminated with a regression that ceased with progradation of tide-influenced delta systems. The stratigraphic evolution described in this study documents an eustatic sea-level fall interposed between the top of the Lalun Formation and the base of transgressive tidal bars of the overlying Fasham Formation reflecting the complex (sub-)globally recognizable regressive–transgressive event at the lower–middle Cambrian boundary interval, which led to the establishment of an extensive middle–late Cambrian carbonate platform in present-day northern and central Iran. Highlights • Stratigraphic analyses of the early Cambrian Lalun Formation has been conducted. • Synthesis of tectonic and eustatic controls on stratigraphic architecture. • The depositional models were proposed based on sequence stratigraphic framework. • Results are useful for correlation to Cambrian strata in other parts of Gondwana. [ABSTRACT FROM AUTHOR]

The Middle Devonian (Givetian) of central Kentucky is represented by a complex and somewhat enigmatic succession of sandy dolomitic limestones and chert-rich wackestones, silty dolostones, and thin dark shales belonging to the Boyle Formation and Portwood Member of the New Albany Formation. The lower contact of the Boyle Formation is a distinct, regionally angular unconformity on rocks of Late Ordovician to mid-Silurian age. New exposures of Middle Devonian strata in the vicinity of Irvine, Estill County, Kentucky, reveal a series of distinctive depositional sequences, each with a sharply erosive base, overlain by phosphatic grains, fish teeth, and bone-rich quartz sandstone. The lower sequences, forming the Kiddville Member, are siliciclastic-rich, Zoophycos-bioturbated, silty, dolomitic carbonates that contain typical Hamilton brachiopod associations. The Kiddville is missing in some successions apparently owing to erosional overstep by upper Boyle units (Beechwood Member). The upper Boyle, Beechwood Member, is massive and cherty carbonate, which is highly variable in thickness, owing to major erosional truncation/karstification that locally removes the Boyle completely. Conodont studies indicate that much of the upper Boyle is of Po. ansatus Zone and thus middle Givetian in age. It is probably equivalent to the Moscow Formation of New York State. The overlying Portwood Member of the New Albany Shale belongs to the later Po. ansatus and “Oz.” semialternans zones and consists of dark-brownish-grey shales and muddy dolosiltites. In many localities to the west, the basal unit is a lenticular dolomitic breccia, the Duffin Bed, which may represent a lowstand karst breccia that mantles the irregular upper contact of the Boyle Formation at a regional unconformity. A lower dark shale contains rare small brachiopods Emmanuella and Leiorhynchus, suggestive of the lower Tully fauna of the Appalachian Basin; locally, this shale appears to fill paleokarst in the Boyle carbonates. It is overlain by a dolosiltite that has a highly distinctive “megaburrow” trace fossil assemblage on the base and yields rare Tullypothyridina and the conodonts Po. ansatus and “Po.” alveoliposticus, diagnostic of the Lower Tully Limestone in the Appalachian Basin. It is overlain by dark grey to black, typically deformed (seismites) calcareous mudstone of the middle Portwood Member. An upper pale grey, lenticular massive dolomitic bed rests sharply on the middle Portwood in channel-like scours with relief of about 0.5 m and a width of up to tens of meters. This bed yields poorly preserved corals, atrypid brachiopods (Spinatrypa sp.), and phacopid trilobites as is typical of the Upper Tully member. Overlying thinner bedded rhythmically bedded calcareous mudstones and dark shales of the uppermost Portwood yield conodonts of the “Oz.” semialternans Zone; this lithology resembles the Fillmore Glen interval of the Upper Tully Limestone. The sharply overlying black shale of the Trousdale Member yields hermanni Zone elements, indicating correlation with the basal upper Givetian lower Geneseo black shales of the Appalachian Basin. The highly variable thicknesses, complex internal discordances, and abundant seismites of the Portwood and Boyle Formations suggest a dynamic interval with regional far-field tectonics associated with the onset of the third tectophase of the Acadian Orogeny. Despite these tectonic effects, the presence of a consistent internal sequence stratigraphy that correlates with that of the Appalachian Basin and elsewhere reflects strong eustatic effects. [ABSTRACT FROM AUTHOR]

The views of the Jurassic eustatic fluctuations differ significantly: specialists either suggest multiple rises and falls ("Haq's view") or question the idea of global falls ("Hallam's view"). For instance, it is unclear whether there was a stage-long eustatic lowstand in the Aalenian. The presence of the noted alternatives is a serious problem complicating interpretation of events in the geological history. This paper summarizes the evidence of the Aalenian long-term shoreline shifts obtained in different regions of the world since 2000, i.e., after the noted views appeared. This evidence deals with the stratigraphical architecture of regions (interpreted in the present article), the established shoreline shifts (transgressions and regressions), and the knowledge of the regional tectonic activity. The compiled information characterizes "stable" regions located in the different parts of the world (Europe, Asia, Africa, North America, South America, and Australia). It is established that there were no regressions in some of these regions in the Aalenian, whereas regressions in the other regions can be explained by the influence of the tectonic activity. There was no coherence of the basin-scale eustatically-driven regressions (in contrast, the long-term Bajocian eustatic rise is proven by a coherence of regional transgressions). This finding contradicts the idea of the stage-long eustatic lowstand in the Aalenian and, thus, favours the "Hallam's view". This interpretation is in agreement with the present knowledge of the Earth's palaeoclimate and the past plate tectonics. This study demonstrates efficacy of interregional correlation of sea-level changes for resolution of the problem of the alternative views of the Jurassic eustasy. [ABSTRACT FROM AUTHOR]

The Miocene Hanjiang Formation of the Pearl River Mouth Basin (PRMB) forms one of the most productive hydrocarbon reservoirs in China. Sparse biostratigraphic age control and limited dating hinder a thorough understanding of sea-level change and its sedimentary expression through this formation. To establish the relationship between third-order sea-level changes, their expression in the lithological record and astronomical forcing, a sequence stratigraphic and cyclostratigraphic analysis has been conducted through the Hanjiang Formation in the LF14 borehole. One second-order sequence and six third-order sequences are recognized based on gamma ray (GR) data, vertical lithofacies changes and sedimentary stacking patterns. Time series analysis of the GR data and subsequent interpretation allows recognition of approximately eighteen 405 kyr long eccentricity cycles. Based on this cyclostratigraphy, we constructed a ∼7.22-Myr floating astronomical time scale (ATS) for the Hanjiang Formation. We anchored this timescale to globally significant biostratigraphic events preserved in the basin to build an absolute ATS spanning 17.423 ± 0.4 to 10.221 ± 0.4 Ma. A prominent ∼1.2-Myr periodicity is identified in the amplitude modulation (AM) envelope curves of ∼41-kyr obliquity cycles preserved in the record. This ∼1.2-Myr periodicity shows good agreement with our sequence stratigraphic analysis and global eustatic curves. Our results suggest that ∼1.2-Myr obliquity AM was the main driver of third-order sea-level change and sequence development in the PRMB. Combined application of cyclostratigraphic and sequence stratigraphic analysis (utilizing INPEFA and wavelet transform methods) are demonstrated to be useful for understanding the drivers and subdivisions of third-order sequence evolution on a regional scale. • Astronomical calibration of the middle Miocene succession in the Pearl River Mouth Basin. • Long-period ∼1.2-Myr cycles control on third-order sequences and sea-level change. • Third-order sequences subdivision by an integrated INPEFA–wavelet transform–cyclostratigraphic method. [ABSTRACT FROM AUTHOR]

A range of plumbing systems has been identified in deep-water Nigeria by interpreting multi-scale seismic data sets (reprocessed 3D exploration seismic reflection data and 2D very high-resolution near-bottom seismic reflection data) as well as sedimentological and geochemical data obtained from a long sediment core recovered by the seafloor drill rig MARUM-MeBo70. The plumbing systems are characterized by diverse fault networks and lie above tectonic features including thrust/fold structures and strike-slip faults linked to gravity-driven deformation caused by underlying over-pressured shales. The plumbing systems are associated with fluid seeping structures at the seafloor such as pockmarks, mud volcanoes and seafloor zonations colonized by living benthic macrofauna typical of active fluid flow. The comparison of seismic stratigraphic sequences with climate and environmental proxies determined for sediments including lithology, element ratios such as Ca/Fe and Zr/Rb, sedimentation rates, and planktonic foraminifera δ18O records shows a control of short-term (0.1–0.4 Myr) and long-term (around 1 Myr) sedimentary cycles. During short-term fluctuations, the recurrence of fluid seeping structures is controlled by the lithology (coarse-grained versus fine-grained sediments) linked to glacial-interglacial fluctuations and a monsoon regime. Conditions favorable for fluid flow are related to the deposition of coarse-grained layers, glacial periods, sea-level lowstands, and low sedimentation rates. We hypothesize that cyclic gravity-driven sediment deformations controlled by glacial-interglacial and long-term variations in accommodation and sedimentation, have led to the cyclic evolution of the plumbing systems and associated seeping structures since the Plio-Pleistocene. • Diverse faults networks are associated with varied fluid flow structures. • The recurrence of fluid flow structures is coeval to glacial periods. • Gravity-driven deformations possibly control fluid flow during the Pleistocene. [ABSTRACT FROM AUTHOR]

Abstract: Tracing sedimentation through time on existing and vanished seafloor is imperative for constraining long‐term eustasy and for calculating volumes of subducted deep‐sea sediments that contribute to global geochemical cycles. We present regression algorithms that incorporate the age of the ocean crust and the mean distance to the nearest passive margin to predict sediment thicknesses and long‐term decompacted sedimentation rates since 200 Ma. The mean sediment thickness decreases from ∼220 m at 200 Ma to a minimum of ∼140 m at 130 Ma, reflecting the replacement of old Panthalassic ocean floor with young sediment‐poor mid‐ocean ridges, followed by an increase to ∼365 m at present‐day. This increase reflects the accumulation of sediments on ageing abyssal plains proximal to passive margins, coupled with a decrease in the mean distance of any parcel of ocean crust to the nearest passive margin by over 700 km, and a doubling of the total passive margin length at present‐day. Mean long‐term sedimentation rates increase from ∼0.5 cm/ky at 160 Ma to over 0.8 cm/ky today, caused by enhanced terrigenous sediment influx along lengthened passive margins, superimposed by the onset of ocean‐wide carbonate sedimentation. Our predictive algorithms, coupled to a plate tectonic model, provide a framework for constraining the seafloor sediment‐driven eustatic sea‐level component, which has grown from ∼80 to 210 m since 120 Ma. This implies a long‐term sea‐level rise component of 130 m, partly counteracting the contemporaneous increase in ocean basin depth due to progressive crustal ageing. [ABSTRACT FROM AUTHOR]

We present new biostratigraphic analyses of approximately 200 outcrop samples and review biostratigraphic data from 136 public domain exploration wells across western New Guinea. Biostratigraphic ages and palaeodepositional environments were interpreted from occurrences of planktonic and larger benthic foraminifera, together with other fossils and environmental indicators where possible. These data were compared with existing geological maps and exploration well data to reconstruct the palaeogeography of western New Guinea from the Carboniferous to present day. In addition, we used the known bathyal preferences of fossils to generate a regional sea-level curve and compared this with global records of sea-level change over the same period. Our analyses of the biostratigraphic data identified two major transgressive-regressive cycles in regional relative sea-level, with the highest sea levels recorded during the Late Cretaceous and Late Miocene and terrestrial deposition prevalent across much of western New Guinea during the Late Paleozoic and Early Mesozoic. An increase in the abundance of carinate planktonic foraminifera indicates a subsequent phase of relative sea-level rise during a regional transgressive event between the Late Jurassic and Late Cretaceous. However, sea-levels dropped once more during a regressive event between the Late Cretaceous and the Paleogene. This resulted in widespread shallow water carbonate platform development in the Middle to Late Eocene. A minor transgressive event occurred during the Oligocene, but this ceased in the Early Miocene, likely due to the collision of the Australian continent with intra-Pacific island arcs. This Miocene collision event resulted in widespread uplift that is marked by a regional unconformity. Carbonate deposition continued in platforms that developed in shallow marine settings until these were drowned during another transgressive event in the Middle Miocene. This transgression reached its peak in the Late Miocene and was followed by a further regression culminating in the present day topographic expression of western New Guinea. [ABSTRACT FROM AUTHOR]

Several mass extinctions are known from the history of life, but knowledge about “minor” biotic crises remains incomplete. The Ladinian is the second stage of the Middle Triassic epoch. Available reconstructions of the diversity dynamics of fossil organisms across the entire Triassic allow the proposed Ladinian biotic crisis to be investigated. Total biodiversity curves (both the conventional curve and that based on sampling standardization) fail to identify the crisis, but this may be explained by low resolution data or “noise”. In fact, the global generic diversity of ammonoids, brachiopods, and tetrapods declined significantly (by 1.1–2.5 times) during the Ladinian, as did the species diversity of conodonts. Bivalves radiated, but their origination rate also decreased during the Ladinian. Land plants were apparently unaffected. Based on the representative regional record for the Northwestern Caucasus, the number of macroinvertebrate genera dropped by ~ 7.5 times, and brachiopods almost totally disappeared; foraminifers were also affected significantly. Thus, the proposed biotic crisis appears to have been selective. It appears the Ladinian biotic crisis was a relatively long-term event, and its magnitude is comparable to that of other “minor” mass extinctions, e.g., those of the Silurian, Early Jurassic, or end-Cenomanian. There are several possible explanations for what caused the Ladinian biotic crisis. It is possible that global climate cooling was responsible, although it is unclear why the palaeobiogeographical differentiation was not favourable for a biotic radiation. A eustatic explanation for the drop in diversity is unlikely. Instead, the crisis was mostly likely caused by unstable recovery of the Earth's biota after the end-Permian catastrophe. [ABSTRACT FROM AUTHOR]

This study surveyed the mitochondrial haplotype diversity of nine freshwater fish species and two estuarine-marine species from the coastal basins and drainages of the highland plateaus of Paraná, Brazil. Portions of the cytochrome b gene or the control region were sequenced. The demographic history of each species was inferred using the Bayesian skyline method, mismatch distribution analysis and statistical neutrality tests. Demographic reconstruction analyses revealed a single pattern of variation in the effective population size ( Ne) among species. No dramatic changes in Ne were detected in upland species. By contrast, evidence of population expansion over the past 200 000 years was detected in all coastal plain and estuarine species. These findings correspond to periods of low sea-level (regressions) followed by a rapid increase in the sea-level by >100 m. The resulting reconnections and subsequent fragmentation and isolation between the estuarine and freshwater bodies were putatively relevant to the historical demography of the fish species in these areas. [ABSTRACT FROM AUTHOR]

Paleoclimatic indicators suggest that the mid-Cretaceous was one of the warmest intervals of the Phanerozoic. The period of the mid-Cretaceous “super-greenhouse” also experienced an equator-to-pole temperature gradient much lower than that of the present day, implying greater meridional heat transport by the atmosphere and/or oceans. However, reconstructions of Cretaceous atmospheric circulation have been hindered by a lack of relevant datasets based on reliable proxies or direct geological evidence. Aeolian deposits provide direct information about paleoclimate, as well as the direction and intensity of paleo-wind in the interiors of continents. Using petrologic and sedimentologic observations, this study reassesses the terrestrial deposits of the mid-Cretaceous Mangang Formation in the Simao Basin of southwestern China. Originally considered to be aqueous deposits, we reinterpret these strata as representing aeolian transport in a desert environment. We suggest that the development of aeolian deposits in the Mangang Formation (and coeval strata in adjacent basins) was a local response to the prevailing desert climate in the mid- to low-latitudes of the Northern Hemisphere during the mid-Cretaceous, which were dominated by subtropical high-pressure systems on a planetary scale. In addition, with the closure of the Mesotethys Ocean, the intermontane basins of the South China, Simao, and Indochina blocks became more isolated from atmospheric circulation. Bidirectional subduction of the Bangong-Nujiang oceanic crust and the Izanagi Plate beneath East Asia led to the development of Andean-type margins, which created a rain-shadow effect in continental East Asia. These factors caused the development of a tropical desert climate, characterized by aeolian dunes and evaporite deposition. We speculate that the severe depletion of groundwater reservoirs via the desertification of East Asia may represent a previously unrecognized trigger for short-term sea-level changes during the ice-free Cretaceous greenhouse interval. [ABSTRACT FROM AUTHOR]

The Yangtze Sea of the South China Craton experienced strong environmental perturbations during the first ~ 5-6 Myr of the Silurian. The Lower Silurian Lungmachi Formation in the Jiaoye-1 drillcore (Chongqing, China) records three sea-level cycles (stratigraphic sequences) characterized by rapid deepening at the base of each cycle followed by slow shallowing. Each deepening event was associated with shifts toward higher marine productivity, more intensely reducing bottomwater conditions, reduced watermass restriction, lower detrital input, and enhanced siliciclastic weathering intensity. We infer control by glacio-eustasy, in which deglacial sea-level rises and concurrent climatic warming triggered the observed environmental changes. Shallowing was associated with renewed glaciation and characterized by the opposite set of conditions. The results of this study thus provide evidence in support of continued continental glaciation during the Early Silurian, i.e., following the termination of the major end-Ordovician Hirnantian glaciation. The study core also exhibits a long-term shallowing trend through the entire Lower Silurian, the origin of which may have been tectono-epeirogenic uplift of the South China Craton during the Kwangsian Orogeny. [ABSTRACT FROM AUTHOR]

Coastal deserts are geologically dynamic areas of the Earth, affected by historical changes in sea levels and in some cases also by fault-line tectonic activity. An example of such a dynamic area is the Chilean coastal desert of the Antofagasta and Atacama regions, which harbours many endemic species, such as the bothriurid scorpion species Brachistosternus paposo and Brachistosternus roigalsinai. In this work, we carry out phylogeographic and population genetic analyses on these scorpions, using two mitochondrial (COI and cyt b) and two nuclear (Actin 5C and wingless) markers to identify species and population structuring, and link these findings to the geological history of the area. The geographical feature separating the two species is identified as the Huasco River, and distinguishing morphological features for these scorpions are presented. Population genetic and phylogeographic outcomes reflect an unstable history across this region for B. paposo and B. roigalsinai, related to sea-level changes affecting coastal habitats, including nearby islands. [ABSTRACT FROM AUTHOR]

This paper reviews global records of anoxic events of the Middle Devonian – earliest Mississippian, as well as the possible triggers and controls of these events. These "anoxic events" are complex multistage paleoenvironmental disturbances manifested in multiple proxies, which we showcase with the Horn River Group (HRG) – a succession of basinal organic-rich shales and cherts deposited during the latest Eifelian – earliest Late Frasnian (∼386–373 My ago) on the western continental margin of Laurentia near the paleo-equator. Four major events imprinted in the HRG are the Kačák, Frasnes, basal punctata, and late punctata events, but positive δ13C excursions (measured on organic matter) are more numerous and can potentially be matched to other global events. The Kačák event in the base of the HRG manifests as a regional switch from carbonate-platform to anoxic sedimentation. Three major events of the latest Givetian – Middle Frasnian display repeating sequences characterized by: (1) an early shift to heavier δ13C values coupled with siliciclastic enrichment and mercury enrichment spikes of up to 0.48 ppm; (2) late-stage δ13C reversal to background values coincident with the onset of severe anoxia (buildup of authigenic U, Mo, V) and attenuation of siliciclastic supply. Devonian anoxic sediments, including HRG, display widespread presence of chlorobi biomarkers, which indicates episodes of photic-zone euxinia in the water column. Most of these sediments were deposited under open ocean conditions, precluding a Black Sea water-column stratification scenario. These observations indicate Devonian anoxic events are similar to classical Mesozoic oceanic anoxic events (OAEs), consistently with growing evidence for a volcanic trigger for these events (e.g. spikes in Hg and negative 187Os/188Os anomalies). Oxygen minimum zones in a greenhouse ocean, such as the one recorded in basinal HRG, were prone to expansion under volcanic CO 2 reinforcement. This volcanic press-pulse also intensified the hydrological cycle, which resulted in a boost of weathering and eutrophication of shelfal seas. These factors, amplified by deoxygenation and acidification of the habitable upper ocean, drove extinctions of various magnitude. As a proxy for the input of land-plant detritus, the oxygen index from pyrolysis data shows zero response to anoxic events in the HRG, which aligns with broader evidence that counters expanding vascular vegetation to be the driver of the marine biotic crises. Finally, our review highlights how controversial the evidence of high-frequency (3rd to 5th orders) sea-level fluctuations is in the Devonian. In particular, none of the geochemical proxies usually employed to interpret sea-level changes translates unequivocally into transgressions and regressions in the greenhouse world. This sea-level puzzle clearly calls for new scrutiny and justifies scepticism in the validity of the classical "eustatic sea-level curve of the Devonian", as well as estimates of eustatic amplitudes in excess of ∼25 m for 3rd and 4th order cycles. [ABSTRACT FROM AUTHOR]

• Thermal maturity varies from low to early oil window between 4.45 and 31.50 Ma. • Bulk geochemistry indicates low organic matter content in the samples. • The low hydrogen indices indicate mainly Type III and Type IV kerogen. • Tectonic activity influenced organic matter accumulation in the Canterbury Basin. • Sedimentary deposition was influenced by global sea-level variations. The various influences of global sea level (eustasy) and local tectonic changes on sedimentation processes in continental margin deposits are important topics in sedimentary research. International Ocean Discovery Program Expedition 317 to the Canterbury Basin, on the eastern margin of the South Island of New Zealand, provided an opportunity to study sediment geochemistry in contrasting depositional settings, from mid-shelf to upper continental slope sedimentary rocks from the Eocene to the Holocene. This paper provides the first examination of the organic geochemical record from Pliocene, Miocene, and Oligocene sediment samples recovered during the expedition from the U1351, U1352, and U1353 sites, using bulk geochemistry and hydrocarbon distributions, including biomarkers. The main aim of this research was to correlate changes in organic accumulation with local tectonic activity and global climate changes that occurred in the Miocene. There is good preservation of C 11 to C 35 n -alkanes, with varying predominance of odd-over-even chain length n -alkanes, and much variation in the terrigenous/aquatic ratio over the cores. Based on biomarker and Rock Eval parameters, thermal maturity varies from low in the Pliocene, to early oil window in the deeper Miocene and Oligocene sedimentary rocks. The pristane/phytane ratios for the three cores indicate anoxic to oxic depositional environments. Marine organic matter input is indicated by the high C 30 sterane index, whilst high relative amounts of oleanane, C 24 tetracyclic terpane, and C 29 steranes indicates major terrigenous organic matter input. Local tectonic activity is suggested to have had a significant influence on the accumulation of the organic matter in the Canterbury Basin. The influence of eustasy and global sea temperature variations are suggested for the periods < 14 Ma, 12–7 Ma, and ∼ 6 Ma. An increase in terrigenous organic matter input during the late Miocene correlates with the uplift of the Southern Alps and an increase in the continental slope angle for the South Island of New Zealand. [ABSTRACT FROM AUTHOR]