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Objective The disputes among humans, water and land have seriously restricted the sustainable development of the Dongting Lake region (TDLR). Methods To address this issue, it is crucial to understand the evolution of the hydrological environment in the TDLR, enabling solutions to the competition for space between human activities and water. By determining the evolution of the human-water relationship in the TDLR over the past 500 years, the influences of natural and human factors on the evolution of the hydrological environment are studied. Results Considering the characteristics of tectonic subsidence and sediment inflow in the TDLR, an evolutionary model of the hydrological environment induced by human activities and the geological environment was obtained, and not only the changing trends in the storage and drainage of water and sediment in the TDLR and Yangtze River but also the possibility of future evolution of the TDLR were clarified. Conclusion The key finding are as follows: (1) The continuous land reclamation has encroached on floodwater retention areas, significantly reducing Dongting Lake's flood storage capacity. (2) The construction of the Jingjiang Dyke has raised flood levels in the Jingjiang River and exerted a backwater effect on Dongting Lake, exacerbating flood disasters during the high-water period. (3) The straightening of the Jingjiang River has led to sediment deposition from Chenglingji to Wuhan, and the decline of the three distributaries of the Jingjiang River, causing shrinkage at the lake's inlets and blockage at its outlets. (4) Since the operation of the Three Gorges Reservoir, the sediment accumulation of the inflow water from Dongting Lake decreased significantly, and that of the Jingjiang reach below Chenglingji increased significantly. Under the influence of human activities, the flood storage capacity of Dongting Lake has decreased annually; therefore, the water inflow during flood periods is difficult to discharge, and dry water replenishment has gradually decreased; therefore, the dry period in the TDLR has lengthened, and water has difficulty flowing. As a result, both flood and drought disasters have intensified. (5) The Jianghan-Dongting Lake Plain is still undergoing rapid structural subsidence, but the rate of sedimentation exceeds the amount of tectonic settlement; hence, Dongting Lake is at risk of morphing into marshes and land.

This paper is a continuation of the previous one (Widera, 2024. Acta Geologica Polonica, 74 (1), e2). A new, alternative interpretation of the tectonic development of two lignite-rich deposits in the Lubstów and Kleszczów grabens in central Poland is presented. The maximum thickness of lignite mined from both deposits is >86 and >250 m, respectively. These grabens were selected for detailed tectonic analysis because syn-depositional or post-depositional tectonic uplift is undeniably evident. The current study focuses on the distinction between tectonic subsidence/uplift and autocompactional subsidence, and on the timing of their occurrence. Such a research approach allows for the presentation of new conceptual models of Cenozoic tectonic evolution during the formation of the third, very thick, Ścinawa lignite seam (ŚLS-3) and the second Lusatian lignite seam (LLS-2). As a result, it is shown here that the magnitude of both the downward and upward tectonic movements are significantly smaller than previously thought. This new interpretation is also confirmed by the low rank of lignite coalification and the net calorific value of the ŚLS-3 and LLS-2. [ABSTRACT FROM AUTHOR]

Understanding the Cenozoic tectonic evolution of grabens rich in lignite is important in the context of the accumulation of *40-650 m of peat, as well as the exploitation of later formed lignite seams with a thickness of *20-250 m. Six such areas were selected for a detailed palaeotectonic analysis: the Gostyń, Szamotuły, Legnica, Zittau, Lubstów, and Kleszczów grabens. During the analysis, borehole data were used, taking into account the compaction of peat at the transition to lignite, in order to reconstruct the magnitude of the total subsidence. This made it possible to distinguish between regional (covering areas also outside the grabens) and local (occurring only in the grabens) tectonic movements, and among the latter, tectonic and compactional subsidence. The hypothetical palaeosurface of the mires was reconstructed based on the lignite decompaction. As a result, it was possible to determine whether the examined peat/lignite seams underwent post-depositional uplift and/or subsidence. Between one (Gostyń Graben) and four (Zittau Basin and Kleszczów Graben) stages of tectonic subsidence were distinguished in the studied lignite-bearing areas. In the case of the Zittau Basin, as well as the Lubstów and Kleszczów grabens, post-depositional stages of tectonic uplift were also indicated. Like the boundaries of lithostratigraphic units, the successive stages of the Cenozoic tectonic development of the examined grabens are diachronic. [ABSTRACT FROM AUTHOR]

The Upper Assam Basin is an intermontane foreland basin surrounded by gigantic mountain belts in NE India. The structural geometry of the basin is controlled by the tectonic interactions of the Himalayan orogenic belt in the north, Mishmi thrusts in the east, and the Assam-Arakan fold-and-thrust belts in the south. The basin has received significant attention not only because of its complex geological set-up but also due to its petroliferous nature for hosting significant hydrocarbon resources. The present study attempts to explore the tectonic subsidence history of the Cenozoic succession using subsurface stratigraphic details of ten (10) boreholes drilled within the upper shelf of the basin. Subsidence analysis is carried out using the backstripping technique. It is observed that the tectonic subsidence in the basin developed through four different stages. During the Paleocene-Eocene epoch, the basin witnessed slow subsidence. It increased gradually through Oligocene and attained rapid speed in the Miocene. Further, during the deposition of post-Miocene sediments (Plio-Pleistocene epoch), the tectonic subsidence in the basin remained accelerated. Subsidence curves obtained from the studied borehole depict a convex-upward profile, indicating that the basin attained a foreland configuration over time and is presently a SE dipping shelf bounded by opposite verging fold-and-thrust belts. Overall, the basin experienced tectonic subsidence of ∼2 km throughout its lifespan with an average subsidence rate of ∼30 m/Ma. This case study prominently elucidates the tectonic history of the basin, which underwent during the Cenozoic time. Our findings stress the importance of subsidence analysis through the backstripping technique as a potential approach for untangling the geohistory of sedimentary basins worldwide.

How seafloor spreading in marginal basins controls subsidence patterns in continental margins under rift propagation settings remains poorly understood. Herein, based on detailed geological interpretation and backstripping of 37 high‐resolution multichannel seismic reflection sections, we calculate the Cenozoic tectonic subsidence across the Dangerous Grounds (DG), South China Sea, in order to study interactions between seafloor spreading and the propagation of rift basins. Our results show that rapid subsidence occurred in the eastern Dangerous Grounds (EDG) from the Palaeocene to early Oligocene, then migrated westwards to the middle Dangerous Grounds (MDG) during the early Oligocene to early Miocene, and finally reached the western Dangerous Grounds (WDG) during the early to middle Miocene. We interpret this western migration of intensive subsidence as the response of the inherited pre‐Cenozoic heterogeneous lithospheric structure of South China. Thermal re‐equilibration of the lithosphere then dominated the rapid post‐spreading subsidence throughout the whole DG from the middle Miocene. An anomalous subsidence deficit occurred in the EDG during the early Oligocene to early Miocene, and in the MDG during the early to middle Miocene; this phenomenon might be related to small‐scale mantle convection associated with the propagation of seafloor spreading from east to southwest. [ABSTRACT FROM AUTHOR]

Miocene carbonate successions found on many isolated oceanic islands throughout south‐east Asia commonly include unconformity capped 'island dolostones' units. On Shidao, located in the Xisha Islands in the South China Sea, well XK‐1 (1268.2 m deep) penetrated a thick succession of carbonates before being terminated in the Jurassic metamorphic basement. The lower part of the succession is composed of the Sanya Formation (Early Miocene) and the overlying Meishan Formation (Middle Miocene), ca 700 m thick, that are formed of limestones and dolostones. An unconformity divides the Sanya Formation into a Lower Member formed largely of limestones, and an Upper Member formed of dolostones (DI‐8). DI‐8 is separated by a major unconformity into lower (DI‐8L) and upper (DI‐8U) units, that both include numerous subaerial unconformities. The overlying Meishan Formation is a limestone succession that includes three unconformity‐capped dolostones intervals (DI‐5, DI‐6 and DI‐7). Strata below the numerous exposure surfaces throughout the Sanya and Meishan formations are highlighted by Fe‐staining, biomoulds, cavities, caves and solution breccia development. The weakly fabric‐retentive dolostones in DI‐5 to DI‐8 are formed of dolomite crystals that have a dirty core encased by a clear rim, with δ18O values of +0.3 to +4.7‰ (average +2.0‰, n = 50), δ13C values of +2.2 to +3.2‰ (average +2.5‰, n = 50), Fe concentrations of 44 to 442 ppm (average 149 ppm, n = 50), Mn concentrations of 5 to 197 ppm (average 27 ppm, n = 50), Sr concentrations of 169 to 257 ppm (average 218 ppm, n = 50) and 87Sr/86Sr values of 0.70847 to 0.70900 (average 0.70879, n = 32). In all cases, dolomitization post‐dated the subaerial exposure. The 87Sr/86Sr values suggest that the dolostones in DI‐8L formed during the late Early Miocene, whereas the dolostones in DI‐8U, DI‐7, DI‐6 and DI‐5 probably formed simultaneously during the Late Miocene even though these units are stratigraphically hundreds of metres apart and were located well below sea‐level. Dolomitization was preferentially focused in those strata with high porosities and permeabilities that allowed easy circulation of the seawater through the rock. This model suggests that dolomitization was not restricted to strata that were at or close to sea‐level. Although dolomitization may have been related to the new oceanographic circulation regime established during that time, the exact properties of the seawater that promoted dolomitization are open to debate. This model of dolomitization may be applicable to many of the 'island dolostones' that are found in the oceans throughout the world. [ABSTRACT FROM AUTHOR]

The Red Sea basin is considered one of the world-class examples of continental rifting, breakup and seafloor spreading. This study focuses on the structural framework of the northwestern part of the Egyptian Red Sea margin and the identification of the different rift domains using surface and subsurface data. Subsurface mapping using 2D seismic and borehole data indicates that the northern part of this area represents the continuation of the structural style of the southern Gulf of Suez rift as the mapped structures are mainly down to the northeast main faults with southwest dipping strata. In addition, two negative flower structures have been observed and represent the southern continuation of the Gulf of Aqaba -Dead Sea left-lateral transform fault system. The NE dip of the main rift-parallel faults that characterizes most of the study area flips in the southern part of the area (south of the Duwi accommodation zone) where the fault blocks dip northeastward and the main faults dip SW. Based on the integration of the structural style, continental crust stretching factor (β) and the crustal thickness, the northwestern margin of the Red Sea can be divided into proximal domain, necking domain and potential hyper-extended domain that seems to extend southeast of the area of study and may represent the future locus for oceanic crust development in the northern Red Sea. Each domain is characterized by a distinct structural style and subsidence profiles, and variable preservation and distribution of the pre-rift and syn-rift stratigraphic units. [ABSTRACT FROM AUTHOR]

Abstract—The GALO basin modeling system is used to numerically reconstruct the thermal regime of the lithosphere of the West Siberian basin in the Koltogor-Urengoi graben in the vicinity of the Tyumen SG-6 superdeep well. The reconstruction explains the features in the formation of the thermal regime of the basin, which were not considered in the previous reconstructions of the region. These features include anomalously high growth of organic matter maturity in the Jurassic and Triassic rocks, high temperature gradients observed in the upper basement and in the Triassic–Permian sedimentary complex, the anomalously low temperatures of rocks in the upper layers of the modern sedimentary section of the basin. The time variations in the tectonic subsidence of the basin are analyzed to estimate the intensity and duration of the events of thermal activation and stretching of the lithosphere of the basin. The thermal influence of the sill that intruded into the upper horizons of the basement in the Lower Jurassic explained the high degree of maturation of the organics in the Lower Triassic rocks. Taking into account sharp climate fluctuations in the Pliocene–Quaternary together with hydrothermal activity in the bottom part of the sedimentary cover in the Upper Pliocene–Lower Pleistocene, we obtained the deep profiles of temperatures and vitrinite reflectance, which are consistent with the measured values. [ABSTRACT FROM AUTHOR]

[Display omitted] • A decaying syn -rift subsidence is observed in the Baiyun Rift in the Eocene. • The average subsidence rate is higher in the western than that in the eastern Baiyun Rift during the Late Eocene. • An accelerated post-rift subsidence occurred in eastern Baiyun Rift during the middle Miocene. • This syn- and post-rift subsidence pattern could be induced by the detachment faulting. How detachment fault controls the basin subsidence at hyper-extended passive margin remains mysterious. Based on a detailed geological interpretation and backstripping on 29 high-resolution multi-channel seismic profiles, we calculate the basin-scale tectonic subsidence across the Baiyun Rift to study the relationship between tectonic subsidence and detachment faulting. Our results confirm that detachment faulting is the primary factor controlling the syn -rift subsidence. A decaying subsidence rate, or deficit subsidence is observed in the eastern Baiyun Rift from the early to late Eocene, which is in marked contrast to the intensive brittle stretching. We attribute this to the doming of the detachment fault footwall involving the syn -rift magmatism during its hyper-extension process. While in the western Baiyun Rift the average subsidence rate is over 45 m Myr−1 higher than that in the eastern as the response of flexural loading in the late Eocene. During the post-rift stage, the subsidence rate shows a similar oceanward increasing trend, and an anomalous rapid subsidence event during the middle Miocene in the eastern Baiyun Rift, which can be ascribed to the magma-assisted weakened rheological condition of the lithosphere deriving from the syn -rift detachment faulting. We propose that this relationship between subsidence pattern and detachment faulting has global applicability for other hyper-extended rift systems developing detachments and magmatic-related dome structures. [ABSTRACT FROM AUTHOR]

The evolution and mechanisms of tectonic subsidence in the Xisha area are poorly investigated, especially the spatiotemporal distribution features and reasons for the variations in tectonic subsidence. In this study, multi-channel seismic data and stratigraphic and lithologic features of wells are used to examine tectonic subsidence in the Xisha area from the Paleogene to Quaternary. The largest tectonic subsidence in the Xisha area is located in the Changchang Depression, with a maximum subsidence of 5.4 km, while the smallest tectonic subsidence is located on the Guangle Uplift and Xisha Uplift, which are close to 1.0 km and 1.5 km, respectively. Two rapid tectonic subsidence phases were mainly in the Oligocene, and from Middle to Late Miocene, with maximum subsidence rates of 0.45 m/ky and 0.32 m/ky, respectively. Five phases for the tectonic subsidence are proposed since the Paleogene based on our data. (1) The slow subsidence phase during the Eocene (53.5–32 Ma) was due to the transchronicity of the basement in the pro-rifted stage. (2) The rapid subsidence phase was common in the south and north margins of Qiongdongnan Basin, because of the faults triggered by the inherited stretched and thinned of crust in the Oligocene from 32 to 23.3 Ma. (3) The interim phase followed the rapid subsidence phase was in the Early Miocene (23.3–15.5 Ma) and marked the end of the rifted stage. (4) The accelerated rise phase started from the Middle Miocene (15.5 Ma) to the Late Miocene (5.5 Ma), and the reversal of the Red River Fault Zone may be tied to the acceleration of the tectonic subsidence. (5) The transitional phase started in the Pliocene (5.5 Ma) and lasts to the present. As the Red River Fault Zone changed from sinistral to dextral movement, the stress field of the study area has changed. Our results are helpful to better understand the spatiotemporal coupling relationship between tectonic subsidence and regional geological evolution in the Xisha area, South China Sea. [ABSTRACT FROM AUTHOR]

The generally accepted foreland interpretation of the Nanpanjiang basin has been regarded as providing support for the hypothesized Indosinian collision between the South China and Indochina blocks, and it has led to the long‐standing view that crustal shortening dominated the Triassic intracontinental development of South China. Here, we examine the stratigraphic architecture, magmatism and gross structural features of the Nanpanjiang basin. Outcrop studies indicate that a north‐stepping axial turbidite system was confined by intrabasinal faults, the active development of which is indicated by mass‐transport complexes. Field mapping combined with U–Pb dating of baddeleyite and zircon reveals that magmatism in the southern part of the basin coincides with a distinct episode of bimodal volcanism from ca. 244 to 242 Ma, and is unrelated to the middle Permian Emeishan plume. Differences in tectonic subsidence between hanging‐wall and footwall blocks, as that has been quantified by the backstripping of composite sections, show that synsedimentary dip slip along intrabasinal faults was of normal sense. Meanwhile, a role for strike‐slip deformation is registered by the left‐lateral offset of middle Permian and Middle Triassic piercing points and the exceptional preservation in outcrop of syndepositional negative flower structures. For these reasons, therefore, the pre‐Norian Triassic Nanpanjiang basin is thought to represent a transtensional back‐arc setting, a result that leads to an unresolved paradox: in adjacent parts of South China to the east, coeval development involves crustal thickening, nonmarine sedimentation and granitic plutonism. A new lateral decoupling model consistent with palaeomagnetic evidence for large‐scale block rotation is tentatively proposed here as a working hypothesis to explain the observed intracontinental evolution of South China during the Triassic assembly of eastern Asia. We propose that such decoupling may relate in part to the configuration of inherited crustal weaknesses. [ABSTRACT FROM AUTHOR]

A recent discovery of a Bronze Age harbor site in Çamçalık provides new data for the relative sea level history along the coast of the Bozburun Peninsula over the last 3600 years. In this study, we compared the new and previously published data from nearby sites to determine the long‐term relative sea level changes. Further comparison of the observed sea level data and newly produced glacial isostatic adjustment (GIA) models clarified the tectonic contribution to the relative sea level changes. Our results suggest a nonlinear tectonic subsidence trend in the coastal zone since 3600 B.P. The increase in the relative sea level accelerated over the last 1400 years, mostly due to the seismic events controlled by the tectonic regime of the southeastern Aegean Sea. We can conclude that, as in the past, this active tectonic process will have a major impact on the future sea level evolution of the coastal sector of the Bozburun Peninsula. Notably, our study can be used to understand the historical trend of sea level rise while providing a foundation for future trend prediction. [ABSTRACT FROM AUTHOR]

The Zengmu and Beikang Basins, separated by the West Baram Line (WBL) in the southwestern South China Sea margin, display distinct geological and geophysical features. However, the nature of the basins and the WBL are debated. Here we explore this issue by conducting the stratigraphic and structural interpretation, faults and subsidence analysis, and lithospheric finite extension modelling using seismic data. Results show that the WBL is a trans-extensional fault zone comprising normal faults and flower structures mainly active in the Late Eocene to Early Miocene. The Zengmu Basin, to the southwest of the WBL, shows an overall synformal geometry, thick folded strata in the Late Eocene to Late Miocene (40.4–5.2 Ma), and pretty small normal faults at the basin edge, which imply that the Zengmu Basin is a foreland basin under the Luconia and Borneo collision in the Sarawak since the Eocene. Furthermore, the basin exhibits two stages of subsidence (fast in 40.4–30 Ma and slow in 30–0 Ma); but the amount of observed subsidence and heat flow are both greater than that predicted by crustal thinning. The Beikang Basin, to the NE of the WBL, consists of the syn-rift faulted sub-basins (45–16.4 Ma) and the post-rift less deformed sequences (16.4–0 Ma). The heat flow (∼60 mW/m2) is also consistent with that predicted based on crustal thinning, inferring that it is a rifted basin. However, the basin shows three stages of subsidence (fast in 45–30 Ma, uplift in 30–16.4 Ma, and fast in 16.4–0 Ma). In the uplift stage, the strata were partly folded in the Late Oligocene and partly eroded in the Early Miocene, which is probably caused by the flexural bulging in response to the paleo-South China Sea subduction and the subsequent Dangerous Grounds and Borneo collision in the Sabah to the east of the WBL. [ABSTRACT FROM AUTHOR]

Channel avulsions on river deltas are the primary means to distribute sediment and build land at the coastline. Many studies have detailed how avulsions generate delta lobes, whereby multiple lobes amalgamate to form a fan‐shaped deposit. These studies often assume a steady subsidence and uniform basin depth. In nature, however, lobe building is disrupted by variable subsidence, and progradation of lobes into basins with variable depth: conditions that are prevalent for tectonically active areas. Herein, we explore sediment dispersal and deposition patterns across scales using measurements of delta and basin morphology compiled from field surveys and remote sensing, collected over 150 years, from the Selenga Delta (Baikal Rift Zone), Russia. Tectonic subsidence events, associated with earthquakes on normal faults crossing the delta, displace portions of the topset several meters below mean lake level. This allogenic process increases regional river gradient and triggers lobe‐switching avulsions. The timescale for these episodes is shorter than the predicted autogenic lobe avulsion timescale. During quiescent periods between subsidence events, channel‐scale avulsions occur relatively frequently because of in‐channel sediment aggradation, dispersing sediment to regional lows of the delta. Avulsion settings for the Selenga Delta preserve discrete stratal packages that could contain predominately deep channels. Exploring the interplay between tectonic subsidence and sediment accumulation patterns will improve interpretations of stratigraphy from active margins and basin models. Plain Language Summary: River deltas distribute sediment and build land in coastal regions by abruptly shifting course through a process called channel avulsion. The fan‐shaped morphology of river deltas arises from multiple avulsion events that deposits sediment in a radial fashion over time. Our understanding of how deltas build such morphology assumes that size of the downstream basin, such as a lake or ocean, is constant over time. However, geological activities like earthquakes and basin subsidence alter the size and shape of the delta. We complied and analyzed 150 years of delta morphology data from the Selenga Delta (residing in a tectonically active area) in Russia to understand how earthquakes and subsidence impacts channel avulsions and delta landforms. We determined two distinct avulsion styles for the Selenga Delta: a regional‐scale avulsion that is driven by earthquakes, and a local‐scale avulsion that is caused by sediment deposition. The two distinct scales of avulsions blend over time to shape the delta system. In addition, the regional‐scale avulsion produce unique subsurface records that can be used to understand the history of a delta. Our work highlights the importance of understanding the variety in downstream basin processes that impact delta morphology. Key Points: Tectonic subsidence produces variable receiving basin depth, and drives lobe‐scale avulsions by modifying delta‐topset gradientChannel‐scale avulsions occur during periods of tectonic quiescence, and disperse sediment to nourish the deltaic shorelineHierarchical avulsion styles could lead to preservation of discrete stratal packages that contain predominately deep channels [ABSTRACT FROM AUTHOR]

The Yangtze (Changjiang) Delta serves as a prominent depocenter for siliciclastic sediments from the Tibetan Plateau and Yangtze Craton, providing essential data on sediment source-to-sink dynamics and geomorphological evolution of large river drainage systems. This study presents the detrital zircon geochronology of Plio–Pleistocene sediments in the Yangtze Delta, alongside the data from modern river sediments, to elucidate provenance evolution since the Pliocene. The zircon geochronology reveals a considerable shift in sediment provenance during the Pliocene–Pleistocene transition. The Pliocene sediments exhibit a straightforward and predominant zircon age spectrum characterized by a typical peak age of 100–200 Ma. This spectrum markedly differs from the modern upper–middle Yangtze River sediments but closely resembles those of local rivers in the lower Yangtze River region. This demonstrates that the Pliocene sediments originated from local mountainous rivers, indicating the paleo-Yangtze River channelization prior to the Quaternary. In contrast, the zircon age spectra of Pleistocene sediments in the present-day delta reveal several dominant age groups ranging from 11.9 ± 1 to 3643 ± 30 Ma, similar to those found in present-day upper–middle Yangtze River sediments. This implies that the Pleistocene sediments were mainly derived from the upper–middle Yangtze River, showing a diversity of source rocks with varying geological ages and origins. The presence of the upper Yangtze River provenance signal, characterized by Cenozoic (<65 Ma) zircons, in early Pleistocene strata (ca. 1.6 Ma) of the delta suggests that the paleo-Yangtze River transported Tibet-sourced sediments into the modern delta area no later than that time. These findings indicate the geomorphological evolution of the Yangtze River Delta from an intermontane basin in the Pliocene to an alluvial–fluvial plain during the Quaternary. This geomorphological and geographic evolution, along with changes in sediment source, directly reflect extensive tectonic subsidence in eastern China since the late Cenozoic. • The Pliocene sediments of Yangtze River Delta differ markedly from modern Yangtze-, but closely resembles those from local regions. • At the initial Quaternary, middle-upper Yangtze River sediment had arrived in northern Yangtze River Delta area. • The paleo-Yangtze River delivered the Tibet-sourced sediments into the modern delta no later than ca.1.6 Ma. [ABSTRACT FROM AUTHOR]

The Miocene Zhujiang Formation is one of the most productive oil and gas-bearing strata in the Pearl River Mouth Basin (PRMB), South China Sea. The disagreement of the stratigraphic scheme and the lack of high-precision stratigraphic scheme and mechanism understanding have seriously constrained the further deepening exploration of the rocky oil and gas reservoirs. Based on the analysis of the Gamma ray series, lithologic sequence variations, the cyclostratigraphy, and sequence stratigraphy of wells A1 and B2 were in the Zhujiang Formation analyzed. The 4 third-order sequences and 17 fourth-order sequences were identified, 19 long eccentricity cycles were also obtained and significant Myr-obliquity signals were identified. An astronomical time scale was established with the formation time of the Baiyun movement (23.8 Ma) as the boundary time of the Zhujiang Formation-Zhuhai Formation. In addition, tectonic subsidence analysis was also performed. The results suggest that 1.2-Myr obliquity and tectonics were the main factors of the third-order sea-level fluctuations and the third-order sequences in the PRMB, and long eccentricity played a role in the development of the fourth-order sequences. The main drivers of stratigraphy may also differ at different stages of basin evolution. The combination of cyclostratigraphy, sequence stratigraphy, and tectonic subsidence is useful for establishing an objective delineation and understanding the driving mechanism of the sequence stratigraphy. • The driver analysis of sequence stratigraphy in the Pearl River Mouth Basin. • Third-order and fourth-order sequences are delineated by INPEFA and wavelet transforms. • Tectonic subsidence and ∼1.2-Myr obliquity control on third-order sequences and relative sea-level. • Fourth-order sequences responding to long eccentricity cycles. [ABSTRACT FROM AUTHOR]

In extensional and transtensional basins, the dual action of basin‐forming tectonism and explosive volcanic activity results in deposition of complex volcano‐sedimentary successions. Since both aspects contemporaneously affect sediment‐dispersal systems, it is difficult to distinguish one from the other by analyzing volcano‐sedimentary successions. To discriminate tectonic influence, basin fills of the Miocene, pull‐apart Janggi Basin were investigated. Here, the contemporaneous influence of tectonic subsidence and explosive volcanism formed <966 m thick, conformable volcano‐sedimentary successions composed of laterally extensive, pumice‐bearing, unwelded pyroclastic deposits and nonmarine sedimentary rocks formed under humid climatic conditions. Based on Laser Ablation – Multiple Collector – Inductively Coupled Plasma Mass Spectrometry zircon U–Pb age data, these successions were deposited from 21.1 ± 0.2 to 20.1 ± 0.1 Ma. After deposition of basinwide, tens of metres thick, and unwelded pyroclastic deposits, the directly overlying facies successions (FS‐1 and FS‐2) show contrasting depositional features to the classical model of volcaniclastic sedimentation. Facies succession‐1 is represented by fluvial conglomerates composed mostly of (sub)rounded pebble and cobble sourced from basement. The supply of basement‐derived clasts through fluvial systems resulted from development of physiographic relief during or soon after the eruption by syndepositional tectonic subsidence. Facies succession‐2 occurs directly on pyroclastic deposits that cover FS‐1 and show coarsening‐upward trends, and is composed of basal lacustrine mudstones and overlying resedimented volcaniclastic sandstones showing a progradational geometry, interpreted as a result of progressive filling of the lake by remobilized volcaniclastic sediments. Occurrence of basal lacustrine laminated mudstones indicates that syndepositional creation of the accommodation by tectonic subsidence exceeded forceful input of pyroclastic and remobilized volcaniclastic sediments, resulting in a delayed sedimentary response to explosive volcanic eruptions. This study shows that, despite voluminous production of volcaniclastic sediments, tectonic activity controlled sediment type and stacking patterns. Therefore, these depositional features allow to discriminate tectonic effects from complex volcano‐sedimentary successions, enabling to reconstruct basin evolution. [ABSTRACT FROM AUTHOR]

The southern continental margin of the South China Sea has documented multiphase continental rifting corresponding to the propagation of seafloor spreading. Here we investigate three multi-channel seismic reflection profiles across different segments of the Dangerous Grounds with a NE-SW direction. Stratigraphic correlation reveals that the Cenozoic tectono-stratigraphic framework in the Dangerous Grounds is featured with diachronous rifting, which records the successive spreading of East Subbasin and Southwest Subbasin, South China Sea. By reconstructing the tectono-sedimentary evolution history in different segments, we combine the quantification of the brittle extension, tectonic subsidence, as well as the crustal thinning. Results provide evidence that the extensional stress migrated from northeast to southwest with the progressive propagation of the seafloor spreading in the oceanic basin. Besides, the impact of the tectonic propagation persists even after the cessation of seafloor spreading, evidenced by a longer stretching duration in the West-Dangerous Grounds than that in the eastern area. Moreover, a temporary syn-rift subsidence delay synchronously to the spreading of the adjacent oceanic basin is observed along the southern margin. This observation proves the secondary mantle convection during the seafloor spreading in the southern continental margin, which is related to the propagating rift. [ABSTRACT FROM AUTHOR]

The fault activity, tectonic subsidence history, and geodynamics are analysed based on borehole information and seismic datasets from Liaodong Bay. The results reveal that the faults are intensely active (resulting in the faults that are characterized by more lengths and more throws) both in the northern and southern portions of the study area, while the faults are not active in the central portion of the study area during Kongdian Formation and Shahejie Formation deposition. However, the faults are generally more active in the northern portion of the study area than that in the southern portion of the study area. In contrast, the faults are intensely active in central and southern portion of the study area during Dongying Formation deposition. The numerous syn‐depositional faults, which are intensely active, result in southward movement of depositional centre. The tectonic subsidence history of wells (including well JZ‐A, well JZ‐B, well JZ‐C, well JZ‐D, well JX‐A, and well SZ‐A) in Liaodong Bay indicates that it shows obvious episodic tectonic evolution during the Palaeogene in Liaodong Bay. The episodic tectonic movement (initial rifting, rifting climax, thermal subsiding, and strike‐slip rifting) corresponds to Kongdian Formation and Shahejie Formation deposition, and Dongying Formation deposition, respectively. The spatio‐temporal variation of tectonic subsidence history is closely related to fault activity. The analysis results of balanced cross‐sections show that faults are intensely active during Dongying Formation deposition. However, a few faults are much active than that during Shahejie Formation deposition. There is a slight decrease in tectonic activity intensity during Kongdian Formation and Shahejie Formation deposition. In contrast, there is a significant decrease in tectonic activity intensity during third‐member to first‐member of Dongying Formation deposition. The tectonic activity intensity tends to cease by the end of Dongying Formation. [ABSTRACT FROM AUTHOR]

Ubiquitous onshore Cenozoic basins of the southern margin of the South China Block (SCB) systematically show a stratigraphic hiatus in the sedimentary succession. The absence of strata between the residual Paleogene and the overlying Quaternary in the onshore basin is a serious obstacle to reconstruct their evolutionary history and completely understand the tectonic evolution of the southern SCB margin. Using multiple independent methods, this study reconstructs the entire tectonic subsidence and uplift history in the Sanshui Basin. To do so, we first constrain the eroded thickness and initial erosion time between the Quaternary strata and the residual Huayong Formation (∼41 Ma). The results show that the erosion thickness at the unconformity in the northwestern Sanshui Basin was approximately 2200 m, and the erosion event lasted from approximately 29 Ma to the early Quaternary. The tectonic evolution of the Sanshui Basin during the Paleogene to early Quaternary was characterized by four successive tectonic episodes, three rifting events, and one uplift stage. The first rifting episode lasted from ca. 66–48 Ma, during which approximately 1000 m of tectonic subsidence accommodated the deposition of the Xinzhuangcun (66–59 Ma), Buxin (59–53 Ma), and Baoyue (53–48 Ma) formations. This was followed by the second and third rifting episodes from ca. 48–29 Ma, during which the average tectonic subsidence was approximately 650–850 m, and the residual Huayong Formation (ca. 48–41 Ma) and eroded strata (ca. 41–29 Ma) accumulated. From 29 Ma to the early Quaternary, a tectonic uplift of approximately 1150 m occurred, with a rate of 43 m/Myr, which triggered the erosion of most sediments deposited during the second and third rifting episodes. Our results strongly suggest that although the main depocenters were located offshore since the second rifting episode, rifting in the Sanshui Basin continued until the occurrence of the late Cenozoic erosion event. The differential evolution between uplift (and erosion) onshore and subsidence offshore since the late Paleogene is probably related to the coastward attenuation of southeastern extrusion caused by the Indo–Asian plate collision. • The late Cenozoic erosion thickness is about 2200 m. • The basin did not stop rifting until the late Early Oligocene. • Tectonic inversion made the basin lose part of its rifting episodes. • Subsidence center has moved from onshore to offshore since the second episode. [ABSTRACT FROM AUTHOR]

The Quaternary sedimentary history of the Yellow Sea and Bohai Sea offers significant insights into global sea-level changes. This history is intricately linked to tectonic subsidence. However, the process of the Quaternary transgressions of these areas remains controversial due to the lack of cores with comprehensive sedimentary sequences and reliable chronological frameworks in representative sites. This study evaluated the grain size, benthic foraminifera assemblages, quartz optically stimulated luminescence (OSL) dates, and magnetostratigraphy of Core CSH05 (102.4 m) from the eastern boundary of the Bohai Sea. By comparing these results with previous research, new insights were gained into sea-level changes and tectonic events in the Bohai Sea. The paleomagnetic analysis revealed the existence of Brunhes and Matuyama chrons in the core, including the Jaramillo and Cobb Mountain subchrons and Blake excursion. The boundary between the Brunhes and Matuyama chrons was determined at 57.2 m in the core, aligning with adjacent cores. The basal age of the core is estimated to be ∼1.35 Ma. Thirteen sedimentary units (U1-U13), consisting of seven neritic deposits and six terrestrial/littoral deposit layers, were identified in the core through sedimentology and environmental proxies (grain size and benthic foraminifera), indicating alternating transgression-regression cycles. OSL samples suggest that the neritic deposits layer (16.2–20.6 m) probably originated during the early Marine Isotope Stage 3 (MIS3), exhibiting a weaker transgression than MIS5 and MIS1. The initial transgression (U13) dates back to no later than 1.35 Ma, representing the earliest documentation in the Bohai Sea. U11 shows a transgression to 1 Ma, aligning with results from adjacent cores, indicating that the Miaodao Island uplift experienced further subsidence between 1 and 0.83 Ma, allowing seawater to inundate the central basin of the Bohai Sea during high sea level periods. The current sea-land configuration structure emerged after 0.3 Ma due to the complete subsidence of the Miaodao Islands Uplift. The Quaternary transgressions in the Bohai Sea demonstrate a coupling relationship with the uplift of the Qinghai Tibet Plateau, glacial-interglacial cycles, and integration of the Yellow River. This study traces the initial transgression in the Bohai Sea to 1.35 Ma and provides a new detailed evolutionary model of the timing and routes for the Quaternary transgression of the Bohai Sea and Yellow Sea, thereby enhancing our understanding of sedimentary evolution and paleoenvironmental changes in the region. • Initial transgression in the Bohai Sea began no later than 1.35 Ma, probably related to MIU subsidence. • A weak MIS3 transgression was limited to the eastern and southern Bohai Sea, weaker than that of MIS 5. • Quaternary transgression in the Bohai Sea is mainly influenced by tectonic subsidence. [ABSTRACT FROM AUTHOR]

The evolution and mechanisms of tectonic subsidence in the Xisha area are poorly investigated, especially the spatiotemporal distribution features and reasons for the variations in tectonic subsidence. In this study, multi-channel seismic data and stratigraphic and lithologic features of wells are used to examine tectonic subsidence in the Xisha area from the Paleogene to Quaternary. The largest tectonic subsidence in the Xisha area is located in the Changchang Depression, with a maximum subsidence of 5.4 km, while the smallest tectonic subsidence is located on the Guangle Uplift and Xisha Uplift, which are close to 1.0 km and 1.5 km, respectively. Two rapid tectonic subsidence phases were mainly in the Oligocene, and from Middle to Late Miocene, with maximum subsidence rates of 0.45 m/ky and 0.32 m/ky, respectively. Five phases for the tectonic subsidence are proposed since the Paleogene based on our data. (1) The slow subsidence phase during the Eocene (53.5–32 Ma) was due to the transchronicity of the basement in the pro-rifted stage. (2) The rapid subsidence phase was common in the south and north margins of Qiongdongnan Basin, because of the faults triggered by the inherited stretched and thinned of crust in the Oligocene from 32 to 23.3 Ma. (3) The interim phase followed the rapid subsidence phase was in the Early Miocene (23.3–15.5 Ma) and marked the end of the rifted stage. (4) The accelerated rise phase started from the Middle Miocene (15.5 Ma) to the Late Miocene (5.5 Ma), and the reversal of the Red River Fault Zone may be tied to the acceleration of the tectonic subsidence. (5) The transitional phase started in the Pliocene (5.5 Ma) and lasts to the present. As the Red River Fault Zone changed from sinistral to dextral movement, the stress field of the study area has changed. Our results are helpful to better understand the spatiotemporal coupling relationship between tectonic subsidence and regional geological evolution in the Xisha area, South China Sea.

The Mid-Permian Maokou Formation in the Sichuan Basin shows good petroleum prospectivity. However, knowledge of the stratigraphy in the northern and eastern Sichuan Basin during the late Maokou period are still unclear. The interface between the Maokou and Wujiaping formations was re-identified, and the sedimentary pattern in the study area during the late Maokou period was clarified based on the logging data from 120 wells combined with the measured data of three field profiles. The results suggest the following. (1) Natural gamma-ray spectral logging can effectively identify the siliceous sediments at the top of Maokou Formation and the mud shale at the bottom of Wujiaping Formation. According to a new stratigraphic division, the erosional edge on LHST2 section of Maokou Formation moved eastward to the Kaixian area. (2) Tectonic subsidence controlled the eastward thinning and the sedimentary evolution in the late Maokou period. (3) The sedimentary evolution in the late Maokou period was from the homoclinal carbonate ramp facies to the distal steepening ramp facies, and then to the weak rimmed platform facies. Distal steepening ramp facies controlled the formation of dolomite and siliceous sediments, while the weak rimmed platform facies controlled the formation of the platform margin.

This study integrates ichnological and sedimentological data to interpret depositional environments of the carbonate sediments of the Tirgan Formation (Lower Cretaceous) in the eastern Kopet-Dagh Basin, north-east Iran. Lithofacies analysis shows that these sediments were deposited in inner ramp, middle ramp and offshore (outer ramp) environments. Five ichnoassemblages are identified in the sediments that consist of Thalassinoides, Thalassinoides–Rhizocorallium, Planolites–Rhizocorallium, Arenicolites–Diplocraterion, and Arenicolites. Th, Th-Rh and Pl-Rh with low diversity and abundance of the trace fossils formed during waning phase of storms in a predominantly medium to high-energy hydrodynamic regime. High sedimentation rate and mobile substrate condition featuring a shallow-marine setting. Ar–Di ichnoassemblage, consisting of horizontal and vertical traces of deposit and suspension feeders, respectively, portray two different phases. A predominantly high energy phase with instable substrate is displayed by the vertical traces, while a minor omission phase, associated with a decrease in sedimentation rate or non-deposition, is indicated by the horizontal structures. Arenicolites ichnoassemblage with low bioturbation index and low ichnodiversity is related to a semi-sheltered area of lagoon environments with periodically marine water circulation. The study of the ichnological attributes in the studied successions indicates the presence of a shallowing up-ward trend in the storm‒tide-dominated ramp sequence. Ichnoassemblage development is largely controlled by depositional and ecological conditions, e.g., the stability of substrate, hydrodynamic regime (wave and tide), and food abundance, which altogether control the substrate colonization. Based on an integrated ichnological and sedimentological approach, we characterize the depositional environment, deciphering allogenic and autogenic environmental controls on the trace fossil distribution on a passive margin depositional setting. [ABSTRACT FROM AUTHOR]

The exploration and development of the shale in the Lower Silurian Longmaxi Formation in the Chongqing area has shown that gas production here is commercially viable. In contrast, the Longmaxi Formation shale in Hunan shows that gas production is not commercial. Why is there such a difference between the Chongqing and Hunan areas for the same formation. A mount of previous studies showed that gas is stored primarily in the organic matter (OM) pores in shale. This study has investigated the Longmaxi shale from two well locations in Chongqing and Hunan in order to understand whether differences in pore structure are the cause of the difference in commerciality in the two areas. The formation burial histories were established, analyzing samples for mineral composition, total organic carbon (TOC) content, thermal maturity (Ro), and OM pore structures. The results show that the Longmaxi shale in Chongqing and Hunan has similar TOC content and Ro. The average TOC content is above 3.0% for samples from both areas, and the thermal maturity was all between 2.4 and 2.9%. OM pores of the Longmaxi shale in Chongqing are abundant in number and relatively large sized, with mostly circular and oval shapes. In contrast, the number and size of the OM pores in the Longmaxi shale in Hunan are small, and the shape is irregular. OM pore structure of the Longmaxi shale in Chongqing is therefore favorable for preservation of gas. The poor pore structure of the Longmaxi shale in Hunan is not conducive to gas preservation. The OM pore structure difference of the Longmaxi shale in Chongqing and Hunan is determined by the formation burial history. The Longmaxi shale in the Chongqing area experienced rapid burial in the Early Jurassic and rapid uplift in the Late Cretaceous. The Longmaxi Formation in Hunan experienced rapid burial in the Early Triassic and rapid uplift in the Early Jurassic. The long evolution time (100 Ma) of the Longmaxi shale in Chongqing produced a large amount of gas supply and enough storage space (OM pores) for the gas occurrence, which makes the amount of gas be preserved in geological history. The short evolution time (50 Ma) of the Longmaxi shale in Hunan produced insufficient gas supply and not enough OM pores in reservoir, which leads to gas loss in geological history, resulting in low gas content. Therefore, to evaluate the potential of shale gas, the evolution time of organic matter must be considered. In other words, the time interval between rapid subsidence and uplift of formation during geological history must be considered.

To reveal the tectonic characteristics of the continental margins in the southwest subbasin (SWB) of the South China Sea, a long high-resolution seismic profile was studied using empty basin subsidence. We find that tectonic subsidence features on both margins are uniformly divided into three stages: (1) slow subsidence from Tg to 18.5 Ma (synrift stage); (2) extremely slow subsidence/uplift from 18.5 to 16 Ma (spreading stage); and (3) accelerated subsidence from 16 to 0 Ma (post-spreading stage). This feature differs from the classic tectonic subsidence pattern of rifted basins, which exhibits fast subsidence during synrift stage and slow subsidence during the post-rift stage. The tectonic uplift occurred during the spreading stage and the magnitude increased from the continent to the ocean, which is likely related to mantle flow during seafloor spreading. We propose that lower crustal flow played a significant role in the tectonic evolution of the continental margins of the SWB. The lower crust of the SWB margins was warmer and therefore weaker, and more prone to flow beneath the faulting center, which compensated for the upper crustal thinning caused by brittle faulting during the synrift period and thus reduced the tectonic subsidence rate. During the spreading stage, faulting attenuated rapidly, and a necking zone appeared at the continent-ocean transition formed by lithospheric extension. With upwelling asthenosphere, small-scale secondary mantle convection occurred under the necking zone, which raised the continental margin isotherms and increased the buoyancy. Simultaneously, secondary mantle convection lifted the overriding crust, thus the overall subsidence rate decreased sharply or even reversed to uplift. After seafloor spreading, the effect of mantle convection faded away, and sediment loading drove the lower crust to flow landward. Thermal relaxation, lower crust flow, and vanish of secondary mantle convection together led to rapid subsidence in this stage. [ABSTRACT FROM AUTHOR]

The Upper Ediacaran to Lower Cambrian of the Sichuan Basin in South China has long been considered to be dominated by shallow‐water deposition. Hydrocarbon exploration, however, has revealed that a NW‐SE trending intraplatform trough formed in the basin during the same period. Although different models have been proposed, the formation and evolution of the trough are still not fully understood. In this study, we investigate both the origin of the intraplatform trough and the formation of the Sichuan Basin by integrating seismic interpretation, well correlation and tectonic subsidence analysis. The seismic and well data clearly show three stages of development of the trough. The first stage, in the early Late Ediacaran, is characterized by considerable thinning of the lower two members of the Upper Ediacaran from the platform margins to the trough. In the second stage, in the late Late Ediacaran, the platform margins backstepped and the extent of the trough expanded significantly to a width of ca. ~400 km. The third stage, in the early Early Cambrian, was dominated by gradual filling of the trough and onlapping of the platform margins. Backstripped tectonic subsidence curves show one, or two closely spaced episodes of linear subsidence starting at ~550 Ma and then decreasing exponentially until ~450 Ma. The shape of the subsidence curves is consistent with formation of the Sichuan Basin by low, and slow amounts of lithospheric stretching of thickened cratonic lithosphere. The tectonic subsidence increases from the centre to the NW of the basin. Interestingly the margins of the trough do not correlate with contoured values of increased tectonic subsidence and we infer that the trough was a palaeogeographic embayment in a large carbonate platform that developed in a broad, ramp‐like area of slow and low subsidence tilting down to the proto‐Tethyan ocean located to the NW of the basin. [ABSTRACT FROM AUTHOR]

This study investigates the evolution of the Miocene Guangle carbonate platform (or Triton Horst) of the northwestern South China Sea margin. The platform is located at a junction area surrounded by Yinggehai basin, Qiongdongnan basin and Zhongjiannan basin. Well and regional geophysical data allow the identification of the morphologic and stratigraphic patterns. The Guangle carbonate platform was initiated on a tectonic uplift during the Early Miocene. The early platform was limited at Mesozoic granitic basement, pre‐Paleogene sediments localized tectonic uplift and was small extension at the beginning stage. While during the Middle Miocene, the carbonate buildup flourished, and grow a thrived and thick carbonate succession overlining the whole Guangle Uplift. The isolated platforms then united afterward and covered an extensive area of several tens of thousands of square kilometers. However, it terminated in the Late Miocene. What are the control factors on the initiation, growth and demise of the Guangle carbonate platform? The onset of widespread carbonate deposits largely reflected the Early Miocene transgression linked with early post‐rift subsidence and the opening of the South China Sea. Stressed carbonate growth conditions on the Guangle carbonate platform probably resulted from increased inorganic nutrient input derived from the adjacent uplifted mainland, possibly enhanced by deteriorated climatic conditions promoting platform drowning. Therefore, tectonics and terrigenous input could be two main controlling factors on the development of the Guangle carbonate platforms and main evolution stages. [ABSTRACT FROM AUTHOR]

The thermal evolution of the Mawson Sea Basin, offshore East Antarctic, was modelled using the GALO basin modelling programme. As there exist no deep temperature or vitrinite reflectance data for the Mawson Sea Basin, the simulation was based on a limited nonthermal database. This includes the present‐day sedimentary section along a multichannel seismic profile which crosses the western part of the Mawson Sea along with geophysical assessments of the depth of the Moho. An analysis of the variations in tectonic subsidence was used to estimate the duration and magnitude of thermal activation or stretching of the lithosphere. This analysis suggested that a proportion of the lithospheric stretching took place before the start of synrift sediment deposition at about 160 Ma (Late Jurassic). This pre‐sedimentation lithospheric stretching has been ignored in previous studies, resulting in significant underestimation of the total stretching which has occurred. The analysis also suggests that the thermal maturity of Lower Jurassic potential source rocks along the profile may reach and even exceed the onset of the oil generation window, whereas source rocks in less deeply buried parts of the profile are less mature. In general, the results of the modelling indicate that the Mawson Sea Basin is a promising area for future oil and gas exploration. [ABSTRACT FROM AUTHOR]

The article substantiates the conclusion about the tectonic nature of the last global transgression of the World Ocean. It is based on the results of marine studies in which complete sections of transgression sediments were obtained that were separated from their substrate by the diachronous boundary of a stratigraphic uncomformity or those beginning with littoral facies. The radiocarbon dating of such sections at different levels made it possible to calculate the average rate of relative sea level rise by plotting the radiocarbon age of sediments against depth from the seafloor surface. This was constructed based on three reference areas: the underwater slope of the island of Barbados, the North Sea shelf, and the Barents Sea shelf. It was revealed that the average rates of relative sea level rise at different points in the same water area sometimes differ by an order of magnitude, which is incompatible with the eustatic nature of transgression. The maximum transgression amplitudes in the Barents and North seas are several times higher than those permissible for glacio-eustasy. It is assumed that tectonic subsidence of the area due to the planetary nature of the last marine transgression overlapped its immersion, associated with the incomplete formation of the youngest oceanic depressions of the planet located north of the submarine Greenland–Scotland Ridge. [ABSTRACT FROM AUTHOR]

An analysis of variations in the tectonic subsidence of the Bremer sub‐basin (offshore SW Australia) since 160 Ma using the GALO numerical basin modelling programme has made it possible both to refine previous models and to estimate the intensity of stretching and thermal activation of the lithosphere. The new model explains the rapid subsidence of the sub‐basin and the deposition of the synrift Bremer 1 unit during the initial rift phase in the Late Jurassic (160 to 130 Ma). This phase of extension was accompanied by high heat flows, typical of the axial zones of continental rifts, and lithospheric stretching with a β‐factor of about 1.4. Between 130 and 43 Ma, the abnormally low depositional rate and the shallow water depths suggest moderate thermal activation of the mantle and the absence of extension‐driven subsidence. However during the Eocene (43 to 37 Ma), the modelling suggests that another phase of intense stretching of the sub‐basin lithosphere took place with β = 1.7, explaining both the subsidence and an abrupt increase in water depth from about 50–200 m to nearer 2000 m. The high heat flows during the initial stage of rifting and thermal activation during Cenozoic extension contributed to the early generation of hydrocarbons by source rocks in the Bremer 1 unit at the base of sedimentary cover. At the present day, these source rocks are overmature. At the same time, the modelling suggests that generation of light and heavy oil in the overlying Bremer 2 and 3 units has occurred. Source rock intervals in the upper half of the Bremer 3 unit and in the overlying successions are early mature or immature and may have generated minor volumes of hydrocarbons. [ABSTRACT FROM AUTHOR]

To help characterise the palaeogeographic and lacustrine environmental changes that resulted from the Holocene transgression and residual subsidence in the eastern Kanto Plain of central Japan, we analysed four drill cores and reviewed other core data from the southern part of the Lake Inba area. Fossil diatom assemblages yielded evidence of centennial-scale palaeogeographic and salinity responses to sea-level changes since the late Pleistocene. We determined that the seawater incursion into the Lake Inba area during the Holocene transgression occurred at approximately 9000 yr. We also recognised a late Holocene regression event corresponding to the Yayoi regression, considered to have occurred from ca. 3000 to ca. 2000 yr, and a subsequent transgression. Our data clarify some of the palaeogeographic changes that occurred in the Lake Inba area and document an overall trend toward lower salinity in the lake during the regression. In particular, the environment in Lake Inba changed from brackish to freshwater no later than 1000 yr. From the detailed palaeogeographic and palaeo-sea-level reconstruction, we recognised that residual subsidence occurred during the Holocene in this area. Thus, comparison of sea-level reconstructions based on modelling and fossil diatom assemblages is effective in interpreting Holocene long-term subsidence. [ABSTRACT FROM AUTHOR]

As the largest siliciclastic sink in the South China block, the Triassic Nanpanjiang basin is generally thought of as a foreland basin related to Indosinian collision between the South China and Indochina blocks. Our basin analysis, spanning an eight years period, provides details of Lopingian to Middle Triassic stratigraphic fill and tectonic subsidence of the basin. Field observation and sedimentological analyses reveal that the basin was not filled by a monotonous turbidite system and suggest instead the development of five primary depositional units constituted by deep-water turbidite systems, mass-transport deposits, condensed drapes, shallow-water isolated carbonate platforms, and volcano-volcaniclastic rocks. The stratigraphic completeness of the basin, the coexistence of widespread but localized carbonate platforms within axially filled deep-water basin, tectonically generated cyclothems of transverse mass-transport deposits along intrabasinal faults and basin fill of extrusive rocks of bimodal composition together apparently call in question the claim that crustal shortening prevailed during the Late Permian to pre-Norian Triassic. Patterns of basin fill, differential tectonic subsidence and very high subsidence rate of the region adjacent to master fault are more closely match the pattern expected for extensional to transtensional basin in a back-arc setting. The crustal extension in the southwestern South China was not consistent with hypothesized Indosinian collision between South China and Indochina blocks, but more likely developed in response to northwestward subduction of the paleo-Pacific plate. Our results, combined with regional considerations, lead to a new model for the Triassic tectonic evolution of South China during Triassic assembly of the southeastern and eastern Asia. Image 1 • Lopingian to Middle Triassic stratigraphic fill and tectonic subsidence of the Nanpanjiang basin of South China. • Basin formation in extensional/transtensional continental back-arc setting caused by subduction of paleo-Pacific. • Triassic intracontinental tectonics of the South China during collision with North China block. [ABSTRACT FROM AUTHOR]

Extensional systems of back-arc basins have been widely recognized and studied in SE Asia, however the interactions between extensional tectonics and spatial-temporal distributions of tectonic subsidence in an active back-arc basin are poorly known. Using a backstripping technique, we analysed 33 multichannel seismic profiles to calculate the Neogene tectonic subsidence across the entire Okinawa Trough (OT) for the first time. Reconstruction of the tectonic subsidence shows that the OT can be roughly divided into four subsidence stages with variable rate. By comparing the temporal-spatial distribution of the intensive subsidence area, we confirmed that rifting events first occurred in the northern segment (NOT) and middle segment (MOT) from the Miocene to Late Pliocene, and then propagated to the southern segment (SOT) after the Late Pliocene. The factors controlling the rapid tectonic subsidence over the entire OT can be classified into two categories: 1) NE-to NNE-trending normal faulting, related to extension of the OT, and NW- to NWW-trending strike-slip faulting; i.e., the Tokara Fault and the Miyako Fault, related to subduction of the Philippine Sea Plate under the Eurasian Plate; 2) The anomalous rapid subsidence occurred in the southernmost part of the SOT is likely related to the subducted Gagua Ridge which caused magma intrusion resulting from partial melting. We suggest that magmatic bodies produced by partial melting of subducted materials intruded into the crust and created a dense lithosphere, causing this rapid tectonic subsidence. • The subsidence center first occurred in the NOT and MOT since Miocene, then propagated to the SOT after the Late Pliocene. • Rapid tectonic subsidence focuses on the NE-NEE-trending rifting center and the NW-NWW-trending strike slip faults. • Anomalous rapid subsidence in the center and southernmost part of the SOT was related with the subduction of Gagua Ridge. [ABSTRACT FROM AUTHOR]

Archaeological and geomorphological features, as well as traces left by tsunamis, earthquakes, and vertical earth-crust displacements, are used to identify sea-level and coastal changes. Such features may be displaced, submerged or eroded by natural processes and human activities. Thus, identifying ancient sea levels and coastal changes associated with such processes may be controversial and often leads to misinterpretations. We exemplify the use of sediment deposits and sea-level and coastline indicators by discussing the enigmatic demise of the Roman harbor of Caesarea, one of the greatest marine constructions built in antiquity, which is still debated and not fully understood. It was suggested that the harbor destruction was mainly the result of either tectonic subsidence associated with a local, active fault line, or as a result of an earthquake/tsunami that struck the harbor. Here we examine and reassess the deterioration of the harbor in light of historical records, and geological, geomorphological and archaeological studies of natural and man-made features associated with the harbor. We show that the alleged evidence of an earthquakes or tsunami-driven damage to the outer breakwaters is equivocal. There is no supporting evidence for the assumed tectonic, active fault, nor is there a reliable historic account of such a catastrophic destruction. It is suggested that geo-technic failure of the breakwater’s foundations caused by a series of annual winter storms was the main reason for the destruction and ultimate collapse of the western basin of the harbor. The breakwaters were constructed on unconsolidated sand that was later washed away by storm waves and sea currents that frequently hit the Israeli coast and undercut the breakwaters. The pounding effect of the waves could have contributed to the destruction by scouring and liquefying the sandy seabed underlying the foundations. Tsunamis that may have hit Caesarea could have added to the deterioration of the breakwaters, but did not constitute the main cause of its destruction.