Uplift History Research Articles

Reconstructing the thermal history of the Morondava Basin, Madagascar, after Gondwanan breakup as resolved through detrital zircon (U–Th)/He and U–Pb geochronology

Formation of the Phanerozoic basins of Madagascar coincided with the initial stages of Permian break-up of Gondwana. The largest of these, the Morondava Basin, records the tectonic history of rifting, drifting, and uplift of the Malagasy terrane over the last 300 Myr. Herein, we have applied detrital zircon U–Pb geochronology and (U–Th)/He low-temperature thermochronology to resolve the thermal history of the basin as Madagascar separated from Africa and subsequently India. Coarse-grained siliciclastic samples were taken along two transects parallel to the Morondava River in the central basin, including from the Permo-Triassic failed rift basin and from post-Jurassic passive margin sequences. Detrital zircon U–Pb age distributions are defined by common Neoarchean and Neoproterozoic populations which suggests input from the basement terranes of the Malagasy Central Highlands (Antananarivo domain). Samples also contain Paleo-to Mesoarchean and Cambrian populations likely associated with metamorphic terranes amalgamated during the Pan-African orogeny. Single crystal zircon (U–Th)/He dates are 503 ± 17 Ma to 40 ± 1 Ma with effective uranium (eU) values ranging from 35 to 1760 ppm, which exhibit a strong negative date-eU relationship that indicates partial resetting of the He systematics in zircon throughout the basin. Inverse and forward thermal history models from the data reveal separate thermal histories for strata on either side of basin-dividing Illovo Fault. Under an elevated geothermal gradient, temperatures did not exceed 180 °C either during post-Gondwanan burial of Jurassic rift strata or during Late Cretaceous burial of Early Cretaceous passive margin strata. Intrusion of Turonian-age dikes and sills related to the Marion hot spot likely promoted subtle yet widespread heating. The time of latest cooling during the Paleogene recorded in the basin is poorly constrained by the detrital zircon thermochronology.

Early uplift and exhumation of the Tanggula granitoid pluton since the Late Cretaceous: Implications for the stepwise topographic growth model in the eastern Qiangtang terrane

Abstract Reconstructing the uplift process of the eastern Qiangtang terrane is crucial for understanding the growth model of the central Tibetan Plateau. However, due to the limited amount of data available, it is not well constrained. The Tanggula granitoid pluton is an outstanding geological feature in the eastern Qiangtang terrane, and thus could provide crucial constraints on its uplift history. We applied multiple thermochronologic systems over a broad temperature range, including apatite U-Pb, biotite and K-feldspar 40Ar/39Ar, apatite and zircon fission-track, and zircon (U-Th)/He, to study samples from the Tanggula granitoid pluton. The results exhibit the expected relative age order of these thermochronologic systems, with 242–238 Ma apatite U-Pb ages, 218–204 Ma biotite 40Ar/39Ar ages, 197–191 Ma K-feldspar 40Ar/39Ar ages, 94–81 Ma zircon fission-track ages, 70–58 Ma zircon (U-Th)/He ages, and 61–39 Ma apatite fission-track ages. Using these thermochronologic ages and thermal history modeling results, we reconstructed a comprehensive thermal history for the pluton, from which three rapid cooling phases were revealed. The earliest rapid cooling phase (220–180 Ma; ~5.25 °C/m.y.) closely followed the emplacement of the Tanggula granitoid pluton, and thus is primarily an expression of natural cooling triggered by conduction with the surrounding rocks. In contrast, the rapid cooling during 100–60 Ma and since 20 Ma can be interpreted to represent intense exhumation, with corresponding exhumation of 5.0–6.0 km and 2.3–2.8 km, as well as an average exhumation rate of 0.125–0.150 mm/yr and 0.115–0.140 mm/yr, respectively. According to the thermal history, the earliest uplift in the Tanggula region could have been initiated as early as the Late Cretaceous. Using the published data, we determined that the onset of rapid uplift and exhumation in the entire eastern Qiangtang terrane had a northeastward, stepwise propagation process. The region within or around Anduo first experienced rapid uplift and exhumation that initiated during the late Early Cretaceous (ca. 130 Ma), the Tanggula region to the northeast experienced rapid uplift and exhumation that initiated during the Late Cretaceous (ca. 100 Ma), and the region farther to the northeast in Tuotuohe and Yushu–Nangqian experienced rapid uplift and exhumation that initiated in the late Paleocene (ca. 60 Ma). The northeastward stepwise uplift and exhumation in the eastern Qiangtang terrane was likely caused by the combined Lhasa–Qiangtang and India–Asia continental collisions.

Late Pleistocene sea level change and tectonism control on the formation of the Old Red Sand along the southeastern coast of China

The Zhe-Min Uplift (ZMU) has undergone tectonic subsidence, which has been associated with a notable transgression in the northern marginal seas of China since the middle Pleistocene. However, its uplift history during the late Quaternary is still inadequate. The Old Red Sand (ORS) is a late Pleistocene deposit that is widely distributed along the southeastern coast of China. The ORS consists of partially-cemented fine- to medium-grained sand. In this paper, we focus on mud-rich ORS deposits of the Liushui area, Pingtan Island, Fujian Province, and report optically stimulated luminescence (OSL) ages, and new datasets of grain size, mineralogy (detrital zircon, clay and detrital minerals) and organic carbon and nitrogen isotope profiles to improve understanding of chronology, provenance, palaeoenvironmental evolution and tectonic infuence. Based on the OSL data, we hypothesize that the development of the ORS was associated with lower sea levels, with most deposition occurring within MIS4. Based on comparison of detrital zircon UPb ages, the coarse fraction of the Liushui ORS was mainly derived from the Minjiang River, with modest input from weathering of coastal granites. The East Asian Winter Monsoon contributed some materials from the East China Sea shelf during the last glacial period, as indicated by the fine-grained nature of the Liushui ORS, low K-feldspar/plagioclase ratios, high dolomite content and the frequency of Neoproterozoic and Palaeoproterozoic detrital zircons. The deposition of the ORS was influenced by both the East Asian Winter Monsoon and sea level changes. The clay minerals in the mud layers of the Liushui ORS were dominated by kaolinite and illite, with little chlorite and no smectite, indicating that they originated from the Minjiang River. The TOC/TN ratios of the mud layers, as well as their isotope characteristics, indicate the organic matter was derived from marine sources, presumably during the transgression event in MIS5. The average uplift rate of the ORS was about 0.03 mm/yr. The uplift of the ORS provided new insights into the geological records of the ZMU, which differed from the subsidence observed in the northern region of the Minjiang River during the late Pleistocene.

Cave Levels in the Totes Gebirge (Eastern Alps)

Abstract The Totes Gebirge is not only the largest karst massif in the Northern Calcareous Alps, it also contains the most cave passages. In this area we are investigating the vertical distribution of phreatic cave passages to determine cave levels. These are vertical zones with clusters of cave passages that can be correlated with former valley floors. Since only phreatic cave passages (i.e. caves that were permanently or episodically filled with water during their formation) are to be analysed, a genetic classification is made on the basis of field observations, cave maps, 3D surveys and descriptions. As of Sept. 2023, the Totes Gebirge range, including the adjacent Warscheneck and the Hohe Schrott, contains 3172 known caves with a total length of 821 km, including the two longest cave systems in Austria, the Schönberg- (156 km) and the Schwarzmooskogel-Höhlensystem (137 km). As small caves do not contribute significantly to these statistics, only caves ≥50 m were included. The remaining 754 caves have a total length of 790 km. Only 46 % of these caves are at least partially of phreatic origin, but they contain 92 % of the total passage length. After subtracting the caves from which no data were available and cave sections that are not phreatic in origin (i.e. vadose or those created by weathering and erosion), 641 km of cave sections remained, which were analysed for their vertical distribution in 25 m increments. The histogram of cave length distribution vs. elevation for the Totes Gebirge range shows only a single significant cluster of phreatic cave sections between 1300 and 1850 m above see level (a.s.l.), with a clear maximum at 1500 m. The massif was divided into four sub-regions and all of them show this main interval, which is why it was interpreted as a cave level. It correlates well with the Giant Cave Level known from all other karst massifs in the Northern Calcareous Alps analysed so far. However, it is peculiar that in the other massifs at least three cave levels are present. Other reasons, such as the lack of known caves and the large size of the massif, which could lead to overlapping of cave levels, are unlikely. Therefore, it seems possible that the palaeo surface drainage pattern around the Totes Gebirge or its uplift history was different from the other karst massifs in the Northern Calcareous Alps and that low-lying cave levels (Spring and Berger Cave Level) or an elevated one (Ruin Cave Level) did not develop. For each of the 21 largest cave systems (≥5 km in length), the peak of the vertical distribution of the phreatic passages was determined. Vectors were calculated in order to test whether palaeo-flow directions could be inferred from their distribution. These phreatic maxima indicate a general dip from ESE to WNW, which could be interpreted either as a palaeo-drainage direction or as a tectonic tilting of the whole massif after the formation of the passages.

Uplift rate calculation based on the comparison between marine terrace data and river profile analysis: A morphotectonic insight form the Ionian coastal belt of Basilicata, Italy

Geomorphological analyses of a wide coastal belt between northern Calabria and Puglia, where a well-exposed staircase of marine terraces extensively crops out, were performed in order to unravel the uplift history of this key-area. As a matter of fact, the Ionian coast of southern Italy represents a strategic sector for investigating the middle-late Quaternary morphotectonic evolution of the orogenic system of southern Italy.The main goal of our research was the reconstruction of a detailed uplift history using spatial distribution of marine terraces and river profile inversion. This was achieved by producing a new, detailed and complete map of the entire sequence of marine terraces and associated palaeoshorelines along the entire coastal sector. A critical review of the literature related to geochronological data from the study area, integrated with a modeling of the interaction between eustatic changes and tectonic uplift allowed demonstrating that the different terraces are correlated to many highstand peaks, dating the highest/oldest terrace to mid-Pleistocene times. Additional constraints on the spatio-temporal variation of tectonic uplift (or base-level fall) have been derived from the inversion of longitudinal river profiles. Such an approach adopts an independent geomorphic marker than the marine terraces and allowed us to obtain an additional estimation the uplift history of the area. The uplift values from the two methods differ in some cases by an order of magnitude, which could be attributed to the rigorous assumption of the river profile inversion or a limitation related to the chronological scheme of marine terraces.Our results highlight a spatial and temporal variation in the uplift rates, which can be only explained with a morphotectonic framework and likely the whole chain-foredeep-foreland system, remained under a prevailingly compressional tectonic regime during the Quaternary, with significant consequences for the seismic hazard of the region.

Multi-phase subsidence history of the Sarawak continental margin and its regional significance

Subsidence analysis of Sarawak Basin using stratigraphic data from a selection of exploration wells revealed a multi-phase history of crustal extension (rifting), subsidence and uplift. A relatively rapid subsidence during the early rift phase from Eocene to Oligocene (ca. 37–28 Ma) was followed by a gradual decrease in subsidence rate as the extended lithosphere underwent post-rift thermal relaxation (ca. 28–22 Ma). A second phase of extension during the Early Miocene (ca. 22–17 Ma) resulted in an increase in subsidence rate, which coincided with a major episode of compressional deformation, uplift and localised erosion. This deformation event culminated in a major unconformity dated ~16 Ma, known as the Middle Miocene Unconformity (MMU), which is recognised throughout the Bunguran Trough and North Luconia regions of Sarawak Basin as a major stratigraphic hiatus spanning the Early to Middle Miocene. Since the Late Miocene, there had been an increase in the subsidence rate, probably due to progradation of the Sarawak shelf to its present-day configuration. The complex subsidence history of Sarawak Basin is similar to those reported from other parts of the South China Sea margin. The subsidence histories indicate a common, underlying tectonic factor which is probably related to rifting and sea-floor spreading in the southwestern prong of the South China Sea oceanic basin.

The late Eocene rise of SE Tibet formed an Asian ‘Mediterranean’ climate

Southeastern (SE) Tibet forms the transition zone between the high interior Tibetan Plateau and the lowlands of southwest China. So understanding the elevation history of SE Tibet, a biodiversity hotspot, enlightens our understanding of the interactions between tectonics, monsoon dynamics and biodiversity. Here we reconstruct the uplift history of the Markam Basin, SE Tibet, during the middle−late Eocene based on U − Pb dating, plant fossil assemblages, and stable and clumped isotope analyses. Our results suggest that the floor of the Markam Basin was at an elevation of 2.6 ± 0.9 km between 42 Ma and 39 Ma, where the mean annual air temperature (MAAT) was 13.2 ± 2.4 °C. The basin then rose rapidly to 3.8 (+0.6/−0.8) km before 36 Ma. Integrated with existing paleoelevation data, we propose that the high plateau boundary (∼3.0 km) of SE Tibet formed during the late Eocene. Numerical climate modeling with realistic paleo-landscapes shows that with the rise of SE Tibet, a Mediterranean-like climate developed in the region characterized by bi-modal precipitation with two wet seasons in boreal spring and autumn. The high topographic relief of SE Tibet, coupled with this distinctive Mediterranean-like climate system, helped develop the high biodiversity of the Hengduan Mountains.

Inversion of Late Miocene uplift history from the transient Daxia River landscape, NE Tibetan Plateau

The mechanisms of the upward and outward growth of the Tibetan Plateau are crucial for understanding the geodynamic significance of Cenozoic continental collisions. Northeastern Tibet has been suggested as one of the youngest deforming and uplifting margins surrounding the plateau. The existence of fluvial knickpoints and low-relief topographic surfaces along the Yellow River and its tributaries indicate the transience of the landscape in response to active tectonic uplift. Therefore, the uplift history of the North Eastern Tibetan Plateau (NETP) can be potentially inverted from the disequilibrium channel profiles of the Yellow River and its tributaries. The West Qinling Fault (WQF) is part of the geomorphological and topographic boundaries of the NETP. Its uplift history helps to clarify the deformation history of the Tibetan Plateau. In this study, the focus was on the Daxia River (one of the Yellow River tributaries) to identify the distribution of peneplain surfaces and knickpoints, and to present a linear inversion on the fluvial longitudinal profiles for the relative uplift history of the West Qinling. We obtained a relative uplift history with two pulses of change in the uplift rates at ∼5 and ∼2 Ma. Rates of relative uplift maintained low values during the Late Miocene, then slowly increased from 0.1 to 0.2 mm a −1 after ∼5 Ma and suddenly jumped to 0.3 mm a −1 at ∼2 Ma, consistent with recent findings on the deformation records in the NE Tibetan Plateau. We suggest that (1) the Late Miocene–Pliocene landscape evolution was driven by both tectonics and climate change and (2) inversion of the transient longitudinal channel profiles, if applied, may provide broader insights into the upward and outward growth patterns of the NE Tibetan Plateau. Thematic collection: This article is part of the Mesozoic and Cenozoic tectonics, landscape and climate change collection available at: https://www.lyellcollection.org/topic/collections/mesozoic-and-cenozoic-tectonics-landscape-and-climate-change

Holocene vertical velocity fields in the Calabrian Arc (southern Italy): New insights from uplifted sea-level markers in the Crotone Peninsula

The study of fossil coastlines is one of the most widely used methods to unravel the vertical movements of the Earth's solid surface. All along the coast of the Calabrian Subduction Arc, well preserved Pleistocene marine terrace sequences document a protracted uplift history. Although Pleistocene vertical movements have been extensively explored, the Holocene history is not well understood. Numerous uplifted coastlines of the Holocene period have been studied along the Tyrrhenian side of Calabria, but the Ionian coastal sector is considerably under-studied. Our new data from the coast of the Crotone Peninsula fill this crucial data-gap. AMS 14C dating of seventeen sea level markers, elevated above the current mean sea level, show ages between 2300 and 7000 Cal. Yr BP. The elevation of the markers was corrected for the paleo sea level using the most updated GIA models ICE-6G (VM5a) and ICE-7G (VM7). We found that a coastline dated to 7 ka shows uplift rates of 0.8 mm/yr, consistent with late Pleistocene uplift rates (≈0.8 mm/yr). In contrast, a 2.3 ka coastline was uplifted by only 1 m, resulting in lower uplift rates of ≈0.5 mm/yr. However, there are clues that the abandonment of this younger coastline may have occurred with a rapid uplift pulse. Reconstructing the past vertical movements of the Crotone Peninsula reveals an unsteady uplift history. At some times fast uplift rates are required, while for other periods, lasting as long as 3–4 kyr, the uplift rate is slower or zero. An uplift history consisting of periods of accelerated uplift, or even coseismic pulses, would also explain the difference in uplift rates between short term (<5 ka) and long term (>5 ka) markers through a metric we have defined as uplift rate sensitivity. Understanding the details of this uplift history has social relevance. The co-seismic uplift hypothesis requires further investigation but if confirmed would likely affect the seismic and tsunami hazard of the Crotone Peninsula. Similarly, the unsteady uplift rate would cause a risk given the current rapid rate of global sea level rise. Periods of sustained vertical stability would increase the risk of flooding even in areas characterized by long-term uplift and thus considered safe.

Paleogene sediment provenance in the Gaize Basin: Implications for early Cenozoic paleogeography of central Tibet

A comprehensive study of the sediment source-to-sink history of basins arranged along the Bangong-Nujiang Suture Zone (BNSZ) is critical for understanding the early Cenozoic topography and drainage systems of central Tibet and its implications for the uplift history of the Tibetan Plateau. Nevertheless, previous provenance analyses work mainly focused on the middle-eastern segment of the BNSZ, those Paleogene basins in the western segment have received less attention, which hinders a full understanding of the early Cenozoic topography of central Tibet. In this study, based on a chronostratigraphic framework developed for the lower Cenozoic continental redbeds of the Gaize Basin, we applied detrital zircon U-Pb geochronology to the well-exposed Paleogene Suonahu Formation in order to reconstruct the basin's source-to-sink history. Integrating these new data with detrital zircon U-Pb results from the underlying Kangtuo Formation, we recognize a major secular shift in sediment provenance characterized by inputs of Lhasa-derived clasts during the Late Eocene. Moreover, we applied statistical analysis to compare the U-Pb age spectra of Eocene strata in the Gaize-Nima-Lunpola basins in order to assess similarities between them and potential source regions. Our study confirms a paleogeographic scenario in which these Paleogene basins most likely were part of a low-elevation intermontane valley.

Subsidence and Uplift History of the UAE and the Western Flank of the UAE‐Oman Mountain Range

AbstractThe western flank of the UAE‐Oman mountain range offers a unique geodynamic setting to study the development of a cratonic rift into a mature passive margin and its subsequent flexure under orogenic load. However, the geodynamic processes driving this evolution are not fully understood. In this study, seismic and biostratigraphic data from 283 exploration wells were utilized to assess the regional subsidence and uplift history of the United Arab Emirates (UAE) and neighboring areas of the western flank of the UAE‐Oman mountain range. Three major sequences have been identified: pre‐Permian, Permian‐Turonian rifted margin, and Coniacian‐Pleistocene active margin. Backstripping of biostratigraphic data reveals Early Permian (ca. 272 Ma) and Late Jurassic (ca. 160) rift phases, that have been linked to Gondwana's early and final fragmentation. A NE‐SW‐oriented basin in central UAE suggests a Jurassic intracratonic rift that has been influenced by pre‐existing structures. Compressional phases were identified during the Late Cretaceous and in the Oligocene‐Miocene, coinciding with the emplacement of the Semail ophiolite and the Arabian‐Eurasian plates collision, respectively. These events caused additional subsidence and flank uplift, forming the Aruma foreland basin in the east and the Pabdeh foreland basin in the eastern and northern UAE. Crustal thickness following the rift episodes ranges from 30 to 36 km, resulting in a sedimentary cover thickness of 11–14 km. These estimates are in accord with Moho depths derived from teleseismic receiver functions and gravity inversion. These findings can be used to better understand Gondwana fragmentation and the opening and closing of the Neo‐Tethys Ocean.

River inverse modeling of the late Cenozoic uplift history of the Pamir-Tian Shan orogens: Implications for aridification of Central Asia

The uplift history of the Pamir-Tian Shan orogens remains debated, and is crucial to understanding the aridification of Central Asia. To address this question, we performed inverse modeling of the westward-flowing Vakhsh River along the Alai Valley between the Pamir and Tian Shan orogens. We validated the application of this method in reconstructing uplift history of mountains with complex climatic and tectonic settings. The modeled results reveal three episodes of accelerated uplift of the Vakhsh River drainage at ca. 10–7 Ma, ca. 5 Ma, and 2–0 Ma. The late Miocene rapid uplift at rates of 0.6–0.8 mm/yr of the Vakhsh River drainage occurred at ca. 10–7 Ma. Rock uplift, coeval with compressional deformation and exhumation around the Alai Valley, was likely driven by crustal shortening during the Pamir-Tian Shan convergence. Narrowing of the Alai Valley started to impact westerly atmospheric flow, leading to incipient rain shadow responsible for emergence of desert in the proximal leeward Tarim Basin. Accelerated uplift at ca. 5 Ma and 2–0 Ma at rates of 1.0–1.4 mm/yr and 1.7–2.3 mm/yr, increased surface elevations to near modern heights (3.5–5 km) that largely blocked the westerlies, causing enhanced aridification in the Tarim Basin. Our modeling results highlight the important role of mountain building in shaping late Cenozoic climate in Central Asia.

Validating the potential application of δ2Hwax and soil brGDGTs in paleoelevation estimates on the southern slopes of the Himalaya

Paleoelevation reconstructions of the Himalayan mountains and Tibetan Plateau have been a focus of geoscientists, as they can improve our understanding of the temporal evolution of climate, biodiversity, and ecosystems. Although a few approaches for paleoelevation reconstruction have been developed in the past decades, each method has inherent strengths and weaknesses, and the uplift histories of the Tibetan Plateau based on different proxies differ considerably. Therefore, developing novel approaches and applying multidisciplinary methods to reconstruct paleoelevation is badly needed. Plant leaf wax δ2H (δ2Hwax) and brGDGTs-derived indices (MBT, MBT' or MBT'5ME) show potential for tracking environmental changes along elevation transects. However, few studies have verified the reliability of the coupled δ2Hwax-brGDGTs-derived proxies for paleoelevation reconstructions. In addition, many elevation transects studied so far were dominated by different water vapor sources, which may influence the relationship between these two proxies and elevation. In this study, δ2Hwax and brGDGTs were analyzed in topsoil along an elevation transect between 971 m and 5307 m asl (above sea level) near Mt. Annapurna, on the southern slopes of the Himalaya. With the large elevation contrast of 4336 m, and the small horizontal span (40 km), this transect is an ideal place to further evaluate the potential of δ2Hwax, MBT'5ME, and coupled δ2Hwax-MBT′5ME proxies for local paleoelevation reconstruction. The results showed that both δ2Hwax and MBT'5ME proxy indices decreased significantly with increasing elevation, suggesting that both proxies were reliable in paleoelevation estimates. Moreover, the coupled δ2Hwax-MBT′5ME proxy showed greater potential for paleoelevation estimates than the single δ2Hwax or MBT'5ME proxies. This study highlighted the great potential of the coupled δ2Hwax-MBT′5ME proxy in paleoelevation estimates, as this dual proxy can improve the correlation coefficients (R2) and reduce the uncertainties (RMSE) in paleoelevation estimates over a wide area of the globe. In addition, in order to effectively constrain the influence of environmental factors on these proxies, it is necessary to have a thorough understanding of the climatic and environmental background when applying the two proxies for paleoelevation.

Cretaceous mountain building processes triggered the aridification and drainage evolution in east Asia

Knowledge of the late Mesozoic topography and drainage system of the Tibetan Plateau is essential for understanding the Cenozoic tectonic dynamics of the plateau. However, systematic analyses of the pre-Cenozoic surface uplift history and sediment-routing systems of the Tibetan Plateau remain sparse. Here we present new results for paleocurrents and U-Pb detrital zircon geochronology from the Lanping Basin, a key junction in the southeastern (SE) Tibetan Plateau, and integrate multidisciplinary data sets to constrain sediment provenance and reconstruct paleotopography and its drainage system throughout the Cretaceous. Our results indicate that mid- to Late Cretaceous (ca. Albian−Santonian) tectonically induced surface uplift occurred in the SE Tibetan Plateau, leading to the build-up of an extensive topographic barrier, and resultant rain shadows in the interior of east Asia. Superimposition of this topographic pattern by uplands in the eastern margin of Asia meant that the Cretaceous topography of east Asia was characterized by an enclosed paleo-relief pattern that was high in both the east and west, with drainage from the east and west to the south, contrasting with previously proposed configurations. This topographic pattern interrupted the atmospheric circulation pattern and generated widespread intracontinental desertification and drainage network evolution in east Asia. Our study constrains a key part of the late Mesozoic growth of the Tibetan Plateau prior to the Cenozoic collision between India and Eurasia and will improve our understanding of the paleoclimate, atmospheric circulation, and modern drainage system evolution of the east Asian continent.

Electron spin resonance and optically stimulated luminescence chronology of the Sanggan River terraces in the Nihewan Basin, North China

The chronology study of river terraces is important to reconstruct the history of regional climate change and tectonic uplift. Due to greater signal dose saturation levels, electron spin resonance (ESR) dating became as a potentially powerful tools for the chronology of Middle Pleistocene terraces. In this study, two profiles of terrace fluvial sediments from the Sanggan River Canyon were dated using quartz Ti–Li center ESR method. The ESR dating results show that the terraces T3 to T6 were formed at 125 ± 16 ka, 181 ± 20 ka, 315 ± 31 ka and 379 ± 44 ka, respectively. T1 and T2 were formed at 7 ± 0.3 ka and 43 ± 4 ka respectively obtained from optically stimulated luminescence (OSL) dating. These are among the first numerical ages obtained for such high terraces in the Nihewan Basin. The present work contributes to establish the chronological framework of the Late Middle Pleistocene and Holocene terraces of the Sanggan river and to improve the Quaternary stratigraphy of the Nihewan Basin.

Single-Grain Detrital Apatite Sr Isotopic Composition as an Indicator to Trace Sedimentary Sources: A Case Study of Sedimentary Rocks in the Hui-Cheng Basin, South Qinling, China

Sediments or clastic rocks can record the evolution history of basins, orogenic processes, crustal uplift and erosion, and even paleo-environments. Detrital minerals such as zircon, garnet, and apatite are useful media for studies of sedimentary sources and basin evolution. Detrital zircon has been widely taken as an indicator for provenances and tectonic evolution of geological terrenes via age distribution patterns. Apatite can remain stable during erosion and transportation and is also considered as an ideal object for source tracing. This mineral normally contains high Sr and negligible Rb. Its Sr isotopic composition can remain almost unchanged after crystallization. Unlike isotopic ages of detrital minerals, Apatite isotopic compositions have been less frequently used for tracing the provenance of sedimentary rocks in the last few decades. In the present study, we report on the Sr isotopic composition of individual apatite grains of Neogene and Jurassic conglomerates from the Hui-Cheng basin in the South Qinling orogenic belt, obtained via thermal ionization mass spectrometry. Detrital apatite grains of Jurassic rocks have narrow ranges of 87Sr/86Sr values from 0.7076 to 0.7100, but those of Neogene rocks gave variant 87Sr/86Sr values from 0.7055 to 0.7534, providing distinct evidence for complex sources of Neogene sedimentary rocks. Analytical results show that the distribution patterns of 87Sr/86Sr values of single-grain detrital apatite fit the distribution patterns of detrital zircon U-Pb from the isotopic ages very well. Detrital apatite Sr isotopic composition can provide essential information for tracing the origins and evolution of sedimentary sources.

Regional mudstone compaction trends in the Vienna Basin: top seal assessment and implications for uplift history

Seal quality assessment is not only essential in petroleum systems studies but also in the context of other geo energy applications such as underground hydrogen storage. Capillary breakthrough pressure controls top seal capacity in the absence of faults or other discontinuities. In basins that lack measured capillary pressure data (e.g., from drill cores), regional compaction-porosity trends can be used as a first prediction tool to estimate the capillary properties of mudstones. Mathematical compaction models exist but need to be calibrated for each basin. This study aims to establish a compaction trend based on theoretical models, then compare it with theoretical maximum hydrocarbon column heights inferred from true measured capillary pressure curves. Middle to upper Miocene mudstone core samples from the Vienna Basin, covering a broad depth interval from 700 to 3400 m, were investigated by X-ray diffractometry, with an Eltra C/S analyzer, and by Rock–Eval pyrolysis for bulk mineralogy, total organic carbon, and free hydrocarbon contents. Broad ion beam—scanning electron microscopy, mercury intrusion capillary porosimetry, and helium pycnometry were applied to obtain pore structural properties to compare the mathematical compaction models with actual porosity data from the Vienna Basin. Clear decreasing porosity depth trends imply that mechanical compaction was rather uniform in the central Vienna Basin. Comparing the Vienna Basin trend to global mudstone compaction trends, regional uplift causing erosion of up to ~ 500 m upper Miocene strata is inferred. A trend of increasing Rock–Eval parameters S1 and production index [PI = S1/(S1 + S2)] with decreasing capillary sealing capacity of the investigated mudstones possibly indicates vertical hydrocarbon migration through the low-permeable mudstone horizons. This observation must be considered in future top-seal studies for secondary storage applications in the Vienna Basin.

Towards Inverse Modeling of Landscapes Using the Wasserstein Distance

AbstractExtricating histories of uplift and erosion from landscapes is crucial for many branches of the Earth sciences. An objective way to calculate such histories is to identify calibrated models that minimize misfit between observations (e.g., topography) and predictions (e.g., synthetic landscapes). In the presence of natural or computational noise, widely used Euclidean measures of similarity can have complicated objective functions, obscuring the search for optimal models. Instead, we introduce the Wasserstein distance as a means to measure misfit between observed and theoretical landscapes. Our results come in two parts. First, we show that this approach can generate much smoother objective functions than Euclidean measures, simplifying the search for optimal models. Second, we show how locations and amplitudes of uplift can be accurately recovered from synthetic landscapes even when seeded with different noisy initial conditions. We suggest that this approach holds promise for inverting real landscapes for their histories.

Mesozoic−Cenozoic uplift of Qiman Tagh Range in northern Tibet Plateau, western China

The Tibetan Plateau is the highest plateau on Earth. As an ideal place to decipher the intracontinental deformation mechanisms, the Tibetan Plateau has become a focus of Cenozoic geological studies. The surface uplift history of the Tibetan Plateau can help us to better understand continental collision and processes ranging from global cooling to the onset of the Asian monsoon. Although a lot of research has been done over the years, the mechanism and timing of uplift of the Tibetan Plateau, especially the northern part, continue to be debated. To address how the Tibetan Plateau developed, a better understanding of the uplift and deformation history is needed. The Qiman Tagh Range lies on the northeastern margin of the Tibetan Plateau. Knowing what led to the exhumation of the Qiman Tagh Range could help us to constrain the tectonic evolution of the northern boundaries of the Tibetan Plateau. Here, we present new apatite fission-track data and the thermal history for the north Qiman Tagh Range. The thermal history modeling indicates that the Qiman Tagh Range experienced a four-stage cooling history (i.e., at ca. 230 Ma, 130−90 Ma, ca. 35 Ma, and 20/10−0 Ma). The results reveal that the initial exhumation of the Qiman Tagh Range occurred in the Middle Triassic due to the collision between the western Qiangtang and eastern Qiangtang terranes and the northward colliding and collaging of the Kumukuri microcontinent with the south Qiman Tagh Terrane. The rapid exhumation during the Cretaceous resulted from the collisions between the Lhasa and Qiangtang terranes. The Cenozoic exhumation may be related to the far-field stress effect of the India-Asia collision. Based on our new data, together with tectonic studies around the Qaidam Basin, we reconstructed the big Paleo-Qaidam Basin as it was during late Mesozoic and early Cenozoic time. The Mesozoic uplift of the Qiman Tagh Range was not high enough to form topographical isolation, but the rapid uplift of the Qiman Tagh at ca. 35 Ma completely separated the Kumukol Basin to the south from the Qaidam Basin to the north. The Qiman Tagh Range has experienced an acceleration of uplift since the Miocene to present, which formed the current basin-range landform. The study constrains the uplift history of the northern Tibetan Plateau and helps us to better understand its growth mechanism.

Thermal evolution and hydrocarbon generation history of the Weibei uplift in the Ordos Basin

The Weibei uplift in the Ordos Basin has a distinctive tectonic setting and intricate evolutionary history. Along these lines, we have used the stratum temperature, apatite fission track, and vitrinite reflectance data to restore the thermal and hydrocarbon generation histories of the Weibei uplift. The average value of the present geothermal gradient of the Weibei uplift was 27.9°C/km, and the heat flow was 64.9 mW/m2. The Weibei uplift exhibited a moderate geothermal field. Three uplift cooling events occurred in the Weibei uplift during the Mesozoic era: the late Jurassic-early Cretaceous (162–125 Ma), the late Cretaceous (105–65 Ma), and the Eocene-Oligocene (40–27 Ma). The uplift history indicates an early uplift in the south region and a late uplift in the later stage. The thermal evolution history simulation demonstrates that the lower Palaeozoic Ordovician source rocks began to enter the hydrocarbon generation threshold in the middle Permian-late Permian (270 Ma) era and joined the hydrocarbon generation peak in the early-middle Jurassic event (180 Ma). The upper Palaeozoic Carboniferous-Permian source rocks began to enter the hydrocarbon generation threshold in the later period of the middle Permian period (235 Ma). They joined the hydrocarbon generation peak in the late Jurassic-early Cretaceous period (150 Ma). In addition, Triassic source rocks entered the hydrocarbon generation threshold in the early Cretaceous era (135 Ma) and did not enter the hydrocarbon generation peak until now. The low geothermal gradient of the Weibei uplift in the Palaeozoic-early Mesozoic reached the maximum paleotemperature in the early Mesozoic era (100 Ma) because of tectonic thermal events. The highest geothermal gradient of the early Cretaceous reached 51.5°C/km. The peak period of the hydrocarbon generation of source rocks of the different horizons in the Weibei uplift was regulated by the geothermal field of the early Cretaceous event. Since the late Cretaceous period, the stratum has been uplifted and cooled rapidly, and the hydrocarbon generation process of the source rocks has ceased.