Thermal History Modeling Research Articles

1D basin modeling and hydrocarbon generation potential of the Late Carboniferous Limburg Group formations, Northwest European Basin, Netherlands

The Carboniferous rock samples of the Limburg Group formations were studied to investigate the source rock characteristics and the hydrocarbon generative potential. The source rock samples have been collected representing four rock units from three different wells. These samples were analyzed using Rock-Eval pyrolysis results and measured vitrinite reflectance values, and also by generating a one-dimensional basin model of K1 Field. The total organic carbon in these samples varies from 0.31 to 83.56% with a mean of 37.68%, suggesting that Limburg Group formations have excellent potential as a source of hydrocarbons. Kerogen in the Limburg Group formations is type II-III and type III, generate gas prominently. The outcomes of thermal maturation by Tmax and measured vitrinite reflectance reveal that the examined Limburg source rocks are located in the mature zone. The burial and thermal history models show irregular trend patterns due to uplift, erosion, and non-deposition events that took place in the K1 field (where the structural element is Cleaver Bank High). For the Maurits Formation, the oil generation took place at 2011 m at 230.1Ma ago and the top of the gas window was encountered 217.8Ma ago at 2535 m, whereas for the Hospital Ground Formation, the top of the oil window was encountered 186.8Ma ago at 2404 m and the gas generation took place at 2404 m at 161.9Ma ago.

Burial history, thermal history and hydrocarbon generative potential and modelling of Urandab Shale within Ogaden Basin, Ethiopia

Burial history, thermal history and hydrocarbon generative potential and modelling of Urandab Shale within Ogaden Basin, Ethiopia

Low-temperature thermochronology of the Longmala - Mengya’a Pb-Zn deposits (southern Tibet): Implications for ore exhumation and preservation

The large Gangdese metallogenic belt, located in the southern part of the Tibetan Plateau, hosts a variety of magmatic-hydrothermal ore deposits. Previous works in the area primarily concerned the ore genesis, while the exhumation history of these ore deposit has received less attention. In this contribution we explore the multi-stage thermo-tectonic evolution of the Longmala and Mengya’a Pb-Zn deposits, two large magmatic-hydrothermal ore deposits in the central Lhasa sub-terrane. In more detail, the thermal history of granitoids and deformed Paleozoic sediments inside and on the periphery of the ore districts have been constrained by low-temperature thermochronological methods, including the zircon (U-Th)/He and apatite fission track thermochronology. Additionally, zircon U-Pb geochronology was conducted on granitic host rocks to determine their emplacement ages. Our thermochronological data and inverse thermal history modeling results reflect two phases of accelerated basement cooling during the Cenozoic (i.e., ∼46–41 Ma and ∼20–5 Ma), interpreted as exhumation phases. The ore body was exhumed to the near surface during the Miocene, which provides essential information for ore exploration in the region. We also explore the degrees of basement rock exhumation along the Gangdese metallogenic belt and their spatio-temporal relations to major ore deposit distributions. It is suggested that complex interactions between tectonic-structural activities and surface erosion occurred during the late Oligocene-Miocene (∼25–5 Ma), which resulting in widespread exhumation along the Gangdese batholith. During this period, the ore-bearing rocks were gradually (with medium to high cooling rates) exhumed to the near-surface from ∼3–4 km crustal depth, making these ore deposits feasible for commercial mining.

Along-strike tectonic evolution of the Neogene Bermejo foreland basin and Eastern Precordillera thrust front, Argentina (30-32°S)

The Bermejo retroarc foreland basin system formed in flexural response to Cenozoic crustal thickening in the Andean orogenic system, specifically, the eastward propagation of the Precordillera fold-thrust belt and the basement-involved uplift of the Sierras Pampeanas. Previous work in the region has mainly focused on the mechanisms and expression of flat slab subduction and the structural geometry of the basement-involved Sierras Pampeanas and east-directed Precordillera fold-thrust belt at depth, advancing our understanding of the Bermejo basin history north of 31°S. However, the along strike evolution of the basin system to the south remains unresolved and contrasting tectonic models have proposed the Bermejo basin evolved synchronously versus asynchronously through time. Our study seeks to constrain the along-strike Neogene tectonics of the Bermejo basin via well-exposed Miocene fluvial stratigraphic intervals along the Eastern Precordillera, integrated with detrital zircon U–Pb geochronology provenance and detrital apatite (U–Th)/He thermochronology datasets. New data from two Neogene stratigraphic sections in the southern Bermejo basin constrain deposition between 13 and 6 Ma. Dominant fluvial-lacustrine mudstones, siltstones, and sandstones transition into fluvial-megafan deposits capped by alluvial fan conglomerate facies, tracking the eastward migration of Precordillera deformation. The cessation of sedimentation, and thermal history models of apatite (U–Th-Sm)/He thermochronology ages, indicates basin incorporation into the orogenic wedge by 6 Ma. When we compare our southern datasets with previous constraints from the northern Bermejo basin, we observe, from north to south: (1) a time-transgressive trend in basin initiation, (2) a ∼3 km decrease in stratigraphic thicknesses, and (3) older exhumation along the thrust front. These trends highlight the asynchronous nature of the Bermejo foreland basin system and along-strike variability of Precordillera thrust-front evolution.

New Constraints on the Late Oligocene‐Miocene Thermo‐Tectonic Evolution of the Southeastern Tibetan Plateau From Low‐Temperature Thermochronology

AbstractThe southeastern (SE) Tibetan Plateau (Yunnan) is characterized by low‐relief uplands that were deeply incised by large rivers. The thermal history of basement rocks in this region remains poorly investigated, while this data is needed to elucidate the complex relationship between tectonics and climate in shaping the surface. To better understand its thermo‐tectonic evolution, we carried out apatite fission track thermochronology on 31 samples collected from a large area that covers different tectonic units, including a vertical profile in the middle Mekong River valley; additional zircon LA‐ICP‐MS U‐Pb dating was performed on four basement rocks. Our results confirm that a large portion of Mesozoic crystalline rocks constitute the basement of the SE Tibetan Plateau. Inverse thermal history modeling of fission track data reveal extensive late Oligocene to Miocene rapid basement cooling and exhumation episodes from both inside and outside the active zones (i.e., ductile shear zone and river valley). These thermal events were coincident with the activities of large‐scale strike‐slip faults that dominate the structural framework. Combined with the published data, we propose that widespread crustal shortening and thickening took place in the SE Tibetan Plateau during the Oligocene‐Miocene in the context of a compressive tectonic regime. Low‐temperature thermochronological data reveal that both tectonic forcing and climate‐driven erosion have played important roles in exhuming the basement rocks in the region. It is also deduced that the present‐day relatively low‐elevation landscape of the Yunnan area resulted from complex interaction between regional tectonic activity and surficial erosion since the late Oligocene.

Late Triassic Tectonic Setting in Northeastern Margin of North China Craton: Insight into Sedimentary and Apatite Fission Tracks

The closure timing of the Paleo-Asian Ocean and the terminal stage of the Central Asian Orogenic Belt have been widely debated in the geological community. It’s known that the gradual scissor-like closure of the Paleo-Asian Ocean occurred from west to east during the Paleozoic period. However, it was not until the Triassic period that the complete closure of the ocean occurred at the northeastern margin of the North China Craton. Nevertheless, there is still much uncertainty regarding the Late Triassic tectonic setting in Northeast China. In this study, we focused on the Upper Triassic Dajianggang Formation, located in the Shuangyang area of central Jilin Province, which is situated on the northeastern margin of the North China Plate. Our aim was to determine the formation age of the Dajianggang Formation by analyzing the detrital particle composition, petrogeochemistry, detrital zircon U-Pb isotope dating, and apatite fission track thermochronology. Our results indicated that the primary sandstone provenance area of the Dajianggang Formation in the Shuangyang area is the island arc orogenic belt. The tectonic background of the sandstone provenance area is mainly a continental island arc environment. The provenance area is mostly composed of felsic rocks with sedimentary tendencies, and some of its material may have originated from the northern margin of the North China Craton or the eroded recycle orogenic belt. LA-ICP-MS U-Pb dating of detrital zircons shows that the Dajianggang Formation formed after 226.8 ± 5 Ma. Moreover, analysis of the thermal evolution history modelling shows that the Dajianggang Formation in the Shuangyang area continued to be deposited and heated in the early stage, and then experienced rapid exhumation around 30 Ma. This suggests that the study area underwent an orogenic process during the early stage of formation, but then transitioned into a post-orogenic extension period, which constrained the final closure of the Paleo-Asian Ocean prior to the Late Triassic period. In addition, our study indicates that the remote effect of the Pacific subduction did not reach the study area until 30 Ma. The central age of the detrital apatite fission track of sample 19DJ-1 is 94.2 ± 8.3 Ma, which is younger than its corresponding stratigraphic age. The two peak ages of the fission track analysis are 62.9 ± 5.4 Ma and 126 ± 11 Ma. These findings provide new evidence for the tectonic evolution of Northeast China and shed light on the Late Triassic tectonic setting, as well as the influence time of subsequent tectonic domains in the southern part of Northeast China.

About this title - Tectonic Development, Thermal History and Hydrocarbon Habitat Models of Transform Margins: their Differences from Rifted Margins

Transform margins form a significant portion of Earth's continent–ocean transition and are integral to continental break-up, yet compared to other margins are poorly understood. This volume brings together new multidisciplinary research to document the structural, sedimentological and thermal evolution of transform margins, highlighting their relationship to continental structure, neighbouring oceanic segments, pull-apart basins and marginal plateaus. Special emphasis is given to the comparison of transform and rifted margins, and to the economic implications of transform margin structure and evolution. Transform case studies include the Agulhas–Falkland transform, Coromandal transform (East India), Davie margin and Limpopo transform (East Africa), Guyana transform margin, Demerara transform margin (Suriname), Romanche and St Paul transforms (equatorial Africa), Sagaing transform (Andaman Sea) and Zenith–Wallaby–Perth transform (West Australia). The broad-scale interplay between transform and rifted margin segments in the North and Central Atlantic, and Caribbean, is also examined.

Mesozoic Thermo-Tectonic Evolution of the Western Altai Orogenic Belt (NW China): Insights from Low-Temperature Thermochronology

Abstract The Meso-Cenozoic tectonic activities of the Central Asian Orogenic Belt (CAOB) played an important role in controlling the present-day topography of Central Asia. The Altai orogenic belt is a key component in the southern CAOB; so far, there is still a lack of sufficient constraints on the time and mechanism of its tectonic reactivation since the Mesozoic. In this contribution, we present new zircon and apatite (U-Th)/He and apatite fission track thermochronological data from granitoid samples in the Habahe area, western Altai orogenic belt. Therein zircon (U-Th)/He ages range from ~230 to ~238 Ma, apatite fission track central ages are ~140–157 Ma, and apatite (U-Th)/He ages vary from ~134 to ~149 Ma. Based on the associated thermal history modeling results, the Habahe area underwent a moderate cooling during the Late Triassic to Middle Jurassic (~230–170 Ma) with a cooling rate of ~0.8–1.1℃/Ma and a subsequent moderate to slightly rapid cooling stage during the Middle Jurassic to Early Cretaceous (170–130 Ma) with a cooling rate of ~1.5–2.3℃/Ma. We propose that this prolonged cooling stage occurred under a long-lasting contractional tectonism in the western Altai throughout the early Mesozoic, which was produced by multiplate convergence in East Asia during this period, mainly including the consumption of the Mongol-Okhotsk Ocean in the northeast and the Meso-Tethys Ocean in the south. The region experienced rather limited Late Cretaceous-Cenozoic cooling and exhumation due to insufficient reactivation and weak surficial erosion.

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.

Phanerozoic Tectonic and Sedimentation History of the Arctic: Constraints From Deep‐Time Low‐Temperature Thermochronology Data of Ellesmere Island and Northwest Greenland

AbstractRocks exposed along both sides of the Smith Sound in Ellesmere Island and NW Greenland record the tectono‐sedimentary evolution of the whole Phanerozoic, including two periods of mountain building—the Palaeozoic Ellesmerian Orogeny and the Palaeogene Eurekan Orogeny—and the formation of two major sedimentary basins, the Franklinian and the Sverdrup Basins. We used geo‐ and thermochronology and apatite chemistry data to unravel this evolution. Apatite fission track and (U‐Th)/He dates vary strongly from >600 to <100 Ma. We present internally consistent thermal history models, which allow to explain the data variations by a unitized exhumation and burial history. Our models suggest that the cratonic areas were buried beneath a several km‐thick succession of Franklinian Basin deposits. During the Ellesmerian Orogeny, the craton acted as sediment source, as also suggested by the composition of apatite and by U‐Pb ages of zircon contained in Devonian foreland sediments. The Ellesmerian foreland was buried by up to 4–5 km thick strata on top of the preserved sedimentary rocks. During the Triassic, the Sverdrup Basin strongly widened and extended at least ∼370 km further toward the east, as compared with previous reconstructions of the basin based on the preservation of Triassic deposits. Thermal history modeling suggests Late Cretaceous to early Cenozoic reheating, which may be caused by deposition associated with the Eurekan Orogeny and/or enhanced heat flow associated with continental breakup. Our data also show that low‐temperature thermochronology is not suitable for resolving potential strike‐slip movements along the Wegener Fault.

Several Problems in Low-Temperature Thermal History Modeling

Thermal history modeling based on low-temperature thermochronological data is widely used in the study of geology. Despite its common applications, several problems remain easy to ignore yet should not be overlooked in the execution of such models. This paper describes four key problems of thermal history modeling, namely, (1) is the best-fit thermal history the best? (2) Is the date constraint box a suitable constraint? (3) Does the bimodal distribution of the apatite fission track confined track length absolutely correspond to the cooling reheating model? (4) Is the whole thermal history path credible? Counterexamples are then provided to stress the importance of accounting for these problems in the application of thermal history modeling. Acknowledging the uncertainty and considering the geological constraints are recommended to improve the accuracy of thermal history models. Moreover, thermal historical intervals with high credibility and strong constraint ability are recommended to interpret the selected geological phenomenon.

Thermal history of the Peel Plateau, northern Canadian Cordillera, resolved through multikinetic apatite fission-track dating

The Peel Plateau of the northern Canadian Cordillera has undergone multiple burial and unroofing events throughout the Phanerozoic, including subsidence and uplift associated with emergence of the Mackenzie Mountains. Episodic unroofing events are evinced by unconformities that represent a period where an unknown amount of material was deposited and eroded. Thermochronological studies have been conducted in neighboring physiographic regions, however no work has been conducted in the Peel Plateau and there is interest to determine whether it shares a similar thermal evolution as the surrounding regions. Apatite fission-track thermochronology (AFT) is a useful method for reconstructing basinal thermal histories as the system is sensitive to upper crustal temperatures, although the kinetics of the thermochronometer are complicated by numerous elemental substitutions within apatite that are known to control the specific temperature window within which fission-tracks anneal. This study uses three strategically positioned AFT samples from Phanerozoic sedimentary rocks to investigate the thermal history of the region from the Devonian to the present. Pooled AFT ages from all samples fail the χ2 test, implying there is a high level of intra-sample age dispersion and potentially indicating the samples contain multiple age populations. To assess whether the data are consistent with multiple kinetic AFT populations, we use grain-specific apatite compositions to derive rmro, a kinetic parameter that accounts for elemental substitutions known to control annealing kinetics of fission-tracks. By plotting AFT ages and track lengths against rmro we identify more-retentive and less-retentive apatite populations within each sample, which serve as independent thermochronometers when incorporated into inverse thermal history modelling. Results from a thermal history model of the Upper Devonian Imperial Formation indicate that the uppermost Paleozoic strata in the Peel Plateau reached maximum burial temperatures (∼165°C–185 °C) in the Triassic and were reheated to lower temperatures (∼90°C–100 °C) under a Cretaceous-Paleocene foreland basin. The temperature regime of the latter burial event is supported by thermal history models of two Cretaceous samples that record peak burial temperatures (∼80°C–90 °C) in the Paleocene to Eocene. This study highlights the capabilities of thermal history modelling from multikinetic AFT data and serves as a reminder that addressing variable annealing kinetics of apatite grains can improve the resolution of thermal models and the associated geologic interpretations.

Reconstruction of the topographic evolution of the coastal mountain system in southeastern China

The coastal mountain system (CMS) of southeastern China has been a natural place to study paleotopographic changes primarily due to its marked topographical contrast since the Late Cretaceous. For a quantitative reconstruction of the paleotopographic evolution of the CMS, this paper provides key information from along the Ningde–Jianyang and Huilai–Longchuan cross-sections using apatite (U-Th)/He (AHe) and zircon (U-Th)/He (ZHe) data combined with thermal history and paleotopographic modeling. For the Ningde–Jianyang section, the AHe dates are in the range of 44.3–70.8 Ma, and the ZHe dates are between 58.5 and 102.9 Ma. For the Huilai–Longchuan section, the resulting AHe dates are in the range of 37.9–73.8 Ma, and ZHe dates are between 65.5 and 119.7 Ma. The modeling results suggest that: 1) the CMS had an asymmetric topography during the Late Cretaceous with the SE segment being significantly higher (peak elevation = 3.8 km) than the NW segment (peak elevation = ~2 km). The marked decreases in elevation and relief of the CMS occurred during 80–40 Ma, followed by relatively minor topographic changes since ~40–30 Ma; 2) The SE segment of the southern CMS experienced significantly faster exhumation (~0.44 km/Myr) than northern CMS (0.16 km/Myr) during 70–60 Ma, which was probably related to thinning of the crust and orogenic collapse linked to the initial-rifting of the South China Sea; 3) The SE segment of southern CMS experienced slower exhumation than northern CMS during 60–40 Ma, likely resulting from the lower elevations in the southern CMS than in the northern CMS during 60–40 Ma.

Mesozoic exhumation of the northern West Junggar, NW China: Insights from low-temperature thermochronometers

As an important component of the Central Asian Orogenic Belt (CAOB), the West Junggar represents a natural laboratory to explore intracontinental deformation in a complex terrane. Although some low-temperature thermochronological studies have been conducted in this range, the number of exhumation stages and the corresponding driving forces behind exhumation remain highly debated. In particular, the exhumation history of the northern West Junggar remains poorly studied owing to a lack of data. Here, we present a study that integrates apatite fission track (AFT) and (UTh)/ He (AHe) dating from the igneous rock in the Sawur Mountains in northern West Junggar to further constrain the exhumation history of the region. AFT dating of the samples dominantly yields Late Triassic ages (200–227 Ma) with mean track lengths (MTLs) varying between 13.33 and 14.98 μm, while AHe dating produced widely dispersed Late Triassic to Late Cretaceous single grain ages (73–215 Ma), with sample mean ages between 100 and 195 Ma. Inverse thermal history modeling of our results and analysis of age-elevation relationships reveal that the Sawur Mountains experienced an extended period of rapid cooling related to local exhumation during the Middle–Late Triassic. A gradual reduction in surface relief following rapid erosion is related to peneplanation processes. The timing and patterns of this exhumation indicate it was caused by reverse oblique-lip reactivation of older strike-slip faults, and it can be explained as the response to the far-field effects of the final closure of the Paleo-Asian Ocean.

Breaking plates: Creation of the East Anatolian fault, the Anatolian plate, and a tectonic escape system

Abstract Lateral movement of lithospheric fragments along strike-slip faults in response to collision (escape tectonics) has characterized convergent settings since the onset of plate tectonics and is a mechanism for the formation of new plates. The Anatolian plate was created by the sequential connection of strike-slip faults following ≥10 m.y. of distributed deformation that ultimately localized into plate-bounding faults. Thermochronology data and seismic images of lithosphere structure near the East Anatolian fault zone (EAFZ) provide insights into the development of the new plate and escape system. Low-temperature thermochronology ages of rocks in and near the EAFZ are significantly younger than in other fault zones in the region, e.g., apatite (U-Th)/He: 11–1 Ma versus 27–13 Ma. Young apatite (U-Th)/He ages and thermal history modeling record thermal resetting along the EAFZ over the past ~5 m.y. and are interpreted to indicate thermal activity triggered by strike-slip faulting in the EAFZ as it formed as a through-going, lithosphere-scale structure. The mechanism for EAFZ formation may be discerned from S-wave velocity images from the Continental Dynamics–Central Anatolian Tectonics (CD-CAT) seismic experiment. These images indicate that thin but strong Arabian lithospheric mantle extends ~50–150 km north beneath Anatolian crust and would have been located near the present surficial location of the Bitlis-Zagros suture zone (co-located with the EAFZ in our study area) at ca. 5 Ma. Underthrusting of strong Arabian lithosphere facilitated localization of the EAFZ and thus was a fundamental control on the formation of the Anatolian plate and escape system.

Thermal history of the Carrara Sub-basin: insights from modelling of the NDI Carrara 1 drill hole

NDI Carrara 1 is a 1751 m stratigraphic drill hole completed in 2020 as part of the MinEx CRC National Drilling Initiative, in collaboration with Geoscience Australia and Northern Territory Geological Survey under the Exploring for the Future program. It is the first stratigraphic test of the Carrara Sub-basin, a recently discovered depocentre in the South Nicholson region. The drill hole intersected Cambrian and Proterozoic sediments consisting of organic-rich black shales and a thick sequence of interbedded black shales and silty-sandstones with hydrocarbon shows. A comprehensive analytical program carried out by Geoscience Australia on the recovered continuous core from 283 m to total depth at 1751 m provides critical data for understanding this area. Using data from this drilling campaign, thermal history modelling was undertaken to provide an estimate of the time-temperature maxima that the sub-basin has experienced, contributing to an understanding of hydrocarbon maturity. Kerogen kinetics are used to estimate the petroleum prospectivity of the sub-basin and attempt to understand the timing and nature of hydrocarbon generation. Combined, these newly modelled data provide insights into the resource potential of this frontier Proterozoic–Paleozoic hydrocarbon province, delivering foundational data to support explorers across the eastern Northern Territory and northwest Queensland.

Control of inherited structural fabric on the development and exhumation of passive margins – Insights from the Araçuaí Orogen (Brazil)

The Araçuaí Orogen, in eastern Brazil, was formed during the Neoproterozoic – Cambrian amalgamation of West Gondwana. During the Mesozoic – Cenozoic opening of the South Atlantic Ocean, and the associated divergent tectonics, the orogen developed as basement to the passive margin of South America and was progressively covered by thick offshore sedimentary basins, particularly the Espírito Santo, Mucuri, and Cumuruxatiba basins, in which hydrocarbon systems have been exploited. Our understanding of the Araçuaí Orogen's passive margin evolution, erosion, and sediment transfer to these basins ultimately depends on constraining the onshore exhumation in response to Mesozoic – Cenozoic events. Here, new and previously published data from apatite fission-track (AFT) analyses and inverse thermal history modelling of (Pre)Cambrian basement rocks from the Araçuaí Orogen resolve three discrete basement cooling and associated erosional exhumation episodes. In the Pre-Rift phase, Jurassic – Hauterivian erosion of the Araçuaí Orogen is most likely related to the adjoining intra-continental West Gondwana flexural subsidence, which increased hillslope and river erosion power. In the Rift and Transitional phases, Barremian – Albian accelerated phase of erosion is associated with the uplift of the Atlantic rift shoulders and the establishment of an oceanic base-level. In the Drift phase, reactivations in response to far-field stresses likely triggered a Late Cretaceous – Paleocene rapid erosion event. The rates at which these events unfolded vary spatially and are controlled by inherited structures. The Araçuaí Orogen experienced slower denudation rates in areas closer to the São Francisco Craton, which suggests that the tectonic reactivation and related surface uplift during the Mesozoic–Cenozoic is in first-order controlled by lithospheric rigidity. Furthermore, the structural framework of the Paramirim and Pirapora aulacogens and NE-oriented shear zones in the orogen’s southeast facilitated later reactivations. From the spatial pattern of denudation/exhumation of the Araçuaí Orogen during the Mesozoic – Cenozoic, we draw inferences on the tectonic development of the offshore basins regarding their hydrocarbon potentials.

Uplift and exhumation of the Chakabeishan ore district in the northern margin of the Qaidam Basin, China: Constraints from fission track thermochronology

The Chakabeishan area is located in the northern margin of the Qaidam Basin, Northwest China, and is an important lithium mining area. However, there is a relatively lower research degree and lack of data constraints of tectonic uplift and exhumation. Using fission track technology, new apatite and zircon fission track results have been reported for the first time in order to reveal the tectonic processes and uplift histories of this area. A total of 11 sample results were obtained, these ages could be divided into four groups, namely, 159–144 Ma, 114–100 Ma, 72 Ma and 52–32 Ma, revealing four periods of tectonic activities. Thermal history modelling provided three episodes of uplift at 120–60 Ma, 60–18 Ma and 18–0 Ma. In the first stage, the Southern Qilian Mountains was reactivated and subducted southward due to collision of the Lhasa and the Qiangtang blocks, resulting in rapid uplift in this area. The second stage is tectonic quiescence period corresponding to a relatively steady uplift. The third stage showing rapid uplift caused by the collision between the Indian and Eurasian Plates. The average uplift rate and total uplift amount of the three stages calculated according to the geological thermal histories are 0.039 km/Myr and 3.27 km, respectively. Using the age–closure temperature method, the exhumation rate has been calculated as 0.034–0.148 km/Myr from zircon closure–temperature of 250 °C to apatite closure–temperature of 100 °C and 0.049–0.076 km/Myr form the apatite closure–temperature of 100 °C to 15 °C of surface temperature. The exhumation rate is fastest from the Late Cretaceous to Eocene and has then changed a little since the Eocene, with the average exhumation rate of about 0.059 km/Myr. Synthesizing the zircon ages and geological characteristics, this area is characterized by multi–stages mineralization, and the metallogenic age is mainly in the Late Jurassic–Cretaceous.

Localized Cenozoic erosion on the southern African Plateau: A signal of topographic uplift?

Constraints on the erosion history of the southern African Plateau have played a key role in the debate over the plateau’s age and origins. Previous low-temperature thermochronology from the region has illuminated the Cretaceous erosion history but yielded little insight into Cenozoic erosion patterns. We capitalize on the low-temperature sensitivity of apatites with low effective uranium concentration (eU) from kimberlites and examine a compilation of kimberlite apatite (U-Th)/He dates from across the plateau to investigate Cenozoic cooling. Dates from low-eU (<25 ppm) apatites show a range of Miocene to Cretaceous dates while higher-eU dates are dominantly Cretaceous. Thermal history modeling shows that these data patterns are well replicated by a phase of spatially variable cooling in the Cenozoic that ranges from minimal to 25 °C, equating to as much as ∼1250 m of erosion. Not all kimberlites record this cooling phase, but those that do are concentrated near paleo- and modern river valleys. These patterns appear best explained by Cenozoic river incision driven by increased rock uplift that caused associated topographic development. Although more data and different tools are needed to resolve temporal and spatial details, this compilation provides the first glimpse of Cenozoic erosion patterns across the plateau surface from thermochronology.

Cenozoic low temperature cooling history of the eastern Lhasa terrane: Implications for high-relief topography of external drainage area in the southern Tibetan Plateau

The Tibetan Plateau geographically contains internal and external drainage areas based on the distributions of river flows and catchments. The internal and external drainage areas display similar high-elevations, while their topographic reliefs are not comparable; the former shows a large low-relief surface, whereas the latter is characterized by relatively high relief. The eastern Lhasa terrane is a key tectonic component of the Tibetan Plateau. It is characterized by high topography and relief, but the thermal history of its basement remains relatively poorly constrained. In this study we report new apatite fission track data from the eastern part of the central Lhasa terrane to constrain the thermo-tectonic evolution of the external drainage area in the southern Tibetan Plateau. Twenty-one new AFT ages and associated thermal history models reveal that the basement underlying the external drainage area in southern Tibet experienced three main phases of rapid cooling in the Cenozoic. The Paleocene-early Eocene (∼60–48 Ma) cooling was likely induced by crustal shortening and associated rock exhumation, due to accelerated northward subduction of the NeoTethys oceanic lithosphere. A subsequent cooling pulse lasted from the late Eocene to early Oligocene (∼40–28 Ma), possibly due to the thickening and consequential erosion of the Lhasa lithosphere resulted from the continuous northward indentation of the India plate into Eurasia. The most recent rapid cooling event occurred in the middle Miocene-early Pliocene (∼16–4 Ma), likely induced by accelerated incision of the Lhasa River and local thrust faulting. Our AFT ages and published low-temperature thermochronological data reveal that the external drainage area experienced younger cooling events compared with the internal drainage area, and that the associated differentiated topographic evolution initiated at ca. 30 Ma. The contributing factors for the formation of the high-relief topography mainly contain active surface uplift, fault activity, and the enhanced incision of the Yarlung River.