Journal of Asian Earth Sciences最新文献

Corrigendum to “Characteristics and Genesis of Geothermal Systems in the Southern Junggar Foreland Basin, NW China” [J. Asian Earth Sci. 276 (2024) 106363]

IF 2.7 3区地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY

Journal of Asian Earth Sciences

Pub Date : 2024-11-29 DOI: 10.1016/j.jseaes.2024.106425

Wei Zhang , Chaodong Wu , Shaobo Liu , Xuesong Lu , Qiulin Guo , Guorong Wang

引用次数: 0

New paleomagnetic and geochronologic results from the eastern Tethyan Himalaya refine the size of Greater India in the Early Cretaceous

IF 2.7 3区地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY

Journal of Asian Earth Sciences

Pub Date : 2024-11-27 DOI: 10.1016/j.jseaes.2024.106428

Jie Yuan, Wenxing Hao, Ruoyuan Qiu

Knowledge of the original size of Greater India in the Early Cretaceous is critical for Late Mesozoic East Gondwana reconstructions. However, estimates of Greater India extent have significant discrepancies in the Early Cretaceous. Here we report geochronologic and paleomagnetic studies on rocks of the Jiabula Formation in the northern subzone of the Tethyan Himalaya. The studied limestones are characterized by two-component magnetizations carried by detrital magnetite, which retains a primary remanence. Correspondingly, the high temperature magnetization components (350−525 °C) are isolated from 204 specimens using high-resolution thermal demagnetization. The new paleomagnetic data provide, after inclination shallowing estimation, an Early Cretaceous paleopole of 11.2°N/300.5°E, A₉₅ = 2.6°, which places the eastern part of the Tethyan Himalaya at a paleolatitude of 40.9° ± 2.6°S at ca. 126 Ma. Comparison of the new observed paleolatitude with the expected paleolatitude (49.7° ± 2.8°S) of India implies that Greater India had an extension of 968±418 km (8.8° ± 3.8°) at ca. 126 Ma. Integrating the new results with our previous Campanian results (ca. 75 Ma), we conclude that Greater India had a comparable extension of ∼900 km during ca. 126−75 Ma. The improved estimate of the dimensions of Greater India leads to an updated reconstruction of paleogeography in the Early Cretaceous.

{"title":"New paleomagnetic and geochronologic results from the eastern Tethyan Himalaya refine the size of Greater India in the Early Cretaceous","authors":"Jie Yuan, Wenxing Hao, Ruoyuan Qiu","doi":"10.1016/j.jseaes.2024.106428","DOIUrl":"10.1016/j.jseaes.2024.106428","url":null,"abstract":"<div><div>Knowledge of the original size of Greater India in the Early Cretaceous is critical for Late Mesozoic East Gondwana reconstructions. However, estimates of Greater India extent have significant discrepancies in the Early Cretaceous. Here we report geochronologic and paleomagnetic studies on rocks of the Jiabula Formation in the northern subzone of the Tethyan Himalaya. The studied limestones are characterized by two-component magnetizations carried by detrital magnetite, which retains a primary remanence. Correspondingly, the high temperature magnetization components (350−525 °C) are isolated from 204 specimens using high-resolution thermal demagnetization. The new paleomagnetic data provide, after inclination shallowing estimation, an Early Cretaceous paleopole of 11.2°N/300.5°E, A<sub>95</sub> = 2.6°, which places the eastern part of the Tethyan Himalaya at a paleolatitude of 40.9° ± 2.6°S at ca. 126 Ma. Comparison of the new observed paleolatitude with the expected paleolatitude (49.7° ± 2.8°S) of India implies that Greater India had an extension of 968±418 km (8.8° ± 3.8°) at ca. 126 Ma. Integrating the new results with our previous Campanian results (ca. 75 Ma), we conclude that Greater India had a comparable extension of ∼900 km during ca. 126−75 Ma. The improved estimate of the dimensions of Greater India leads to an updated reconstruction of paleogeography in the Early Cretaceous.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"278 ","pages":"Article 106428"},"PeriodicalIF":2.7,"publicationDate":"2024-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142747269","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Gravity anomalies and deep structure of the northeastern Tibetan Plateau and adjacent areas

IF 2.7 3区地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY

Journal of Asian Earth Sciences

Pub Date : 2024-11-26 DOI: 10.1016/j.jseaes.2024.106430

Guoming Gao, Guofa Kang, Chunhua Bai, Limin Wen, Zaijiao Wang, Yecheng Li

The northeastern Tibetan Plateau is a region having experienced subduction, collision, and intracontinental extension. In this study, a gravity model (SGG-UGM-2) was used to investigate the distribution of gravity anomalies, Moho depth, and lithospheric effective elastic thickness in the northeastern Tibetan Plateau and adjacent areas. The results were compared with the regional heat flow, crustal magnetic anomalies, and seismicity. The Bouguer gravity anomalies correlate with the surrounding stable blocks (i.e., the Tarim Basin, Alxa Block, Ordos Basin, and Sichuan Basin) and lateral crustal extrusion of the Tibetan Plateau. The isostatic gravity anomalies, Moho depth, and lithospheric effective elastic thickness are –80 to 80 mGal, 35–70 km, and 5–105 km, respectively. Isostatic disequilibrium occurs mainly near boundaries between blocks and is associated with seismic activity. The distribution of Bouguer gravity anomalies and the Moho surface record the northeastward expansion of the Tibetan Plateau. The lithospheric effective elastic thickness decreases gradually from west to east in the Bayan Har Block, reaching its lowest values (<10 km) in the Longmenshan tectonic belt, which confirms the eastward extrusion along the block. The lithospheric effective elastic thickness in the Qaidam Basin is higher than that in the Bayan Har Block and Qilian orogenic belt, which reflects underthrusting of the East Asian lithosphere beneath the Qilian orogenic belt and the fact that extrusion from the Qiangtang Block is blocked by the Qaidam Basin.

{"title":"Gravity anomalies and deep structure of the northeastern Tibetan Plateau and adjacent areas","authors":"Guoming Gao, Guofa Kang, Chunhua Bai, Limin Wen, Zaijiao Wang, Yecheng Li","doi":"10.1016/j.jseaes.2024.106430","DOIUrl":"10.1016/j.jseaes.2024.106430","url":null,"abstract":"<div><div>The northeastern Tibetan Plateau is a region having experienced subduction, collision, and intracontinental extension. In this study, a gravity model (SGG-UGM-2) was used to investigate the distribution of gravity anomalies, Moho depth, and lithospheric effective elastic thickness in the northeastern Tibetan Plateau and adjacent areas. The results were compared with the regional heat flow, crustal magnetic anomalies, and seismicity. The Bouguer gravity anomalies correlate with the surrounding stable blocks (i.e., the Tarim Basin, Alxa Block, Ordos Basin, and Sichuan Basin) and lateral crustal extrusion of the Tibetan Plateau. The isostatic gravity anomalies, Moho depth, and lithospheric effective elastic thickness are –80 to 80 mGal, 35–70 km, and 5–105 km, respectively. Isostatic disequilibrium occurs mainly near boundaries between blocks and is associated with seismic activity. The distribution of Bouguer gravity anomalies and the Moho surface record the northeastward expansion of the Tibetan Plateau. The lithospheric effective elastic thickness decreases gradually from west to east in the Bayan Har Block, reaching its lowest values (<10 km) in the Longmenshan tectonic belt, which confirms the eastward extrusion along the block. The lithospheric effective elastic thickness in the Qaidam Basin is higher than that in the Bayan Har Block and Qilian orogenic belt, which reflects underthrusting of the East Asian lithosphere beneath the Qilian orogenic belt and the fact that extrusion from the Qiangtang Block is blocked by the Qaidam Basin.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"278 ","pages":"Article 106430"},"PeriodicalIF":2.7,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142746669","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Coexistence of episodic and prolonged magmatism during the exhumation of subducted continental crust revealed by multi-method chronology of Early Paleozoic granites in South Altyn, western China

IF 2.7 3区地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY

Journal of Asian Earth Sciences

Pub Date : 2024-11-26 DOI: 10.1016/j.jseaes.2024.106427

Long Tian , Lei Kang , Liang Liu , Danling Chen , Yuting Cao , Yongsheng Gai , Tuo Ma

This study presents a comprehensive multi-method chronology, integrating zircon, titanite, and monazite dating, combined with detailed field geological investigations, petrology, and whole-rock geochemical analyses of granodiorite, diorite enclave, and monzogranite in the South Altyn Tatelekebulake area. The granodiorite yields a zircon age of 483 Ma and two episodic monazite age of 488 ± 3 Ma and 430 ± 1 Ma. In contrast, the monzogranite, with a zircon age of 451 Ma, exhibits a continuous monazite age range of 491 Ma – 431 Ma. The diorite enclave shows a titanite age of 444 ± 11 Ma. Geochemical features suggest that both the granodiorite and diorite enclave originated from the partial melting of mafic rocks within the middle and lower crust during the exhumation stage of subducted continental crust, characterized by low pressure (<1.0 GPa) and a gradual decrease in temperature over time (850°C – 700°C). The trace elements characteristics of all samples implies potential influence from fluid flux within the subduction zone during magma emplacement and ascent. In conjunction with accessory mineral dating, these ages reflect coexistence of both episodic and prolonged magmatic activity within the study area. This prolonged magmatic activity provides evidence that partial melting of Early Paleozoic continental crust rocks in the South Altyn area may have undergone complete continental crust subduction, subsequent exhumation, and post-collisional extension processes. This study emphasizes the importance of multi-method chronology in unraveling the magmatic and tectonic evolution of orogenic belts and provides new insights into the Early Paleozoic tectonic evolution of the South Altyn orogenic belt.

{"title":"Coexistence of episodic and prolonged magmatism during the exhumation of subducted continental crust revealed by multi-method chronology of Early Paleozoic granites in South Altyn, western China","authors":"Long Tian , Lei Kang , Liang Liu , Danling Chen , Yuting Cao , Yongsheng Gai , Tuo Ma","doi":"10.1016/j.jseaes.2024.106427","DOIUrl":"10.1016/j.jseaes.2024.106427","url":null,"abstract":"<div><div>This study presents a comprehensive multi-method chronology, integrating zircon, titanite, and monazite dating, combined with detailed field geological investigations, petrology, and whole-rock geochemical analyses of granodiorite, diorite enclave, and monzogranite in the South Altyn Tatelekebulake area. The granodiorite yields a zircon age of 483 Ma and two episodic monazite age of 488 ± 3 Ma and 430 ± 1 Ma. In contrast, the monzogranite, with a zircon age of 451 Ma, exhibits a continuous monazite age range of 491 Ma – 431 Ma. The diorite enclave shows a titanite age of 444 ± 11 Ma. Geochemical features suggest that both the granodiorite and diorite enclave originated from the partial melting of mafic rocks within the middle and lower crust during the exhumation stage of subducted continental crust, characterized by low pressure (<1.0 GPa) and a gradual decrease in temperature over time (850°C – 700°C). The trace elements characteristics of all samples implies potential influence from fluid flux within the subduction zone during magma emplacement and ascent. In conjunction with accessory mineral dating, these ages reflect coexistence of both episodic and prolonged magmatic activity within the study area. This prolonged magmatic activity provides evidence that partial melting of Early Paleozoic continental crust rocks in the South Altyn area may have undergone complete continental crust subduction, subsequent exhumation, and post-collisional extension processes. This study emphasizes the importance of multi-method chronology in unraveling the magmatic and tectonic evolution of orogenic belts and provides new insights into the Early Paleozoic tectonic evolution of the South Altyn orogenic belt.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"278 ","pages":"Article 106427"},"PeriodicalIF":2.7,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142746671","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Crust and uppermost mantle S-wave velocity structure of the Wudalianchi volcanic belt from direct surface-wave tomography

IF 2.7 3区地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY

Journal of Asian Earth Sciences

Pub Date : 2024-11-26 DOI: 10.1016/j.jseaes.2024.106426

Xiaoyan Song , Jianshe Lei , Dapeng Zhao , Yinshuang Ai

The Wudalianchi volcanic belt is located at the junction among the Greater Xing’an range, the Lesser Xing’an range, and the Songliao basin. Investigation of detailed crustal velocity structure under the Wudalianchi volcanic belt is of great significance to better understand the deep geodynamics of Northeast Asia. Applying the direct surface-wave tomography method to ambient noise records of our newly deployed dense WAVESArray stations from 2015 to 2019, we aim to determine a high-resolution three-dimensional (3-D) S-wave velocity (Vs) model of the crust and uppermost mantle down to 45 km depth beneath the Wudalianchi volcanic belt and surrounding areas. The WAVESArray stations have good azimuthal coverage around the Wudalianchi volcano. Our high-resolution tomographic model reveals low-Vs anomalies in the upper crust and the uppermost mantle beneath the Wudalianchi volcano and high-Vs anomalies in the mid-lower crust, indicating the presence of hot mantle upwelling and lower crust cooling solidification. This upwelling process is related to the complex dynamics of the big mantle wedge that has developed above the subducted Pacific slab that is stagnant in the mantle transition zone beneath East Asia. In addition, low-Vs anomalies are visible beneath the Erkeshan, Wudalianchi, Keluo, and Xunke volcanoes in the upper crust and they are connected with a low-Vs layer in the mid-lower crust, which provides a new piece of seismological evidence for the homology of these volcanoes, suggesting that there might be exchanges of material and energy between these volcanoes.

{"title":"Crust and uppermost mantle S-wave velocity structure of the Wudalianchi volcanic belt from direct surface-wave tomography","authors":"Xiaoyan Song , Jianshe Lei , Dapeng Zhao , Yinshuang Ai","doi":"10.1016/j.jseaes.2024.106426","DOIUrl":"10.1016/j.jseaes.2024.106426","url":null,"abstract":"<div><div>The Wudalianchi volcanic belt is located at the junction among the Greater Xing’an range, the Lesser Xing’an range, and the Songliao basin. Investigation of detailed crustal velocity structure under the Wudalianchi volcanic belt is of great significance to better understand the deep geodynamics of Northeast Asia. Applying the direct surface-wave tomography method to ambient noise records of our newly deployed dense WAVESArray stations from 2015 to 2019, we aim to determine a high-resolution three-dimensional (3-D) S-wave velocity (Vs) model of the crust and uppermost mantle down to 45 km depth beneath the Wudalianchi volcanic belt and surrounding areas. The WAVESArray stations have good azimuthal coverage around the Wudalianchi volcano. Our high-resolution tomographic model reveals low-Vs anomalies in the upper crust and the uppermost mantle beneath the Wudalianchi volcano and high-Vs anomalies in the mid-lower crust, indicating the presence of hot mantle upwelling and lower crust cooling solidification. This upwelling process is related to the complex dynamics of the big mantle wedge that has developed above the subducted Pacific slab that is stagnant in the mantle transition zone beneath East Asia. In addition, low-Vs anomalies are visible beneath the Erkeshan, Wudalianchi, Keluo, and Xunke volcanoes in the upper crust and they are connected with a low-Vs layer in the mid-lower crust, which provides a new piece of seismological evidence for the homology of these volcanoes, suggesting that there might be exchanges of material and energy between these volcanoes.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"278 ","pages":"Article 106426"},"PeriodicalIF":2.7,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142747270","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Evidence from zircon and apatite thermochronology provides evidence for the tectonic-thermal evolution and denudational processes in Dulan, Eastern Kunlun Mountains, China 锆石和磷灰石热年代学为中国东昆仑山都兰地区的构造-热演化和剥蚀过程提供证据

IF 2.7 3区地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY

Journal of Asian Earth Sciences

Pub Date : 2024-11-19 DOI: 10.1016/j.jseaes.2024.106417

Xiaolong Wang , Wanming Yuan , Zhiqiang Hu , Chenguang Ji

Since the Middle Jurassic, the East Kunlun orogenic belt in China has undergone significant denudation. This region offers crucial insights into the tectonic processes that have shaped the Tibetan Plateau. Moreover, the region boasts abundant mineral resources. This study uses techniques, such as zircon and apatite fission track (ZFT&AFT) analyses as well as citing several apatite (U-Th)-He (AHe) ages and FT ages data from the study areas, to unravel the tectonic-thermal evolution and denudation processes. The results reveal ZFT ages spanning from 167 ± 5 to 92 ± 4 Ma, and AFT ages spanning from 116 ± 6 to 64 ± 4 Ma. Based on the AFT, ZFT, and AHe data, this paper constructed a tectonic-thermal history model. In the first stage (ca. 170–120 Ma), rapid cooling at 2.00 ℃/Ma and denudation of 2.85 km occurred. The second stage (ca. 120–20 Ma) showed cooling rates of 0.60 ℃/Ma and denudation of 1.70 km. In the third stage (ca. 20–0 Ma), rapid cooling with rates of 1.50 ℃/Ma and denudation of 0.86 km were speculated. The first stage indicates the closure of the Paleo-Tethys Ocean in the Middle Jurassic, with the collision of the Lhasa and Qiangtang blocks with Eurasia along the Bangong-Nujiang suture zone in the Cretaceous. The second stage is mainly related to the northward subduction of the Neo-Tethys Ocean and the far-flung effects of the India-Eurasia collision. The uplift of the Tibetan plateau due to the Himalayan orogeny likely contributed to the third stage. The denuded thickness in the study area since 170 Ma is 5.41 km.

自中侏罗世以来，中国东昆仑造山带经历了严重的剥蚀。该地区为了解塑造青藏高原的构造过程提供了重要信息。此外，该地区还拥有丰富的矿产资源。本研究利用锆石和磷灰石裂变轨迹（ZFT&AFT）分析等技术，并引用研究地区的多个磷灰石（U-Th）-He（AHe）年龄和FT年龄数据，来揭示构造-热演化和剥蚀过程。研究结果显示，ZFT年龄跨度为167±5至92±4Ma，AFT年龄跨度为116±6至64±4Ma。根据AFT、ZFT和AHe数据，本文构建了一个构造-热历史模型。在第一阶段（约 170-120 Ma），发生了 2.00 ℃/Ma 的快速冷却和 2.85 km 的剥蚀。第二阶段（约 120-20 Ma）的冷却速度为 0.60 ℃/Ma，剥蚀长度为 1.70 km。在第三阶段（约 20-0 Ma），推测出现了 1.50 ℃/Ma 的快速冷却和 0.86 km 的剥蚀。第一阶段表明古特提斯洋在中侏罗世关闭，拉萨和羌塘地块在白垩纪沿班公错-怒江缝合带与欧亚大陆碰撞。第二阶段主要与新特提斯洋向北俯冲和印度-欧亚大陆碰撞的远距离影响有关。喜马拉雅造山运动造成的青藏高原隆升可能是第三阶段的原因。研究区域自170Ma以来的剥蚀厚度为5.41千米。

{"title":"Evidence from zircon and apatite thermochronology provides evidence for the tectonic-thermal evolution and denudational processes in Dulan, Eastern Kunlun Mountains, China","authors":"Xiaolong Wang , Wanming Yuan , Zhiqiang Hu , Chenguang Ji","doi":"10.1016/j.jseaes.2024.106417","DOIUrl":"10.1016/j.jseaes.2024.106417","url":null,"abstract":"<div><div>Since the Middle Jurassic, the East Kunlun orogenic belt in China has undergone significant denudation. This region offers crucial insights into the tectonic processes that have shaped the Tibetan Plateau. Moreover, the region boasts abundant mineral resources. This study uses techniques, such as zircon and apatite fission track (ZFT&AFT) analyses as well as citing several apatite (U-Th)-He (AHe) ages and FT ages data from the study areas, to unravel the tectonic-thermal evolution and denudation processes. The results reveal ZFT ages spanning from 167 ± 5 to 92 ± 4 Ma, and AFT ages spanning from 116 ± 6 to 64 ± 4 Ma. Based on the AFT, ZFT, and AHe data, this paper constructed a tectonic-thermal history model. In the first stage (ca. 170–120 Ma), rapid cooling at 2.00 ℃/Ma and denudation of 2.85 km occurred. The second stage (ca. 120–20 Ma) showed cooling rates of 0.60 ℃/Ma and denudation of 1.70 km. In the third stage (ca. 20–0 Ma), rapid cooling with rates of 1.50 ℃/Ma and denudation of 0.86 km were speculated. The first stage indicates the closure of the Paleo-Tethys Ocean in the Middle Jurassic, with the collision of the Lhasa and Qiangtang blocks with Eurasia along the Bangong-Nujiang suture zone in the Cretaceous. The second stage is mainly related to the northward subduction of the Neo-Tethys Ocean and the far-flung effects of the India-Eurasia collision. The uplift of the Tibetan plateau due to the Himalayan orogeny likely contributed to the third stage. The denuded thickness in the study area since 170 Ma is 5.41 km.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"278 ","pages":"Article 106417"},"PeriodicalIF":2.7,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142704118","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Late Pleistocene palynological records from the Qaidam Basin (North Tibet) and their implications for Qarhan Lake evolution 柴达木盆地（藏北）的晚更新世古生物记录及其对察尔汗湖演变的影响

IF 2.7 3区地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY

Journal of Asian Earth Sciences

Pub Date : 2024-11-19 DOI: 10.1016/j.jseaes.2024.106418

Xue Ke , Fang Han , Xudong Bai , Tinglu Yang , Taizhong Song , Zongyan Zhang , Wenjun Yang , Jinming Zhang , Bowen Song

Qarhan Salt Lake was the depocenter of the Qaidam Basin during the Quaternary, with a very thick sequence of lacustrine sediments. Continuous lacustrine sediments provide excellent archives of detailed paleoenvironmental data regarding climatic changes in the Qaidam Basin and northern Tibetan Plateau. Nevertheless, there is considerable controversy concerning the lake and climatic evolution during Marine Isotope Stage 3 (MIS3). In this study, the palynological remains from two drill cores in Qarhan Salt Lake, Qaidam Basin, were analyzed in conjunction with Accelerator Mass Spectrometry (AMS) ¹⁴C dating, with the aim of reconstructing the vegetation and paleoenvironment changes in the Qarhan Lake area during the Late Pleistocene. In addition, based on modern pollen–climate transfer functions for the Qaidam Basin and its surrounding areas, together with the fossil pollen data from dated sediment cores, we quantitatively reconstructed the mean annual precipitation in Qarhan Salt Lake area during the Late Pleistocene. By integrating these new data with lithological and palynological records from adjacent cores in Qarhan Salt Lake, the spatial distribution pattern of the lake evolution of Qarhan Lake in the Late Pleistocene was also reconstructed.

察尔汗盐湖是第四纪柴达木盆地的沉积中心，拥有非常厚的湖相沉积物序列。连续的湖沼沉积物为有关柴达木盆地和青藏高原北部气候变化的详细古环境数据提供了极好的档案。然而，关于海洋同位素第三阶段（MIS3）的湖泊和气候演变还存在相当大的争议。本研究结合加速器质谱（AMS）14C 测定方法，对柴达木盆地察尔汗盐湖两个钻孔岩心的古生物遗迹进行了分析，旨在重建晚更新世察尔汗盐湖地区的植被和古环境变化。此外，根据盖达姆盆地及其周边地区的现代花粉-气候传递函数，结合年代沉积岩芯中的花粉化石数据，我们定量重建了晚更新世期间卡尔汗盐湖地区的年平均降水量。通过将这些新数据与Qarhan盐湖相邻岩心的岩性和古生物学记录相结合，我们还重建了Qarhan湖在晚更新世湖泊演变的空间分布格局。

{"title":"Late Pleistocene palynological records from the Qaidam Basin (North Tibet) and their implications for Qarhan Lake evolution","authors":"Xue Ke , Fang Han , Xudong Bai , Tinglu Yang , Taizhong Song , Zongyan Zhang , Wenjun Yang , Jinming Zhang , Bowen Song","doi":"10.1016/j.jseaes.2024.106418","DOIUrl":"10.1016/j.jseaes.2024.106418","url":null,"abstract":"<div><div>Qarhan Salt Lake was the depocenter of the Qaidam Basin during the Quaternary, with a very thick sequence of lacustrine sediments. Continuous lacustrine sediments provide excellent archives of detailed paleoenvironmental data regarding climatic changes in the Qaidam Basin and northern Tibetan Plateau. Nevertheless, there isconsiderable controversyconcerning the lake and climatic evolution during Marine Isotope Stage 3 (MIS3). In this study, the palynological remains from two drill cores in Qarhan Salt Lake, Qaidam Basin, were analyzed in conjunction with Accelerator Mass Spectrometry (AMS) <sup>14</sup>C dating, with the aim of reconstructing the vegetation and paleoenvironment changes in the Qarhan Lake area during the Late Pleistocene. In addition, based on modern pollen–climate transfer functions for the Qaidam Basin and its surrounding areas, together with the fossil pollen data from dated sedimentcores, we quantitatively reconstructed the mean annual precipitation in Qarhan Salt Lake area during the Late Pleistocene. By integrating these new data with lithological and palynological records from adjacent cores in Qarhan Salt Lake, the spatial distribution pattern of the lake evolution of Qarhan Lake in the Late Pleistocene was also reconstructed.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"278 ","pages":"Article 106418"},"PeriodicalIF":2.7,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142704112","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

New subsurface structural insights of Northeast Vietnam: Advanced implications from high-resolution magnetic data 对越南东北部地下结构的新认识：高分辨率磁数据的先进意义

IF 2.7 3区地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY

Journal of Asian Earth Sciences

Pub Date : 2024-11-17 DOI: 10.1016/j.jseaes.2024.106413

Luan Thanh Pham , Ahmed M. Eldosouky

Northeast Vietnam is covered by sedimentary rocks, and its subsurface structures can be determined by geophysical studies. However, the structural patterns in Northeast Vietnam have so far been poorly studied and there is a lack of addressing the complex geological features of this area. Outlining such geological features is commonly achieved by applying various edge detection methods to magnetic fields. In this research, we applied nine enhancement techniques to magnetic data of Northeast Vietnam to identify geological features in this area. The methods are tested on synthetic data before applying to RTP (reduction to pole) magnetic data that are obtained from the multiple stage RTP technique. Four semiautomated depth estimation methods are also used to obtain the depth of magnetic structures in Northeast Vietnam. The results indicate that the normalized total gradient and power transform of the tilt angle of the total horizontal gradient can produce geological features more clearly than others. The findings show that the study area is dominated by NE-SW and ENE-WSW trending lineaments, and most of magnetic sources are around 1–2.5 km deep in the area. The NE-SW and ENE-WSW trending structures are possibly related to the left-lateral motion along the Ailaoshan–Red River shear zone. Our findings also show that Northeast Vietnam may be considered as a southwestern continuation of the South China Block. Our results provide a better picture of the structural features of Northeast Vietnam and overcome the gap in understanding the tectonic and geological framework of this important area.

越南东北部被沉积岩覆盖，其地下结构可通过地球物理研究确定。然而，迄今为止，对越南东北部构造模式的研究很少，也缺乏对该地区复杂地质特征的研究。概述此类地质特征通常是通过对磁场应用各种边缘检测方法来实现的。在这项研究中，我们对越南东北部的磁数据应用了九种增强技术，以识别该地区的地质特征。这些方法先在合成数据上进行测试，然后再应用于通过多级 RTP 技术获得的 RTP（磁极还原）磁数据。此外，还使用了四种半自动深度估算方法来获取越南东北部磁性结构的深度。结果表明，归一化总梯度和总水平梯度倾斜角的幂变换比其他方法能更清楚地显示地质特征。研究结果表明，研究区域以 NE-SW 和 ENE-WSW 走向的线状构造为主，大部分磁源位于该区域约 1-2.5 千米深处。NE-SW 和 ENE-WSW 走向构造可能与沿爱老山-红河剪切带的左侧运动有关。我们的研究结果还表明，越南东北部可视为华南地块的西南延续。我们的研究结果更好地揭示了越南东北部的构造特征，克服了对这一重要地区构造和地质框架认识上的空白。

{"title":"New subsurface structural insights of Northeast Vietnam: Advanced implications from high-resolution magnetic data","authors":"Luan Thanh Pham , Ahmed M. Eldosouky","doi":"10.1016/j.jseaes.2024.106413","DOIUrl":"10.1016/j.jseaes.2024.106413","url":null,"abstract":"<div><div>Northeast Vietnam is covered by sedimentary rocks, and its subsurface structures can be determined by geophysical studies. However, the structural patterns in Northeast Vietnam have so far been poorly studied and there is a lack of addressing the complex geological features of this area. Outlining such geological features is commonly achieved by applying various edge detection methods to magnetic fields. In this research, we applied nine enhancement techniques to magnetic data of Northeast Vietnam to identify geological features in this area. The methods are tested on synthetic data before applying to RTP (reduction to pole) magnetic data that are obtained from the multiple stage RTP technique. Four semiautomated depth estimation methods are also used to obtain the depth of magnetic structures in Northeast Vietnam. The results indicate that the normalized total gradient and power transform of the tilt angle of the total horizontal gradient can produce geological features more clearly than others. The findings show that the study area is dominated by NE-SW and ENE-WSW trending lineaments, and most of magnetic sources are around 1–2.5 km deep in the area. The NE-SW and ENE-WSW trending structures are possibly related to the left-lateral motion along the Ailaoshan–Red River shear zone. Our findings also show that Northeast Vietnam may be considered as a southwestern continuation of the South China Block. Our results provide a better picture of the structural features of Northeast Vietnam and overcome the gap in understanding the tectonic and geological framework of this important area.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"278 ","pages":"Article 106413"},"PeriodicalIF":2.7,"publicationDate":"2024-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142704111","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

3-D shallow crustal structure and offshore geothermal potential of the Aegean region of Türkiye from ambient noise tomography 通过环境噪声断层扫描研究土耳其爱琴海地区的三维浅层地壳结构和近海地热潜力

IF 2.7 3区地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY

Journal of Asian Earth Sciences

Pub Date : 2024-11-17 DOI: 10.1016/j.jseaes.2024.106414

Emre Mulumulu , Orhan Polat , Francisco J. Chávez‑García

The definition of the upper crustal structure is a necessary input in seismic hazard studies or in geothermal exploration projects. In this study, we use ambient noise tomography (ANT) to illuminate the 3-D crustal structure of the Aegean Region of Türkiye. The results allow us to identify tectonic control on seismic velocities and to image the shear-wave velocity (Vs) structure. In addition, our results characterize offshore-onshore geothermal potential in this region. Our data consists of 3-months of continuous ambient noise data recorded by 43 seismometers. The cross-correlation of seismic noise between station pairs was used to estimate Rayleigh wave pulses from which group velocity dispersion curves were derived. The results were used to estimate a group velocity dispersion curve for each cell in a square grid using tomography. Local dispersion curves were inverted to estimate a 1-D Vs profile for each cell. Integration of the results for all cells allowed us to build a 3-D Vs model of the studied region. Our Vs model is reliable for the upper 18 km of the crust. The Vs variations show narrow anticlines and basin-type wide synclines and sedimentary layers that correspond to the shallow crustal structure. An arc-shaped low velocity zone is identified to the west of the study area and is interpreted as a promising offshore geothermal zone. The southern coastal region of the investigated area also presents high hot fluid content in cracks and therefore has significant offshore geothermal potential. Our interpretation is in good agreement with available geophysical results and with the shallow crustal geometry reported in previous studies.

确定上地壳结构是地震灾害研究或地热勘探项目的必要投入。在这项研究中，我们使用环境噪声层析成像技术（ANT）来揭示土耳其爱琴海地区的三维地壳结构。研究结果使我们能够确定构造对地震速度的控制，并对剪切波速度（Vs）结构进行成像。此外，我们的研究结果还描述了该地区离岸-近岸地热潜力的特征。我们的数据包括 43 台地震仪记录的 3 个月连续环境噪声数据。台站对之间地震噪声的交叉相关性被用来估算瑞利波脉冲，并从中推导出群速度频散曲线。使用层析成像法对方格网中每个单元的群速度频散曲线进行估算。对局部频散曲线进行反演，估算出每个单元的一维 Vs 曲线。综合所有单元的结果，我们建立了所研究区域的三维 Vs 模型。我们的 Vs 模型对地壳上部 18 千米的区域是可靠的。Vs 变化显示了与浅层地壳结构相对应的窄反斜线和盆地型宽向斜以及沉积层。在研究区西部发现了一个弧形低速区，被认为是一个很有潜力的近海地热区。调查区南部沿海地区的裂缝中也含有大量热流体，因此具有巨大的近海地热潜力。我们的解释与现有的地球物理结果以及以往研究中报告的浅地壳几何形状十分吻合。

{"title":"3-D shallow crustal structure and offshore geothermal potential of the Aegean region of Türkiye from ambient noise tomography","authors":"Emre Mulumulu , Orhan Polat , Francisco J. Chávez‑García","doi":"10.1016/j.jseaes.2024.106414","DOIUrl":"10.1016/j.jseaes.2024.106414","url":null,"abstract":"<div><div>The definition of the upper crustal structure is a necessary input in seismic hazard studies or in geothermal exploration projects. In this study, we use ambient noise tomography (ANT) to illuminate the 3-D crustal structure of the Aegean Region of Türkiye. The results allow us to identify tectonic control on seismic velocities and to image the shear-wave velocity (Vs) structure. In addition, our results characterize offshore-onshore geothermal potential in this region. Our data consists of 3-months of continuous ambient noise data recorded by 43 seismometers. The cross-correlation of seismic noise between station pairs was used to estimate Rayleigh wave pulses from which group velocity dispersion curves were derived. The results were used to estimate a group velocity dispersion curve for each cell in a square grid using tomography. Local dispersion curves were inverted to estimate a 1-D Vs profile for each cell. Integration of the results for all cells allowed us to build a 3-D Vs model of the studied region. Our Vs model is reliable for the upper 18 km of the crust. The Vs variations show narrow anticlines and basin-type wide synclines and sedimentary layers that correspond to the shallow crustal structure. An arc-shaped low velocity zone is identified to the west of the study area and is interpreted as a promising offshore geothermal zone. The southern coastal region of the investigated area also presents high hot fluid content in cracks and therefore has significant offshore geothermal potential. Our interpretation is in good agreement with available geophysical results and with the shallow crustal geometry reported in previous studies.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"278 ","pages":"Article 106414"},"PeriodicalIF":2.7,"publicationDate":"2024-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142723603","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Uncovering the hidden architecture of the Rengali Province, eastern Indian shield using high-resolution aero-geophysics, ground-gravity, structure: Insights towards geology and tectonics 利用高分辨率航空地球物理、地面重力和结构揭示印度东部盾构地区伦加利省的隐蔽结构：对地质学和构造学的启示

IF 2.7 3区地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY

Journal of Asian Earth Sciences

Pub Date : 2024-11-16 DOI: 10.1016/j.jseaes.2024.106416

Debojit Talukdar , Shuva Sankha Ganguli , Avisekh Ghosh , Bijay Kumar Sahu , Manoranjan Mohanty , Ashish Kumar Raul

The Rengali Province is a shear zone bounded discrete domain of amalgamation among two Archean Cratons viz. the Singhbhum and Bastar cratons and a mobile belt namely Eastern Ghat Mobile belt. Based on geological evidences, it also displays an India-Antarctica connection in the past geological time-slice and supports supercontinental reconstruction. Although, the tectonothermal evolution of this province has been largely probed based on lithological, structural and metamorphic accounts, however, correlative geophysical-geology integration is absent. Hence, we analyze and interpret newly acquired high-resolution aero-geophysical data for the first time. The interpretations of high-resolution aero-geophysics, ground gravity and radiometric anomaly have been connected with geology to provide insights into tectonic evolution. Multi-scale geological-geophysical-structural analysis has been employed for understanding the subsurface architecture and contact relationship with the nearby cratons-mobile belt. Based on the aero-magnetic signature, three different zones have been delineated viz. northern, central and southern zones within the Rengali Province. The three zones are characterized by their distinct geophysical fabric and further are correlated with the geology. The gravity anomaly and modeling suggest the presence of a high-density body at mid-upper crustal depth (∼5–10 km). Three major shear zones, viz. the Barakot, Riamal and Kerajang delineate the bounding surfaces of the Rengali Province. However, the current geophysical signature indicate that the western part of the Kerajang Fault zone (KFZ) shares an inter-domain status between the Rengali Province and the Bastar Craton while the eastern part showcases an intra-domain character. Based on the complex series of magnetic fabric and anastomosing geophysical (particularly, magnetic) signature, the Rengali Province (RP) displays a classical signature of multiple accretionary histories supported by various episodic tectono-thermal activities at different time-slices.

伦加里省是一个以剪切带为边界的离散区域，由辛格布姆和巴斯塔两个阿尔奇安地壳以及一个流动带（即东盖特流动带）混合而成。根据地质证据，它还显示了印度与南极洲在过去地质时间片中的联系，并支持超大陆重建。虽然该省的构造热演化在很大程度上是基于岩石学、结构学和变质学的描述，但却缺乏相关的地球物理学-地质学整合。因此，我们首次对新获得的高分辨率航空地球物理数据进行了分析和解释。高分辨率航空地球物理、地面重力和辐射异常的解释与地质学相联系，为构造演化提供了见解。采用了多尺度地质-地球物理-结构分析方法，以了解地下结构以及与附近板块-移动带的接触关系。根据航磁特征，在伦加利省内划分出三个不同的区域，即北部、中部和南部区域。这三个区域具有不同的地球物理结构，并与地质相关联。重力异常和建模表明，在地壳中上层深度（5 至 10 千米）存在一个高密度岩体。三个主要剪切带，即 Barakot、Riamal 和 Kerajang，划定了 Rengali 省的边界面。然而，目前的地球物理特征表明，Kerajang 断裂带（KFZ）的西部在伦加里省和巴斯塔克拉通之间具有域间地位，而东部则显示出域内特征。根据一系列复杂的磁性构造和吻合地球物理（尤其是磁性）特征，伦加里省（RP）显示出多种增生历史的经典特征，这些增生历史在不同时间片段受到各种偶发构造热活动的支持。

{"title":"Uncovering the hidden architecture of the Rengali Province, eastern Indian shield using high-resolution aero-geophysics, ground-gravity, structure: Insights towards geology and tectonics","authors":"Debojit Talukdar , Shuva Sankha Ganguli , Avisekh Ghosh , Bijay Kumar Sahu , Manoranjan Mohanty , Ashish Kumar Raul","doi":"10.1016/j.jseaes.2024.106416","DOIUrl":"10.1016/j.jseaes.2024.106416","url":null,"abstract":"<div><div>The Rengali Province is a shear zone bounded discrete domain of amalgamation among two Archean Cratons viz. the Singhbhum and Bastar cratons and a mobile belt namely Eastern Ghat Mobile belt. Based on geological evidences, it also displays an India-Antarctica connection in the past geological time-slice and supports supercontinental reconstruction. Although, the tectonothermal evolution of this province has been largely probed based on lithological, structural and metamorphic accounts, however, correlative geophysical-geology integration is absent. Hence, we analyze and interpret newly acquired high-resolution aero-geophysical data for the first time. The interpretations of high-resolution aero-geophysics, ground gravity and radiometric anomaly have been connected with geology to provide insights into tectonic evolution. Multi-scale geological-geophysical-structuralanalysis has been employed for understanding the subsurface architecture and contact relationship with the nearby cratons-mobile belt. Based on the aero-magnetic signature, three different zones have been delineated viz. northern, central and southern zones within the Rengali Province. The three zones are characterized by their distinct geophysical fabric and further are correlated with the geology. The gravity anomaly and modeling suggest the presence of a high-density body at mid-upper crustal depth (∼5–10 km). Three major shear zones, viz. the Barakot, Riamal and Kerajang delineate the bounding surfaces of the Rengali Province. However, the current geophysical signature indicate that the western part of the Kerajang Fault zone (KFZ) shares an inter-domain status between the Rengali Province and the Bastar Craton while the eastern part showcases an intra-domain character. Based on the complex series of magnetic fabric and anastomosing geophysical (particularly, magnetic) signature, the Rengali Province (RP) displays a classical signature of multiple accretionary histories supported by various episodic tectono-thermal activities at different time-slices.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"278 ","pages":"Article 106416"},"PeriodicalIF":2.7,"publicationDate":"2024-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142704113","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0