Journal of Asian Earth Sciences: X最新文献

Fate of the Late Triassic Songpan-Ganzi Basin in the eastern Paleo-Tethys Ocean: Geochemical and geochronological constraints in the NE Tibetan Plateau

IF 1.7

Journal of Asian Earth Sciences: X Pub Date : 2025-03-30 DOI: 10.1016/j.jaesx.2025.100194

Hong-Xu Mu , Dan-Ping Yan , Liang Qiu , Ruo-Yan Kong , Ling-Xiao Gong

{"title":"Fate of the Late Triassic Songpan-Ganzi Basin in the eastern Paleo-Tethys Ocean: Geochemical and geochronological constraints in the NE Tibetan Plateau","authors":"Hong-Xu Mu , Dan-Ping Yan , Liang Qiu , Ruo-Yan Kong , Ling-Xiao Gong","doi":"10.1016/j.jaesx.2025.100194","DOIUrl":"10.1016/j.jaesx.2025.100194","url":null,"abstract":"<div><div>The Songpan-Ganzi Basin in the northeastern Tibetan Plateau preserves well-developed Late Triassic flysch sequences, making it an ideal region for investigating the provenance and tectonic evolution of the basin. This study aimed to constrain the provenance and tectonic setting of the basin by analyzing whole-rock geochemistry and detrital zircon U-Pb ages from Late Triassic flysch sediments. The flysch sequences show low SiO<sub>2</sub> (average 51.16 wt%), Al<sub>2</sub>O<sub>3</sub> (average 9.85 wt%) and Fe<sub>2</sub>O<sub>3</sub><sup>T</sup> + MgO (average 6.56 wt%) values, and K<sub>2</sub>O/Na<sub>2</sub>O (average 2.71) ratios, along with high SiO<sub>2</sub>/Al<sub>2</sub>O<sub>3</sub> ratios (averaging 6.99), suggesting a continental arc setting. They also exhibit moderate chemical weathering (CIA: 60.32–83.72) and high component variability (0.9–2.34, average 1.61), revealing a moderately weathered source. Tectonic discrimination diagrams based on La-Sc-Th and Th-Sc-Zr/10 ratios suggest a continental arc setting. U-Pb ages of detrital zircons mainly range from 222 to 300 Ma and 450 to 520 Ma, reflecting the time of the emplacement of Paleozoic to Late Triassic plutons in the Qinling orogenic belt and Kunlun arc. Minor age peaks (720–850 Ma, 950–1300 Ma and 1400–2400 Ma) suggest subordinate contribution from the northern and western margins of the Yangtze Block. Cumulative proportion curves of zircon U-Pb ages for lower formations exhibit a steep accumulation trend, suggesting a convergent tectonic setting. In contrast, upper formations display a relatively flat accumulation curve, indicative of a collisional environment. This shift in curve characteristics suggests that the sedimentary environment evolved from convergent to collisional settings among the North China, South China, and Qiangtang blocks.</div></div>","PeriodicalId":37149,"journal":{"name":"Journal of Asian Earth Sciences: X","volume":"13 ","pages":"Article 100194"},"PeriodicalIF":1.7,"publicationDate":"2025-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143768140","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Provenance of Middle Jurassic sandstones from the Yuqia depression in the northern Qiadam Basin (NW China): Implications for basin evolution and paleoclimatic conditions

IF 1.7

Journal of Asian Earth Sciences: X Pub Date : 2025-03-29 DOI: 10.1016/j.jaesx.2025.100195

Kai Zhou , Minfang Yang , Ran Gao , Zhiming Yan , Peixin Zhang , Wanqing Wang , Weichao Wang , Lei Wang , Longyi Shao , Jing Lu

{"title":"Provenance of Middle Jurassic sandstones from the Yuqia depression in the northern Qiadam Basin (NW China): Implications for basin evolution and paleoclimatic conditions","authors":"Kai Zhou , Minfang Yang , Ran Gao , Zhiming Yan , Peixin Zhang , Wanqing Wang , Weichao Wang , Lei Wang , Longyi Shao , Jing Lu","doi":"10.1016/j.jaesx.2025.100195","DOIUrl":"10.1016/j.jaesx.2025.100195","url":null,"abstract":"<div><div>The petrography of 106 clastic rock samples from the Middle Jurassic Dameigou and Shimengou Formations in the Qaidam Basin was analyzed to investigate their provenance and basin evolution. Five distinct sandstone units have been identified from the base of the Dameigou Formation to the top of the Shimengou Formation, hereafter termed as S-I, S-II, S-III, S-IV, and S-V. Petrographic analysis suggests that during the deposition of S-I (Aalenian stage), sediments were sourced from the Qaidam Main Block at the southern margin of the basin and the South Qilian Mountains at the northern margin. However, during the deposition of S-II, S-III, S-IV, and S-V (Bajocian to early Callovian stages), the basin received sediments from the East Kunlun Mountains to the south and the Qilian Mountains to the north. Mineralogical Index of Alteration (MIA) values, along with discrimination diagrams, indicate that the Middle Jurassic climate in the Qaidam Basin transitioned from semi-humid and warm (S-I) to humid and warm (S-II to S-IV), before returning to semi-humid and warm conditions (S-V). A basin evolution model was developed according to our findings, which provide a better understanding in the basin-forming processes and the principle of resource accumulation in the Middle Jurassic.</div></div>","PeriodicalId":37149,"journal":{"name":"Journal of Asian Earth Sciences: X","volume":"13 ","pages":"Article 100195"},"PeriodicalIF":1.7,"publicationDate":"2025-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143739515","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Quantitative evaluation and effectiveness criteria for the crystalline bedrock-type reservoir in the central uplift zone of the northern Songliao basin, NE China

IF 1.7

Journal of Asian Earth Sciences: X Pub Date : 2025-03-29 DOI: 10.1016/j.jaesx.2025.100193

Bo Zhao , Shumin Yin , Zhongquan Li , Zheng Liu , Guoxin Sun , Chunming Lin , Zhen Li , Shun Zhang , Jing Li

{"title":"Quantitative evaluation and effectiveness criteria for the crystalline bedrock-type reservoir in the central uplift zone of the northern Songliao basin, NE China","authors":"Bo Zhao , Shumin Yin , Zhongquan Li , Zheng Liu , Guoxin Sun , Chunming Lin , Zhen Li , Shun Zhang , Jing Li","doi":"10.1016/j.jaesx.2025.100193","DOIUrl":"10.1016/j.jaesx.2025.100193","url":null,"abstract":"<div><div>The crystalline bedrock-type gas reservoirs in the central uplift zone of the northern Songliao Basin represent a significant target for deep natural gas exploration. However, few studies have evaluated and identified effective reservoirs within this specific zone. In this paper, we present a comprehensive study on several exploration drill cores to constrain the pore structure, fracture parameters, minimum porosity and permeability thresholds required for fluid migration in the crystalline bedrock-type reservoirs in the central uplift zone, in an attempt to establish the criteria for identifying effective reservoirs. The results reveal that nanometer- to micron-sized pores, microfissures, and fracture zones are well developed in the crystalline bedrock-type reservoirs, indicating that they can be classified as low-porosity, ultra-low-permeability reservoirs. The identified thresholds for an effective reservoir consist of porosity of 1.5 % and permeability of 0.015 × 10<sup>−3</sup> μm<sup>2</sup>, and a minimum pore-throat radius of 0.02 μm for fluid mobility. These criteria provide useful guides for identifying effective reservoirs within the crystalline bedrocks.</div></div>","PeriodicalId":37149,"journal":{"name":"Journal of Asian Earth Sciences: X","volume":"13 ","pages":"Article 100193"},"PeriodicalIF":1.7,"publicationDate":"2025-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143761101","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Are hydropower dams and sand mining responsible for hydrological change in the Red river (Asia)?

IF 1.7

Journal of Asian Earth Sciences: X Pub Date : 2025-03-22 DOI: 10.1016/j.jaesx.2025.100192

Anh Duc Trinh , Nho Lan Nguyen , Thu Nga Do , Andrew Watson , Michael Stockinger , Christine Stumpp

{"title":"Are hydropower dams and sand mining responsible for hydrological change in the Red river (Asia)?","authors":"Anh Duc Trinh , Nho Lan Nguyen , Thu Nga Do , Andrew Watson , Michael Stockinger , Christine Stumpp","doi":"10.1016/j.jaesx.2025.100192","DOIUrl":"10.1016/j.jaesx.2025.100192","url":null,"abstract":"<div><div>The Red River (RR) in Southeast Asia provides water for food and energy production, building materials in the form of sand mining and facilitates the movement of people and goods for millions of inhabitants in the Yunnan province in China and provinces in northern Vietnam. Since the late 20th century, rapid economic development in the region has led to significant human-induced changes to the RR. In this study, we applied multiple statistical tests (Mann-Kendall, Pettitt, Mann-Whitney and principal component analysis) to analyse daily water flow data from seven hydro-meteorological stations in the lower section of the RR, aiming to identify the primary factors altering the water flow regime. Our findings indicate that the Hoa Binh reservoir, commissioned in 1989, and the Son La reservoir, commissioned in 2010, have significantly modified the flow regime, reducing the annual mean water flow of the RR main tributary from 1763 m<sup>3</sup> s<sup>−1</sup> between 1986 and 2008 to 1334 m<sup>3</sup> s<sup>−1</sup> between 2009 and 2023. This study is the first to identify that widespread and loosely regulated sand mining in the lower RR region has not only lowered the riverbed and water levels, as reported in recent studies, but also increased groundwater discharge into the river. As a result, despite the reduced upstream water flow from the mountains, the river discharge in the downstream region has remained statistically unchanged over the past decade in the RR.</div></div>","PeriodicalId":37149,"journal":{"name":"Journal of Asian Earth Sciences: X","volume":"13 ","pages":"Article 100192"},"PeriodicalIF":1.7,"publicationDate":"2025-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143682753","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Spatial distribution of structural lineaments in the Al-Lith geothermal field, western Saudi Arabia: Remote sensing and aeromagnetic data analysis

IF 1.7

Journal of Asian Earth Sciences: X Pub Date : 2025-03-08 DOI: 10.1016/j.jaesx.2025.100191

Jawad Rafiq, Israa S. Abu-Mahfouz, Konstantinos Chavanidis, Daffa Arrofi, Pantelis Soupios

{"title":"Spatial distribution of structural lineaments in the Al-Lith geothermal field, western Saudi Arabia: Remote sensing and aeromagnetic data analysis","authors":"Jawad Rafiq, Israa S. Abu-Mahfouz, Konstantinos Chavanidis, Daffa Arrofi, Pantelis Soupios","doi":"10.1016/j.jaesx.2025.100191","DOIUrl":"10.1016/j.jaesx.2025.100191","url":null,"abstract":"<div><div>Saudi Arabia is enriched in numerous geothermal resources. Among these, Wadi Al-Lith is regarded as one of the favorable geothermal prospects in western Saudi Arabia, featuring several hot springs with a discharge temperature of around 95 °C. However, there is still uncertainty regarding the delineation of the prospective geothermal reservoir, and the assessment of the geothermal energy reserves. Therefore, this paper aims to delineate the prospective geothermal area, utilizing remote sensing and geophysical (magnetic) data. This research maps the surface and subsurface geological and structural features (faults, fractures, and fold axes) and analyzes their densities using an integrated geological-remote sensing-geophysical investigation. Digital elevation models and Landsat-8 imagery, supported by field investigations, were used to analyze surface lineament density, while airborne magnetic data was used to analyze subsurface lineament density. The study area was subdivided into ten zones based on surface lineament density, with the northernmost zone presenting the highest lineament density. Subsurface lineament density analysis revealed five high-density zones, three of which correspond well with those identified on the surface. The study also identified the main high-permeability zones and associated geothermal anomalies in the Wadi Al-Lith area, improving the understanding of its potential geothermal resources. The results of this study could serve as a preliminary guide for further geothermal exploration, highlighting surface manifestations that require in-depth investigation using geoscientific and drilling tools.</div></div>","PeriodicalId":37149,"journal":{"name":"Journal of Asian Earth Sciences: X","volume":"13 ","pages":"Article 100191"},"PeriodicalIF":1.7,"publicationDate":"2025-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143580378","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Differential diagenetic and densification processes of low-permeability and tight sandstones: A case study of the Jurassic Shaximiao Formation in the central and western Sichuan Basin, China

IF 1.7

Journal of Asian Earth Sciences: X Pub Date : 2025-01-09 DOI: 10.1016/j.jaesx.2025.100190

Laixing Cai , Chengfang Yuan , Shaomin Zhang , Xiaojuan Wang , Yinglin Liu , Weixue Guo , Tian Yang

{"title":"Differential diagenetic and densification processes of low-permeability and tight sandstones: A case study of the Jurassic Shaximiao Formation in the central and western Sichuan Basin, China","authors":"Laixing Cai , Chengfang Yuan , Shaomin Zhang , Xiaojuan Wang , Yinglin Liu , Weixue Guo , Tian Yang","doi":"10.1016/j.jaesx.2025.100190","DOIUrl":"10.1016/j.jaesx.2025.100190","url":null,"abstract":"<div><div>Tight sandstone reservoirs of low permeability are of both scientific and economic significance, but their origin and formation process remain not well understood.. In this paper, we present a comprehensive study of the tight sandstone reservoir of the Middle Jurassic Shaximiao Formation distributed in central and western Sichuan Basin, by integrating scanning electron microscopy, X-ray diffraction, high-pressure mercury injection, and nuclear magnetic resonance. The aim of this study was to investigate the differential diagenetic sequences constrained by quantifying the provenance of the sandstones and densification processes. Overall, the Shaximiao Formation sandstones have low porosity of 0.46 %–18.76 % (averaging 10.17 %) and low permeability ranging from 0.0003 to 632.42 × 10<sup>−3</sup> μm<sup>2</sup> (averaging 3.67 × 10<sup>−3</sup> μm<sup>2</sup>), with 73.72 % being classified as tight reservoirs. The sandstone samples from the western Sichuan Basin commonly display tubular or needle-shaped throats with less developed microfractures, consequently having weaker seepage capacity compared to the varieties in the central Sichuan Basin that are characterized by abundant lamellar and necked throats. The results suggest that the slightly lower contents of rigid particles and higher contents of fragments and argillaceous matrix facilitated continuous compaction and multitype cementation processes. Meanwhile, strong compaction of the rocks with cements of carbonate, siliceous materials, and laumontite being the cement lead to porosity reduction of 29.8 %, 12.27 %, 13.34 %, and 12.33 %, respectively. In contrast, chlorite coating and dissolution events have crucial roles in preserving pores and enhancing permeability.</div></div>","PeriodicalId":37149,"journal":{"name":"Journal of Asian Earth Sciences: X","volume":"13 ","pages":"Article 100190"},"PeriodicalIF":1.7,"publicationDate":"2025-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143176462","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Origin and evolution of serpentinized peridotite from the Ciletuh Mélange in Sunda Arc, Indonesia: Evidence from petrography, mineralogy, and geochemistry

IF 1.7

Journal of Asian Earth Sciences: X Pub Date : 2025-01-03 DOI: 10.1016/j.jaesx.2024.100188

Rinaldi Ikhram , Takashi Hoshide , Tsukasa Ohba , Mega Fatimah Rosana , Adi Hardiyono

{"title":"Origin and evolution of serpentinized peridotite from the Ciletuh Mélange in Sunda Arc, Indonesia: Evidence from petrography, mineralogy, and geochemistry","authors":"Rinaldi Ikhram , Takashi Hoshide , Tsukasa Ohba , Mega Fatimah Rosana , Adi Hardiyono","doi":"10.1016/j.jaesx.2024.100188","DOIUrl":"10.1016/j.jaesx.2024.100188","url":null,"abstract":"<div><div>The Ciletuh Mélange in southern Sundaland (West Java, Indonesia) is a key location for ophiolitic mélanges, featuring widespread serpentinized peridotite. These rocks exhibit varied textures and structures and can be classified into three types based on the extent of serpentinization: type 1 (lherzolite, <10 % serpentinization), type 2 (60–80 % serpentinization), and type 3 (>90 % serpentinization). Olivine and spinel mineral chemistry indicates two origins for the peridotite: magmatic cumulate (type 1, olivine Fo#: ∼81, spinel Cr#: 63–70) and mantle-derived (types 2 and 3, olivine Fo: 88–90, spinel Cr#: 55–66). Protoliths of both types 2 and 3 show abyssal (mid-oceanic ridge basalt) and fore-arc mantle peridotite characteristics, formed by partial melting (∼5–25 %) and melt-rock interaction (TiO<sub>2</sub> in spinel > 1 wt%). Type 1 lherzolite, by contrast, crystallized as a cumulate at the mantle-crust boundary. The variation of geochemical signatures, along with evidence of melt influence, suggest formation in a supra-subduction zone. In subduction systems, the protoliths underwent serpentinization at varying metamorphic grades, producing serpentines such as lizardite, antigorite, chrysotile, and polygonal serpentine. Antigorite formed under high-grade metamorphism, while lizardite, chrysotile, and polygonal serpentine form under lower-grade conditions. The presence of rodingite dikes cutting through serpentinite suggests metasomatic processes, notably rodingitization, involving diffusional metasomatism between serpentinization fluids and metamorphosed gabbro in the subduction zone. Serpentinized peridotites and rodingites were later exhumed as part of the ophiolitic mélange.</div></div>","PeriodicalId":37149,"journal":{"name":"Journal of Asian Earth Sciences: X","volume":"13 ","pages":"Article 100188"},"PeriodicalIF":1.7,"publicationDate":"2025-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143176463","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Assessing the performance of machine learning and analytical hierarchy process (AHP) models for rainwater harvesting potential zone identification in hilly region, Bangladesh

IF 1.7

Journal of Asian Earth Sciences: X Pub Date : 2025-01-03 DOI: 10.1016/j.jaesx.2024.100189

Md. Mahmudul Hasan , Md. Talha , Most. Mitu Akter , Md Tasim Ferdous , Pratik Mojumder , Sujit Kumar Roy , N.M. Refat Nasher

{"title":"Assessing the performance of machine learning and analytical hierarchy process (AHP) models for rainwater harvesting potential zone identification in hilly region, Bangladesh","authors":"Md. Mahmudul Hasan , Md. Talha , Most. Mitu Akter , Md Tasim Ferdous , Pratik Mojumder , Sujit Kumar Roy , N.M. Refat Nasher","doi":"10.1016/j.jaesx.2024.100189","DOIUrl":"10.1016/j.jaesx.2024.100189","url":null,"abstract":"<div><div>Water scarcity in hilly regions presents unique challenges, particularly in Bangladesh, where obtaining fresh drinking water has become difficult to access. This study aims to evaluate the potential zones for rainwater harvesting (RWH) using machine learning (ML) algorithms and geospatial analysis. Specifically, four ML algorithms—random forest (RF), boosted regression trees (BRT), k-nearest neighbors (KNN), and naïve bayes (NB)—alongside the analytical hierarchy process (AHP) were employed to delineate potential RWH zones in the Chattogram hilly districts, including Chattogram, Rangamati, Bandarban, Khagrachari, and Cox’s Bazar. Eleven influencing factors were considered: aspect, distance from road, drainage density, elevation, hill shade, lineament density, land use/land cover (LULC), slope, topographic wetness index (TWI), rainfall, and geology. Inventory data from the study area, consisting of 135 suitable and 135 non-suitable points, were randomly split, with 70% used for training the models and the remaining 30% for validation using the area under the curve (AUC) values. The southern regions are highly suitable for harvesting rainwater. Among the five models, BRT and RF demonstrated superior performance with AUC values of 0.93 for both models. In contrast, the AHP method yielded the lowest AUC value at 0.82. Notably, drainage density and elevation emerged as the most influential factors in constructing these models. The application of machine learning algorithms has enhanced the precision of rainwater harvesting zone estimate systems by examining diverse aspects. The findings of this study can provide valuable insights for policymakers in making informed decisions regarding RWH in these regions.</div></div>","PeriodicalId":37149,"journal":{"name":"Journal of Asian Earth Sciences: X","volume":"13 ","pages":"Article 100189"},"PeriodicalIF":1.7,"publicationDate":"2025-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143176461","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Structural and bio-stratigraphic records of Janakor valley in north-western Himalayas, Pakistan: Implications for closure of Neo-Tethys Ocean

IF 1.7

Journal of Asian Earth Sciences: X Pub Date : 2024-12-24 DOI: 10.1016/j.jaesx.2024.100187

Ferdous Jamal , Liang Qiu , Shah Faisal , Suleman Khan , Rafi Ullah , Ahsan Naseer , Qihui Zhang , Dan-Ping Yan , Zhicheng Zhou

{"title":"Structural and bio-stratigraphic records of Janakor valley in north-western Himalayas, Pakistan: Implications for closure of Neo-Tethys Ocean","authors":"Ferdous Jamal , Liang Qiu , Shah Faisal , Suleman Khan , Rafi Ullah , Ahsan Naseer , Qihui Zhang , Dan-Ping Yan , Zhicheng Zhou","doi":"10.1016/j.jaesx.2024.100187","DOIUrl":"10.1016/j.jaesx.2024.100187","url":null,"abstract":"<div><div>The closure of the Tethys Sea, driven by the collision between the Indian and Eurasian plates, represent a significant event in Earth’s tectonic history. However, many aspects of its structural and stratigraphic implications remain poorly understood. This study investigates on the structural style and biostratigraphic framework of the northwestern Himalayas, focusing on the region at the junction of the Attock-Cherat and Kalachitta Ranges, where deformation is dominated by two major faults, e.g., the Hissartang Fault in the Attock-Cherat Ranges to the north and the Janakor Fault along the Main Boundary Thrust (MBT) to the south. Our analysis reveals a tectonostratigraphic sequence ranging from the Cambrian to the Miocene. Notably, units from the Mid-Cretaceous, Early Paleocene, and Eocene periods are conspicuously absent. Structurally, the region exhibits east–west trending tight, isoclinal folds, where Early and Late Cretaceous units occupy the fold crests and troughs, respectively. Jurassic and Paleocene strata are also involved in deformation, with a network of forethrusts, backthrusts, and overturned thrust contributing to the development of pop-up structure and triangular zones. This study further delineates the boundary marking the Neo-Tethys Ocean closure defined between Eocene marine and Miocene fluvial units. These findings enhance our understanding of the tectonic evolution during this critical period and provide new insights into the kinematic linkage of surface structures with a subsurface décollement within Jurassic strata. This article addresses the scientific challenges of the Neo-Tethys Ocean closure and present a clear and precise account of the structural and biostratigraphic implications of this tectonic event.</div></div>","PeriodicalId":37149,"journal":{"name":"Journal of Asian Earth Sciences: X","volume":"13 ","pages":"Article 100187"},"PeriodicalIF":1.7,"publicationDate":"2024-12-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143176460","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Geochemical features of the Lower Silurian strata in Xiushan, Chongqing: Implications for paleoclimate reconstruction

IF 1.7

Journal of Asian Earth Sciences: X Pub Date : 2024-12-10 DOI: 10.1016/j.jaesx.2024.100186

La Zhang , Yang Chen , Jinhua Luan , Ruigang Zhang , Zhiwei Cui , Haitong Zhao , Qian Wang

{"title":"Geochemical features of the Lower Silurian strata in Xiushan, Chongqing: Implications for paleoclimate reconstruction","authors":"La Zhang , Yang Chen , Jinhua Luan , Ruigang Zhang , Zhiwei Cui , Haitong Zhao , Qian Wang","doi":"10.1016/j.jaesx.2024.100186","DOIUrl":"10.1016/j.jaesx.2024.100186","url":null,"abstract":"<div><div>The Silurian was featured by frequent climatic and environmental changes. Impoverished marine faunas slowly recovered from the end-Ordovician mass extinction. Diverse fossils have been reported from the Lower Silurian strata in Xiushan, Chongqing, southwest China, revealing a previously unrecognized diversification of jawed vertebrates in the Early Silurian. However, the paleoclimatic evolution during this period and the geochemical features of these strata are ambiguous. To reconstruct the Early Silurian paleoclimatic evolution, we have collected samples from the Lower Silurian (Xiaoheba, Rongxi, Xiushan, and Huixingshao formations) and Upper Silurian (Xiaoheba formation) strata in the Xiushan area. These Lower Silurian strata have a similar felsic source with insignificant sorting and recycling during deposition as documented by TiO<sub>2</sub>/Zr, La/Yb, Th/Sc, Zr/Sc, Cr/Th ratios, and ICV. The parent rocks of the Xiaoxi formation are complex and have been affected by recycled sediments. Weathering indices (CIA<sub>corr</sub>, PIA<sub>corr</sub>, WIP<sub>corr</sub>, and CIW) of the Lower Silurian vary within the range of moderate weathering, indicating that although there are small-scale climatic changes, the climate remained relatively stable from the Aeronian to the middle-late Telychian, generally characterized by a warm environment, except for a cooler interval during the early Telychian. Combined with the report of the Chongqing Lagerstätte and various fossils in this area, we speculate that a relatively stable climate and abundant terrestrial nutrient influx may have facilitated the evolution of the early gnathostomes in the Early Silurian.</div></div>","PeriodicalId":37149,"journal":{"name":"Journal of Asian Earth Sciences: X","volume":"13 ","pages":"Article 100186"},"PeriodicalIF":1.7,"publicationDate":"2024-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143175983","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0