Journal of Asian Earth Sciences最新文献_第5页

Phosphogenesis of Kakul Garlaniyan phosphorites during the early Cambrian in northeastern Pakistan 巴基斯坦东北部早寒武世Kakul Garlaniyan磷矿的成磷作用

IF 2.4 3区地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY

Journal of Asian Earth Sciences

Pub Date : 2025-12-21 DOI: 10.1016/j.jseaes.2025.106927

Massam Ali , Haifeng Fan , Danish Khan , Fang Zhang , Ishfaq Ahmad , Muhammad Asif Sherliyat , Yuhan Ma , Jibran Hussain , Hanjie Wen

The largest phosphogenesis event in Earth’s history occurred during the Precambrian-Cambrian transition, characterized by the formation of extensive global phosphorite deposits. One of the most notable examples is the Kakul Garlaniyan phosphorite, located at the topmost part of the Sirban member of the Abbottabad Formation in the Hazara region of northeastern Pakistan, dating to the Early Cambrian (∼541 Ma, Terreneuvian). Despite its significance, limited studies have addressed the origin and formation processes of the phosphorite deposits in this area. To enhance our understanding, we conducted petrographic and geochemical analyses on samples from three intercalated phosphorite layers within the Sirban Member. The phosphorite comprises both primary and reworked grains, with quartz supplied by terrestrial input. The grains are derived from a marine origin, enriched by upwelling of nutrient-rich bottom seawater. Additionally, the radiogenic ⁸⁷Sr/⁸⁶Sr isotope ratios (0.7113–0.7129) indicate terrestrial flux to the inner shelf environment through the chemical weathering of continental rocks. Rare earth and yttrium (REY) patterns exhibit a seawater-like, post-Archean Australian Shale (PAAS)-normalized REY distribution, with significant negative Ce/Ce* anomalies (0.40–0.54) and super-chondritic Y/Ho ratios (∼50–60), indicating a hydrogenous origin and supporting oxic conditions. The (La/Yb)_N and (La/Sm)_N ratios in Kakul Garlaniyan phosphorite layer suggest REY adsorption during early diagenesis, consistent with modern seawater conditions. Based on these findings, we propose a phosphogenesis depositional model: phosphorite formed via upwelling and reworking rather than hydrothermal activity under mainly oxic (with rarely anoxic conditions) and abiotic conditions. Winnowing and transgression events transformed pre-existing phosphate mud into reworked grains, occurring in the absence of microbial mediation. These findings provide new insights into the processes governing phosphorite formation during the Early Cambrian period in the Abbottabad region.

地球历史上最大的产磷事件发生在前寒武纪-寒武纪过渡时期，其特征是形成了广泛的全球磷矿矿床。最著名的例子之一是Kakul Garlaniyan磷矿，位于巴基斯坦东北部哈扎拉地区Abbottabad组的Sirban成员的顶部，可追溯到早寒武纪（~ 541 Ma, Terreneuvian）。尽管具有重要意义，但对该地区磷矿床成因和形成过程的研究有限。为了加强我们的理解，我们对来自Sirban成员的三个插层磷矿层的样品进行了岩石学和地球化学分析。磷矿包括原生颗粒和改造颗粒，石英由陆源输入提供。这些谷物来自海洋，由于营养丰富的海底海水上涌而变得更加丰富。87Sr/86Sr同位素比值（0.7113 ~ 0.7129）表明陆相通过陆相岩石的化学风化作用进入陆架内部环境。稀土和钇（REY）模式呈海水状，后太古代澳大利亚页岩（PAAS）标准化REY分布，具有显著的负Ce/Ce*异常（0.40-0.54）和超球球体Y/Ho比（~ 50-60），表明其氢成因和支持氧条件。Kakul Garlaniyan磷矿层的（La/Yb）N和（La/Sm）N比值表明，在早期成岩作用中吸附了REY，与现代海水条件一致。基于这些发现，我们提出了一种磷矿沉积模式：磷矿主要在氧（很少缺氧）和非生物条件下，通过上升流和改造而不是热液活动形成。筛选和海侵事件将先前存在的磷酸盐泥浆转化为重新加工的颗粒，发生在没有微生物中介的情况下。这些发现为阿伯塔巴德地区早寒武世磷矿形成过程提供了新的认识。

{"title":"Phosphogenesis of Kakul Garlaniyan phosphorites during the early Cambrian in northeastern Pakistan","authors":"Massam Ali , Haifeng Fan , Danish Khan , Fang Zhang , Ishfaq Ahmad , Muhammad Asif Sherliyat , Yuhan Ma , Jibran Hussain , Hanjie Wen","doi":"10.1016/j.jseaes.2025.106927","DOIUrl":"10.1016/j.jseaes.2025.106927","url":null,"abstract":"<div><div>The largest phosphogenesis event in Earth’s history occurred during the Precambrian-Cambrian transition, characterized by the formation of extensive global phosphorite deposits. One of the most notable examples is the Kakul Garlaniyan phosphorite, located at the topmost part of the Sirban member of the Abbottabad Formation in the Hazara region of northeastern Pakistan, dating to the Early Cambrian (∼541 Ma, Terreneuvian). Despite its significance, limited studies have addressed the origin and formation processes of the phosphorite deposits in this area. To enhance our understanding, we conducted petrographic and geochemical analyses on samples from three intercalated phosphorite layers within the Sirban Member. The phosphorite comprises both primary and reworked grains, with quartz supplied by terrestrial input. The grains are derived from a marine origin, enriched by upwelling of nutrient-rich bottom seawater. Additionally, the radiogenic <sup>87</sup>Sr/<sup>86</sup>Sr isotope ratios (0.7113–0.7129) indicate terrestrial flux to the inner shelf environment through the chemical weathering of continental rocks. Rare earth and yttrium (REY) patterns exhibit a seawater-like, post-Archean Australian Shale (PAAS)-normalized REY distribution, with significant negative Ce/Ce* anomalies (0.40–0.54) and super-chondritic Y/Ho ratios (∼50–60), indicating a hydrogenous origin and supporting oxic conditions. The (La/Yb)<sub>N</sub> and (La/Sm)<sub>N</sub> ratios in Kakul Garlaniyan phosphorite layer suggest REY adsorption during early diagenesis, consistent with modern seawater conditions. Based on these findings, we propose a phosphogenesis depositional model: phosphorite formed via upwelling and reworking rather than hydrothermal activity under mainly oxic (with rarely anoxic conditions) and abiotic conditions. Winnowing and transgression events transformed pre-existing phosphate mud into reworked grains, occurring in the absence of microbial mediation. These findings provide new insights into the processes governing phosphorite formation during the Early Cambrian period in the Abbottabad region.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"298 ","pages":"Article 106927"},"PeriodicalIF":2.4,"publicationDate":"2025-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145808546","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

Genesis and evolution of ore-forming fluids in the Liushashan Mo deposit, Inner Mongolia: Insights from fluid inclusions and C–H–O–S isotopes 内蒙古柳沙山钼矿成矿流体的成因与演化：流体包裹体和C-H-O-S同位素的启示

IF 2.4 3区地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY

Journal of Asian Earth Sciences

Pub Date : 2025-12-21 DOI: 10.1016/j.jseaes.2025.106930

Shuopu Yuan , Jianping Wang , Jichun Wang , Dongxing Wang , Jinghao Sun , Degao Zhai , Jiajun Liu , Fangfang Zhang , Zhenjiang Liu

The Liushashan molybdenum deposit is located in the northern Beishan orogenic belt. The orebodies are predominantly hosted within Late Paleozoic granodiorite and quartz diorite. Two distinct mineralization types have been identified: porphyry-style mineralization and quartz-vein-style mineralization, which are characterized by stockwork-disseminated and massive quartz-vein features, respectively. Mineralization includes four paragenetic stages: (1) quartz-K-feldspar, (2) quartz-polymetallic sulfide, (3) quartz-molybdenite, and (4) quartz-calcite. Integrated fluid inclusions microthermometry and C–H–O–S stable isotope analyses were performed to constrain the properties, sources, and evolution of the ore-forming fluids, as well as the metallogenic mechanisms. Three types of fluid inclusions were identified: liquid-rich two-phase (LV-type), vapor-rich two-phase (VL-type), and pure liquid-phase (PL-type) inclusions, with LV-type constituting over 90 % of the total. Microthermometric analyses of fluid inclusions assemblages in quartz from different stages indicate homogenization temperatures of 331–431°C (Stage I), 273–367 °C (Stage II), 206–299 °C (Stage III), and 172–207 °C (Stage IV), with fluid salinities of 2.4–9.5 wt% NaCl equiv., 3.6–13.0 wt% NaCl equiv., 2.4–10.0 wt% NaCl equiv., and 2.4–7.6 wt% NaCl equiv., respectively. Combined C–H–O–S stable isotope data suggest that the ore-forming fluids were derived from deep-seated magmatic-hydrothermal systems and progressively mixed with meteoric water in later stages. Fluid boiling and mixing are the dominant ore precipitation mechanisms. Based on geological, fluid inclusions, and isotopic features, the Liushashan deposit is classified as a subduction-related porphyry Mo deposit.

柳山山钼矿床位于北山造山带北部。矿体主要赋存于晚古生代花岗闪长岩和石英闪长岩中。发现斑岩型矿化和石英脉型矿化两种不同的成矿类型，分别以网状浸染型和块状石英脉型为特征。成矿包括四个共生阶段：(1)石英-钾长石、(2)石英-多金属硫化物、(3)石英-辉钼矿和(4)石英-方解石。综合流体包裹体显微测温和C-H-O-S稳定同位素分析，对成矿流体的性质、来源、演化及成矿机制进行了约束。鉴定出富液两相（lv型）、富气两相（lv型）和纯液相（pl型）包裹体3种类型，其中lv型占90%以上。石英中不同阶段流体包裹体组合的显微测温分析表明，均一温度为331-431°C（第一阶段）、273-367°C（第二阶段）、206-299°C（第三阶段）和172-207°C（第四阶段），流体盐度分别为2.4-9.5 wt% NaCl当量、3.6-13.0 wt% NaCl当量、2.4-10.0 wt% NaCl当量和2.4-7.6 wt% NaCl当量。C-H-O-S稳定同位素资料表明成矿流体来源于深部岩浆-热液系统，并在后期逐渐与大气水混合。流体沸腾和混合是主要的矿石沉淀机制。综合地质、流体包裹体和同位素特征，将柳沙山矿床划分为与俯冲有关的斑岩型钼矿床。

{"title":"Genesis and evolution of ore-forming fluids in the Liushashan Mo deposit, Inner Mongolia: Insights from fluid inclusions and C–H–O–S isotopes","authors":"Shuopu Yuan , Jianping Wang , Jichun Wang , Dongxing Wang , Jinghao Sun , Degao Zhai , Jiajun Liu , Fangfang Zhang , Zhenjiang Liu","doi":"10.1016/j.jseaes.2025.106930","DOIUrl":"10.1016/j.jseaes.2025.106930","url":null,"abstract":"<div><div>The Liushashan molybdenum deposit is located in the northern Beishan orogenic belt. The orebodies are predominantly hosted within Late Paleozoic granodiorite and quartz diorite. Two distinct mineralization types have been identified: porphyry-style mineralization and quartz-vein-style mineralization, which are characterized by stockwork-disseminated and massive quartz-vein features, respectively. Mineralization includes four paragenetic stages: (1) quartz-K-feldspar, (2) quartz-polymetallic sulfide, (3) quartz-molybdenite, and (4) quartz-calcite. Integrated fluid inclusions microthermometry and C–H–O–S stable isotope analyses were performed to constrain the properties, sources, and evolution of the ore-forming fluids, as well as the metallogenic mechanisms. Three types of fluid inclusions were identified: liquid-rich two-phase (LV-type), vapor-rich two-phase (VL-type), and pure liquid-phase (PL-type) inclusions, with LV-type constituting over 90 % of the total. Microthermometric analyses of fluid inclusions assemblages in quartz from different stages indicate homogenization temperatures of 331–431°C (Stage I), 273–367 °C (Stage II), 206–299 °C (Stage III), and 172–207 °C (Stage IV), with fluid salinities of 2.4–9.5 wt% NaCl equiv., 3.6–13.0 wt% NaCl equiv., 2.4–10.0 wt% NaCl equiv., and 2.4–7.6 wt% NaCl equiv., respectively. Combined C–H–O–S stable isotope data suggest that the ore-forming fluids were derived from deep-seated magmatic-hydrothermal systems and progressively mixed with meteoric water in later stages. Fluid boiling and mixing are the dominant ore precipitation mechanisms. Based on geological, fluid inclusions, and isotopic features, the Liushashan deposit is classified as a subduction-related porphyry Mo deposit.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"298 ","pages":"Article 106930"},"PeriodicalIF":2.4,"publicationDate":"2025-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145842789","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

Petrogenesis of Himalayan NYF-type granitic pegmatites: Constraints from accessory minerals in the beryl-bearing pegmatite, Kangmar Dome, China 喜马拉雅nyf型花岗质伟晶岩的岩石成因：来自康玛山含绿柱石伟晶岩副矿物的制约

IF 2.4 3区地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY

Journal of Asian Earth Sciences

Pub Date : 2025-12-20 DOI: 10.1016/j.jseaes.2025.106926

Qiaoli Wang , Lei Xie , Rucheng Wang , Zhichao Liu

The Kangmar Dome is located in the eastern Tethyan-Himalayan leucogranite belt. A distinctive feature of this dome is the absence of leucogranite outcrops, but numerous beryl-bearing granitic pegmatite veins (hereafter referred to as beryl pegmatite) intrude the granitic gneiss host rocks. Distinct from the LCT-type pegmatite found in Himalaya, the Kangmar beryl pegmatites (pegmatite I) contain large numbers of Nb-Y-Ti oxide minerals and fluorite, which are the typical minerals of NYF-type pegmatite. Whereas, pegmatite II is characterized by abundant beryl (16 vol%) and Ta-enriched oxide minerals. Hafnian zircon (0.1 < Hf^#<0.5) are commonly present in pegmatite I whereas hafnon (Hf^#>0.5) is only found in pegmatite II, indicating extreme fractional crystallization and intense hydrothermal fluid activity of pegmatite II. The beryl pegmatites yielded zircon ²⁰⁶Pb/²³⁸U ages, monazite ²⁰⁸Pb/²³²Th ages and muscovite Rb-Sr isochron ages of 26–25 Ma. Zircons within beryl pegmatites generally exhibit Paleozoic cores (∼499 Ma), consistent with the age of the host granitic gneisses. However, ε_Nd(t) values of the beryl pegmatites have a wider range (−16.8 to −7.7) as compared with the narrow range (−12.1 to −10.6) for the granitic gneisses. Consequently, we suggest that the Kangmar NYF-type pegmatites are genetically related to A-type granites that are possibly hidden at depth in a post-orogenic extensional setting. The granite was likely derived from Higher Himalayan Crystallines, with additional contribution from an undefined source that characterized by depleted isotopic signature. The melts experienced contamination by the host granitic gneiss during the emplacement. Our results highlight the unique type of rare-metal pegmatites of the Tethyan Himalaya.

康玛尔穹窿位于特提斯—喜马拉雅浅花岗带东部。该圆顶的一个显著特征是没有亮花岗岩露头，但大量含绿柱石的花岗质伟晶岩脉（以下简称绿柱石伟晶岩）侵入花岗质片麻岩为主岩。与喜马拉雅地区发现的lct型伟晶岩不同，康玛绿柱石伟晶岩（I型伟晶岩）含有大量的Nb-Y-Ti氧化物矿物和萤石，是nyf型伟晶岩的典型矿物。而伟晶岩II则具有丰富的绿柱石（16 vol%）和富ta的氧化矿物。半晶锆石（0.1 < Hf#<0.5）普遍存在于伟晶岩I中，而半晶锆石（Hf# <0.5）仅存在于伟晶岩II中，说明伟晶岩II具有极强的分馏结晶和强烈的热液活动。绿柱伟晶岩锆石年龄为206Pb/238U，独居石年龄为208Pb/232Th，白云母Rb-Sr等时年龄为26 ~ 25 Ma。绿柱石伟晶岩中的锆石一般具有古生代（~ 499 Ma）的岩心，与寄主花岗质片麻岩的年龄一致。绿柱石伟晶岩的εNd(t)值范围较宽（−16.8 ~−7.7），而花岗质片麻岩的εNd(t)值范围较窄（−12.1 ~−10.6）。因此，我们认为康玛nyf型伟晶岩可能与a型花岗岩有遗传关系，a型花岗岩可能隐藏在造山后伸展环境中。花岗岩可能来自高喜马拉雅结晶岩，另外还有一个未确定的来源，其特征是耗尽同位素特征。熔体在就位过程中受到寄主花岗岩片麻岩的污染。我们的结果突出了特提斯喜马拉雅地区稀有金属伟晶岩的独特类型。

{"title":"Petrogenesis of Himalayan NYF-type granitic pegmatites: Constraints from accessory minerals in the beryl-bearing pegmatite, Kangmar Dome, China","authors":"Qiaoli Wang , Lei Xie , Rucheng Wang , Zhichao Liu","doi":"10.1016/j.jseaes.2025.106926","DOIUrl":"10.1016/j.jseaes.2025.106926","url":null,"abstract":"<div><div>The Kangmar Dome is located in the eastern Tethyan-Himalayan leucogranite belt. A distinctive feature of this dome is the absence of leucogranite outcrops, but numerous beryl-bearing granitic pegmatite veins (hereafter referred to as beryl pegmatite) intrude the granitic gneiss host rocks. Distinct from the LCT-type pegmatite found in Himalaya, the Kangmar beryl pegmatites (pegmatite I) contain large numbers of Nb-Y-Ti oxide minerals and fluorite, which are the typical minerals of NYF-type pegmatite. Whereas, pegmatite II is characterized by abundant beryl (16 vol%) and Ta-enriched oxide minerals. Hafnian zircon (0.1 < Hf<sup>#</sup><0.5) are commonly present in pegmatite I whereas hafnon (Hf<sup>#</sup>>0.5) is only found in pegmatite II, indicating extreme fractional crystallization and intense hydrothermal fluid activity of pegmatite II. The beryl pegmatites yielded zircon <sup>206</sup>Pb/<sup>238</sup>U ages, monazite <sup>208</sup>Pb/<sup>232</sup>Th ages and muscovite Rb-Sr isochron ages of 26–25 Ma. Zircons within beryl pegmatites generally exhibit Paleozoic cores (∼499 Ma), consistent with the age of the host granitic gneisses. However, ε<sub>Nd</sub>(t) values of the beryl pegmatites have a wider range (−16.8 to −7.7) as compared with the narrow range (−12.1 to −10.6) for the granitic gneisses. Consequently, we suggest that the Kangmar NYF-type pegmatites are genetically related to A-type granites that are possibly hidden at depth in a post-orogenic extensional setting. The granite was likely derived from Higher Himalayan Crystallines, with additional contribution from an undefined source that characterized by depleted isotopic signature. The melts experienced contamination by the host granitic gneiss during the emplacement. Our results highlight the unique type of rare-metal pegmatites of the Tethyan Himalaya.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"298 ","pages":"Article 106926"},"PeriodicalIF":2.4,"publicationDate":"2025-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145842655","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

Hydrocarbon generation and evolution of shale and mudstone: Insights from the Triassic Chang 7 Member in the Ordos Basin, NW China 鄂尔多斯盆地三叠系长7段页岩泥岩生烃与演化

IF 2.4 3区地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY

Journal of Asian Earth Sciences

Pub Date : 2025-12-20 DOI: 10.1016/j.jseaes.2025.106929

Ruihui Zheng , Zhihuan Zhang , Yuan Bao , Zhipeng Li , Wenhao Li , Jiao Xue

Shale and mudstone are critical source rocks in continental basins, however, systematic studies on the differences in hydrocarbon generation and evolution processes between these two lithologies remain limited. This paper investigates the shale and mudstone of the seventh member of the Triassic Yanchang Formation (Chang 7 Member) in the Ordos Basin. The Chang 7 Member shale demonstrates a relatively high hydrocarbon generation threshold, rapid conversion rates, and a short generation cycle. Whereas mudstone is characterized by a low generation threshold, slower conversion rates, and a longer generation cycle. The maturity values (R_o) required for the oil generation threshold (conversion ≥ 20 %) are 0.68 % for shale and 0.58 % for mudstone. The onset, peak, and termination maturity values for oil generation are 0.63 %, 0.97 %, and 1.61 %, respectively, for shale, compared to 0.43 %, 1.05 %, and 1.68 % for mudstone. The optimal maturity ranges for oil generation are 0.68 %–1.21 % for shale and 0.58 %–1.33 % for mudstone. Spatial variations in burial depth and thermal evolution history across the Ordos Basin result in a progressive northward increase in the depth intervals corresponding to peak oil generation for both lithologies within the Chang 7 Member. Notably, the Chang 7 Member shale and mudstone in the Jiyuan area exhibit higher oil generation conversion efficiency, indicating significant potential for shale oil exploration. These findings provide valuable insights for advancing shale oil resource exploration and determining optimal temperature conditions for in-situ shale pyrolysis in the Ordos Basin.

页岩和泥岩是陆相盆地重要的烃源岩，但对这两种岩性生烃演化差异的系统研究仍然有限。本文对鄂尔多斯盆地三叠系延长组7段（长7段）页岩和泥岩进行了研究。长7段页岩具有生烃门槛高、转化速率快、生烃周期短的特点。而泥岩的特点是生成阈值低，转化率较慢，生成周期较长。页岩和泥岩形成生油阈值（转化率≥20%）所需的Ro值分别为0.68%和0.58%。页岩生油的起始、峰值和终止成熟度值分别为0.63%、0.97%和1.61%，泥岩生油的起始、峰值和终止成熟度分别为0.43%、1.05%和1.68%。页岩的最佳生油成熟度范围为0.68% ~ 1.21%，泥岩为0.58% ~ 1.33%。鄂尔多斯盆地埋深和热演化史的空间差异导致长7段两种岩性的生油高峰对应的深度区间逐渐向北增加。特别是姬塬地区长7段页岩、泥岩生油转化效率较高，页岩油勘探潜力巨大。这些研究结果为进一步推进鄂尔多斯盆地页岩油资源勘探和确定页岩原位热解的最佳温度条件提供了有价值的见解。

{"title":"Hydrocarbon generation and evolution of shale and mudstone: Insights from the Triassic Chang 7 Member in the Ordos Basin, NW China","authors":"Ruihui Zheng , Zhihuan Zhang , Yuan Bao , Zhipeng Li , Wenhao Li , Jiao Xue","doi":"10.1016/j.jseaes.2025.106929","DOIUrl":"10.1016/j.jseaes.2025.106929","url":null,"abstract":"<div><div>Shale and mudstone are critical source rocks in continental basins, however, systematic studies on the differences in hydrocarbon generation and evolution processes between these two lithologies remain limited. This paper investigates the shale and mudstone of the seventh member of the Triassic Yanchang Formation (Chang 7 Member) in the Ordos Basin. The Chang 7 Member shale demonstrates a relatively high hydrocarbon generation threshold, rapid conversion rates, and a short generation cycle. Whereas mudstone is characterized by a low generation threshold, slower conversion rates, and a longer generation cycle. The maturity values (<em>R</em><sub>o</sub>) required for the oil generation threshold (conversion ≥ 20 %) are 0.68 % for shale and 0.58 % for mudstone. The onset, peak, and termination maturity values for oil generation are 0.63 %, 0.97 %, and 1.61 %, respectively, for shale, compared to 0.43 %, 1.05 %, and 1.68 % for mudstone. The optimal maturity ranges for oil generation are 0.68 %–1.21 % for shale and 0.58 %–1.33 % for mudstone. Spatial variations in burial depth and thermal evolution history across the Ordos Basin result in a progressive northward increase in the depth intervals corresponding to peak oil generation for both lithologies within the Chang 7 Member. Notably, the Chang 7 Member shale and mudstone in the Jiyuan area exhibit higher oil generation conversion efficiency, indicating significant potential for shale oil exploration. These findings provide valuable insights for advancing shale oil resource exploration and determining optimal temperature conditions for <em>in-situ</em> shale pyrolysis in the Ordos Basin.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"298 ","pages":"Article 106929"},"PeriodicalIF":2.4,"publicationDate":"2025-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145842630","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

Multi-proxy provenance records from the Yanyuan Basin reveal the Cenozoic tectonic evolution along the southeastern Tibetan Plateau 盐源盆地的多代物源记录揭示了青藏高原东南部新生代构造演化

IF 2.4 3区地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY

Journal of Asian Earth Sciences

Pub Date : 2025-12-20 DOI: 10.1016/j.jseaes.2025.106928

Yuquan Jiang , Linlin Li , Xiangjiang Yu , Zhongtai He , Dewen Li , Yingying Li

The timing of surface uplift and the evolution of paleodrainage systems in the southeastern Tibetan Plateau remain highly debated. The Yanyuan Basin on the southeastern margin of the Tibetan Plateau preserves key sedimentary archives of the Cenozoic tectonic evolution. This study integrates detrital zircon U-Pb geochronology with single-grain geochemical analyses of tourmaline, garnet, and rutile to reconstruct provenance changes from the Eocene Hongyazi Formation to the Pliocene–Early Pleistocene Xigeda Formation. The Eocene strata along the western margin were mainly derived from weakly metamorphosed Triassic clastic rocks of the southern Yidun Terrane, together with Neoproterozoic toTriassic intermediate–acidic intrusions exposed along the basin margins, whereas the southern margin was dominated by detritus from the Emeishan basalts. In contrast, the Xigeda Formation records a markedly different sedimentary source-to-sink system: both the western and northern margins were primarily supplied by proximal sources exhumed from the Jinhe–Qinghe and Muli thrust faults, particularly Neoproterozoic intermediate–acidic plutons. This transition reflects a fundamental reorganization of drainage networks and catchment boundaries, associated with the shift from early-stage plateau uplift and regionally integrated paleodrainage to late-stage tectonic compartmentalization under thrusting and strike-slip deformation. The combined zircon age spectra and detrital heavy mineral geochemistry provide robust constraints on sediment provenance, paleogeographic reconfiguration, and the mechanisms of tectonic transformation along the southeastern margin of the Tibetan Plateau during the Cenozoic.

青藏高原东南部地表隆升的时间和古水系的演化至今仍有争议。青藏高原东南缘盐源盆地保存了新生代构造演化的重要沉积档案。结合碎屑锆石U-Pb年代学和电气石、石榴石、金红石的单粒地球化学分析，重建了始新世洪崖子组至上新世—早更新世西格达组的物源变化。西缘始新世地层主要来自南一顿地系三叠系弱变质碎屑岩，以及盆地边缘暴露的新元古代至三叠系中酸性侵入岩，而南缘则以峨眉山玄武岩碎屑岩为主。西格达组沉积源-汇体系明显不同，西缘和北缘主要由金河-清河和木里逆冲断层的近端源供给，特别是新元古代中酸性岩体。这种转变反映了流域网络和流域边界的根本性重组，与早期高原隆升和区域综合古排水向晚期逆冲和走滑变形作用下的构造分区化转变有关。结合锆石年龄谱和碎屑重矿物地球化学特征，对青藏高原东南缘新生代沉积物源、古地理重构和构造转化机制提供了强有力的约束。

{"title":"Multi-proxy provenance records from the Yanyuan Basin reveal the Cenozoic tectonic evolution along the southeastern Tibetan Plateau","authors":"Yuquan Jiang , Linlin Li , Xiangjiang Yu , Zhongtai He , Dewen Li , Yingying Li","doi":"10.1016/j.jseaes.2025.106928","DOIUrl":"10.1016/j.jseaes.2025.106928","url":null,"abstract":"<div><div>The timing of surface uplift and the evolution of paleodrainage systems in the southeastern Tibetan Plateau remain highly debated. The Yanyuan Basin on the southeastern margin of the Tibetan Plateau preserves key sedimentary archives of the Cenozoic tectonic evolution. This study integrates detrital zircon U-Pb geochronology with single-grain geochemical analyses of tourmaline, garnet, and rutile to reconstruct provenance changes from the Eocene Hongyazi Formation to the Pliocene–Early Pleistocene Xigeda Formation. The Eocene strata along the western margin were mainly derived from weakly metamorphosed Triassic clastic rocks of the southern Yidun Terrane, together with Neoproterozoic toTriassic intermediate–acidic intrusions exposed along the basin margins, whereas the southern margin was dominated by detritus from the Emeishan basalts. In contrast, the Xigeda Formation records a markedly different sedimentary source-to-sink system: both the western and northern margins were primarily supplied by proximal sources exhumed from the Jinhe–Qinghe and Muli thrust faults, particularly Neoproterozoic intermediate–acidic plutons. This transition reflects a fundamental reorganization of drainage networks and catchment boundaries, associated with the shift from early-stage plateau uplift and regionally integrated paleodrainage to late-stage tectonic compartmentalization under thrusting and strike-slip deformation. The combined zircon age spectra and detrital heavy mineral geochemistry provide robust constraints on sediment provenance, paleogeographic reconfiguration, and the mechanisms of tectonic transformation along the southeastern margin of the Tibetan Plateau during the Cenozoic.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"298 ","pages":"Article 106928"},"PeriodicalIF":2.4,"publicationDate":"2025-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145842632","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

Evolution of non-colinear fault systems from extension to transtension: Northern Dongying Sag, Bohai Bay Basin, East China 非共线断裂体系从伸展到张拉的演化：渤海湾盆地东营凹陷北部

IF 2.4 3区地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY

Journal of Asian Earth Sciences

Pub Date : 2025-12-20 DOI: 10.1016/j.jseaes.2025.106925

Meng Zhang , Kuihua Zhang , Shuang Song , Yanjun Cheng , Zhiping Wu

Many rift basins present non-colinear fault systems; however, different mechanisms can contribute to such fault patterns. Understanding the evolution of non-colinear faults is crucial for evaluating the paleo-stress and kinematics of rift basins. Using well-constrained 3D seismic data, we demonstrate the evolution of a basin-bounding fault and non-colinear minor faults over 40 Myr in the northern Dongying Sag, Bohai Bay Basin, East China. During the Paleocene–Middle Eocene (66–42.7 Ma), an E–W-striking basin-bounding fault and many minor faults with the same strike developed in response to regional extension. A small number of NW–SE-striking minor faults also developed, attributed to the reactivation of pre-Cenozoic faults. In the subsequent ∼ 2 Myr, the through-going basin-bounding fault surface bifurcated upwards into two overlapping master faults, accompanied with the development of splay faults. Depocentres started to migrate towards hanging walls of the splay faults. At ∼ 40.9 Ma, splay faults with a left-stepping configuration along the NE–SW direction developed and linked with the main fault plane, leading to a transition of sedimentary distribution from E–W to NE–SW. Meanwhile, E–W-, NE–SW- and NW–SE-striking minor faults synchronously developed, and some of the NE–SW-striking minor faults present a left-stepping, en-echelon arrangement. The non-colinear faults are likely to correspond to subsidiary structures in a dextral transtensional setting, associated with the right-lateral movement of a continental-scale fault, Tan-Lu Fault Zone. The Bohai Bay Basin may be suitable for a kinematic model of extension followed by dextral transtension during the Paleogene.

许多断陷盆地呈现非共线断裂体系；然而，不同的机制可能导致这样的故障模式。了解非共线断裂的演化对裂谷盆地古应力和运动学的评价具有重要意义。利用约束良好的三维地震资料，研究了渤海湾盆地东营凹陷北部40 Myr以上的盆界断裂和非共线小断裂的演化过程。古新世—中始新世（66 ~ 42.7 Ma），受区域伸展影响，发育了一条东西向的盆地边界断裂和多条相同走向的小断裂。少量北西-东向的小断裂也发育，这是由于前新生代断裂的活化所致。在随后的~ 2 Myr中，贯穿式盆地边界断裂面向上分叉成两条重叠的主断裂，并伴有展张断裂的发育。沉积中心开始向展斜断层上盘迁移。在~ 40.9 Ma时，沿NE-SW方向发育左步状断层，并与主断平面相连接，沉积分布由东西向北东向西西过渡。同时，东西向、北东向、西南向和北西向小断裂同步发育，部分北东向、西南向小断裂呈左步进、阶梯式排列。非共线断层可能对应于右旋张性背景下的附属构造，与大陆尺度断层郯庐断裂带的右向运动有关。渤海湾盆地可能适合古近纪伸展后右向张拉的运动学模式。

{"title":"Evolution of non-colinear fault systems from extension to transtension: Northern Dongying Sag, Bohai Bay Basin, East China","authors":"Meng Zhang , Kuihua Zhang , Shuang Song , Yanjun Cheng , Zhiping Wu","doi":"10.1016/j.jseaes.2025.106925","DOIUrl":"10.1016/j.jseaes.2025.106925","url":null,"abstract":"<div><div>Many rift basins present non-colinear fault systems; however, different mechanisms can contribute to such fault patterns. Understanding the evolution of non-colinear faults is crucial for evaluating the paleo-stress and kinematics of rift basins. Using well-constrained 3D seismic data, we demonstrate the evolution of a basin-bounding fault and non-colinear minor faults over 40 Myr in the northern Dongying Sag, Bohai Bay Basin, East China. During the Paleocene–Middle Eocene (66–42.7 Ma), an E–W-striking basin-bounding fault and many minor faults with the same strike developed in response to regional extension. A small number of NW–SE-striking minor faults also developed, attributed to the reactivation of pre-Cenozoic faults. In the subsequent ∼ 2 Myr, the through-going basin-bounding fault surface bifurcated upwards into two overlapping master faults, accompanied with the development of splay faults. Depocentres started to migrate towards hanging walls of the splay faults. At ∼ 40.9 Ma, splay faults with a left-stepping configuration along the NE–SW direction developed and linked with the main fault plane, leading to a transition of sedimentary distribution from E–W to NE–SW. Meanwhile, E–W-, NE–SW- and NW–SE-striking minor faults synchronously developed, and some of the NE–SW-striking minor faults present a left-stepping, <em>en-echelon</em> arrangement. The non-colinear faults are likely to correspond to subsidiary structures in a dextral transtensional setting, associated with the right-lateral movement of a continental-scale fault, Tan-Lu Fault Zone. The Bohai Bay Basin may be suitable for a kinematic model of extension followed by dextral transtension during the Paleogene.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"298 ","pages":"Article 106925"},"PeriodicalIF":2.4,"publicationDate":"2025-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145842661","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

Crustal structure of Sulaimaniyah, NE Iraq: Joint analysis of receiver functions and surface wave dispersion 伊拉克东北部苏莱曼尼亚的地壳结构：接收函数和面波频散的联合分析

IF 2.4 3区地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY

Journal of Asian Earth Sciences

Pub Date : 2025-12-19 DOI: 10.1016/j.jseaes.2025.106920

Suad Mohammed Ali , Emad H. Al-Khersan , Hayder I. Mohammed

The Sulaimaniyah region in northeastern Iraq lies within the seismically active Zagros Fold-Thrust Belt (ZFTB), formed by the ongoing collision between the Arabian and Eurasian plates. Despite its tectonic significance, detailed shear-wave velocity models for this area remain scarce, which limits our understanding of the crustal composition, thickness, and deformation mechanisms. This study presents a new, well-constrained crustal structure model for the region, achieved through the novel integration of P-wave receiver functions and Rayleigh wave group velocity dispersion in a joint inversion framework. It also offers an important understanding of the region’s tectonic framework and its significance for hydrocarbon formation and distribution. The aim is to achieve high-resolution constraints on crustal layering and Moho depth beneath the Sulaimaniyah (SLY) seismic station. Data from nine high-quality teleseismic events and 20 carefully selected Rayleigh wave dispersion curves were processed using the Computer Programs in Seismology (CPS) package. The results reveal a four-layered crust: a 10 km-thick sedimentary layer (Vs ≈ 3.1 km/s), an upper crustal layer at 14–16 km (Vs ≈ 3.3 km/s), a mid-crust at 30–32 km (Vs ≈ 3.4–3.5 km/s), and the Moho at ∼ 46 km depth, separating the lower crust (Vs ≈ 3.6 km/s) from the uppermost mantle (Vs ≈ 3.9 km/s). The model also shows a gradational Moho transition, unlike abrupt boundaries observed in some regional sites, suggesting elevated temperatures or crustal fracturing due to active collision processes. This work provides researchers with a robust reference model for the ZFTB sector of Iraq, thereby enhancing seismic hazard assessment, tectonic modelling, and comparative studies of continental collision zones.

伊拉克东北部的苏莱曼尼亚地区位于地震活跃的扎格罗斯褶皱冲断带（ZFTB）内，该带是由阿拉伯板块和欧亚板块持续碰撞形成的。尽管具有重要的构造意义，但该地区详细的剪切波速度模型仍然缺乏，这限制了我们对地壳组成，厚度和变形机制的理解。本研究通过在联合反演框架中整合p波接收函数和瑞利波群速度频散，提出了该地区一个新的、约束良好的地壳结构模型。对该区的构造格架及其对油气形成和分布的意义也有重要的认识。目的是实现苏莱曼尼亚（SLY）地震台站下地壳分层和莫霍深度的高分辨率约束。使用计算机程序在地震学（CPS）软件包处理了9个高质量的远震事件和20个精心挑选的瑞利波频散曲线的数据。结果显示，地壳为4层：10 km厚的沉积层（Vs≈3.1 km/s）， 14-16 km （Vs≈3.3 km/s）的上地壳层，30-32 km （Vs≈3.4-3.5 km/s）的中地壳，以及约46 km深度的莫霍层，将下地壳（Vs≈3.6 km/s）与上地幔（Vs≈3.9 km/s）分开。该模型还显示了一个渐变的莫霍转变，不像在某些区域观测到的突然边界，这表明由于活跃的碰撞过程，温度升高或地壳破裂。这项工作为伊拉克ZFTB部门的研究人员提供了一个强大的参考模型，从而加强了地震危险性评估、构造建模和大陆碰撞带的比较研究。

{"title":"Crustal structure of Sulaimaniyah, NE Iraq: Joint analysis of receiver functions and surface wave dispersion","authors":"Suad Mohammed Ali , Emad H. Al-Khersan , Hayder I. Mohammed","doi":"10.1016/j.jseaes.2025.106920","DOIUrl":"10.1016/j.jseaes.2025.106920","url":null,"abstract":"<div><div>The Sulaimaniyah region in northeastern Iraq lies within the seismically active Zagros Fold-Thrust Belt (ZFTB), formed by the ongoing collision between the Arabian and Eurasian plates. Despite its tectonic significance, detailed shear-wave velocity models for this area remain scarce, which limits our understanding of the crustal composition, thickness, and deformation mechanisms. This study presents a new, well-constrained crustal structure model for the region, achieved through the novel integration of P-wave receiver functions and Rayleigh wave group velocity dispersion in a joint inversion framework. It also offers an important understanding of the region’s tectonic framework and its significance for hydrocarbon formation and distribution. The aim is to achieve high-resolution constraints on crustal layering and Moho depth beneath the Sulaimaniyah (SLY) seismic station. Data from nine high-quality teleseismic events and 20 carefully selected Rayleigh wave dispersion curves were processed using the Computer Programs in Seismology (CPS) package. The results reveal a four-layered crust: a 10 km-thick sedimentary layer (Vs ≈ 3.1 km/s), an upper crustal layer at 14–16 km (Vs ≈ 3.3 km/s), a mid-crust at 30–32 km (Vs ≈ 3.4–3.5 km/s), and the Moho at ∼ 46 km depth, separating the lower crust (Vs ≈ 3.6 km/s) from the uppermost mantle (Vs ≈ 3.9 km/s). The model also shows a gradational Moho transition, unlike abrupt boundaries observed in some regional sites, suggesting elevated temperatures or crustal fracturing due to active collision processes. This work provides researchers with a robust reference model for the ZFTB sector of Iraq, thereby enhancing seismic hazard assessment, tectonic modelling, and comparative studies of continental collision zones.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"298 ","pages":"Article 106920"},"PeriodicalIF":2.4,"publicationDate":"2025-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145885710","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

The main Paleo-Tethys Ocean suture in the Pamir Region: Revealed by detrital zircon U–Pb geochronology 帕米尔地区古特提斯洋主缝合线：由碎屑锆石U-Pb年代学揭示

IF 2.4 3区地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY

Journal of Asian Earth Sciences

Pub Date : 2025-12-19 DOI: 10.1016/j.jseaes.2025.106921

Murodov Azamdzhon , Wei Dan , Xin Ma , Murodov Davlatkhudzha , Sharifjon Odinaev , Ilhomjon Oimuhammadzoda , Mustafo Gadoev , Upendra Baral , Dzhovid Yogibekov , Gong-Jian Tang

The Pamir Plateau offers valuable insights into the evolution of the Tethys Oceans. Despite numerous studies, the nature and timing of closure of the Paleo–Tethys Ocean remain debated. This study presents detrital zircon U–Pb ages of sedimentary rocks across the Pamir terranes to investigate their tectonic evolution. Detrital zircons from the Paleozoic–Triassic sedimentary succession in the Northern and Central Pamir yielded similar results, with ages ranging from ∼ 233 Ma to 1000 Ma, showing two major peaks one at ∼ 250 Ma and another at 540–600 Ma. Zircons giving these two age peaks are subhedral to anhedral, implying they were likely derived from arc–related magmatic rocks, possibly formed by the subduction of the Paleo–Tethys oceanic lithosphere. In contrast, detrital zircons from the Late Triassic sandstone in Southern Pamir reveal a major peak at 237 Ma, with subordinate peaks at ∼ 430 Ma and 540 Ma, indicating their detritus was largely sourced from the Central Pamir. Age patterns of the detrital zircons from the Northern–Central Pamir and South Pamir are similar to those of the North and South Qiangtang, respectively, indicating that the Rushan–Pshart suture zone was the main suture of the Paleo–Tethys, and the Tanymas suture zone was the back–arc basin of the Paleo–Tethys Ocean.. The obtained data indicate that the northward subduction of the Paleo–Tethys oceanic lithosphere beneath the Northern and Central Pamir was continuous, at least during the Late Devonian to Triassic period, and the collision between the Central and South Pamir was initiated in the Middle Triassic (∼240 Ma).

帕米尔高原为特提斯海洋的演变提供了宝贵的见解。尽管进行了大量的研究，古特提斯洋的性质和关闭时间仍然存在争议。本文研究了帕米尔地体沉积岩的碎屑锆石U-Pb年龄，以探讨其构造演化。来自帕米尔高原北部和中部古生代-三叠纪沉积序列的碎屑锆石也得到了类似的结果，年龄范围从~ 233 Ma到1000 Ma，显示出两个主要峰，一个在~ 250 Ma，另一个在540-600 Ma。给出这两个年龄峰的锆石均为半面体到正面体，表明它们可能来自与弧相关的岩浆岩，可能是由古特提斯洋岩石圈俯冲形成的。南帕米尔高原晚三叠世砂岩碎屑锆石在237 Ma有主峰，在~ 430 Ma和540 Ma有次峰，表明其碎屑主要来自中帕米尔高原。北-中帕米尔和南帕米尔的碎屑锆石年龄模式分别与北羌塘和南羌塘相似，表明如山-普沙特缝合带是古特提斯的主缝合带，坦尼马斯缝合带是古特提斯洋的弧后盆地。得到的资料表明，至少在晚泥盆世至三叠纪期间，古特提斯洋岩石圈在北帕米尔高原和中帕米尔高原的北俯冲是连续的，而中帕米尔高原和南帕米尔高原的碰撞始于中三叠世（~ 240 Ma）。

{"title":"The main Paleo-Tethys Ocean suture in the Pamir Region: Revealed by detrital zircon U–Pb geochronology","authors":"Murodov Azamdzhon , Wei Dan , Xin Ma , Murodov Davlatkhudzha , Sharifjon Odinaev , Ilhomjon Oimuhammadzoda , Mustafo Gadoev , Upendra Baral , Dzhovid Yogibekov , Gong-Jian Tang","doi":"10.1016/j.jseaes.2025.106921","DOIUrl":"10.1016/j.jseaes.2025.106921","url":null,"abstract":"<div><div>The Pamir Plateau offers valuable insights into the evolution of the Tethys Oceans. Despite numerous studies, the nature and timing of closure of the Paleo–Tethys Ocean remain debated. This study presents detrital zircon U–Pb ages of sedimentary rocks across the Pamir terranes to investigate their tectonic evolution. Detrital zircons from the Paleozoic–Triassic sedimentary succession in the Northern and Central Pamir yielded similar results, with ages ranging from ∼ 233 Ma to 1000 Ma, showing two major peaks one at ∼ 250 Ma and another at 540–600 Ma. Zircons giving these two age peaks are subhedral to anhedral, implying they were likely derived from arc–related magmatic rocks, possibly formed by the subduction of the Paleo–Tethys oceanic lithosphere. In contrast, detrital zircons from the Late Triassic sandstone in Southern Pamir reveal a major peak at 237 Ma, with subordinate peaks at ∼ 430 Ma and 540 Ma, indicating their detritus was largely sourced from the Central Pamir. Age patterns of the detrital zircons from the Northern–Central Pamir and South Pamir are similar to those of the North and South Qiangtang, respectively, indicating that the Rushan–Pshart suture zone was the main suture of the Paleo–Tethys, and the Tanymas suture zone was the back–arc basin of the Paleo–Tethys Ocean.. The obtained data indicate that the northward subduction of the Paleo–Tethys oceanic lithosphere beneath the Northern and Central Pamir was continuous, at least during the Late Devonian to Triassic period, and the collision between the Central and South Pamir was initiated in the Middle Triassic (∼240 Ma).</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"298 ","pages":"Article 106921"},"PeriodicalIF":2.4,"publicationDate":"2025-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145808545","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

Mass transport deposits in confined environment, a case study from the Kaiping sag, Pearl River Mouth basin, northern south China sea margin 封闭环境下的块体搬运沉积——以南海北部珠江口盆地开平凹陷为例

IF 2.4 3区地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY

Journal of Asian Earth Sciences

Pub Date : 2025-12-19 DOI: 10.1016/j.jseaes.2025.106924

Lushan Jiang, Xiwu Luan

Mass transport deposits (MTDs) have been extensively discussed in the literature. The prevailing understanding characterizes MTDs as gravity-driven instability phenomena occurring on the seafloors. This study employs high-resolution 2D/3D seismic data integrated with well data to re-evaluate the genesis mechanisms of MTDs in the Kaiping sag, Zhu-II depression, Pearl River Mouth basin (PRMB), northern margin of the South China Sea (SCS). Key diagnostic features interpreted from seismic datasets reveal the absence of typical characteristics of conventional MTDs, including no distinct headwall scarps, and moats, and especially no onlapping structures of isochronous turbidite contourites that usually cover uneven MTD surfaces. In contrast, seismic evidence for a tectonic compression environment is observed, such as thrust fault reactivation, localized stratal folding, and chaotic thrust-related deformation patterns within the study interval-consistent with the post-spreading tectonic setting of the SCS. For the first time, this research concludes that these MTDs formed in a confined environment (rather than an open continental slope), and were induced by mega-earthquakes. The key contributing factors to their formation include: (1) tectonic compression after the cessation of SCS seafloor spreading (post-16 Ma), evidenced by seismic records of thrusting and folding; (2) elevated sedimentation rates since the peak uplift of the eastern Tibetan plateau (since 15 Ma), leading to thick unconsolidated sediments; (3) periods of higher sea level (favouring high pore-water pressure); and (4) mega-earthquakes triggered by the post-spreading compression. Collectively, these factors facilitated the liquefaction processes that drove MTDs development.

质量搬运沉积（MTDs）在文献中得到了广泛的讨论。目前普遍的理解是，MTDs是发生在海底的重力驱动的不稳定现象。利用高分辨率二维/三维地震资料，结合钻井资料，对南海北缘珠江口盆地开平凹陷、珠二坳陷、开平凹陷的MTDs成因机制进行了重新评价。从地震数据集解释的关键诊断特征显示，传统MTD缺乏典型特征，包括没有明显的顶壁陡坡和护城河，特别是没有覆盖不均匀MTD表面的等时浊积等高线的重叠结构。相反，在研究区间内观察到逆冲断层重新激活、局部地层褶皱和与逆冲相关的混乱变形模式等构造压缩环境的地震证据，与南海扩张后的构造环境相一致。这项研究首次得出结论，这些MTDs形成于一个封闭的环境（而不是一个开放的大陆斜坡），并且是由大地震引起的。其形成的关键因素有：(1)南海海底扩张停止后（16 Ma以后）的构造挤压作用，以逆冲和褶皱地震记录为证据；(2)青藏高原东部自15 Ma以来峰值隆升，沉积速率升高，形成较厚的松散沉积；(3)高海平面时期（有利于高孔隙水压力）；(4)伸展后压缩引发的特大地震。总的来说，这些因素促进了液化过程，推动了mtd的发展。

{"title":"Mass transport deposits in confined environment, a case study from the Kaiping sag, Pearl River Mouth basin, northern south China sea margin","authors":"Lushan Jiang, Xiwu Luan","doi":"10.1016/j.jseaes.2025.106924","DOIUrl":"10.1016/j.jseaes.2025.106924","url":null,"abstract":"<div><div>Mass transport deposits (MTDs) have been extensively discussed in the literature. The prevailing understanding characterizes MTDs as gravity-driven instability phenomena occurring on the seafloors. This study employs high-resolution 2D/3D seismic data integrated with well data to re-evaluate the genesis mechanisms of MTDs in the Kaiping sag, Zhu-II depression, Pearl River Mouth basin (PRMB), northern margin of the South China Sea (SCS). Key diagnostic features interpreted from seismic datasets reveal the absence of typical characteristics of conventional MTDs, including no distinct headwall scarps, and moats, and especially no onlapping structures of isochronous turbidite contourites that usually cover uneven MTD surfaces. In contrast, seismic evidence for atectonic compression environmentis observed, such as thrust fault reactivation, localized stratal folding, and chaotic thrust-related deformation patterns within the study interval-consistent with the post-spreading tectonic setting of the SCS. For the first time, this research concludes that these MTDs formed in a confined environment (rather than an open continental slope), and were induced by mega-earthquakes. The key contributing factors to their formation include: (1) tectonic compression after the cessation of SCS seafloor spreading (post-16 Ma), evidenced by seismic records of thrusting and folding; (2) elevated sedimentation rates since the peak uplift of the eastern Tibetan plateau (since 15 Ma), leading to thick unconsolidated sediments; (3) periods of higher sea level (favouring high pore-water pressure); and (4) mega-earthquakes triggered by the post-spreading compression. Collectively, these factors facilitated the liquefaction processes that drove MTDs development.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"298 ","pages":"Article 106924"},"PeriodicalIF":2.4,"publicationDate":"2025-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145842641","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

Eocene SSZ-type ophiolite from Banggi Island, Sabah (Northern Borneo), Malaysia: Zircon U-Pb ages, geochemical characteristics and tectonic implications 马来西亚沙巴（北婆罗洲）邦吉岛始新世ssz型蛇绿岩：锆石U-Pb年龄、地球化学特征及构造意义

IF 2.4 3区地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY

Journal of Asian Earth Sciences

Pub Date : 2025-12-19 DOI: 10.1016/j.jseaes.2025.106919

Rezal Rahmat , Sun-Lin Chung , Azman Abd Ghani , Hao-Yang Lee , Yoshiyuki Iizuka , Chih-Tung Chen , Long Xiang Quek

Ophiolites in Sabah are dispersed in a band-shaped lineament stretching from Darvel Bay in the southeast to Banggi Island in the northmost part of Sabah. This study reports the first set of zircons U-Pb ages and whole-rock geochemical data of the Banggi Island Ophiolite (BIO), conventionally regarded as part of the regional Triassic-Eocene “Chert-Spilite Formations” that had been named as the Sabah Ophiolite, and interpreted as remnants of oceanic crust from the proto-South China Sea. LA-ICPMS analyses of zircons separated from five gabbro and two diorite samples gave a short span of ²⁰⁶Pb/²³⁸U ages of ∼ 55–50 Ma (Early Eocene), with high and positive ε_Hf(t) values from + 16.6 to + 10.2 indicating their magma source from a relatively depleted or juvenile mantle. The crustal sequence of Banggi Island Ophiolite, including basalt, gabbro, and diorite, is characterized by depletion in the light rare earth elements and various degrees of enrichment in the large ion lithophile elements, coupled with depletion in Nb and Ta. Their overall geochemical signatures are comparable to the SSZ (supra-subduction zone)-type ophiolites reported from two nearby islands in Palawan and Mindoro, western Philippines. Integrating our new data with regional geologic information, we argue that the Banggi Island Ophiolite represents an SSZ-type ophiolite that formed in the forearc regime at the initial stage of southward subduction of the proto-South China Sea plate. The subduction initiation started from the Early Eocene in Sabah, leading to upper-plate spreading and associated magmatism that gave rise to the crustal rocks of the ophiolite. It may have caused a regional stratigraphic unconformity and later propagated eastward to Palawan and Mindoro, eventually resulting in the ophiolites there and a volcanic arc exposed now as the Cagayan Ridge.

沙巴蛇绿岩呈带状分布，从东南部的Darvel Bay延伸至最北部的Banggi Island。本文报道了Banggi Island蛇绿岩（BIO）的第一套锆石U-Pb年龄和全岩地球化学数据，该蛇绿岩通常被认为是三叠纪-始新世区域“燧石-碧岩组”的一部分，被命名为Sabah蛇绿岩，被解释为原南海海洋地壳的残余。从5个辉长岩和2个闪长岩样品中分离出的锆石LA-ICPMS分析结果显示，锆石的206Pb/238U年龄跨度较短，为~ 55 ~ 50 Ma（早始新世），εHf(t)值在+ 16.6 ~ + 10.2之间，εHf(t)值较高且正，表明其岩浆来源为相对枯竭或幼年地幔。邦基岛蛇绿岩的地壳序列包括玄武岩、辉长岩和闪长岩，其特征是轻稀土元素亏缺，大离子亲石元素有不同程度的富集，并伴有Nb和Ta的亏缺。其整体地球化学特征与在菲律宾西部巴拉望岛和民都洛岛附近报道的SSZ（超俯冲带）型蛇绿岩相当。结合区域地质资料，我们认为邦基岛蛇绿岩是一种形成于原南海板块向南俯冲初期弧前状态的ssz型蛇绿岩。沙巴早始新世开始俯冲，板块扩张，岩浆作用形成蛇绿岩类地壳岩石。它可能造成了区域地层不整合，后来向东传播到巴拉望岛和民都洛岛，最终形成了那里的蛇绿岩和一条火山弧，现在暴露为卡加延岭。

{"title":"Eocene SSZ-type ophiolite from Banggi Island, Sabah (Northern Borneo), Malaysia: Zircon U-Pb ages, geochemical characteristics and tectonic implications","authors":"Rezal Rahmat , Sun-Lin Chung , Azman Abd Ghani , Hao-Yang Lee , Yoshiyuki Iizuka , Chih-Tung Chen , Long Xiang Quek","doi":"10.1016/j.jseaes.2025.106919","DOIUrl":"10.1016/j.jseaes.2025.106919","url":null,"abstract":"<div><div>Ophiolites in Sabah are dispersed in a band-shaped lineament stretching from Darvel Bay in the southeast to Banggi Island in the northmost part of Sabah. This study reports the first set of zircons U-Pb ages and whole-rock geochemical data of the Banggi Island Ophiolite (BIO), conventionally regarded as part of the regional Triassic-Eocene “Chert-Spilite Formations” that had been named as the Sabah Ophiolite, and interpreted as remnants of oceanic crust from the proto-South China Sea. LA-ICPMS analyses of zircons separated from five gabbro and two diorite samples gave a short span of <sup>206</sup>Pb/<sup>238</sup>U ages of ∼ 55–50 Ma (Early Eocene), with high and positive ε<sub>Hf</sub>(t) values from + 16.6 to + 10.2 indicating their magma source from a relatively depleted or juvenile mantle. The crustal sequence of Banggi Island Ophiolite, including basalt, gabbro, and diorite, is characterized by depletion in the light rare earth elements and various degrees of enrichment in the large ion lithophile elements, coupled with depletion in Nb and Ta. Their overall geochemical signatures are comparable to the SSZ (supra-subduction zone)-type ophiolites reported from two nearby islands in Palawan and Mindoro, western Philippines. Integrating our new data with regional geologic information, we argue that the Banggi Island Ophiolite represents an SSZ-type ophiolite that formed in the forearc regime at the initial stage of southward subduction of the proto-South China Sea plate. The subduction initiation started from the Early Eocene in Sabah, leading to upper-plate spreading and associated magmatism that gave rise to the crustal rocks of the ophiolite. It may have caused a regional stratigraphic unconformity and later propagated eastward to Palawan and Mindoro, eventually resulting in the ophiolites there and a volcanic arc exposed now as the Cagayan Ridge.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"298 ","pages":"Article 106919"},"PeriodicalIF":2.4,"publicationDate":"2025-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145842658","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