Gondwana Research最新文献_第6页

The mid-Cretaceous bauxites of SE France: Geochemistry, U-Pb zircon dating and their implications for the paleogeography at the junction between Alpine Tethys and Pyrenean Rift 法国东南部白垩纪中期的铝土矿：地球化学、U-Pb 锆石年代测定及其对阿尔卑斯特提斯和比利牛斯大裂谷交界处古地理的影响

IF 7.2 1区地球科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY

Gondwana Research

Pub Date : 2024-10-01 DOI: 10.1016/j.gr.2024.09.012

Nicola Mondillo , Cyril Chelle-Michou , Francesco Putzolu , Giuseppina Balassone , Angela Mormone , Licia Santoro , Salvatore Cretella , Gennaro Scognamiglio , Marcella Tarallo , Stefano Tavani

Karst bauxites mark episodic exhumation of carbonate platforms, thus providing key information for basin analysis and paleoclimate processes at the regional to continental scale. Most karst bauxite deposits of SE France lie between Jurassic platform carbonates in the footwall and Upper Cretaceous marine to continental sediments in the hanging wall. These deposits delineate a stratigraphic gap coeval with the Durance extensional tectonics, which led to the separation of the Vocontian and South Provence Basins, and shaped the junction between the Alpine Tethys and the Pyrenean Rift.

Our new mineralogical and geochemical data show that SE France karst bauxites were affected by in-situ weathering and alteration in conjunction to sedimentary reworking. Statistical analysis of geochemical data indicates that bauxite deposits have a similar chemical footprint, likely pointing to a common and long-lasting bauxitization process. New U-Pb zircon data from the Provence deposits confirm that the source material for the SE France bauxites is to be primarily found in the Hercynian basement. The data suggest the presence of an additional exotic zircon source deriving either from Avalonia and/or Baltica. The comparison of the new U-Pb zircon data with those on coeval bauxites evidences a marked difference between the SE France and the Sardinian deposits. This difference indicates diversification in the detritus provenance of the two areas since the Lower Cretaceous, setting the bauxites of SE France and Sardinia in lateral continuity with the bauxites occurring on the two opposite margins of the Pyrenean Rift, and supporting the development of these deposits on the shoulders of the rift-related basin formed at the eastern termination of the Pyrenean Rift.

岩溶铝土矿标志着碳酸盐地台的偶发性掘起，从而为区域到大陆尺度的盆地分析和古气候过程提供了关键信息。法国东南部的大多数岩溶铝土矿沉积位于底壁的侏罗纪平台碳酸盐岩和悬壁的上白垩世海洋至大陆沉积物之间。这些矿床划定了一个与多耐尔延伸构造同时发生的地层间隙，多耐尔延伸构造导致了沃孔蒂盆地和南普罗旺斯盆地的分离，并形成了阿尔卑斯特提斯山脉和比利牛斯大裂谷的交界处。对地球化学数据的统计分析表明，铝土矿床具有相似的化学足迹，这可能表明铝土矿化过程是一个共同而持久的过程。来自普罗旺斯矿床的新 U-Pb 锆石数据证实，法国东南部铝土矿的源材料主要来自海西期基底。这些数据表明，还有一个来自阿瓦鲁尼亚和/或波罗的海的锆石来源。将新的 U-Pb 锆石数据与同时期铝土矿的数据进行比较后发现，法国东南部矿床与撒丁岛矿床之间存在明显差异。这种差异表明，自下白垩世以来，这两个地区的沉积物来源多样化，使法国东南部和撒丁岛的铝土矿与比利牛斯大裂谷两个相对边缘的铝土矿在横向上具有连续性，并支持这些沉积物在比利牛斯大裂谷东部末端形成的与裂谷有关的盆地肩部发展。

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引用次数: 0

Recognizing microbial manganese reduction in lacustrine carbonate and its linkage to terrestrial biogeochemical processes 认识湖沼碳酸盐中的微生物锰还原及其与陆地生物地球化学过程的联系

IF 7.2 1区地球科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY

Gondwana Research

Pub Date : 2024-10-01 DOI: 10.1016/j.gr.2024.09.013

Xubin Wang , Lin Dong , Yiwu Wang , Zhijun Jin

Carbonate authigenesis, the in situ precipitation of carbonate minerals within the sediment porewaters, is a key pathway for carbonate deposition and plays a crucial role in global biogeochemical cycles. Heterotrophic microorganisms are essential in regulating authigenic carbonate formation, primarily through the consumption of organic matter. Although bacterial manganese reduction is known to influence the formation of rhodochrosite and dolomite, its role in limestone deposition is unclear. Here, we present a systematic investigation of mixed calcareous siliciclastic rocks from a Paleogene freshwater lake to identify the formation of authigenic carbonate, decode the role of microbial Mn reduction, and understand the microbial response to ancient lacustrine environmental changes. The positive correlation between carbonate fraction in bulk samples (Carb%) and Mn content in carbonate minerals (Mn_carb) suggests that carbonate precipitation is stimulated by Mn²⁺ enrichment. The dissimilarity between Mn_carb and Fe_carb, along with the synergic variations of Mn_carb and diagenetic indicators, support an authigenic rather than a hydrogenetic origin for the carbonates. Using a one-dimensional diffusion–advection-reaction model, we quantify the impact of Mn reduction on promoting carbonate precipitation. Furthermore, correlations between P_carb and other values–positive with the chemical index alteration (CIA), negative with Mn_carb, and none with TOC–suggest that nitrogen availability, regulated by continental weathering, is likely the primary factor limiting both the primary productivity and the bacterial reduction intensity at the study site. Overall, this study uncovers the role of microbial Mn reduction in stimulating authigenic carbonate precipitation, and reveals the modulation mechanism of Mn-reducing microorganisms in an ancient lake. These findings shed new light on the authigenic limestone formation mechanisms and provide a new perspective on interpreting the authigenic impacts on carbonate chemistry.

碳酸盐自生是指碳酸盐矿物在沉积物孔隙水中的原位沉淀，是碳酸盐沉积的一个关键途径，在全球生物地球化学循环中起着至关重要的作用。异养微生物主要通过消耗有机物来调节自生碳酸盐的形成。虽然已知细菌的锰还原作用会影响菱锰矿和白云石的形成，但其在石灰岩沉积中的作用尚不清楚。在此，我们对一个古新世淡水湖的混合钙质硅质岩进行了系统研究，以确定自生碳酸盐的形成，解读微生物锰还原的作用，并了解微生物对古代湖泊环境变化的反应。大块样品中的碳酸盐部分（Carb%）与碳酸盐矿物中的锰含量（Mncarb）呈正相关，这表明碳酸盐沉淀是由富集的 Mn2+ 刺激的。Mncarb 和 Fecarb 之间的差异，以及 Mncarb 和成岩指标的协同变化，支持碳酸盐的自生起源，而不是水成起源。利用一维扩散-对流-反应模型，我们量化了锰还原对促进碳酸盐沉淀的影响。此外，Pcarb 与其他值之间的相关性--与化学指数变化（CIA）呈正相关，与 Mncarb 呈负相关，而与总有机碳（TOC）无相关性--表明受大陆风化作用调节的氮供应可能是限制研究地点初级生产力和细菌还原强度的主要因素。总之，本研究揭示了微生物还原锰在刺激自生碳酸盐沉淀中的作用，并揭示了古湖泊中还原锰微生物的调节机制。这些发现为自生性石灰岩的形成机制提供了新的启示，并为解释自生性对碳酸盐化学的影响提供了新的视角。

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引用次数: 0

A new “silesaurid” from the oldest dinosauromorph-bearing beds of South America provides insights into the early evolution of bird-line archosaurs 南美洲最古老的恐龙化石岩床中发现的一种新的 "硅龙 "为鸟龙的早期进化提供了启示

IF 7.2 1区地球科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY

Gondwana Research

Pub Date : 2024-09-30 DOI: 10.1016/j.gr.2024.09.007

Rodrigo Temp Müller

Investigations regarding the early evolutionary history of bird-line archosaurs have undergone significant advancements in recent years. However, controversies remain, especially regarding the phylogenetic position of “silesaurids”. Whereas some hypotheses place these archosaurs as the sister-group to dinosaurs, others suggest that “silesaurids” are early ornithischian dinosaurs. Despite the phylogenetic disputes, “silesaurids” are a crucial group for comprehending the origins and early evolution of dinosaurs. In the present study, a new “silesaurid” from the Middle-Upper Triassic of Southern Brazil is described. Gondwanax paraisensis gen. et sp. nov. comes from the Dinodontosaurus Assemblage Zone of the Santa Maria Formation (Ladinian-Carnian boundary), representing one of the oldest “silesaurids” worldwide. Furthermore, Gondwanax paraisensis gen. et sp. nov is the oldest “silesaurid” with three sacral vertebrae, a feature usually observed in more derived forms. In addition, distinct from any other Triassic Pan-Aves, the new taxon bears an incipient fourth trochanter of the femur. This unique combination of features indicates a high diversity of locomotor strategies among early pan-avians. The co-occurrence of Gondwanax paraisensis gen. et sp. nov. and Gamatavus antiquus in the same Assemblage Zone represents the oldest evidence of sympatry among “silesaurids” in South America. Indeed, the unique combination of sacral and hindlimb features may suggest distinct behaviors for these species, potentially leading to niche differentiation within the same ecosystems.

近年来，有关鸟纲古龙早期进化史的研究取得了重大进展。然而，争议依然存在，尤其是关于 "硅龙类 "的系统发育地位。一些假说认为这些古龙是恐龙的姊妹群，而另一些假说则认为 "鸟龙 "是早期的鸟臀目恐龙。尽管在系统发育上存在争议，但 "硅龙类 "是了解恐龙起源和早期演化的一个重要类群。本研究描述了巴西南部中-上三叠世的一种新的 "硅龙类"。Gondwanax paraisensis gen. et sp. nov.来自圣玛丽亚地层（拉迪尼安-卡尼亚边界）的恐龙集合区，是世界上最古老的 "硅龙类 "之一。此外，新发现的 Gondwanax paraisensis gen.此外，与其他三叠纪泛有蹄类动物不同的是，这一新类群具有初生的第四股转子。这种独特的特征组合表明早期泛鸟类的运动策略具有高度的多样性。Gondwanax paraisensis gen. et sp. nov.和 Gamatavus antiquus同时出现在同一集合区，是南美洲 "硅龙类 "共生的最古老证据。事实上，骶骨和后肢特征的独特组合可能暗示了这些物种的不同行为，有可能导致它们在同一生态系统中的生态位分化。

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引用次数: 0

Mercury isotope evidence for Middle Ordovician photic-zone euxinia: Implications for termination of the Great Ordovician biodiversification event 中奥陶世光区优生的汞同位素证据：大奥陶纪生物多样化事件终止的影响

IF 7.2 1区地球科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY

Gondwana Research

Pub Date : 2024-09-29 DOI: 10.1016/j.gr.2024.09.008

Mu Liu , Wei Yuan , Chaogang Fang , Xun Wang , Ning Tan , Mingyu Zhao , Xiangli Wang , Thomas J. Algeo , Peng Sun , Xinbin Feng , Daizhao Chen

The Darriwilian (Middle Ordovician) is marked by a striking peak of the Great Ordovician Biodiversification Event (GOBE) followed by an abrupt ∼50 % decline in invertebrate species. Understanding the ultimate driving mechanism behind this biotic turnover and its correlation with those proximate climatic-oceanic changes that directly result in elevated biotic mortality have garnered considerable attention. One hypothesis posits that oceanic redox evolution actively influenced biodiversification, and progressive expansion of marine anoxia caused the termination of this biotic event. In this study, we present sedimentological and geochemical profiles for three outcrops of different lithofacies across the Middle-Upper Ordovician transition, ranging from carbonate platform to deep-water slope-basinal facies of the Tarim and South China cratons. Mercury isotopes reveal that recurrent and spatially dynamic photic-zone euxinia (PZE) occurred in the slope-basinal facies while being absent in platform facies. Mass balance model results suggest that ∼23 % of local atmospheric Hg was sequestered in marine sediments due to elevated dissolved H₂S in surface waters. This finding suggests that destabilized oceanic redox conditions developed during climatic cooling, particularly shoaling and upwelling of deep-marine euxinic waters into the photic zone, coupled with global carbon-cycle disturbances, resulted in biodiversity decline following the peak of the GOBE.

达里维利期（中奥陶纪）的特点是大奥陶纪生物多样化事件（GOBE）达到惊人的顶峰，随后无脊椎动物物种突然减少了 50%。了解这一生物更替背后的最终驱动机制及其与直接导致生物死亡率上升的近似气候-海洋变化之间的相关性，引起了人们的极大关注。一种假设认为，海洋氧化还原演化对生物多样性产生了积极影响，而海洋缺氧的逐步扩大导致了这一生物事件的终止。在本研究中，我们展示了中奥陶世-上奥陶世过渡时期三个不同岩性露头的沉积和地球化学剖面，包括塔里木和华南环形山的碳酸盐平台和深水斜坡-基底面。汞同位素显示，在斜坡-基底面发生了经常性的、空间动态的光区蜕变（PZE），而在平台面则不存在。质量平衡模型的结果表明，由于表层水溶解的 H2S 升高，当地大气中的汞±23%被螯合在海洋沉积物中。这一发现表明，在气候变冷期间，海洋氧化还原条件不稳定，特别是深海富欣水域向光照区的浅滩和上涌，再加上全球碳循环的干扰，导致了全球生物多样性高峰期之后的生物多样性衰退。

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引用次数: 0

Ediacaran-type non-mineralized tube-dwelling organisms persisted into the early Cambrian (Terreneuvian) in Baltica 埃迪卡拉类非矿化管栖生物在波罗的海的寒武纪早期（特雷努纪）一直存在

IF 7.2 1区地球科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY

Gondwana Research

Pub Date : 2024-09-29 DOI: 10.1016/j.gr.2024.09.009

Olev Vinn , Karma Nanglu , Mark A. Wilson , Mare Isakar , Ursula Toom

The Ediacaran taxon Conotubus hemiannulatus has been discovered in the Terreneuvian blue clays of Estonia. Alongside Conotubus, Gaojiashania-like tubes are also found in these clays. These tubes are fully compressed and pyritized. The well-developed peristomes of Conotubus might have provided stability if the living worm was partially buried in the soft sea floor, suggesting that Conotubus was a sessile suspension feeder. The presence of the archaic Conotubus hemiannulatus in the Fortunian of Estonia indicates that the tube morphology of some cloudinids did not change between the Ediacaran and the Terreneuvian. The existence of these old-fashioned cloudinids in the Terreneuvian suggests either that the early Cambrian ecosystem in Baltica was not significantly different from that of the Ediacaran, or that cloudinids with organic tubes were more resilient to ecological changes than previously thought. Most Terreneuvian faunas originate from lower latitudes, whereas Baltica, during the Terreneuvian, was located at middle-high latitudes and experienced a cold climate. We hypothesize that the cold climate zone ecosystem was more archaic in the Fortunian than the tropical ecosystem, providing a final refuge for the Ediacaran non-mineralized tubicolous organisms. The increased competition pressure from diverse modern animals in the tropics could have driven Ediacaran-type non-mineralized tubicolous organisms to seek refuge in the colder regions of the ocean, where the competition from more advanced animals was less intense.

在爱沙尼亚的特雷努维蓝色粘土中发现了埃迪卡拉分类群 Conotubus hemiannulatus。除了 Conotubus 外，在这些粘土中还发现了类似 Gaojiashania 的管状物。这些管子完全被压缩和黄铁矿化。如果活体蠕虫部分埋藏在松软的海底，那么Conotubus发达的蠕动体可能会提供稳定性，这表明Conotubus是一种无柄悬浮取食器。在爱沙尼亚的福尔图尼亚发现了古老的半圆管虫（Conotubus hemiannulatus），这表明在埃迪卡拉纪和泰伦卢纪之间，一些云虫的管状形态并没有发生变化。这些老式的云纹类动物在泰瑞努瓦纪的存在表明，要么波罗的海早寒武纪的生态系统与埃迪卡拉纪的生态系统没有明显不同，要么具有有机管的云纹类动物比以前认为的更能适应生态变化。大多数震旦纪动物群起源于低纬度地区，而波罗的海在震旦纪位于中高纬度地区，气候寒冷。我们推测，寒带生态系统在福尔图尼亚期比热带生态系统更为古老，为埃迪卡拉非矿化管状生物提供了最后的避难所。热带地区来自多种现代动物的竞争压力增大，可能促使埃迪卡拉纪类型的非矿化管状生物到海洋的寒冷地区寻求避难，因为那里来自更先进动物的竞争不那么激烈。

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引用次数: 0

Porphyry-type mineral prospectivity mapping with imbalanced data via prior geological transfer learning 通过先验地质转移学习利用不平衡数据绘制斑岩型矿产远景图

IF 7.2 1区地球科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY

Gondwana Research

Pub Date : 2024-09-26 DOI: 10.1016/j.gr.2024.09.004

Ana Mantilla-Dulcey , Paul Goyes-Peñafiel , Rosana Báez-Rodríguez , Sait Khurama

Mineral prospectivity mapping is crucial for identifying areas with economically valuable minerals. Therefore, several methods based on machine learning have been applied to predict the likelihood of mineral occurrences, especially deep learning (DL), which provides a flexible and precise approach to the use of continuous data. It allows the approximation of predictive variables with probability values related to new ore targets. However, in the early stages of mineral exploration, DL-based methods face a challenge related to class and sampling imbalance due to scarce mineral deposits, resulting in a lack of enough samples to train, limiting the model’s predictive ability. This work proposed a detailed and systematic framework to address imbalanced data issues with prior geological transfer learning and a weighted loss function. We exploited the abundant pixel information of input variables to develop a pretext geological classification and a feature data extraction task as an initializer for the trainable variables of the neural network. The proposed workflow was tested in a porphyry-rich Yukon (Canada) region and overperformed other state-of-the-art classification algorithms such as random forest, support vector machines, and logistic regression. Moreover, our results were contrasted against different geological reports, where our mineral prospectivity map was coherent with regional and local potential assessments of porphyry-type mineral occurrences. The quantitative metrics with a validation dataset suggested that the proposed method can effectively predict mineral prospective areas in different imbalanced data scenarios.

矿产远景测绘对于确定具有经济价值的矿产区域至关重要。因此，一些基于机器学习的方法已被用于预测矿物出现的可能性，特别是深度学习（DL），它为连续数据的使用提供了一种灵活而精确的方法。它允许用与新矿石目标相关的概率值来近似预测变量。然而，在矿产勘探的早期阶段，基于深度学习的方法面临着一个挑战，即由于矿藏稀少，类和采样不平衡，导致缺乏足够的样本进行训练，从而限制了模型的预测能力。这项工作提出了一个详细而系统的框架，利用先验地质转移学习和加权损失函数来解决不平衡数据问题。我们利用输入变量丰富的像素信息，开发了一个地质分类前置任务和一个特征数据提取任务，作为神经网络可训练变量的初始化器。我们在斑岩丰富的育空（加拿大）地区对所提出的工作流程进行了测试，结果优于随机森林、支持向量机和逻辑回归等其他最先进的分类算法。此外，我们还将结果与不同的地质报告进行了对比，发现我们的矿产远景图与斑岩型矿点的区域和地方潜力评估结果一致。验证数据集的定量指标表明，所提出的方法可以在不同的不平衡数据情况下有效预测矿产远景区。

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引用次数: 0

Carbon-isotope stratigraphy of the Toarcian in Kuwait 科威特托阿尔克地层的碳同位素地层学

IF 7.2 1区地球科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY

Gondwana Research

Pub Date : 2024-09-26 DOI: 10.1016/j.gr.2024.09.005

Thomas De Keyser , Wolfgang Ruebsam , Moujahed Al-Husseini , Sandra Crespo de Cabrera , Ghaida Al-Sahlan

The Early and Middle Jurassic Marrat Formation in Kuwait was deposited along the southwestern margin of the Neo-Tethys Ocean. The formation has been extensively cored and sampled in deep wells by Kuwait Oil Company for sedimentological and biostratigraphic analyses. Based on mainly long-ranging benthic species, the Middle Marrat Member is assigned in published articles to the Toarcian Stage. The formation has also been sampled for stable carbon and oxygen isotopic analyses in 19 wells across a depositional profile extending from sabkha to intrashelf basin. Stable carbon isotope analyses from these wells (∼2000 samples) reveal the signature of the negative Pliensbachian-Toarcian carbon-isotope excursion (Pl-T-CIE) in the uppermost part of the Lower Marrat Member. The younger early Toarcian carbon-isotope excursion (T-CIE) is recognized in the lower part of the Middle Marrat Member. A composite δ¹³C_carb curve spanning the Middle Marrat Member is constructed by combining overlapping δ¹³C segments from six wells guided by correlations of regional sequence boundaries and gamma-ray logs. Cyclostratigraphic analyses of gamma-ray logs in these six wells reveal a periodic signal formed by multiples of the 0.405-Ma long-eccentricity cycle. This result suggests the Middle Marrat Member in Kuwait may represent the complete Toarcian Stage consisting of depositional sequences controlled by sea-level cycles with durations ranging between 0.8 and 1.6 Ma. Correlations of the Toarcian succession between Kuwait, Saudi Arabia and Oman are hampered by imprecise biostratigraphic control. This limitation is bypassed by correlating the T-CIE in Kuwait to published δ¹³C records in the Marrat Formation in central Saudi Arabia and the Mafraq Formation in Wadi Sahtan in Oman. The correlations indicate that whereas the Toarcian Stage is apparently complete in Kuwait, most of the middle and upper Toarcian and the Aalenian are absent in Oman and Saudi Arabia.

科威特的早侏罗世和中侏罗世马拉特地层沿新特提斯洋西南缘沉积。科威特石油公司在深井中对该地层进行了广泛的取芯和取样，以进行沉积学和生物地层学分析。根据主要的长程底栖生物物种，已发表的文章将中马拉特成员归入托尔干期。此外，还在从 sabkha 到陆内盆地的沉积剖面上的 19 口井中对该地层进行了稳定碳和氧同位素分析取样。这些油井（2000 个样本）的稳定碳同位素分析显示，下马拉特组最上部存在负的普利恩巴赫-托阿尔卡斯碳同位素偏移（Pl-T-CIE）特征。在中马拉特岩层的下部，发现了较年轻的早托阿肯碳同位素偏移（T-CIE）。在区域层序边界和伽马射线测井记录相关性的指导下，通过组合六口井的重叠δ13C段，构建了横跨中马拉特组的δ13C-碳同位素复合曲线。对这六口井的伽马射线测井记录进行的周期地层学分析表明，0.405Ma长周期的倍数形成了一个周期信号。这一结果表明，科威特的中马拉特组可能代表了完整的托阿西亚阶段，由受海平面周期控制的沉积序列组成，海平面周期的持续时间在0.8-1.6Ma之间。由于生物地层控制不精确，科威特、沙特阿拉伯和阿曼之间托阿尔纪演替的相关性受到影响。通过将科威特的 T-CIE 与沙特阿拉伯中部 Marrat Formation 和阿曼 Wadi Sahtan Mafraq Formation 中已公布的 δ13C 记录进行关联，可以绕过这一限制。关联结果表明，在科威特，托阿尔阶段显然是完整的，而在阿曼和沙特阿拉伯，中、上托阿尔阶段和阿伦阶段的大部分都不存在。

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引用次数: 0

Impact of artificial intelligence technology applications on corporate energy consumption intensity 人工智能技术应用对企业能源消耗强度的影响

IF 7.2 1区地球科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY

Gondwana Research

Pub Date : 2024-09-26 DOI: 10.1016/j.gr.2024.09.003

Xiaoqian Liu , Javier Cifuentes-Faura , Shikuan Zhao , Long Wang , Jian Yao

Artificial intelligence (AI), as a new technology, not only revolutionizes economic development, but also provides an opportunity for environment governance. Extant studies primarily explore the environmental performance of AI from a macro perspective, while evidence on how AI technology applications affect firms’ energy-saving behavior is scarce. Employing Python technology to recognize AI-related keywords in the annual reports of listed enterprises and adopting data on corporate energy consumption from 2011 to 2020, we explore the impact of AI on corporate energy consumption intensity (CECI) and its mechanisms. We observe that AI technology applications reduce CECI. After a range of robustness tests, the conclusions are still solid. The mechanism analysis reveals that AI cuts CECI through spurring firm green innovation, stimulating firms to introduce new equipment, and reducing firms’ internal management costs. Heterogeneity analysis reveals that this negative impact is more prominent for SOEs and private enterprises’ energy intensity; we also find that this effect is more pronounced for high-tech industry enterprises and high-polluting enterprises. Our findings provide micro evidence for policymakers to reduce corporate energy intensity and realize energy conservation and emission abatement targets.

人工智能（AI）作为一种新技术，不仅为经济发展带来了革命性的变化，也为环境治理提供了契机。现有研究主要从宏观角度探讨人工智能的环境绩效，而关于人工智能技术应用如何影响企业节能行为的证据却很少。我们利用 Python 技术识别上市企业年报中与人工智能相关的关键词，并采用 2011 年至 2020 年的企业能耗数据，探讨了人工智能对企业能耗强度（CECI）的影响及其机制。我们发现，人工智能技术的应用降低了 CECI。经过一系列稳健性检验后，结论依然可靠。机制分析表明，人工智能通过推动企业绿色创新、刺激企业引进新设备和降低企业内部管理成本来降低企业能源消耗强度。异质性分析表明，这种负面影响对国有企业和民营企业的能源强度更为突出；我们还发现，这种影响对高科技行业企业和高污染企业更为明显。我们的研究结果为决策者降低企业能源强度、实现节能减排目标提供了微观证据。

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引用次数: 0

Late Triassic extension of thickened lithosphere of the East Kunlun orogenic Belt, northern Tibetan Plateau: Evidence from the geochemistry and geochronology of mafic magmatism 晚三叠世青藏高原北部东昆仑造山带增厚岩石圈的延伸：岩浆岩的地球化学和地质年代证据

IF 7.2 1区地球科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY

Gondwana Research

Pub Date : 2024-09-24 DOI: 10.1016/j.gr.2024.08.018

Bin Zhang , Yunpeng Dong , Shengsi Sun , Dengfeng He , Bo Hui , Yuangang Yue , Xiang Ren , Weidong He

The East Kunlun Orogenic Belt (E-KOB) evolved into an extensional tectonic setting with plenty of mafic magmatism after the closure of the Paleo-Tethys Ocean. However, the deep tectonic system and geodynamic processes in this context still need further clarification. The detailed field geological, petrological, geochronological and geochemical works carried out on the Yeniugou gabbros in this study could provide key evidence for clarifying this issue. The gabbros are predominantly composed of clinopyroxene, orthopyroxene, plagioclase, olivine and ilmenite. Zircon U–Pb dating results suggest that their formation at ca. 209–207 Ma. Characterized by a relatively low SiO₂ content and a moderate total alkaline content, these rocks are classified as alkalic to subalkaline series. High values of Mg^# (42.2–59.4) and high concentrations of compatible elements (V, Cr, Co, Ni) suggest that their parent magma was generated through high partial melting of a lithospheric mantle source. The left-leaning rare earth element distribution patterns, combined with the characteristic spikes of Nb-Ta, indicate that they were originated from the lithospheric mantle metasomatized by subducting components. The positive zircon ε_Hf(t) values (0.1–5.7), along with elevated Nb/La ratios (0.45–0.67), further confirm a small amount of asthenosphere mantle contribution. Elevated Zr/Y ratios, plus a slightly positive correlation between Al_z and TiO₂ in clinopyroxene, imply that they formed within an extensional setting, where the upwelling of the asthenospheric mantle provided heat for partial melting of the metasomatic lithospheric mantle. Combined with previous data, we suggest that E-KOB underwent delamination of thickened lithosphere in the late Triassic, following the closure of the Paleo-Tethys Ocean.

东昆仑造山带（E-KOB）在古特提斯洋闭合后演化为扩展构造环境，并伴有大量岩浆活动。然而，这一背景下的深部构造体系和地球动力学过程仍有待进一步澄清。本研究对叶牛沟辉长岩进行了详细的野外地质、岩石学、地质年代和地球化学研究，可为澄清这一问题提供关键证据。辉长岩主要由闪长岩、正长岩、斜长石、橄榄石和钛铁矿组成。锆石 U-Pb 测定结果表明，它们形成于大约 209-207 Ma。这些岩石的特征是二氧化硅含量相对较低，总碱性含量适中，因此被归类为碱性至亚碱性系列。高镁#值（42.2-59.4）和高浓度的相容元素（V、Cr、Co、Ni）表明，它们的母岩浆是通过岩石圈地幔源的高部分熔融生成的。稀土元素的左倾分布模式与 Nb-Ta 的特征性峰值相结合，表明它们源自经俯冲成分变质的岩石圈地幔。正的锆石εHf（t）值（0.1-5.7）以及升高的铌/钽比（0.45-0.67）进一步证实了少量的星体地幔成分。Zr/Y比值的升高，加上Alz与褐辉石中TiO2之间的轻微正相关，意味着它们是在延伸环境中形成的，在这种环境中，星体层地幔的上涌为元岩石圈地幔的部分熔化提供了热量。结合之前的数据，我们认为 E-KOB 在三叠纪晚期，即古特提斯洋关闭之后，经历了加厚岩石圈的分层。

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引用次数: 0

Tectonic evolution of the Qiangtang Basin (northern Tibet): Constraints from detrital zircon geochronology 羌塘盆地（藏北）的构造演化：来自碎屑锆石地质年代学的制约因素

IF 7.2 1区地球科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY

Gondwana Research

Pub Date : 2024-09-19 DOI: 10.1016/j.gr.2024.08.019

Yanxiong Zhang , Bo Zheng , Jie Dai , Gideon Rosenbaum , Jian Wang

The Mesozoic evolution of the Qiangtang Basin in the Tibetan Plateau, which potentially hosts oil and gas resources, is not fully understood, particularly in the context of the opening and closure of the Tethyan oceans. To better understand the tectonic evolution of the Qiangtang Basin and the history of sedimentation, we obtained 788 new U-Pb detrital zircon ages from 12 sandstone samples. Our results show that the provenance of the Mesozoic strata varies both in space and time. In the central part of the basin (Central Qiangtang), older sedimentary rocks are characterized by unimodal age spectra (300–233 Ma) that indicate a proximal arc source. Trace-element compositions of Permian to Triassic zircons from Lower Triassic strata are characteristic of crystallization in arc and backarc environments, thus supporting previous suggestions that the Qiangtang Basin formed as a backarc basin during subduction of the Paleo-Tethys oceanic lithosphere. Younger (Upper Triassic and Jurassic) strata in the Qiangtang Basin received detrital zircons from diverse sources that included Cambrian to Triassic magmatic rocks and Paleozoic strata in the Central Qiangtang, and Triassic flysch deposits in the Songpan-Garze Terrane. We suggest that this change in provenance — from a unimodal arc source that produced zircons in Lower–Middle Triassic rocks to the diverse provenance recognized in the Upper Triassic strata — marks the closure of the Paleo-Tethys Ocean during the Late Triassic. Jurassic sedimentation in the Qiangtang Basin occurred during the expansion of the Meso-Tethys Ocean (Early–Middle Jurassic) and the subsequent subduction of this ocean (since the Callovian). During the Early Cretaceous, the closure of the Meso-Tethys Ocean led to an uplift and a sedimentary hiatus that marked the end of marine sedimentation in the Qiangtang Basin.

青藏高原羌塘盆地可能蕴藏着石油和天然气资源，但人们对该盆地的中生代演化尚未完全了解，特别是在哲罗纪大洋开闭的背景下。为了更好地了解羌塘盆地的构造演化和沉积历史，我们从 12 个砂岩样本中获得了 788 个新的 U-Pb 铁锆石年龄。结果表明，中生代地层的产状在空间和时间上都存在差异。在盆地中部（中羌塘），较老的沉积岩具有单峰年龄谱（300-233Ma）的特征，表明其来源于近弧区。下三叠统地层中二叠纪至三叠纪锆石的痕量元素组成具有在弧和弧后环境中结晶的特征，从而支持了之前的观点，即羌塘盆地是在古特提斯洋岩石圈俯冲过程中形成的弧后盆地。羌塘盆地较年轻（上三叠统和侏罗纪）地层的锆石来自不同的来源，包括中羌塘的寒武系至三叠系岩浆岩和古生代地层，以及松潘-嘉泽地层的三叠系飞沙沉积。我们认为，从三叠纪中下段岩石中产生锆石的单模弧源到三叠纪上段地层中发现的多种来源，这种来源的变化标志着古特提斯洋在三叠纪晚期的关闭。羌塘盆地的侏罗纪沉积发生在中特提斯洋扩张时期（早-中侏罗世）和该洋随后的俯冲时期（自卡勒维世起）。在早白垩世，中特提斯洋的关闭导致了隆升和沉积的中断，这标志着羌塘盆地海洋沉积的结束。

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引用次数: 0