Pub Date : 2024-11-14DOI: 10.1016/j.gr.2024.11.004
Yong Cao , Zhiming Sun , Zhenyu Yang , Haibing Li , Junling Pei , Xiaozhou Ye , Xinwen Cao , Bailing Wu , Chenguang Liu , Lei Zhang
The collision of India and Asia formed the Himalayas and caused the uplift of the Tibetan Plateau. Greater India comprises the part of the Indian plate that was subducted beneath Asia and the Tethyan Himalaya. Quantitative constraints on the extent of Greater India are needed to study the process of the India-Asia collision. However, such constraints are lacking and the topic remains debated. We present paleomagnetic data from late Paleocene (∼58 Ma) mafic rocks from the western Tethyan Himalaya. The mean paleomagnetic direction is Ds/Is = 348.5°/+6.5° with k = 38.7 and a95 = 5.2°, which passed the fold, reversals, and paleosecular variation tests. The results define the paleolatitude of the Tethyan Himalaya as 3.3 ± 4.5°N at ∼ 58 Ma for the reference site of 29.9°N/83.3°E. A comparison of the Paleogene paleolatitudes of the Tethyan Himalaya shows that the terrane moved northward by 1540 ± 290 km between ∼ 60 Ma and ∼ 50 Ma, with a rate of movement of 15.4 ± 2 cm/yr. The new paleomagnetic result confirms that the extent of Greater India was 1130 ± 400 km and was essentially uniform from east to west. This finding implies that the collision between India and Asia was nearly be quasi-synchronous from the middle-eastern to western segments along the Indus-Tsangpo suture zone.
{"title":"Constraining the extent of Greater India: New late Paleocene paleomagnetic data from the Tethyan Himalaya, Tibetan Plateau","authors":"Yong Cao , Zhiming Sun , Zhenyu Yang , Haibing Li , Junling Pei , Xiaozhou Ye , Xinwen Cao , Bailing Wu , Chenguang Liu , Lei Zhang","doi":"10.1016/j.gr.2024.11.004","DOIUrl":"10.1016/j.gr.2024.11.004","url":null,"abstract":"<div><div>The collision of India and Asia formed the Himalayas and caused the uplift of the Tibetan Plateau. Greater India comprises the part of the Indian plate that was subducted beneath Asia and the Tethyan Himalaya. Quantitative constraints on the extent of Greater India are needed to study the process of the India-Asia collision. However, such constraints are lacking and the topic remains debated. We present paleomagnetic data from late Paleocene (∼58 Ma) mafic rocks from the western Tethyan Himalaya. The mean paleomagnetic direction is <em>Ds</em>/<em>Is</em> = 348.5°/+6.5° with <em>k</em> = 38.7 and <em>a<sub>95</sub></em> = 5.2°, which passed the fold, reversals, and paleosecular variation tests. The results define the paleolatitude of the Tethyan Himalaya as 3.3 ± 4.5°N at ∼ 58 Ma for the reference site of 29.9°N/83.3°E. A comparison of the Paleogene paleolatitudes of the Tethyan Himalaya shows that the terrane moved northward by 1540 ± 290 km between ∼ 60 Ma and ∼ 50 Ma, with a rate of movement of 15.4 ± 2 cm/yr. The new paleomagnetic result confirms that the extent of Greater India was 1130 ± 400 km and was essentially uniform from east to west. This finding implies that the collision between India and Asia was nearly be quasi-synchronous from the middle-eastern to western segments along the Indus-Tsangpo suture zone.</div></div>","PeriodicalId":12761,"journal":{"name":"Gondwana Research","volume":"138 ","pages":"Pages 128-138"},"PeriodicalIF":7.2,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142658923","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-14DOI: 10.1016/j.gr.2024.11.003
Zhiheng Ma , James C. Lamsdell , Maxwell Wang , Jingwen Chen , Paul A. Selden , Ben He
This paper describes a new stylonurine eurypterid: Qujingopterus spineus gen. et sp. nov., from the Early Devonian (late Lochkovian to early Pragian) Xitun formation of Yunnan Province, South China. This discovery represents one of the earliest stylonurine records from Gondwana and further supports the global distribution of stylonurines. Considering the probable region of origin of the clade and and their lack of anatomical structures adapted for swimming, we propose that stylonurines migrated to Gondwana as the Rheic Ocean dwindled while Gondwana rapidly approached Laurussia. An additional specimen from this locality is described, and can be assigned to the eurypterine family Pterygotidae. Based on the environmental analysis, it can be inferred that the eurypterids from South China underwent adaptations to cope with decreasing salinity levels. This discovery provides valuable insights into the timing and mechanisms underlying eurypterid invasion into freshwater ecosystems.
本文描述了中国云南西屯早泥盆世(晚泥盆世至早泥盆世)地层中发现的一种新的stylonurine eurypterid:Qujingopterus spineus gen. et sp.这一发现代表了冈瓦纳最早的石龙子记录之一,进一步证实了石龙子的全球分布。考虑到该支系可能的起源地区,以及它们缺乏适应游泳的解剖结构,我们认为,当冈瓦纳迅速接近劳鲁西亚时,莱茵洋逐渐缩小,斯泰隆人迁移到了冈瓦纳。我们还描述了该地点的另一个标本,该标本可归属于翼龙科(Pterygotidae)。根据环境分析,可以推断华南地区的极龙类经历了适应盐度下降的过程。这一发现为了解极翅目昆虫入侵淡水生态系统的时间和机制提供了宝贵的信息。
{"title":"Early Devonian stylonurine eurypterids from northern Gondwana: Late Lochkovian to early Pragian records from South China","authors":"Zhiheng Ma , James C. Lamsdell , Maxwell Wang , Jingwen Chen , Paul A. Selden , Ben He","doi":"10.1016/j.gr.2024.11.003","DOIUrl":"10.1016/j.gr.2024.11.003","url":null,"abstract":"<div><div>This paper describes a new stylonurine eurypterid: <em>Qujingopterus spineus</em> gen. et sp. nov., from the Early Devonian (late Lochkovian to early Pragian) Xitun formation of Yunnan Province, South China. This discovery represents one of the earliest stylonurine records from Gondwana and further supports the global distribution of stylonurines. Considering the probable region of origin of the clade and and their lack of anatomical structures adapted for swimming, we propose that stylonurines migrated to Gondwana as the Rheic Ocean dwindled while Gondwana rapidly approached Laurussia. An additional specimen from this locality is described, and can be assigned to the eurypterine family Pterygotidae. Based on the environmental analysis, it can be inferred that the eurypterids from South China underwent adaptations to cope with decreasing salinity levels. This discovery provides valuable insights into the timing and mechanisms underlying eurypterid invasion into freshwater ecosystems.</div></div>","PeriodicalId":12761,"journal":{"name":"Gondwana Research","volume":"138 ","pages":"Pages 118-127"},"PeriodicalIF":7.2,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142658924","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-08DOI: 10.1016/j.gr.2024.10.014
Ugur Korkut Pata , Kamel Si Mohammed , Cheloufi Omeyr , Selin Karlilar Pata , Hind Alofaysan , Mustafa Tevfik Kartal
With the evolving world order, countries are using financial technologies (Fintech) to access financial resources more effectively, and Fintech can have an impact on the environment. This study aims to investigate the influence of Fintech on ecological sustainability, focusing on the contribution of renewable energy (RE) and government effectiveness (GE) under the Load Capacity Curve (LCC). This research analyzes data from 69 middle-income economies between 2006 and 2022 using the dynamic panel threshold model (DPTR). The outcomes document that GDP reduces the LCF below a certain threshold, but a positive impact above this threshold. Specifically, the model yielded a threshold value of $US 5222.234, which is higher than the average GDP of $US 4276.802. This finding suggests a U-shaped relationship between GDP and LCF, which supports the LCC hypothesis. The outcome also reports that Fintech plays a crucial role in improving ecological sustainability, while government effectiveness has a negative effect. The study emphasizes that middle-income countries should support Fintech and renewable energy along development with economic progress to improve ecological quality.
{"title":"Scrutinizing the load capacity curve for a global perspective: The role of Fintech, government effectiveness and renewable energy","authors":"Ugur Korkut Pata , Kamel Si Mohammed , Cheloufi Omeyr , Selin Karlilar Pata , Hind Alofaysan , Mustafa Tevfik Kartal","doi":"10.1016/j.gr.2024.10.014","DOIUrl":"10.1016/j.gr.2024.10.014","url":null,"abstract":"<div><div>With the evolving world order, countries are using financial technologies (Fintech) to access financial resources more effectively, and Fintech can have an impact on the environment. This study aims to investigate the influence of Fintech on ecological sustainability, focusing on the contribution of renewable energy (RE) and government effectiveness (GE) under the Load Capacity Curve (LCC). This research analyzes data from 69 middle-income economies between 2006 and 2022 using the dynamic panel threshold model (DPTR). The outcomes document that GDP reduces the LCF below a certain threshold, but a positive impact above this threshold. Specifically, the model yielded a threshold value of $US 5222.234, which is higher than the average GDP of $US 4276.802. This finding suggests a U-shaped relationship between GDP and LCF, which supports the LCC hypothesis. The outcome also reports that Fintech plays a crucial role in improving ecological sustainability, while government effectiveness has a negative effect. The study emphasizes that middle-income countries should support Fintech and renewable energy along development with economic progress to improve ecological quality.</div></div>","PeriodicalId":12761,"journal":{"name":"Gondwana Research","volume":"138 ","pages":"Pages 104-117"},"PeriodicalIF":7.2,"publicationDate":"2024-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142658922","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-07DOI: 10.1016/j.gr.2024.11.001
Alanielson Ferreira , Gary Stevens , Elton L. Dantas , Reinhardt A. Fuck , Ticiano J.S. dos Santos
The high-pressure followed by high-temperature metamorphism related to the evolution of collisional orogens is the expected Pressure-Temperature-time (P-T-t) path for modern-style plate tectonics. However, these P-T-t paths are rarely preserved even in Phanerozoic orogens. In this matter, the Campo Grande migmatite-gneiss area presents an exhumed Archean crust with heterogeneous retrograde eclogites overprinted by amphibolite-facies in NE Brazil. Retrogressed eclogites in the area core are formed by Mn-rich garnet + clinopyroxene porphyroblasts layer with a minor amphibole + quartz + titanite assemblage, whereas the margins display dismembered lenses of Mg-rich garnet porphyroblasts with plagioclase + amphibole coronae and clinopyroxene + plagioclase + ortopyroxene sympleticte mainly within shear zones. Phase equilibria modelling reveals that these distinct retro-eclogites record similar eclogite conditions (up to 18 kbar and 660 ± 20 °C). Mn-rich eclogites display widespread magmatic zoned zircon grains from Mesoarchean to Paleoproterozoic and recrystallized metamorphic grains of 607.7 ± 5.4 Ma. Zircon from Mg-rich eclogites crystallized at 2.67 Ga and overgrowth rims formed at 2.0 Ga and 590.1 ± 1.8 Ma. REE in zircon lack Eu anomaly, displaying flat HREE patterns in 590.1 ± 1.8 Ma Neoproterozoic grains indicate recrystallization under eclogite-facies conditions. In situ U-Pb titanite dating yielded two younger age sets at 574.7 ± 0.5 and 562.8 ± 2.1 Ma. Lastly, in situ U-Pb dating of rutile inclusions in garnet cores present ages of 606.1 ± 4.0 Ma, whereas rutile included in retrograde coronae and sympleticte yielded concordant ages from 559.0 ± 2.3 to 523.2 ± 1.9 Ma. Thus, combined phase equilibria modelling and U-Pb ages reveal a progressive change in metamorphic conditions from eclogite conditions (at least 607.7 ± 5.4 to 590 ± 1.8 Ma; zircon dating and rutile ages included in eclogite garnet) to nearly isothermal decompression (574.7 ± 0.5 Ma; titanite age) of ancient Archean deep crust, which was followed by suggested final exhumation and metamorphic cooling at shallower crustal levels between 559.0 ± 2.3 and 523.2 ± 1.9 Ma (rutile age in retrogressed assemblage). Therefore, the high-pressure conditions followed by decompression and metamorphic cooling during sin- to post-collisional settings were associated with the final assembly of West Gondwana.
与碰撞造山运动演化有关的先高压后高温的变质作用是现代板块构造的预期压力-温度-时间(P-T-t)路径。然而,即使在新生代造山运动中也很少保留这些 P-T-t 路径。在这一问题上,巴西东北部的坎普格兰德伟晶岩-片麻岩地区展示了一个被阿新世地壳挤压的地壳,其上覆盖着闪长岩岩相的异质逆冲闪长岩。该地区核心的逆冲闪长岩由富锰石榴石+霞石斑岩层与少量闪石+石英+榍石组合形成,而边缘则主要在剪切带内显示富镁石榴石斑岩与斜长石+闪石冠层和霞石+斜长石+正长石共生的肢解透镜体。相平衡模型显示,这些不同的后斜长岩记录了相似的蚀变条件(高达 18 千巴和 660 ± 20 °C)。富锰斜长岩显示了从中生代到古近代的广泛岩浆带状锆石颗粒,以及 607.7 ± 5.4 Ma 的重结晶变质岩颗粒。富镁蚀变岩中的锆石在 2.67 Ga 时结晶,在 2.0 Ga 和 590.1 ± 1.8 Ma 时形成过生缘。锆石中的 REE 缺乏 Eu 异常,在 590.1 ± 1.8 Ma 新元古代的晶粒中显示扁平的 HREE 模式,表明是在埃克洛辉石时代的条件下重结晶的。原位铀-铅榍石年代测定得出了两个较年轻的年龄组,分别为 574.7 ± 0.5 Ma 和 562.8 ± 2.1 Ma。最后,对石榴石岩芯中的金红石包裹体进行原位 U-Pb 测定,得出的年龄为 606.1 ± 4.0 Ma,而逆行冠岩和共生岩中的金红石则得出了 559.0 ± 2.3 至 523.2 ± 1.9 Ma 的一致年龄。因此,结合相平衡模型和 U-Pb 年龄可以看出,变质条件从斜长岩条件(至少 607.7 ± 5.4 至 590 ± 1.8 Ma;锆石测年和斜长岩石榴石中的金红石年龄)逐步变化到近乎等温减压条件(574.7 ± 0.5 Ma;钛铁矿测年和金红石年龄)。其后,在 559.0 ± 2.3 至 523.2 ± 1.9 Ma 之间的较浅地壳水平上发生了最后的掘起和变质冷却(逆冲组中的金红石年龄)。因此,在撞击前至撞击后的高压条件下,减压和变质冷却与西冈瓦纳的最终组装有关。
{"title":"Crustal thickening, exhumation and metamorphic cooling of Neoproterozoic eclogites in NE Brazil: Timescale for the assembly of West Gondwana","authors":"Alanielson Ferreira , Gary Stevens , Elton L. Dantas , Reinhardt A. Fuck , Ticiano J.S. dos Santos","doi":"10.1016/j.gr.2024.11.001","DOIUrl":"10.1016/j.gr.2024.11.001","url":null,"abstract":"<div><div>The high-pressure followed by high-temperature metamorphism related to the evolution of collisional orogens is the expected Pressure-Temperature-time (P-T-t) path for modern-style plate tectonics. However, these P-T-t paths are rarely preserved even in Phanerozoic orogens. In this matter, the Campo Grande migmatite-gneiss area presents an exhumed Archean crust with heterogeneous retrograde eclogites overprinted by amphibolite-facies in NE Brazil. Retrogressed eclogites in the area core are formed by Mn-rich garnet + clinopyroxene porphyroblasts layer with a minor amphibole + quartz + titanite assemblage, whereas the margins display dismembered lenses of Mg-rich garnet porphyroblasts with plagioclase + amphibole coronae and clinopyroxene + plagioclase + ortopyroxene sympleticte mainly within shear zones. Phase equilibria modelling reveals that these distinct <em>retro</em>-eclogites record similar eclogite conditions (up to 18 kbar and 660 ± 20 °C). Mn-rich eclogites display widespread magmatic zoned zircon grains from Mesoarchean to Paleoproterozoic and recrystallized metamorphic grains of 607.7 ± 5.4 Ma. Zircon from Mg-rich eclogites crystallized at 2.67 Ga and overgrowth rims formed at 2.0 Ga and 590.1 ± 1.8 Ma. REE in zircon lack Eu anomaly, displaying flat HREE patterns in 590.1 ± 1.8 Ma Neoproterozoic grains indicate recrystallization under eclogite-facies conditions. In situ U-Pb titanite dating yielded two younger age sets at 574.7 ± 0.5 and 562.8 ± 2.1 Ma. Lastly, in situ U-Pb dating of rutile inclusions in garnet cores present ages of 606.1 ± 4.0 Ma, whereas rutile included in retrograde coronae and sympleticte yielded concordant ages from 559.0 ± 2.3 to 523.2 ± 1.9 Ma. Thus, combined phase equilibria modelling and U-Pb ages reveal a progressive change in metamorphic conditions from eclogite conditions (at least 607.7 ± 5.4 to 590 ± 1.8 Ma; zircon dating and rutile ages included in eclogite garnet) to nearly isothermal decompression (574.7 ± 0.5 Ma; titanite age) of ancient Archean deep crust, which was followed by suggested final exhumation and metamorphic cooling at shallower crustal levels between 559.0 ± 2.3 and 523.2 ± 1.9 Ma (rutile age in retrogressed assemblage). Therefore, the high-pressure conditions followed by decompression and metamorphic cooling during sin- to post-collisional settings were associated with the final assembly of West Gondwana.</div></div>","PeriodicalId":12761,"journal":{"name":"Gondwana Research","volume":"138 ","pages":"Pages 70-88"},"PeriodicalIF":7.2,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142658899","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-04DOI: 10.1016/j.gr.2024.10.011
Linghao Kong , Wenkai Feng , Xiaoyu Yi , Zhenghai Xue , Luyao Bai
Given the critical need to assess landslide hazards, producing landslide susceptibility map (LSM) in regions with scarce historical landslide inventories poses significant challenges. This study introduces a novel landslide susceptibility assessment framework that combines unsupervised learning strategies with few-shot learning methods to increase the accuracy of LSM in these areas. The framework has been practically validated in a representative geological disaster-prone area along the West-East Gas Pipeline in Shaanxi Province, China. We employed three advanced few-shot learning models: a support vector machine, meta-learning, and transfer learning. These models implement feature representation learning for weakly correlated influencing factors through an unsupervised approach, thereby constructing an effective landslide susceptibility assessment model. We compared traditional learning methods and used the receiver operating characteristic (ROC) curve and SHAP values to quantify the effectiveness of the models. The results indicate that the meta-learning algorithm outperforms both the SVM and transfer learning in areas with limited landslide data. The integration of unsupervised strategies significantly improves performance, achieving area under the curve (AUC) values of 0.9385 and 0.9861, respectively. Compared with using meta-learning alone, incorporating unsupervised learning strategies increased the AUC by 4.76%, enhancing both the predictive power of the model and the interpretability of the features. Meta-learning under unsupervised conditions effectively mitigates the evaluation difficulties caused by insufficient landslide records, providing a viable path and empirical evidence for performance improvement in similar data- scarce regions worldwide.
{"title":"Enhanced landslide susceptibility mapping in data-scarce regions via unsupervised few-shot learning","authors":"Linghao Kong , Wenkai Feng , Xiaoyu Yi , Zhenghai Xue , Luyao Bai","doi":"10.1016/j.gr.2024.10.011","DOIUrl":"10.1016/j.gr.2024.10.011","url":null,"abstract":"<div><div>Given the critical need to assess landslide hazards, producing landslide susceptibility map (LSM) in regions with scarce historical landslide inventories poses significant challenges. This study introduces a novel landslide susceptibility assessment framework that combines unsupervised learning strategies with few-shot learning methods to increase the accuracy of LSM in these areas. The framework has been practically validated in a representative geological disaster-prone area along the West-East Gas Pipeline in Shaanxi Province, China. We employed three advanced few-shot learning models: a support vector machine, <em>meta</em>-learning, and transfer learning. These models implement feature representation learning for weakly correlated influencing factors through an unsupervised approach, thereby constructing an effective landslide susceptibility assessment model. We compared traditional learning methods and used the receiver operating characteristic (ROC) curve and SHAP values to quantify the effectiveness of the models. The results indicate that the <em>meta</em>-learning algorithm outperforms both the SVM and transfer learning in areas with limited landslide data. The integration of unsupervised strategies significantly improves performance, achieving area under the curve (AUC) values of 0.9385 and 0.9861, respectively. Compared with using <em>meta</em>-learning alone, incorporating unsupervised learning strategies increased the AUC by 4.76%, enhancing both the predictive power of the model and the interpretability of the features. Meta-learning under unsupervised conditions effectively mitigates the evaluation difficulties caused by insufficient landslide records, providing a viable path and empirical evidence for performance improvement in similar data- scarce regions worldwide.</div></div>","PeriodicalId":12761,"journal":{"name":"Gondwana Research","volume":"138 ","pages":"Pages 31-46"},"PeriodicalIF":7.2,"publicationDate":"2024-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142658925","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-02DOI: 10.1016/j.gr.2024.10.012
Bruna Chagas de Melo, Sergei Lebedev, Nicolas Luca Celli, Sally Gibson, Janneke Iza de Laat, Marcelo Assumpção
The thickness, temperature and mechanical strength of the lithosphere vary greatly across South America and have controlled tectonic and magmatic processes during its evolution. Here, we introduce a new tomographic model of South America’s lithosphere and underlying mantle, SACI-24, and analyse this and other state-of-the-art models together with other geological and geophysical data. The new model is obtained by waveform inversion of surface, S and multiple S waveforms globally, but is optimised for South America and the surrounding oceans. SACI-24 is constrained by ∼ 970,000 seismograms from 9259 stations and maps detailed structure of cratonic lithosphere across the continent, highlighting previously unknown complexities and fragmentation. Within the Amazon Craton, the Guiana and Central Brazil blocks show high Vs exceeding 4.8 km/s in the 80–150 km depth range but are separated by lower velocities below the Amazon Basin, matching the locations of ancient rifting and the flood basalts of the Central Atlantic Magmatic Province. In the São Francisco Craton, high velocities extend north and southwest beyond the previously proposed boundaries. Warmer, thinner lithosphere underlies the Paramirim and Pirapora aulacogens, locations of magmatic and rifting cycles. A fragmented cratonic root underlies the Paraná Basin, with thinner lithosphere along its central rift. High velocities south of the Paraná Block indicate the northern Rio de la Plata Craton’s thick root. The Cenozoic intraplate basalts in the Borborema province, along the southern Atlantic coast and in Paraguay occurred in areas of thin lithosphere and near thick-thin lithospheric boundaries. Most flood basalts of the Phanerozoic large igneous provinces also map on low velocity areas. Smaller flood-basalt portions sit atop cratonic lithosphere and offer new evidence on lateral flow of flood-basalt lava and magma within the crust. About 80 % of known diamondiferous kimberlites are on thick lithosphere, with the exceptions indicating cratonic erosion and thinning since their emplacement.
{"title":"The lithosphere of South America from seismic tomography: Structure, evolution, and control on tectonics and magmatism","authors":"Bruna Chagas de Melo, Sergei Lebedev, Nicolas Luca Celli, Sally Gibson, Janneke Iza de Laat, Marcelo Assumpção","doi":"10.1016/j.gr.2024.10.012","DOIUrl":"https://doi.org/10.1016/j.gr.2024.10.012","url":null,"abstract":"The thickness, temperature and mechanical strength of the lithosphere vary greatly across South America and have controlled tectonic and magmatic processes during its evolution. Here, we introduce a new tomographic model of South America’s lithosphere and underlying mantle, SACI-24, and analyse this and other state-of-the-art models together with other geological and geophysical data. The new model is obtained by waveform inversion of surface, S and multiple S waveforms globally, but is optimised for South America and the surrounding oceans. SACI-24 is constrained by ∼ 970,000 seismograms from 9259 stations and maps detailed structure of cratonic lithosphere across the continent, highlighting previously unknown complexities and fragmentation. Within the Amazon Craton, the Guiana and Central Brazil blocks show high Vs exceeding 4.8 km/s in the 80–150 km depth range but are separated by lower velocities below the Amazon Basin, matching the locations of ancient rifting and the flood basalts of the Central Atlantic Magmatic Province. In the São Francisco Craton, high velocities extend north and southwest beyond the previously proposed boundaries. Warmer, thinner lithosphere underlies the Paramirim and Pirapora aulacogens, locations of magmatic and rifting cycles. A fragmented cratonic root underlies the Paraná Basin, with thinner lithosphere along its central rift. High velocities south of the Paraná Block indicate the northern Rio de la Plata Craton’s thick root. The Cenozoic intraplate basalts in the Borborema province, along the southern Atlantic coast and in Paraguay occurred in areas of thin lithosphere and near thick-thin lithospheric boundaries. Most flood basalts of the Phanerozoic large igneous provinces also map on low velocity areas. Smaller flood-basalt portions sit atop cratonic lithosphere and offer new evidence on lateral flow of flood-basalt lava and magma within the crust. About 80 % of known diamondiferous kimberlites are on thick lithosphere, with the exceptions indicating cratonic erosion and thinning since their emplacement.","PeriodicalId":12761,"journal":{"name":"Gondwana Research","volume":"18 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2024-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142672823","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-24DOI: 10.1016/j.gr.2024.09.017
Carmine C. Wainman , Peter J. McCabe
The onshore intracratonic Cooper Basin of eastern Australia developed during the Late Pennsylvanian to Middle Triassic periods at paleolatitudes of approximately 50°S within the Gondwanan sector of Pangea. Despite the wealth of data available, including the drilling of over 4,800 boreholes, there is limited knowledge about the Cooper Basin’s origins and evolution. To better understand the basin’s geological history, legacy data sets, including composite 2D seismic sections, well logs, measured sections, and 1D burial history models from the west of the basin, are integrated to reinterpret the basin’s tectonic and sedimentary evolution. Interpretation of the seismic sections and calculated subsidence rates indicates an earlier active rift phase with grabens and half-grabens that transitioned, in the latest Permian, into a regional sag phase. The evolution of tectonic styles heavily influenced the paleogeographic evolution of the basin fill and resulting depositional architecture. The basin sediments are entirely terrestrial in nature and facies reflect a transition from glacial environments in the late Pennsylvanian to warmer and drier conditions in the early Triassic. During much of the Permian the basin was underfilled and the relative low influx of fluvial sediment did not keep pace with creation of accommodation, allowing the development of extensive mire and lake systems. Coal beds are up to 30 m thick. By contrast, the basin appears to have been overfilled during the latest Permian to Triassic with rivers flowing along the central axis of the basin. The synchroneity of commencement of rifting, termination of rifting, and commencement of a sag phase within the failed rift systems of the Cooper Basin, the East Gondwana Interior Rift, and the East Australian Rift strongly suggests a continent-wide period of extension related to significant changes in plate motions during the Late Pennsylvanian to Middle Triassic.
{"title":"Anatomy of the late Pennsylvanian to early Triassic failed rift system of the Cooper Basin, eastern Australia","authors":"Carmine C. Wainman , Peter J. McCabe","doi":"10.1016/j.gr.2024.09.017","DOIUrl":"10.1016/j.gr.2024.09.017","url":null,"abstract":"<div><div>The onshore intracratonic Cooper Basin of eastern Australia developed during the Late Pennsylvanian to Middle Triassic periods at paleolatitudes of approximately 50°S within the Gondwanan sector of Pangea. Despite the wealth of data available, including the drilling of over 4,800 boreholes, there is limited knowledge about the Cooper Basin’s origins and evolution. To better understand the basin’s geological history, legacy data sets, including composite 2D seismic sections, well logs, measured sections, and 1D burial history models from the west of the basin, are integrated to reinterpret the basin’s tectonic and sedimentary evolution. Interpretation of the seismic sections and calculated subsidence rates indicates an earlier active rift phase with grabens and half-grabens that transitioned, in the latest Permian, into a regional sag phase. The evolution of tectonic styles heavily influenced the paleogeographic evolution of the basin fill and resulting depositional architecture. The basin sediments are entirely terrestrial in nature and facies reflect a transition from glacial environments in the late Pennsylvanian to warmer and drier conditions in the early Triassic. During much of the Permian the basin was underfilled and the relative low influx of fluvial sediment did not keep pace with creation of accommodation, allowing the development of extensive mire and lake systems. Coal beds are up to 30 m thick. By contrast, the basin appears to have been overfilled during the latest Permian to Triassic with rivers flowing along the central axis of the basin. The synchroneity of commencement of rifting, termination of rifting, and commencement of a sag phase within the failed rift systems of the Cooper Basin, the East Gondwana Interior Rift, and the East Australian Rift strongly suggests a continent-wide period of extension related to significant changes in plate motions during the Late Pennsylvanian to Middle Triassic.</div></div>","PeriodicalId":12761,"journal":{"name":"Gondwana Research","volume":"138 ","pages":"Pages 47-69"},"PeriodicalIF":7.2,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142658898","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-24DOI: 10.1016/j.gr.2024.10.009
Fei Xu , Baoqiang Zhao , Hanjie Wen , Hefan Liu , Xiaofeng Li , Yu Chen , Yi Cui , Chengyu Mi , Jian Yang , Chuan Wang
Lithium (Li), as a strategic critical metal, plays a pivotal role in the emerging energy landscape, particularly in the context of Li-ion batteries driving the new energy economy. Recently, Li-rich strata (with Li2O > 0.3 wt%) have been discovered in the Mesoproterozoic Wumishan Formation in Hebei Province, North China, suggesting a prospective Li reservoir. This study investigates these Li-rich strata using geochemical and in-situ micro-analytical techniques to explore the occurrence of Li and the formation mechanism of Li-host minerals, aiming for a comprehensive understanding of the supernormal enrichment of Li. The Li-rich samples are predominantly composed of dolomite and quartz, followed by clay minerals such as illite, interstratified illite–smectite (I/S), and chlorite, with minor amounts of K-feldspar, albite, biotite, calcite, baryte, fluorite and fluorapatite. In-situ analysis and 7Li NMR spectroscopy reveal that Li predominantly occupies the octahedral sites within the structures of authigenic illite and I/S, while its absence in clastic illite, clastic chlorite, unaltered K-feldspar, and dolomite. The presence of veined minerals (e.g., fluorite, baryte, and calcite) and a strong positive correlation between Li and F imply that post-depositional hydrothermal fluids have significantly contributed to the formation of Li-host minerals. The paragenesis of these minerals suggests that Li-bearing illite has formed through the hydrothermal alteration of K-feldspar. These Li-bearing illites subsequently transformed into Li-bearing I/S, consisting of illite-rich I/S and smectite-rich I/S, under continuous hydrothermal alteration. Lithium could have been leached from the surrounding carbonate rock and tuff through water–rock interaction and subsequently enriched by post-depositional hydrothermal fluids in specific regions, leading to mineralization. These findings provide valuable insights for targeting exploration of this promising Li resource.
锂(Li)作为一种战略性关键金属,在新兴能源领域发挥着举足轻重的作用,尤其是在锂离子电池推动新能源经济发展的背景下。最近,在中国北方河北省的中新生代五米山地层中发现了富锂地层(含 Li2O > 0.3 wt%),这表明该地层具有潜在的锂储层。本研究利用地球化学和原位显微分析技术对这些富锂地层进行了研究,探讨了锂的存在和锂寄主矿物的形成机制,旨在全面了解锂的超常富集。富锂样品主要由白云石和石英组成,其次是伊利石、互层伊利石-直闪石(I/S)和绿泥石等粘土矿物,以及少量的钾长石、白云石、生物橄榄石、方解石、重晶石、萤石和氟磷灰石。原位分析和 7Li NMR 光谱显示,在自生伊利石和 I/S 结构中,锂主要占据八面体位,而在碎屑伊利石、碎屑绿泥石、未改变的 K 长石和白云石中则没有锂。脉石矿物(如萤石、重晶石和方解石)的存在以及锂和F之间的强正相关性意味着沉积后热液在很大程度上促成了锂宿主矿物的形成。这些矿物的副成因表明,含锂伊利石是通过热液蚀变 K 长石形成的。这些含锂伊利石随后在持续的热液蚀变作用下转化为含锂I/S,包括富含伊利石的I/S和富含闪长岩的I/S。锂可能是通过水与岩石的相互作用从周围的碳酸盐岩和凝灰岩中沥滤出来的,随后在特定区域被沉积后热液富集,导致成矿。这些发现为有针对性地勘探这一前景广阔的锂资源提供了宝贵的见解。
{"title":"Hydrothermal overprinting of the Li-rich strata deposited in the Mesoproterozoic Wumishan Formation, Hebei Province, North China","authors":"Fei Xu , Baoqiang Zhao , Hanjie Wen , Hefan Liu , Xiaofeng Li , Yu Chen , Yi Cui , Chengyu Mi , Jian Yang , Chuan Wang","doi":"10.1016/j.gr.2024.10.009","DOIUrl":"10.1016/j.gr.2024.10.009","url":null,"abstract":"<div><div>Lithium (Li), as a strategic critical metal, plays a pivotal role in the emerging energy landscape, particularly in the context of Li-ion batteries driving the new energy economy. Recently, Li-rich strata (with Li<sub>2</sub>O > 0.3 wt%) have been discovered in the Mesoproterozoic Wumishan Formation in Hebei Province, North China, suggesting a prospective Li reservoir. This study investigates these Li-rich strata using geochemical and in-situ micro-analytical techniques to explore the occurrence of Li and the formation mechanism of Li-host minerals, aiming for a comprehensive understanding of the supernormal enrichment of Li. The Li-rich samples are predominantly composed of dolomite and quartz, followed by clay minerals such as illite, interstratified illite–smectite (I/S), and chlorite, with minor amounts of K-feldspar, albite, biotite, calcite, baryte, fluorite and fluorapatite. In-situ analysis and <sup>7</sup>Li NMR spectroscopy reveal that Li predominantly occupies the octahedral sites within the structures of authigenic illite and I/S, while its absence in clastic illite, clastic chlorite, unaltered K-feldspar, and dolomite. The presence of veined minerals (e.g., fluorite, baryte, and calcite) and a strong positive correlation between Li and F imply that post-depositional hydrothermal fluids have significantly contributed to the formation of Li-host minerals. The paragenesis of these minerals suggests that Li-bearing illite has formed through the hydrothermal alteration of K-feldspar. These Li-bearing illites subsequently transformed into Li-bearing I/S, consisting of illite-rich I/S and smectite-rich I/S, under continuous hydrothermal alteration. Lithium could have been leached from the surrounding carbonate rock and tuff through water–rock interaction and subsequently enriched by post-depositional hydrothermal fluids in specific regions, leading to mineralization. These findings provide valuable insights for targeting exploration of this promising Li resource.</div></div>","PeriodicalId":12761,"journal":{"name":"Gondwana Research","volume":"138 ","pages":"Pages 16-30"},"PeriodicalIF":7.2,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142593937","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-21DOI: 10.1016/j.gr.2024.10.008
Yao Wang , Shengling Zhang , Zihao Wu , Yu Hao , Ruijie Li
Responding to China’s green finance policy with enterprise environmental investment (EEI) constitutes a crucial link in achieving environmental governance objectives, exerting crucial influence on the nation’s green transformation and high-quality development. Taking the pilot policy of China’s Green Finance Reform and Innovation Experimental Zone (GFRP) in 2017 as a quasi-natural experiment, this study systematically evaluates the effect of GFRP policy on the decisions of EEI and further explore whether the investments are used for passive end-of-pipe treatment (EOP) or positive source prevention (SP) by using firm-level data. The results indicate that GFRP policy can significantly promote EEI, and mainly reflected in SP, rather than EOP. Through potential mechanism analysis, it can be concluded that GFRP policy facilitates EEI by alleviating financial constraint, reducing agency cost, and enhancing environmental information disclosure. Heterogeneity analysis suggests that there exists asymmetry in policy effects, with greater impacts in high green finance development areas, low concentration industries and large-scale enterprises. Furthermore, micro-level performance consequences examination reveals that the enterprises’ decision to increase EEI under GFRP policy not only effectively realizes energy conservation and emission reduction but also contribute to facilitating enterprise value, to achieve green transformation. This study holds significant policy implications, providing empirical evidence to policymakers for the refinement and dissemination of green finance policy, and offering valuable insights for enterprise investment and management decisions.
{"title":"Responding to green finance with emission reduction and value-added: The role of enterprise environmental investment","authors":"Yao Wang , Shengling Zhang , Zihao Wu , Yu Hao , Ruijie Li","doi":"10.1016/j.gr.2024.10.008","DOIUrl":"10.1016/j.gr.2024.10.008","url":null,"abstract":"<div><div>Responding to China’s green finance policy with enterprise environmental investment (EEI) constitutes a crucial link in achieving environmental governance objectives, exerting crucial influence on the nation’s green transformation and high-quality development. Taking the pilot policy of China’s Green Finance Reform and Innovation Experimental Zone (GFRP) in 2017 as a quasi-natural experiment, this study systematically evaluates the effect of GFRP policy on the decisions of EEI and further explore whether the investments are used for passive end-of-pipe treatment (EOP) or positive source prevention (SP) by using firm-level data. The results indicate that GFRP policy can significantly promote EEI, and mainly reflected in SP, rather than EOP. Through potential mechanism analysis, it can be concluded that GFRP policy facilitates EEI by alleviating financial constraint, reducing agency cost, and enhancing environmental information disclosure. Heterogeneity analysis suggests that there exists asymmetry in policy effects, with greater impacts in high green finance development areas, low concentration industries and large-scale enterprises. Furthermore, micro-level performance consequences examination reveals that the enterprises’ decision to increase EEI under GFRP policy not only effectively realizes energy conservation and emission reduction but also contribute to facilitating enterprise value, to achieve green transformation. This study holds significant policy implications, providing empirical evidence to policymakers for the refinement and dissemination of green finance policy, and offering valuable insights for enterprise investment and management decisions.</div></div>","PeriodicalId":12761,"journal":{"name":"Gondwana Research","volume":"138 ","pages":"Pages 1-15"},"PeriodicalIF":7.2,"publicationDate":"2024-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142573100","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}