Correlation of lithospheric “de-rooting” of the Sulu-Dabie Orogen to tectonic-sedimentary process of the Hefei Basin: Constraints from Mesozoic coupling of basin and orogen

2019 ◽  
Vol 55 (1) ◽  
pp. 694-711
Author(s):  
Feiyu Zhao ◽  
Suhua Jiang ◽  
Sanzhong Li ◽  
Hongyan Chen ◽  
Wei Cao ◽  
...  
Keyword(s):  
Sedimentary Process ◽  
Dabie Orogen ◽  
Hefei Basin

Structural coupling of the Dabie Orogen with Hefei Basin

1997 ◽  
Vol 42 (18) ◽  
pp. 1566-1572 ◽  
Author(s):  
Wang Qingchen ◽  
Cong Bolin ◽  
Ma Li
Keyword(s):  
Dabie Orogen ◽  
Structural Coupling ◽  
Hefei Basin

Detrital zircon U-Pb dating in the southern Hefei Basin: Evidence for exhumation of HP-UHP rocks of the Dabie Orogen

2020 ◽  
Vol 63 (7) ◽  
pp. 954-968
Author(s):  
Yongsheng Wang ◽  
Qiao Bai ◽  
Ziqiang Tian ◽  
Hui Du
Keyword(s):  
Detrital Zircon ◽  
Dabie Orogen ◽  
Hefei Basin

First Discovery of Hadean Xenocrystal Zircons from Granitic Gneisses in the Northern Dabie Orogen

2021 ◽  
Author(s):  
Xiaofei QIU ◽  
Xin DENG ◽  
Tuo JIANG ◽  
Qiong XU ◽  
Wenwu YANG
Keyword(s):  
Dabie Orogen

Late-Holocene palaeoenvironmental reconstruction from a lake in the Amazon Rainforest-Tropical Savanna (Cerrado) boundary in Brazil using a multi-proxy approach

The Holocene ◽  
2021 ◽  
pp. 095968362110190
Author(s):  
Kury Milena Souza ◽  
Moreira Luciane Silva ◽  
Cordeiro Renato Campello ◽  
Sifeddine Abdelfettah ◽  
Turcq Bruno ◽  
...  
Keyword(s):  
Late Holocene ◽  
Amazon Region ◽  
Amazon Rainforest ◽  
Oxbow Lake ◽  
Tropical Savanna ◽  
Sedimentary Process ◽  
Climatic Fluctuations ◽  
Climate Conditions ◽  
Depositional Processes ◽  
Lake Formation

As an ecotone, the region between the Amazon Rainforest and Tropical Savanna (Cerrado) biomes is, by definition, more susceptible to climate change. Therefore, understanding palaeoenvironmental dynamics is essential to address the future responses of such transition areas to climatic fluctuations. In this context, we present a new sediment record for the Late-Holocene retrieved from Barro-Preto, currently an oxbow lake located in an ecotone at the southern Brazilian Amazon border. Our multi-proxy data include carbon and nitrogen isotopes, as well as bulk TOC, chlorophyll derivatives, grain-size and microcharcoal analyses, all anchored on a radiocarbon-dated chronology. The sedimentary process recorded at the Barro-Preto Lake responded to both local and regional climate dynamics. It was influenced by river excursions associated to local responses to precipitation changes by the activation of the palaeochannel connecting the main-stem river and the Barro-Preto lake. This activation was evidenced by the presence of different colour lithology laminations accompanied by coarser sediments and also by climate conditions known to influence the Amazon region. Depositional processes linked to lake dynamics and different oxbow lake cycle stages were also important to explain the changes verified in the Barro-Preto record, endorsing the use of this lake formation for palaeoclimatic reconstructions. The record indicated a rising humidity trend, reflected by a progressive increase in lacustrine productivity, in accordance to other studies carried out in the Amazon region concerning the Late-Holocene, associated with a more southward displacement of the Intertropical Convergence Zone. Despite this rising humidity trend, dry episodic events during the Late-Holocene were evidenced by charcoal data, also coherent with regional Amazon studies, albeit exhibiting increased intensity, suggesting that the transitional nature of the environment might have influenced susceptibility to fires.

Petrogenesis and tectonic significance of the middle Neoproterozoic highly fractionated A-type granite in the South Qinling block

2021 ◽  
pp. 1-20
Author(s):  
Xiao-Fei Qiu ◽  
Qiong Xu ◽  
Tuo Jiang ◽  
Shan-Song Lu ◽  
Long Zhao
Keyword(s):  
Tectonic Setting ◽  
Eastern China ◽  
Continental Rift ◽  
The South ◽  
Yangtze Craton ◽  
Dabie Orogen ◽  
Northern Margin ◽  
South Qinling ◽  
Type Granite ◽  
High Alkali

Abstract The South Qinling block, a segment of the Yangtze craton involved in the Qinling–Dabie orogen, is critical for understanding the tectonic evolution of eastern China. However, the tectonic setting of the South Qinling block and the northern margin of the Yangtze block during middle Neoproterozoic time has long been the subject of debate, with two distinctly different models (continental rift or volcanic arc) proposed. Here, a comprehensive study of zircon U–Pb geochronology and geochemistry has been carried out on the Chengwan granitic pluton from the Suizao terrane in the South Qinling block. The granites are monzogranite and syenogranite in lithology, and are mainly composed of potash feldspar, quartz, plagioclase and biotite. This suite has long been regarded as a Palaeozoic magmatic pluton, but zircon U–Pb ages of 809 ± 9 Ma and 816 ± 4 Ma are obtained in this study. The granites are metaluminous to strongly peraluminous with high alkali contents, and exhibit highly fractionated features, including high SiO2, low Zr/Hf ratios, rare earth element tetrad effects and enrichment of K and Rb. They show Hf–Nd isotopic decoupling, which may be genetically related to their petrogenetic process. Based on the geochemical features and the positive εHf(t) values of the zircons, it is indicated that the granites may have been derived from partial melting of juvenile tonalitic rocks by biotite breakdown under fluid-absent conditions. The Chengwan granite geochemically belongs to the A2-subtype granites, suggesting that it might have formed in a post-orogenic tectonic setting. The highly fractionated A-type granite in this study may represent extensional collapse shortly after the collisional events in the South Qinling block, and thus indicate a tectonic regime switch, from compression to extension, as early as middle Neoproterozoic time. Integrating our new data with documented magmatic, metamorphic and sedimentary events during middle Neoproterozoic time in the region may support a continental rift model, and argues against arc models.

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