{"title":"华南地块早古生代韧性变形:东江南带多相剪切带","authors":"Jun Hu, Xinqi Yu, Wei Li, Nianwei Liu","doi":"10.1144/jgs2023-062","DOIUrl":null,"url":null,"abstract":"Three parallel east–west (E–W)-trending shear zones are components of the polyphase shear zones in the eastern Jiangnan belt. The meso- and microstructural characteristics and the estimates of deformation temperatures, vorticities, and geochronology of these shear zones provide significant information regarding the tectonic evolution of the South China Block (SCB) during the early Paleozoic. Most shear sense indicators (e.g., asymmetric folds, S-C fabrics, and rotating porphyroclasts) reveal that the kinematics were characterized by E–W dextral shear. Finite strain measurements indicate an oblate strain ellipsoid shape with S-type and SL-type tectonites. The rotated rigid porphyroclasts and Mohr circle methods yield vorticity (Wk) values of 0.58–0.80 and 0.66–0.89, respectively, indicating that the flow was generally shear-dominated with almost equal proportions of simple and pure shear. Both mineral deformation thermometers and quartz c-axis fabrics indicate that the deformation occurred at medium temperature conditions of 400–550℃. Combined with our new age and regional geological data, the E–W-trending shear zones might represent an increment of deformation during the last period of the early Paleozoic orogeny in the SCB.","PeriodicalId":17320,"journal":{"name":"Journal of the Geological Society","volume":"51 1","pages":"0"},"PeriodicalIF":2.6000,"publicationDate":"2023-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Early Paleozoic ductile deformation of the South China Block: the polyphase shear zones in the Eastern Jiangnan Belt\",\"authors\":\"Jun Hu, Xinqi Yu, Wei Li, Nianwei Liu\",\"doi\":\"10.1144/jgs2023-062\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"Three parallel east–west (E–W)-trending shear zones are components of the polyphase shear zones in the eastern Jiangnan belt. The meso- and microstructural characteristics and the estimates of deformation temperatures, vorticities, and geochronology of these shear zones provide significant information regarding the tectonic evolution of the South China Block (SCB) during the early Paleozoic. Most shear sense indicators (e.g., asymmetric folds, S-C fabrics, and rotating porphyroclasts) reveal that the kinematics were characterized by E–W dextral shear. Finite strain measurements indicate an oblate strain ellipsoid shape with S-type and SL-type tectonites. The rotated rigid porphyroclasts and Mohr circle methods yield vorticity (Wk) values of 0.58–0.80 and 0.66–0.89, respectively, indicating that the flow was generally shear-dominated with almost equal proportions of simple and pure shear. Both mineral deformation thermometers and quartz c-axis fabrics indicate that the deformation occurred at medium temperature conditions of 400–550℃. Combined with our new age and regional geological data, the E–W-trending shear zones might represent an increment of deformation during the last period of the early Paleozoic orogeny in the SCB.\",\"PeriodicalId\":17320,\"journal\":{\"name\":\"Journal of the Geological Society\",\"volume\":\"51 1\",\"pages\":\"0\"},\"PeriodicalIF\":2.6000,\"publicationDate\":\"2023-09-26\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Journal of the Geological Society\",\"FirstCategoryId\":\"1085\",\"ListUrlMain\":\"https://doi.org/10.1144/jgs2023-062\",\"RegionNum\":3,\"RegionCategory\":\"地球科学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q2\",\"JCRName\":\"GEOSCIENCES, MULTIDISCIPLINARY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of the Geological Society","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1144/jgs2023-062","RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"GEOSCIENCES, MULTIDISCIPLINARY","Score":null,"Total":0}
Early Paleozoic ductile deformation of the South China Block: the polyphase shear zones in the Eastern Jiangnan Belt
Three parallel east–west (E–W)-trending shear zones are components of the polyphase shear zones in the eastern Jiangnan belt. The meso- and microstructural characteristics and the estimates of deformation temperatures, vorticities, and geochronology of these shear zones provide significant information regarding the tectonic evolution of the South China Block (SCB) during the early Paleozoic. Most shear sense indicators (e.g., asymmetric folds, S-C fabrics, and rotating porphyroclasts) reveal that the kinematics were characterized by E–W dextral shear. Finite strain measurements indicate an oblate strain ellipsoid shape with S-type and SL-type tectonites. The rotated rigid porphyroclasts and Mohr circle methods yield vorticity (Wk) values of 0.58–0.80 and 0.66–0.89, respectively, indicating that the flow was generally shear-dominated with almost equal proportions of simple and pure shear. Both mineral deformation thermometers and quartz c-axis fabrics indicate that the deformation occurred at medium temperature conditions of 400–550℃. Combined with our new age and regional geological data, the E–W-trending shear zones might represent an increment of deformation during the last period of the early Paleozoic orogeny in the SCB.
期刊介绍:
Journal of the Geological Society (JGS) is owned and published by the Geological Society of London.
JGS publishes topical, high-quality recent research across the full range of Earth Sciences. Papers are interdisciplinary in nature and emphasize the development of an understanding of fundamental geological processes. Broad interest articles that refer to regional studies, but which extend beyond their geographical context are also welcomed.
Each year JGS presents the ‘JGS Early Career Award'' for papers published in the journal, which rewards the writing of well-written, exciting papers from early career geologists.
The journal publishes research and invited review articles, discussion papers and thematic sets.