Sedimentation and magmatism in the Paleoproterozoic Cuddapah Basin,India: Consequences of lithospheric extension |
| |
| Institution: | 1. Department of Applied Geology, Curtin University, Kent St, Bentley, WA 6102, Australia;2. CSIR - National Geophysical Research Institute, Uppal Road, Hyderabad 500007, Telangana, India;3. College of Earth Sciences, Guilin University of Technology, 12 Jiangan Road, Guilin 541004, China;4. John de Laeter Centre for Isotope Research, Department of Applied Physics, Curtin University, Kent St, Bentley, WA 6102, Australia;1. Department of Geological Sciences, University of Florida, 241 Williamson Hall, Gainesville, FL 32611, USA;2. School of Earth Sciences and Resources, China University of Geosciences Beijing, Beijing 100083, PR China;3. Department of Earth Sciences, The University of Adelaide, Adelaide, SA 5005, Australia;4. Department of Earth System Sciences, Yonsei University, Seoul 03722, Republic of Korea;1. Geological Survey of Canada (GSC), 601 Booth Street, Ottawa, ON, K1A 0E8, Canada;2. Geological Survey of Denmark and Greenland (GEUS), Øster Voldgade 10, DK-1350 Copenhagen K, Denmark |
| |
| Abstract: | The Cuddapah Basin is one of many Proterozoic, intracontinental sedimentary basins across Peninsular India. The basin comprises several unconformity-bounded successions, the lowermost of which (the Papaghni Group and overlying Chitravati Group) are intruded by dolerite sills that contact metamorphosed their host rocks. A mafic-ultramafic sill from the base of the Tadpatri Formation in the Chitravati Group was previously dated at c. 1885 Ma, and interpreted to be part of a large igneous province (LIP). We have dated two samples of a felsic tuff from the upper part of the Tadpatri Formation at 1864 ± 13 Ma and 1858 ± 16 Ma; combining data from the two samples yields a weighted mean date of 1862 ± 9 Ma. Mafic sills intrude rocks stratigraphically above the tuffaceous beds, indicating that mafic magmatism continued until after c. 1860 Ma. Given that the sills intruded lithified rocks, some of the sills may be considerably younger than 1860 Ma. Mafic volcanic rocks are also known from below the unconformity at the base of the Chitravati Group, within the basal Papaghni Group (> c. 1890 Ma). Collectively, these data indicate that mafic sill emplacement spanned more than 30 myr so that it is likely to have been a protracted event or a series of events, and, therefore unlikely to represent a LIP. The time span for mafic magmatism is more compatible with episodic, lithospheric extension (passive rifting) during basin evolution than it is with a mantle plume (active rifting). |
| |
| Keywords: | |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
