DOI: 10.1016/j.earscirev.2021.103702
论文题名: Decratonization and reactivation of the southern Indian shield: An integrated perspective
作者: Dessai A.G. ; Griffin W.L.
刊名: Earth Science Reviews
ISSN: 00128252
出版年: 2021
卷: 220 语种: 英语
中文关键词: Decratonization
; Dharwar craton
; Indian shield
; Lithospheric mantle
; Reworked craton
; Thermal perturbation
英文关键词: craton
; Deccan Traps
; inclusion
; Indian plate
; lithospheric structure
; mantle plume
; mantle structure
; partial melting
; reworking
; Dharwar Craton
; India
; Indian Ocean
; Indian Shield
英文摘要: A 150–200 km thick, cold (35–45 mWm−2), melt-depleted lithospheric keel characterised the eastern cratons of the Indian shield at the end of the Precambrian. Differing chemical- and isotopic-characteristics, and ages of the crust and mantle rocks reveal the decoupling of the crust and mantle beneath the cratons, beginning at 2.45 Ga, in the Bastar craton. The Pan-African event was more pervasive and brought about widespread reworking in most of the cratons of the shield. Major-, trace- and rare-earth elements combined with Sr, Nd and Hf isotope data suggest a heterogenous SCLM beneath southern India. The trace element signatures of xenoliths and the presence of majoritic garnet inclusions in diamond suggest that some kimberlites were derived from the mantle transition zone. Mesoproterozoic (1.2–1.4 Ga) modal and cryptic refertilisation by asthenosphere-derived, low-degree carbonated melts led to the generation of the fluids responsible for the metasomatic transformation of the source rocks. The western craton of the shield has witnessed more severe reactivation than the eastern due to the frequent interaction of the Indian plate with mantle plumes. One plume caused major igneous activity during the late Cretaceous, synchronous with crustal attenuation, rifting and the ridge-jump at 66 Ma, in the Indian Ocean. By the end of the Palaeocene the geotherm of the western craton had risen from 50 to 55 mWm−2 in the Proterozoic to a peak 80–90 mWm−2. This increase in heat flow not only modulated the mantle thermal regime, but led to a net loss of more than 100 km of lithosphere and to destabilisation of the craton. After this thermal event, the lithosphere preserves a thickness of barely 60–80 km, and a thin crust (10–21 km) beneath the continental margin in the west. These changes decratonized the western part of the shield and the transitional region further west in the Indian Ocean where the continental ridges are almost devoid of crustal sections and the lithosphere is ~60 km thick. The waning of the Deccan Traps (65 Ma) magmatism was marked by alkaline intrusive activity along the western margin of the shield, probably derived from the SCLM in response to the rise of the mantle plume. Low degree (2–3%) partial melting of a modally and cryptically metasomatized source may have been involved in the generation of alkaline magmas from a depleted mantle source variously contaminated by an enriched endmember. © 2021 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/166378
Appears in Collections: 气候变化与战略
There are no files associated with this item.
作者单位: School of Earth, Ocean and Atmospheric Science, Goa University, A/4, Primrose Apartments, Baner, Pune, 411045, India; ARC Centre of Excellence for Core to Crust Fluid Systems and GEMOC ARC National Key Centre, Earth and Planetary Sciences, Faculty of Science and Engineering, Macquarie UniversityNSW 2109, Australia
Recommended Citation:
Dessai A.G.,Griffin W.L.. Decratonization and reactivation of the southern Indian shield: An integrated perspective[J]. Earth Science Reviews,2021-01-01,220