DOI: 10.1016/j.tecto.2021.228789
论文题名: Baddeleyite Pb–Pb geochronology and paleomagnetic poles for ~1.89–1.86 Ga mafic intrusions from the Dharwar craton, India, and their paleogeographic implications
作者: Parashuramulu V. ; Shankar R. ; Sarma D.S. ; Nagaraju E. ; Babu N.R.
刊名: Tectonophysics
ISSN: 00401951
出版年: 2021
卷: 805 语种: 英语
中文关键词: Baddeleyite geochronology
; Dharwar craton
; Large Igneous Province
; Mafic dykes
; Paleomagnetism
; Supercontinent
英文关键词: Magnetic polarity
; Metals
; Dykes and sills
; Mafic intrusion
; Paleogeographic reconstruction
; Paleomagnetic poles
; Reverse polarity
; Supercontinents
; Western Australia
; Yilgarn cratons
; Geochronology
; baddeleyite
; craton
; dike
; geochronology
; igneous intrusion
; large igneous province
; lead-lead dating
; mafic rock
; paleogeography
; paleomagnetism
; supercontinent
; Dharwar Craton
; India
; Columbia
英文摘要: We present new key paleomagnetic pole at 13°S, 152°E (k = 21, A95 = 7.8°) for recently identified 1864.4 ± 2.7 Ma (weighted mean age of four Pb–Pb ages) mafic magmatic event, based on a detailed paleomagnetic study of dolerite dykes and sills intruding Archean basement rocks and Tadipatri formation of the Cuddapah basin, Dharwar craton respectively. The Pb–Pb baddeleyite geochronology yields a crystallisation age of 1867.1 ± 1.0 Ma (MSWD = 1.02) for N77°E trending dyke in the southern region to Cuddapah basin. This new age obtained, confirms the presence of ~1864 Ma magmatic episode with a spatial extent of ~400 km in the Eastern Dharwar craton, within the brief period of ~5 Ma. The paleomagnetic results in these dykes revealed reverse polarity magnetisation direction with mean D = 107°, I = 24° (N = 13 sites, α95 = 10°). Here, we also update the normal polarity magnetic directions on ~1.89 Ga swarm, and the corresponding paleopole situated at 21°N, 336°E (N = 79 sites, A95 = 3.6°). The paleoposition of India is constrained around the equator during ~1.89–1.86 Ga time. The paleogeographic reconstructions were also been attempted at ~1.89 Ga and ~ 1.86 Ga with available key poles from other cratons, indicates the possibility of single plume acting as a source for two distinguishable radial emplacement of mafic dyke swarms across India (Dharwar and Bastar craton) and Western Australia (Yilgarn craton) within a time span of ~35 Ma. The individual movement of India, Baltica and Siberia with a drift rate of ~5.55 cm/yr towards the south, whereas Amazonia craton has moved rapidly to the north (~24.9 cm/yr), do not suggest the amalgamation of a supercontinent (Columbia/ Nuna) during ~1.88–1.86 Ga time. © 2021 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/170881
Appears in Collections: 气候变化与战略
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作者单位: CSIR-National Geophysical Research Institute, Council of Scientific and Industrial Research, Uppal Road, Hyderabad, 500 007, India
Recommended Citation:
Parashuramulu V.,Shankar R.,Sarma D.S.,et al. Baddeleyite Pb–Pb geochronology and paleomagnetic poles for ~1.89–1.86 Ga mafic intrusions from the Dharwar craton, India, and their paleogeographic implications[J]. Tectonophysics,2021-01-01,805