Journal Article10.1126/SCIENCE.261.5123.902
Early and Late Alkali Igneous Pulses and a High-3He Plume Origin for the Deccan Flood Basalts
TL;DR: Rocks from the older complexes show a 3He/4He ratio of 14.0 times the air ratio, an initial 87Sr/86Sr ratio of 0.70483, and other geochemical characteristics similar to ocean island basalts; the later alkalic pulse shows isotopic evidence of crustal contamination.
read more
Abstract: Several alkalic igneous complexes of nephelinite-carbonatite affinities occur in extensional zones around a region of high heat flow and positive gravity anomaly within the continental flood basalt (CFB) province of Deccan, India. Biotites from two of the complexes yield (40)Ar/(39)Ar dates of 68.53 +/- 0.16 and 68.57 +/- 0.08 million years. Biotite from a third complex, which intrudes the flood basalts, yields an (40)Ar/(39)Ar date of 64.96 +/- 0.1 1 million years. The complexes thus represent early and late magmatism with respect to the main pulse of CFB volcanism 65 million years ago. Rocks from the older complexes show a (3)He/(4)He ratio of 14.0 times the air ratio, an initial (87)Sr/(86)Sr ratio of 0.70483, and other geochemical characteristics similar to ocean island basalts; the later alkalic pulse shows isotopic evidence of crustal contamination. The data document 3.5 million years of incubation of a primitive, high-(3)He mantle plume before the rapid eruption of the Deccan CFB.
read more
Chat with Paper
AI Agents for this Paper
Find similar papers on Google Scholar, PubMed and Arxiv
Write a critical review of this paper
Analyze citations of this paper to find unaddressed research gaps
Citations
Noble Gas Isotope Geochemistry of Mid-Ocean Ridge and Ocean Island Basalts: Characterization of Mantle Source Reservoirs
TL;DR: In the terrestrial environment, the abundances of noble gases are quite low because they were excluded from solid materials during planetary formation in the inner solar system, which makes the noble gases excellent tracers of mantle reservoirs as mentioned in this paper.
776
Synchrony and causal relations between permian-triassic boundary crises and siberian flood volcanism.
TL;DR: Analysis of 40Ar/39Ar data from two tuffs in southern China yielded a date comparable to the inception of main stage Siberian flood volcanism at 250.0 � 0.2 million years ago for the Permian-Triassic boundary.
589
Age of the earliest known hominids in Java, Indonesia
TL;DR: The hominid fossils, a juvenile calvaria of Pithecanthropus and a partial face and cranial fragments of Meganthropus, commonly considered part of the Asian Homo erectus hypodigm, are at least 0.6 million years older than fossils referred to as Homo erectu from Olduvai Gorge, Tanzania, and comparable in age with the oldest Koobi Fora Homo cf.
560
The longest voyage: Tectonic, magmatic, and paleoclimatic evolution of the Indian plate during its northward flight from Gondwana to Asia
TL;DR: A detailed case history of the Indian plate tectonic evolution can be found in this paper, where the authors present a case study of the repeated rifting of Indian plate from surrounding Gondwana continents, its northward migration, and its collision first with the Kohistan-Ladakh Arc at the Indus Suture Zone, and then with Tibet at the Shyok-Tsangpo Suture.
471
Co2 fluxes from mid-ocean ridges, arcs and plumes
Bernard Marty,Igor Tolstikhin +1 more
TL;DR: In this article, the effect of volatile fractionation during magma degassing, investigated using new rare gas and CO2 abundances determined simultaneously for a suite of Mid-Ocean Ridge (MOR) basalt glasses, is not the major factor controlling the spread of data, which mainly result from volatile heterogeneity in the mantle source.
461
References
Least squares fitting of a straight line with correlated errors
TL;DR: In this paper, the fitting of a straight line when both variables are subject to crrors is generalized to allow for correlation of the z and y errors, illustrated by reference to lead isochron fitting.
2.3K
Flood Basalts and Hot-Spot Tracks: Plume Heads and Tails
TL;DR: Continental flood basalt eruptions have resulted in sudden and massive accumulations of basaltic lavas in excess of any contemporary volcanic processes, thought to result from deep mantle plumes.
1.3K
Implications of mantle plume structure for the evolution of flood basalts
TL;DR: In this article, the authors compare the physical and chemical characteristics of two flood basalt provinces (the Deccan and Karoo) with predictions of the dynamical model and conclude that the high-temperature melts associated with continental flood basalts are derived from hot, relatively uncontaminated plume-source mantle at the plume axis.
1.1K
The age of parana flood volcanism, rifting of gondwanaland, and the jurassic-cretaceous boundary.
Paul R. Renne,Marcia Ernesto,Igor Ivory Gil Pacca,Robert S. Coe,Jonathon M. Glen,Michel Prévot,Mireille Perrin +6 more
TL;DR: The Paran�-Etendeka flood volcanic event produced ∼1.5 x 106 cubic kilometers of volcanic rocks, ranging from basalts to rhyolites, before the separation of South America and Africa during the Cretaceous period.
528