DOI: 10.1016/j.palaeo.2015.06.033
论文题名: Tracing acidification induced by Deccan Phase 2 volcanism
作者: Font E. ; Ponte J. ; Adatte T. ; Fantasia A. ; Florindo F. ; Abrajevitch A. ; Mirão J.
刊名: Palaeogeography, Palaeoclimatology, Palaeoecology
ISSN: 0031-0182
出版年: 2016
卷: 441 起始页码: 181
结束页码: 197
语种: 英语
英文关键词: Acidification
; Deccan Volcanic Province
; Environmental magnetism
; India
; Intertrappean continental sediments
英文摘要: The Deccan Volcanic Province (DVP) was built up by three major phases of eruptions; the most voluminous of which, the Deccan Phase 2, encompassed the Cretaceous-Palaeogene (KT) boundary. Deccan eruptions have been implicated as a contributor to the end-Cretaceous mass extinction, however, mechanism by which volcanic activity affected biota remains poorly understood. We applied a combination of rock magnetic techniques scanning electron microscopy to characterize mineral assemblages of three sections of intertrappean lacustrine sediments from the north-western Maharashtra Deccan Volcanic Provinces. Our results indicate that in sediments deposited during the early stages of the Deccan Phase 2, the Daïwal River and Dhapewada sequences, iron-bearing mineral association is dominated by detrital iron oxides (magnetite and hematite) sourced from the weathering of the surrounding basaltic bedrocks, with minor contribution form authigenic iron sulphides (framboidal pyrite, pyrrhotite and/or greigite). The sediments deposited during the final stages of Phase 2 (the Podgawan sequence) differ significantly in their characteristics. In particular, the Podgawan sediments have 1) very low magnetic susceptibility values, but higher terrigenous fraction (clays and shales) content; 2) more complex assemblage of magnetic minerals, 3) ubiquitous presence of Fe-Ca-Ce vanadates; and 4) unusual lithological variations in the middle part of the section (represented by a charcoal-rich level that is capped by a red clay layer containing fossilized bacterial colonies). We suggest that these unusual characteristics reflect increased acidity in the region during the deposition of the Podgawan sequence, likely due to cumulative effects of volcanic aerosols released during the Deccan Phase 2 eruptions. The combination of these features may be used to recognize episodes of increased acidity in the geological record. Our results also contribute to understanding of local vs. global effects of the Deccan volcanism. © 2015 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/68627
Appears in Collections: 过去全球变化的重建
There are no files associated with this item.
作者单位: IDL-FCUL, Instituto Dom Luís, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, Portugal; ISTE, Geopolis, Lausanne, Switzerland; Istituto Nazionale di Geofisica e Vulcanologia, Via di Vigna Murata 605, Rome, Italy; Institute of Tectonics and Geophysics, Russian Academy of Sciences, Khabarovsk, Russian Federation; Hercules, Evora, Portugal
Recommended Citation:
Font E.,Ponte J.,Adatte T.,et al. Tracing acidification induced by Deccan Phase 2 volcanism[J]. Palaeogeography, Palaeoclimatology, Palaeoecology,2016-01-01,441