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Atmospheric halogen and acid rains during the main phase of Deccan eruptions; magnetic and mineral evidence

Eric Font, Sebastien Fabre, Anne Nedelec, Thierry Adatte, Gerta Keller, Cristina Veiga-Pires, Jorge Ponte, Jose Mirao, Hassan Khozyem and Jorge E. Spangenberg
Atmospheric halogen and acid rains during the main phase of Deccan eruptions; magnetic and mineral evidence (in Volcanism, impacts, and mass extinctions; causes and effects, Gerta Keller (editor) and Andrew C. Kerr (editor))
Special Paper - Geological Society of America (September 2014) 505: 353-368

Abstract

Environmental changes linked to Deccan volcanism are still poorly known. A major limitation resides in the paucity of direct Deccan volcanism markers and in the geologically short interval where both impact and volcanism occurred, making it hard to evaluate their contributions to the mass extinction. We investigated the low-magnetic-susceptibility interval just below the iridium-rich layer of the Bidart (France) section, which was recently hypothesized to be the result of paleoenvironmental perturbations linked to paroxysmal Deccan phase 2. Results show a drastic decrease of detrital magnetite and presence of scarce akaganeite, a hypothesized reaction product formed in the aerosols derived from reaction of a volcanic plume with water and oxygen in the high atmosphere. A weathering model of the consequences of acidic rains on a continental regolith reveals nearly complete magnetite dissolution after approximately 31,000 yr, which is consistent with our magnetic data and falls within the duration of the Deccan phase 2. These results highlight the nature and importance of the Deccan-related environmental changes leading up to the end- Cretaceous mass extinction.


ISSN: 0072-1077
EISSN: 2331-219X
Coden: GSAPAZ
Serial Title: Special Paper - Geological Society of America
Serial Volume: 505
Title: Atmospheric halogen and acid rains during the main phase of Deccan eruptions; magnetic and mineral evidence
Title: Volcanism, impacts, and mass extinctions; causes and effects
Affiliation: Universidade de Lisboa, Instituto Dom Luis, Campo Grande, Portugal
Affiliation: Princeton University, Department of Geosciences, Princeton, NJ, United States
Pages: 353-368
Published: 201409
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 76
Accession Number: 2014-085287
Categories: Igneous and metamorphic petrologyStratigraphy
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. sketch map, 2 tables, strat. cols.
N43°25'60" - N43°25'60", W01°34'60" - W01°34'60"
N43°21'00" - N43°21'00", E12°34'60" - E12°34'60"
Secondary Affiliation: Cardiff University, GBR, United KingdomUniversite de Toulouse, FRA, FranceUniversite de Lausanne, CHE, SwitzerlandPrinceton University, USA, United StatesUniversidade do Algarve, PRT, PortugalUniversity of Evora, PRT, Portugal
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States
Update Code: 201444
Program Name: DSDPDeep Sea Drilling Project
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