Absence of Extraterrestrial 3He in Permian–Triassic Age Sedimentary Rocks

DSpace/Manakin Repository

Absence of Extraterrestrial 3He in Permian–Triassic Age Sedimentary Rocks

Show simple item record

dc.contributor.author Garrison, G.
dc.contributor.author Ward, P.
dc.contributor.author Farley, K. A.
dc.contributor.author Mukhopadhyay, Sujoy
dc.date.accessioned 2011-02-15T15:54:45Z
dc.date.issued 2005
dc.identifier.citation Farley, K.A., P. Ward, G. Garrison, and S. Mukhopadhyay. 2005. Absence of extraterrestrial 3He in Permian-Triassic age sedimentary rocks. Earth and Planetary Science Letters 240(2): 265-275. en_US
dc.identifier.issn 0012-821X en_US
dc.identifier.uri http://nrs.harvard.edu/urn-3:HUL.InstRepos:4725619
dc.description.abstract Helium concentration and isotopic composition were measured in a suite of samples across the Permian–Triassic boundary at Opal Creek, Canada, to determine whether high extraterrestrial helium concentrations are associated with a possible extinction-inducing impact event at this time. No extraterrestrial [super]3He was detected, implying that neither fullerene-hosted nor IDP-hosted He is present at or near the boundary. This observation is consistent with similar studies of some Permian–Triassic sections, but contrasts sharply with reports of both fullerene- and IDP-hosted extraterrestrial [super]3He at other sections. Step-heat experiments indicate rapid diffusion of extraterrestrial helium from sediments heated to temperatures above ~70 °C. Given the likelihood of burial and associated heating in Permian–Triassic age rocks, the initially unexpected absence of IDP-hosted [sup]3He likely indicates thermally induced diffusive loss. Indeed one of the key sections (Graphite Peak, Antarctica) from which extraterrestrial [super]3He has been reported at and near the Permian–Triassic boundary has been sufficiently heated that the reported preservation of extraterrestrial helium, in both IDPs and fullerenes, is inexplicable. Recent contamination provides a plausible explanation for extraterrestrial [super]3He in these samples. While no extraterrestrial [sup]3He was detected at Opal Creek, there is a sharp increase in nucleogenic [super]3He very close to or at the Permian–Triassic boundary. This presumably arises from the major lithologic change at this time, from cherts in the Permian to shales and siltstones in the Triassic. Increased nucleogenic [super]3He is associated with increases in both lithium and organic carbon content into the Triassic. Either the production rate or the retention of this [super]3He is higher in the shales and siltstones than in the cherts. Care must be taken to eliminate such artifacts before interpreting changes in [super]3He concentration in terms of fluctuations in the delivery of [super]3He from space. en_US
dc.description.sponsorship Earth and Planetary Sciences en_US
dc.language.iso en_US en_US
dc.publisher Elsevier Science BV en_US
dc.relation.isversionof doi:10.1016/j.epsl.2005.09.054 en_US
dc.relation.hasversion http://www.people.fas.harvard.edu/%7emukhop/PTB-He.pdf en_US
dash.license META_ONLY
dc.subject fullerene en_US
dc.subject Permian-Triassic boundary en_US
dc.subject cosmic dust en_US
dc.subject extraterrestrial helium en_US
dc.title Absence of Extraterrestrial 3He in Permian–Triassic Age Sedimentary Rocks en_US
dc.type Journal Article en_US
dc.description.version Version of Record en_US
dc.relation.journal Earth and Planetary Science Letters en_US
dash.depositing.author Mukhopadhyay, Sujoy
dash.embargo.until 10000-01-01

Files in this item

Files Size Format View
PTB-He.pdf 492.6Kb PDF View/Open

This item appears in the following Collection(s)

  • FAS Scholarly Articles [7220]
    Peer reviewed scholarly articles from the Faculty of Arts and Sciences of Harvard University

Show simple item record

 
 

Search DASH


Advanced Search
 
 

Submitters