Detecting magma-poor orogens in the detrital record

G. J. O'Sullivan, D. M. Chew, S. D. Samson

Research output: Research - peer-reviewArticle

Abstract

The clastic record is commonly interrogated by analysis of detrital heavy mineral assemblages, with the bulk of modern detrital geochronological studies employing U-Pb dating of detrital zircon. However, the bias of zircon toward felsic igneous sources, and the limited ability of the U-Pb system in zircon to record low- to medium-grade metamorphic events, means that the U-Pb detrital zircon record is largely insensitive to magma-poor orogens. In this study, U-Pb ages were obtained by laser ablation-inductively coupled plasma-mass spectrometry for apatite and rutile extracted from alluvium of the French Broad River (FBR) in the southern Appalachians (southeastern United States). In contrast to previously published FBR U-Pb zircon data sets, which yield essentially no record of the most recent Appalachian metamorphic events (ca. 320 Ma) associated with assembly of Pangea, the U-Pb detrital rutile and especially the U-Pb apatite systems together provide a complete record of complex polyphase Appalachian orogenesis. It is unexpected that the apatite and rutile U-Pb Appalachian age populations differ significantly, with probable low-temperature breakdown of rutile biasing the rutile data set toward the most recent (Alleghanian) metamorphic event. These data make the FBR one of the most intensely studied river systems globally for multiproxy single-grain U-Pb analysis, clearly demonstrate dependence of provenance information on mineral proxy choice, and emphasize the resolving power of multiproxy provenance studies.

LanguageEnglish (US)
Pages871-874
Number of pages4
JournalGeology
Volume44
Issue number10
DOIs
StatePublished - 2016

Fingerprint

rutile
zircon
magma
apatite
river
provenance
analysis
Alleghanian
Pangaea
heavy mineral
ablation
orogeny
alluvial deposit
river system
mass spectrometry
laser
plasma
mineral
dating

ASJC Scopus subject areas

  • Geology

Cite this

O'Sullivan, G. J., Chew, D. M., & Samson, S. D. (2016). Detecting magma-poor orogens in the detrital record. Geology, 44(10), 871-874. DOI: 10.1130/G38245.1

Detecting magma-poor orogens in the detrital record. / O'Sullivan, G. J.; Chew, D. M.; Samson, S. D.

In: Geology, Vol. 44, No. 10, 2016, p. 871-874.

Research output: Research - peer-reviewArticle

O'Sullivan, GJ, Chew, DM & Samson, SD 2016, 'Detecting magma-poor orogens in the detrital record' Geology, vol 44, no. 10, pp. 871-874. DOI: 10.1130/G38245.1
O'Sullivan GJ, Chew DM, Samson SD. Detecting magma-poor orogens in the detrital record. Geology. 2016;44(10):871-874. Available from, DOI: 10.1130/G38245.1
O'Sullivan, G. J. ; Chew, D. M. ; Samson, S. D./ Detecting magma-poor orogens in the detrital record. In: Geology. 2016 ; Vol. 44, No. 10. pp. 871-874
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