Was the latest Devonian glaciation a multiple event? New palynological evidence from Bolivia
Was the latest Devonian glaciation a multiple event? New palynological evidence from Bolivia
Assemblages of acritarchs, prasinophytes, and miospores were recovered from the uppermost Iquiri and lower portion of the Itacua formations in southeast Bolivia. Analysis of the diverse and somewhat abundant well-preserved palynomorph assemblage indicates a Late Devonian (late Famennian) age for both formations, and further subdivision in ascending stratigraphic order into the ?VCo, LL, LE, and LN miospore biozones of Western Europe. The presence of age-diagnostic miospore taxa from South America and North America indicates contemporaneous glaciation events between these two regions. The results from close sampling of the diamictite facies of the Itacua Formation at the Bermejo West section, Bolivia, correlate the latest Famennian spore inceptions used to define the Euramerica miospore biozone sequence (LL, LE, and LN zones). The Itacua Formation diamictite sequence examined is relatively thin compared to other diamictite sequences in Bolivia. Furthermore, the miospore biozones represent an estimated duration of three million years, whereas orbitally-forced glacial-interglacial events (e.g., Ruddiman, 2001) are of the Milankovitch frequency range of between 20,000 and 400,000 years. Therefore, it seems most likely that a number of glacial/interglacial events are represented, rather than a single glacial episode.
Late Devonian, Glaciation, South America, Palynology
75-83
Wicander, Reed
b0deaf42-3328-47f4-b8a6-3affda2115a9
Clayton, Geoff
fce71508-3308-46b2-a87f-38b6f1ba1517
Marshall, J.E.A.
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Troth, Ian
b1a8b695-aa8d-441a-83e5-8c8edd8b2242
Racey, Andrew
f07a55cd-4a56-496e-ba4c-6bd72deb1c6f
15 May 2011
Wicander, Reed
b0deaf42-3328-47f4-b8a6-3affda2115a9
Clayton, Geoff
fce71508-3308-46b2-a87f-38b6f1ba1517
Marshall, J.E.A.
cba178e3-91aa-49a2-b2ce-4b8d9d870b06
Troth, Ian
b1a8b695-aa8d-441a-83e5-8c8edd8b2242
Racey, Andrew
f07a55cd-4a56-496e-ba4c-6bd72deb1c6f
Wicander, Reed, Clayton, Geoff, Marshall, J.E.A., Troth, Ian and Racey, Andrew
(2011)
Was the latest Devonian glaciation a multiple event? New palynological evidence from Bolivia.
Palaeogeography Palaeoclimatology Palaeoecology, 305 (1-4), .
(doi:10.1016/j.palaeo.2011.02.016).
Abstract
Assemblages of acritarchs, prasinophytes, and miospores were recovered from the uppermost Iquiri and lower portion of the Itacua formations in southeast Bolivia. Analysis of the diverse and somewhat abundant well-preserved palynomorph assemblage indicates a Late Devonian (late Famennian) age for both formations, and further subdivision in ascending stratigraphic order into the ?VCo, LL, LE, and LN miospore biozones of Western Europe. The presence of age-diagnostic miospore taxa from South America and North America indicates contemporaneous glaciation events between these two regions. The results from close sampling of the diamictite facies of the Itacua Formation at the Bermejo West section, Bolivia, correlate the latest Famennian spore inceptions used to define the Euramerica miospore biozone sequence (LL, LE, and LN zones). The Itacua Formation diamictite sequence examined is relatively thin compared to other diamictite sequences in Bolivia. Furthermore, the miospore biozones represent an estimated duration of three million years, whereas orbitally-forced glacial-interglacial events (e.g., Ruddiman, 2001) are of the Milankovitch frequency range of between 20,000 and 400,000 years. Therefore, it seems most likely that a number of glacial/interglacial events are represented, rather than a single glacial episode.
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Published date: 15 May 2011
Keywords:
Late Devonian, Glaciation, South America, Palynology
Organisations:
Ocean and Earth Science
Identifiers
Local EPrints ID: 188005
URI: http://eprints.soton.ac.uk/id/eprint/188005
ISSN: 0031-0182
PURE UUID: ecdfded0-c84e-4cda-ab87-0f5816d79d8e
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Date deposited: 19 May 2011 13:18
Last modified: 15 Mar 2024 02:35
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Author:
Reed Wicander
Author:
Geoff Clayton
Author:
Ian Troth
Author:
Andrew Racey
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