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Climatically driven biogeographic provinces of Late Triassic tropical Pangea

Jessica H. Whiteside; Danielle S. Grogan; Paul E. Olsen; Dennis V. Kent

Title:
Climatically driven biogeographic provinces of Late Triassic tropical Pangea
Author(s):
Whiteside, Jessica H.
Grogan, Danielle S.
Olsen, Paul E.
Kent, Dennis V.
Date:
Type:
Articles
Department:
Lamont-Doherty Earth Observatory
Volume:
108
Permanent URL:
Book/Journal Title:
Proceedings of the National Academy of Sciences
Abstract:
Although continents were coalesced into the single landmass Pangea, Late Triassic terrestrial tetrapod assemblages are surprisingly provincial. In eastern North America, we show that assemblages dominated by traversodont cynodonts are restricted to a humid 6° equatorial swath that persisted for over 20 million years characterized by "semiprecessional" (approximately 10,000-y) climatic fluctuations reflected in stable carbon isotopes and sedimentary facies in lacustrine strata. More arid regions from 5-20°N preserve procolophonid-dominated faunal assemblages associated with a much stronger expression of approximately 20,000-y climatic cycles. In the absence of geographic barriers, we hypothesize that these variations in the climatic expression of astronomical forcing produced latitudinal climatic zones that sorted terrestrial vertebrate taxa, perhaps by excretory physiology, into distinct biogeographic provinces tracking latitude, not geographic position, as the proto-North American plate translated northward. Although the early Mesozoic is usually assumed to be characterized by globally distributed land animal communities due to of a lack of geographic barriers, strong provinciality was actually the norm, and nearly global communities were present only after times of massive ecological disruptions.
Subject(s):
Paleoclimate science
Publisher DOI:
http://dx.doi.org/10.1073/pnas.1102473108
Item views:
91
Metadata:
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