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Early Pliocene paleoenvironment of the Sorsdal Formation, Vestfold Hills, based on diatom data


Whitehead, JM and Quilty, PG and Harwood, DM and McMinn, A, Early Pliocene paleoenvironment of the Sorsdal Formation, Vestfold Hills, based on diatom data, Marine Micropaleontology, 41, (3-4) pp. 125-152. ISSN 0377-8398 (2001) [Refereed Article]

DOI: doi:10.1016/S0377-8398(00)00060-8


Comparison of diatom data from modern surface sediments in Prydz Bay and the Kerguelen Plateau with diatom assemblages from the Sørsdal Formation, Vestfold Hills, indicates that the climate was warmer than present during the early Pliocene (4.5-4.1 Ma). Extant, sea-ice associated diatoms are significantly less abundant throughout the Sørsdal Formation than in the modern Antarctic coastal zone. Extant diatoms in the Sørsdal Formation, including Stellarima stellaris, Thalassiosira oliverana, Fragilariopsis sublinearis, Pseudo-nitzschia turgiduloides and Eucampia antarctica var. recta, are consistent with annual sea-surface temperatures (SST) of between - 1.8 and 5.0°C. The presence of S. stellaris indicates that the summer SSTs were >3°C during some intervals. The absence of calcareous coccoliths and the silicoflagellate Dictyocha suggests that the upper limit for summer SST was <5°C. These data indicate that early Pliocene summer SST were between 1.6 and 3°C warmer than today. Abundant Chaetoceros cysts infer that stratified, open-water conditions were present during summer/spring. Ice sheet models suggest that warming of the magnitude evident in the Sørsdal Formation (≤3°C) should have resulted initially in increased snow accumulation and ice sheet growth. However, ice sheet growth was probably short-lived, as the long-term response to this warming in the early Pliocene resulted in a significant decrease in ice volume and deposition of the Sørsdal Formation. Other factors, such as increased basal-ice sliding and higher discharge (icebergs and melt-water), probably led to significantly elevated ablation rates from the Pliocene ice sheet, resulting in ice sheet retreat. © 2001 Elsevier Science B.V.

Item Details

Item Type:Refereed Article
Research Division:Earth Sciences
Research Group:Geology
Research Field:Palaeontology (incl. palynology)
Objective Division:Environmental Management
Objective Group:Other environmental management
Objective Field:Other environmental management not elsewhere classified
UTAS Author:Whitehead, JM (Dr Jason Whitehead)
UTAS Author:Quilty, PG (Dr Pat Quilty)
UTAS Author:McMinn, A (Professor Andrew McMinn)
ID Code:22395
Year Published:2001
Web of Science® Times Cited:39
Deposited By:IASOS
Deposited On:2001-08-01
Last Modified:2011-08-03

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