University of Tasmania
Browse

File(s) not publicly available

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

journal contribution
posted on 2023-05-16, 13:04 authored by Whitehead, JM, Quilty, PG, Harwood, DM, Andrew McMinnAndrew McMinn
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.

History

Publication title

Marine Micropaleontology

Volume

41

Issue

3-4

Pagination

125-152

ISSN

0377-8398

Department/School

Institute for Marine and Antarctic Studies

Publisher

Elsevier Science BV

Place of publication

Amsterdam

Repository Status

  • Restricted

Socio-economic Objectives

Other environmental management not elsewhere classified

Usage metrics

    University Of Tasmania

    Exports

    RefWorks
    BibTeX
    Ref. manager
    Endnote
    DataCite
    NLM
    DC