Evolution of the Antarctic Peninsula Pacific margin offshore from Adelaide Island since the late Miocene; an example of a glacial passive margin

Author(s): Hernández Molina, F. J.; Larter, R. D.; Maldonado, A.; Rodríguez-Fernández, J.
Author Affiliation(s): Primary:
Universidad de Vigo, Departamento de Geociencias Marinas, Vigo, Spain
Universita di Siena, Italy
British Antarctic Survey, United Kingdom
Instituto Andaluz de Ciencias de la Tierra, Spain
Volume Title: Proceedings of the workshop Frontiers and opportunities in Antarctic geosciences
Volume Author(s): Siddoway, Christine, editor; Ricci, Carlo Alberto
Source: Terra Antartica Reports, Vol.12, p.81-90; Frontiers and opportunities in Antarctic geosciences, Siena, Italy, Aug. 29-31, 2004, edited by Christine Siddoway and Carlo Alberto Ricci. Publisher: Terra Antartica Publication, Siena, Italy. ISSN: 1723-7211. ISBN: 978-88-88395-04-3
Note: In English. 23 refs.; illus., incl. sect., sketch maps
Summary: Analysis of the morphology and stratigraphy of the Antarctic Peninsula Pacific margin offshore from Adelaide Island shows 3 main evolutionary stages, from the Late Miocene to the Recent, which represent the growth phase of the margin under glacial influence. The oldest, transitional stage (SU4, latest Miocene-Early Pliocene), represents the first progradational unit over the outer shelf and slope, above the Base of the Glacial Margin Sequences. This unit contains drift facies on the rise, and it represents an important change in the depositional style. The middle, progradational glacial margin stage contains two units (SU 3 & 2, Early to Late Pliocene). SU3 is composed of 3 progradational wedges (a, b & c) although the youngest one (a) is the thickest and represents the most important progradational stage of the margin. SU2 includes both progradational and aggradational deposits and it recorded a significant change in the margin growth pattern. The youngest aggradational glacial margin stage (SU1, Quaternary) recorded the last change in the depositional style of the margin, with upward and outward growth of a relatively thick sediment wedge. These stratigraphic results show a complex, multi-step evolution of the margin, although their precise chronology and details of their paleoenviornmental significance remain uncertain. Resolving these uncertainties in this area and elsewhere on the Antarctic continental margin will require improved ship-based drilling technology, to provide better recovery of glacially-derived sediments, and integrated studies to understand the evolution of the entire Antarctic continental margin, its relation with paleoenvironmental and paleoceanographic changes, and its global linkages.
Year of Publication: 2004
Research Program: ODP Ocean Drilling Program
Key Words: 12 Stratigraphy, Historical Geology and Paleoecology; Adelaide Island; Antarctic Peninsula; Antarctica; Cenozoic; Continental margin; Geophysical methods; Geophysical profiles; Geophysical surveys; Glacial environment; Glaciomarine environment; Leg 178; Lithostratigraphy; Marine environment; ODP Site 1097; Ocean Drilling Program; Passive margins; Plate tectonics; Reflection; Seismic methods; Seismic profiles; Southern Ocean; Surveys
Coordinates: S662334 S662334 W0704523 W0704523
Record ID: 2007091135
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