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Scientific article
OA Policy
English

Seismic stratigraphy of Lago Fagnano sediments (Tierra del Fuego, Argentina) : A potential archive of paleoclimatic change and tectonic activity since the Late Glacial

Contributors

Waldmann, Nicolas; Ariztegui, Daniel; Anselmetti, Flavio S.; Austin, J. A. Jr.; Dunbar, R.; Moy, C. M.; Recasens Vargas, Cristina

Published in

Geologica Acta, vol. 6, no. 1, p. 101-110

Publication date

2008

Abstract

Located at 54ºS in the heart of the Island of Tierra del Fuego, Lago Fagnano occupies the deepest of a chain of en-echelon tectonic depressions along the Magallanes-Fagnano Transform system (MFT). A recent geophysical campaign combining 3.5 kHz (pinger) single-channel with 1 in3 airgun multi-channel systems surveyed more than 100 m of glacio-lacustrine sediments filling two main sub-basins. These data provide a unique opportunity to visualize the most recent lacustrine sequence with high-resolution while simultaneously imaging the oldest infill. A preliminary seismic stratigraphic analysis of the high-resolution 3.5 kHz pinger data allowed the identification of three major seismostratigraphic units (A, the oldest and C, the youngest). While unit A is interpreted as glacially derived sediments, the overlying unit B is interpreted as fining upward sequences of proglacial turbidites reflecting sediment pulses released by the retreating Fagnano glacier during the last deglaciation. A major environmental change occurred during deposition of unit C when pelagic style of sedimentation is intercalated by sequences of downslope mass flow events probably triggered by relatively strong tectonic pulses along the MFT system. Gravity cores show a regular alternation of light and dark laminae occasionally interrupted by homogenous sedimentary units interpreted as turbidites. Ultra-high resolution X-ray fluorescence micro-profiles show fluctuations in major trace elements at mm scale that may indicate seasonal variations in the sedimentary influx. These core data provide a unique record of decadal changes in regional climate that can be compared with other marine and continental archives to improve our understanding of the forcing mechanisms behind climate change.

Keywords

  • Paleoseismology
  • Lacustrine sedimentation
  • Turbidites
  • Paleoclimate

UNIGE affiliation entities

Citation (ISO format)

WALDMANN, Nicolas et al. Seismic stratigraphy of Lago Fagnano sediments (Tierra del Fuego, Argentina) : A potential archive of paleoclimatic change and tectonic activity since the Late Glacial. In: Geologica Acta, 2008, vol. 6, n° 1, p. 101–110.

Main files (1)

Article (Accepted version)

Identifiers

  • PID : unige:1305

Additional URL for this publication

http://www.geologica-acta.com/HomeAC.do
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Technical informations

Creation

01/04/2009 11:02:00

First validation

01/04/2009 11:02:00

Update

14/03/2023 15:04:01

Status update

14/03/2023 15:04:01

Last indexation

29/10/2024 11:25:44
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