Rights statement: Copyright 2011 by the American Geophysical Union.
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Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - Late Quaternary sediments from deep-sea sediment drifts on the Antarctic Peninsula Pacific margin
T2 - climatic control on provenance of minerals
AU - Venuti, Alessadra
AU - Florindo, Fabio
AU - Caburlotto, Andrea
AU - Hounslow, Mark W.
AU - Hillenbrand, Claus Dieter
AU - Strada, Eleonora
AU - Talarico, Franco M.
AU - Cavallo, Andrea
N1 - Copyright 2011 by the American Geophysical Union.
PY - 2011/6/21
Y1 - 2011/6/21
N2 - [1] We present results of detailed paleomagnetic investigations on deep-sea cores from sediment drifts located along the Pacific continental margin of the Antarctic Peninsula. High-resolution magnetic measurements on u channel samples provide detailed age models for three cores collected from drift 7, which document an age of 122 ka for the oldest sediments recovered near the drift crest at site SED-07 and a high sedimentation rate (11 cm/kyr) at site SED-12 located close to the Alexander Channel system. Low- and high-temperature magnetic measurements in conjunction with microscopic and mineralogic observations from drifts 4, 5 and 7 indicate that pseudosingle-domain detrital titanomagnetite (partially oxidized and with limited Ti substitution) is the dominant magnetic mineral in the drift sediments. The titanomagnetite occurs in two magnetic forms: (1) a low-coercivity form similar to laboratory-synthesized titanomagnetite and (2) a high-coercivity form (Bcr > 60 mT). These two forms vary in amount and stratigraphic distribution across the drifts. We did not find evidence for diagenetic magnetic iron sulfides as has been previously suggested for these drift deposits. The observed change of magnetic mineralogy in sediments deposited during Heinrich events on drift 7 appears to be related to warming periods, which temporarily modified the normal glacial transport pathways of glaciogenic detritus to and along the continental rise and thus resulted in deposition of sediments with a different provenance. Understanding this sediment provenance delivery signature at a wider spatial scale should provide information about ice sheet dynamics in West Antarctica over the last ∼100 kyr.
AB - [1] We present results of detailed paleomagnetic investigations on deep-sea cores from sediment drifts located along the Pacific continental margin of the Antarctic Peninsula. High-resolution magnetic measurements on u channel samples provide detailed age models for three cores collected from drift 7, which document an age of 122 ka for the oldest sediments recovered near the drift crest at site SED-07 and a high sedimentation rate (11 cm/kyr) at site SED-12 located close to the Alexander Channel system. Low- and high-temperature magnetic measurements in conjunction with microscopic and mineralogic observations from drifts 4, 5 and 7 indicate that pseudosingle-domain detrital titanomagnetite (partially oxidized and with limited Ti substitution) is the dominant magnetic mineral in the drift sediments. The titanomagnetite occurs in two magnetic forms: (1) a low-coercivity form similar to laboratory-synthesized titanomagnetite and (2) a high-coercivity form (Bcr > 60 mT). These two forms vary in amount and stratigraphic distribution across the drifts. We did not find evidence for diagenetic magnetic iron sulfides as has been previously suggested for these drift deposits. The observed change of magnetic mineralogy in sediments deposited during Heinrich events on drift 7 appears to be related to warming periods, which temporarily modified the normal glacial transport pathways of glaciogenic detritus to and along the continental rise and thus resulted in deposition of sediments with a different provenance. Understanding this sediment provenance delivery signature at a wider spatial scale should provide information about ice sheet dynamics in West Antarctica over the last ∼100 kyr.
KW - Antarctic Peninsula
KW - Pacific margin
KW - sediment drift
KW - late Pleistocene
KW - mineral magnetism
KW - relative palaeointensity
U2 - 10.1029/2010JB007952
DO - 10.1029/2010JB007952
M3 - Journal article
AN - SCOPUS:79959575094
VL - 116
JO - Journal of Geophysical Research: Solid Earth
JF - Journal of Geophysical Research: Solid Earth
IS - B6
M1 - B06104
ER -