Publikationsdatum:
2017-04-04
Beschreibung:
We synthesize environmental magnetic results for sediments from the Victoria Land Basin (VLB), which span a total stratigraphic thickness of 2.6 km and a ~17 Myr age range. We assess how magnetic properties record paleoclimatic, tectonic, and provenance variations or mixtures of signals resulting from these processes. The magnetic properties are dominated by large-scale magnetite concentration variations. In the late Eocene and early Oligocene, magnetite
concentration variations coincide with detrital smectite concentration and crystallinity variations, which reflect paleoclimatic control on magnetic properties through influence on weathering regime; high magnetite and smectite concentrations indicate warmer and wetter climates and vice versa. During the early Oligocene, accelerated uplift of the Transantarctic Mountains gave rise to magnetic signatures that reflect progressive erosion of the Precambrian-Mesozoic metamorphic, intrusive, and sedimentary stratigraphic cover succession associated with unroofing of the adjacent Transantarctic Mountains. From the early Oligocene to the early Miocene, a
consistent fining upward of magnetite particles through the recovered composite record likely reflects increased physical weathering with glacial grinding contributing to progressively finer grained Ferrar Dolerite-sourced magnetite. After 24 Ma, the magnetic properties of VLB sediments are primarily controlled by the weathering
and erosion of McMurdo Volcanic Group rocks; increased volcanic glass contents
contribute to the fining upward of magnetite grain size. Overall, long-term
magnetic property variations record the first-order geological processes that
controlled sedimentation in the VLB, including paleoclimatic, tectonic, provenance, and volcanic influences.
Beschreibung:
Published
Beschreibung:
1845–1861
Beschreibung:
2.2. Laboratorio di paleomagnetismo
Beschreibung:
JCR Journal
Beschreibung:
restricted
Schlagwort(e):
environmental magnetism
;
Antarctica
;
paleoclimate
;
volcanism
;
Ross Sea
;
Cenozoic
;
03. Hydrosphere::03.01. General::03.01.06. Paleoceanography and paleoclimatology
;
04. Solid Earth::04.04. Geology::04.04.08. Sediments: dating, processes, transport
;
04. Solid Earth::04.04. Geology::04.04.10. Stratigraphy
;
04. Solid Earth::04.05. Geomagnetism::04.05.09. Environmental magnetism
Repository-Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Materialart:
article
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