Environmental magnetic record of Antarctic palaeoclimate from Eocene/Oligocene glaciomarine sediments, Victoria Land Basin

1998 ◽  
Vol 134 (3) ◽  
pp. 653-662 ◽  
Author(s):  
Leonardo Sagnotti ◽  
Fabio Florindo ◽  
Kenneth L. Verosub ◽  
Gary S. Wilson ◽  
Andrew P. Roberts
Keyword(s):  
Victoria Land ◽  
Magnetic Record ◽  
Victoria Land Basin ◽  
Glaciomarine Sediments

Clay mineral assemblages as indicators of hydrothermalism in the basal part of the CRP-3 core (Victoria Land Basin, Antarctica)

Clay Minerals ◽  
2009 ◽  
Vol 44 (3) ◽  
pp. 389-404 ◽  
Author(s):  
M. Setti ◽  
L. Marinoni ◽  
A. Lopez-Galindo
Keyword(s):  
Electron Microscopy ◽  
Clay Minerals ◽  
Clay Mineral ◽  
Particle Morphology ◽  
Victoria Land ◽  
Mineral Assemblages ◽  
Variable Chemical ◽  
Victoria Land Basin ◽  
Glaciogenic Sediments ◽  
Glaciomarine Sediments

AbstractThe CRP-3 drilling project collected sediments from 3 to 939 mbsf (metres below sea floor) in the Victoria Land Basin in Antarctica. The upper sequence (down to ~790 m bsf) is of Cenozoic age and made up of detrital glaciogenic sediments; the characteristics of clay minerals in this part have been reported elsewhere. Here, the compositional features of clay minerals in the lower sequence such as conglomerates, Devonian sandstones and dolerites are described and genetic processes clarified. Clay minerals in the deepest part of the sequence derive from the alteration of different lithologies that mostly make up the sedimentary basin.Two clay mineral assemblages were characterized through analysis by X-ray diffraction (XRD), transmission electron microscopy (TEM) and scanning electron microscopy (SEM). From 790 to 823 mbsf, samples consist of authigenic smectite of variable chemical composition forming imbricated texture of plates or flakes. The smectites probably result from hydrothermal/diagenetic transformation of earlier minerals. The primary smectite cement underwent reorganization during shearing and cataclasis. The lowest part of the sequence (below 823 mbsf) is characterized by an assemblage of kaolinite, mixed-layer illite-smectite, Fe oxyhydroxide, sporadic smectite and poorly crystallized illite. It reflects a stronger alteration process than that recorded in the upper units of core CRP-3, related to hydrothermalism connected with the intrusion of an igneous body. Both assemblages show clear differences in particle morphology, texture and smectite composition to the clay assemblages found in the Cenozoic glaciomarine sediments in the upper sequence. The different phases of alteration appear related to the processes of rifting, exhumation and faulting that characterized this region since the Mesozoic.

Mid-Cenozoic record of glaciation and sea-level change on the margin of the Victoria Land basin, Antarctica

Geology ◽  
1987 ◽  
Vol 15 (7) ◽  
pp. 634 ◽  
Author(s):  
P. J. Barrett ◽  
D. P. Elston ◽  
D. M. Harwood ◽  
B. C. McKelvey ◽  
P.-N. Webb
Keyword(s):  
Sea Level ◽  
Sea Level Change ◽  
Level Change ◽  
Victoria Land ◽  
Victoria Land Basin ◽  
And Sea Level

Modelled composition of cryogenically produced subglacial brines, Antarctica

2019 ◽  
Vol 31 (3) ◽  
pp. 165-166 ◽  
Author(s):  
Christopher B. Gardner ◽  
W. Berry Lyons
Keyword(s):  
Dry Valleys ◽  
Important Process ◽  
Antarctic Ice Sheet ◽  
Lake Vostok ◽  
Hydrologic Systems ◽  
Victoria Land ◽  
Flow Through ◽  
Victoria Land Basin ◽  
Subglacial Meltwater ◽  
Permafrost Regions

Polar subglacial hydrologic systems have garnered much interest since the recognition of Lake Vostok in 1996. In Antarctica, these environments are hydrologically diverse, including isolated lakes of different sizes, river–lake flow-through systems, “swamps” and groundwater (Siegert 2016). The refreezing of subglacial meltwater is also an important process beneath a large portion of the East Antarctic Ice Sheet (Bell et al. 2011). As subglacial water refreezes it exsolves salts, potentially leaving behind saline and hypersaline brines. Brines thought to derive from this cryoconcentration process have been observed in the northern polar permafrost regions and in the McMurdo Dry Valleys (MDVs) region of Antarctica. Additionally, sediments in the Victoria Land Basin have diagenetic signatures produced by brine movement dating from 3–11 m.y.a, suggesting hypersaline brines have existed in the McMurdo region since at least this time (Staudigel et al. 2018).

Mineralogical and geochemical characteristics (major, minor, trace elements and REE) of detrital and authigenic clay minerals in a Cenozoic sequence from Ross Sea, Antarctica

Clay Minerals ◽  
2004 ◽  
Vol 39 (4) ◽  
pp. 405-421 ◽  
Author(s):  
M. Setti ◽  
L. Marinoni ◽  
A. López-Galindo
Keyword(s):  
Trace Elements ◽  
Clay Minerals ◽  
Ross Sea ◽  
Clay Fraction ◽  
Geochemical Characteristics ◽  
Victoria Land ◽  
Victoria Land Basin ◽  
Degree Of Crystallization ◽  
Mixed Layers

AbstractThe mineralogy and geochemistry of the clay fraction of Victoria Land Basin (Ross Sea, Antarctica) sediments was investigated, to determine the origin of clay minerals and the features of authigenic smectite. The investigated core (CRP-3) is ~800 m long, mostly of Oligocene age. The clay fraction of the upper sequence consists of mica, chlorite and detrital smectite, while that of the central and lower part is largely made up of authigenic smectite. Authigenic smectites are ditrioctahedral, with a composition close to saponite, while detrital smectites such as Al-Fe beidellites are dioctahedral. Authigenic smectites have no illite mixed layers, show a higher degree of crystallization, higher MgO, Fe2O3, V, Cr, Co, Ni and Sc contents and lower SiO2, Al2O3, K2O, TiO2, Ba, Rb and Zr contents with respect to detrital clay minerals, and a clear depletion of LREE with respect to HREE. Authigenic smectite formed from the alteration of volcanic materials and clay minerals.

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