- Abstract
- Affiliation
- All
- Authors
- Book Series
- DOI
- EISBN
- EISSN
- Full Text
- GeoRef ID
- ISBN
- ISSN
- Issue
- Keyword (GeoRef Descriptor)
- Meeting Information
- Report #
- Title
- Volume
- Abstract
- Affiliation
- All
- Authors
- Book Series
- DOI
- EISBN
- EISSN
- Full Text
- GeoRef ID
- ISBN
- ISSN
- Issue
- Keyword (GeoRef Descriptor)
- Meeting Information
- Report #
- Title
- Volume
- Abstract
- Affiliation
- All
- Authors
- Book Series
- DOI
- EISBN
- EISSN
- Full Text
- GeoRef ID
- ISBN
- ISSN
- Issue
- Keyword (GeoRef Descriptor)
- Meeting Information
- Report #
- Title
- Volume
- Abstract
- Affiliation
- All
- Authors
- Book Series
- DOI
- EISBN
- EISSN
- Full Text
- GeoRef ID
- ISBN
- ISSN
- Issue
- Keyword (GeoRef Descriptor)
- Meeting Information
- Report #
- Title
- Volume
- Abstract
- Affiliation
- All
- Authors
- Book Series
- DOI
- EISBN
- EISSN
- Full Text
- GeoRef ID
- ISBN
- ISSN
- Issue
- Keyword (GeoRef Descriptor)
- Meeting Information
- Report #
- Title
- Volume
- Abstract
- Affiliation
- All
- Authors
- Book Series
- DOI
- EISBN
- EISSN
- Full Text
- GeoRef ID
- ISBN
- ISSN
- Issue
- Keyword (GeoRef Descriptor)
- Meeting Information
- Report #
- Title
- Volume
NARROW
GeoRef Subject
-
all geography including DSDP/ODP Sites and Legs
-
Africa
-
Southern Africa
-
Karoo Basin (1)
-
South Africa (1)
-
-
-
Antarctica
-
Antarctic ice sheet
-
West Antarctic ice sheet (1)
-
-
Ellsworth Land (1)
-
Marie Byrd Land (2)
-
West Antarctica (1)
-
-
Atlantic Ocean
-
South Atlantic (1)
-
-
South America
-
Argentina (1)
-
Patagonia (1)
-
-
-
elements, isotopes
-
isotope ratios (1)
-
isotopes
-
stable isotopes
-
Sr-87/Sr-86 (1)
-
-
-
metals
-
alkaline earth metals
-
strontium
-
Sr-87/Sr-86 (1)
-
-
-
-
-
geochronology methods
-
Ar/Ar (1)
-
K/Ar (1)
-
-
geologic age
-
Cenozoic
-
Quaternary
-
Holocene (1)
-
-
-
Mesozoic
-
Jurassic
-
Ferrar Group (1)
-
Middle Jurassic (1)
-
-
-
-
igneous rocks
-
igneous rocks
-
volcanic rocks
-
basalts (1)
-
phonolites (2)
-
pyroclastics (1)
-
rhyolites
-
pantellerite (1)
-
-
trachytes (2)
-
-
-
-
Primary terms
-
absolute age (1)
-
Africa
-
Southern Africa
-
Karoo Basin (1)
-
South Africa (1)
-
-
-
Antarctica
-
Antarctic ice sheet
-
West Antarctic ice sheet (1)
-
-
Ellsworth Land (1)
-
Marie Byrd Land (2)
-
West Antarctica (1)
-
-
Atlantic Ocean
-
South Atlantic (1)
-
-
Cenozoic
-
Quaternary
-
Holocene (1)
-
-
-
igneous rocks
-
volcanic rocks
-
basalts (1)
-
phonolites (2)
-
pyroclastics (1)
-
rhyolites
-
pantellerite (1)
-
-
trachytes (2)
-
-
-
isotopes
-
stable isotopes
-
Sr-87/Sr-86 (1)
-
-
-
magmas (1)
-
mantle (2)
-
Mesozoic
-
Jurassic
-
Ferrar Group (1)
-
Middle Jurassic (1)
-
-
-
metals
-
alkaline earth metals
-
strontium
-
Sr-87/Sr-86 (1)
-
-
-
-
plate tectonics (1)
-
South America
-
Argentina (1)
-
Patagonia (1)
-
-
Abstract In Marie Byrd Land and Ellsworth Land 19 large polygenetic volcanoes and numerous smaller centres are exposed above the West Antarctic Ice Sheet along the northern flank of the West Antarctic Rift System. The Cenozoic (36.7 Ma to active) volcanism of the Marie Byrd Land Volcanic Group (MBLVG) encompasses the full spectrum of alkaline series compositions ranging from basalt to intermediate (e.g. mugearite, benmoreite) to phonolite, peralkaline trachyte, rhyolite and rare pantellerite. Differentiation from basalt is described by progressive fractional crystallization; however, to produce silica-oversaturated compositions two mechanisms are proposed: (1) polybaric fractionation with early-stage removal of amphibole at high pressures; and (2) assimilation–fractional crystallization to explain elevated 87 Sr/ 86 Sr i ratios. Most basalts are silica-undersaturated and enriched in incompatible trace elements (e.g. La/Yb N >10), indicating small degrees of partial melting of a garnet-bearing mantle. Mildly silica-undersaturated and rare silica-saturated basalts, including tholeiites, are less enriched (La/Yb N <10), a result of higher degrees of melting. Trace elements and isotopes (Sr, Nd, Pb) reveal a regional gradient explained by mixing between two mantle components, subduction-modified lithosphere and HIMU-like plume ( 206 Pb/ 204 Pb >20) materials. Geophysical studies indicate a deep thermal anomaly beneath central Marie Byrd Land, suggesting a plume influence on volcanism and tectonism.
Chapter 7.4 Active volcanoes in Marie Byrd Land
Abstract Two volcanoes in Marie Byrd Land, Mount Berlin and Mount Takahe, can be considered active, and a third, Mount Waesche, may be as well; although the chronology of activity is less well constrained. The records of explosive activity of these three volcanoes is well represented through deposits on the volcano flanks and tephra layers found in blue ice areas, as well as by the presence of cryptotephra layers found in West and East Antarctic ice cores. Records of effusive volcanism are found on the volcano flanks but some deposits may be obscured by pervasive glacerization of the edifices. Based on a compilation of tephra depths–ages in ice cores, the activity patterns of Mount Takahe and Mount Berlin are dramatically different. Mount Takahe has erupted infrequently over the past 100 kyr. Mount Berlin, by contrast, has erupted episodically during this time interval, with the number of eruptions being dramatically higher in the time interval between c. 32 and 18 ka. Integration of the Mount Berlin tephra record from ice cores and blue ice areas over a 500 kyr time span reveals a pattern of geochemical evolution related to small batches of partial melt being progressively removed from a single source underlying Mount Berlin.
Abstract Degassing at Mount Erebus occurs as a plume from a persistent convecting anorthoclase phonolite lava lake, and by flank degassing through warm ground and fumarolic ice towers within the summit caldera. The fumarolic ice towers offer a unique and simple approach to quantifying the flank CO 2 emissions. Carbon dioxide effluxes were determined at openings in the ice towers by measuring the CO 2 concentration, air-flow velocity, and size of the exit orifice. Fluxes ranged from <0.0001 to 0.034 kg s −1 at 43 actively degassing ice towers. Small patches of steaming warm ground contributed 0.010 kg s −1 . The δ 13 C isotopic compositions of the CO 2 samples ranged from -2.1 to -4.7%o, suggesting a magmatic origin for the CO 2 . Fumarolic ice towers allow diffuse degassing to be visually identified, providing a strong advantage in determining the total flux rate of these passive emissions. The estimated output of flank CO 2 degassing is 0.46 kg s −1 (40 Mg d _1 ). Compared with direct airborne measurements of the volcanic plume, passive flank emissions constitute less than 2% of the total volcanic CO 2 budget emitted from Mount Erebus.