scholarly journals Comprehensive paleomagnetic study of a succession of Holocene olivine-basalt flow: Xitle Volcano (Mexico) revisited

2005 ◽  
Vol 57 (9) ◽  
pp. 839-853 ◽  
Author(s):  
Luis M. Alva-Valdivia
Keyword(s):  
Olivine Basalt ◽  
Basalt Flow ◽  
Paleomagnetic Study

Mantle xenoliths from Tertiary lavas and dykes on Ubekendt Ejland, West Greenland

1998 ◽  
pp. 152-154
Author(s):  
Stefan Bernstein ◽  
C. Kent Brooks
Keyword(s):  
Field Work ◽  
Mantle Xenoliths ◽  
Alkaline Basalt ◽  
Basalt Flow ◽  
Volcanic Province ◽  
East Greenland ◽  
Original Series ◽  
West Greenland ◽  
Ultramafic Xenoliths ◽  
Extensive Collection

NOTE: This article was published in a former series of GEUS Bulletin. Please use the original series name when citing this article, for example: Bernstein, S., & Brooks, C. K. (1998). Mantle xenoliths from Tertiary lavas and dykes on Ubekendt Ejland, West Greenland. Geology of Greenland Survey Bulletin, 180, 152-154. https://doi.org/10.34194/ggub.v180.5099 _______________ Mantle xenoliths were found in Tertiary alkaline (basanitic) lavas on Ubekendt Ejland in West Greenland in the mid 1970s by J.G. Larsen. Microprobe analyses of olivine, pyroxene and spinel in two mantle xenoliths, suggested that the xenoliths on Ubekendt Ejland are highly depleted and have high modal olivine contents, and low modal orthopyroxene and clinopyroxene (Larsen 1982). In this respect the mantle xenoliths from Ubekendt Ejland are very similar to the spinel harzburgites from Wiedemann Fjord, in the Tertiary volcanic province of East Greenland (Brooks & Rucklidge 1973; Bernstein et al. 1998). Larsen (1981) also reported dykes containing mantle nodules and a varied suite of cumulates and megacrysts, one of which has subsequently been dated to 34.1 ± 0.2 Ma (Storey et al. 1998) The basalt flow that carries the xenoliths is from what is defined as the Erqua Formation which occurs at the top of the lava succession in western Ubekendt Ejland (Fig. 1; Drever & Game 1948; Larsen 1977a, b). The basalts have not been dated, but are younger than 52.5 Ma, which is the date obtained for the underlying formation (Storey et al. 1998). During July 1997, we spent three weeks collecting xenoliths and prospecting for xenolith-bearing dykes in the Uummannaq district of central West Greenland. The field work resulted in an extensive collection of xenoliths from an alkaline basalt flow described by Larsen (1977a, b), as well as the discovery of a dyke carrying a large number of ultramafic xenoliths of various origins. 

ROCK MAGNETIC AND PALEOMAGNETIC STUDY OF SEDIMENTS FROM IODP SITE U1389 (WEST IBERIAN MARGIN)

2016 ◽  
Author(s):  
Oludamilola Adesiyun ◽  
◽  
Carl Richter ◽  
Gary Acton ◽  
Natalia Sidorovskaia ◽  
...  
Keyword(s):  
Paleomagnetic Study ◽  
Iberian Margin

The chemical composition of leucoxene in Cainozoic bauxite from Boolarra, Victoria

1942 ◽  
Vol 26 (179) ◽  
pp. 273-274 ◽  
Author(s):  
A. B. Edwards
Keyword(s):  
Chemical Composition ◽  
Chemical Analysis ◽  
Olivine Basalt ◽  
Pure Sample ◽  
Residual Structure ◽  
Aluminium Titanate

During a petrological examination of samples of bauxite from Boolarra, in south Gippsland, Victoria, it was noted that some specimens of the bauxite, which is largely derived from Tertiary olivine-basalt, contained numerous grains of yellow-brown to amber-yellow leucoxene. The leucoxene is clearly pseudo-morphous after ilmenite, residual particles of ilmenite being enclosed in many of the leucoxene grains. Most of the leucoxene grains are opaque, but occasional grains are translucent to transparent, though isotropic. Some of them show parallel markings suggestive of cleavage, but probably a residual structure from the replaced ilmenite. In view of the highly aluminous nature of the enclosing rock, there seemed some possibility that this mineral might be the little-known aluminium titanate, xanthitane. It was thought, therefore, that if a pure sample of the mineral could be prepared, a chemical analysis would establish its identity.

Emplacement of the 1907 Mauna Loa basalt flow as derived from precision topography and satellite imaging

2008 ◽  
Vol 177 (4) ◽  
pp. 837-847 ◽  
Author(s):  
James R. Zimbelman ◽  
W. Brent Garry ◽  
Andrew K. Johnston ◽  
Steven H. Williams
Keyword(s):  
Basalt Flow ◽  
Satellite Imaging ◽  
Mauna Loa

Motukoreaite, a new hydrated carbonate, sulphate, and hydroxide of Mg and Al from Auckland, New Zealand

1977 ◽  
Vol 41 (319) ◽  
pp. 389-390
Author(s):  
K. A. Rodgers ◽  
J. E. Chisholm ◽  
R. J. Davis ◽  
C. S. Nelson
Keyword(s):  
New Zealand ◽  
Olivine Basalt ◽  
Unit Cell ◽  
Rock Fragments ◽  
Alkali Olivine Basalt ◽  
Beach Rock ◽  
Wet Chemical ◽  
O 19 ◽  
Olivine Sand ◽  
Sand And Gravel

Motukoreaite occurs as relatively abundant, white, clay-like cement in both beach-rock and basaltic volcanic tuffs on the flanks of a small, extinct, late Pleistocene, basaltic cone at Brown's Island (Motukorea), within Waitemata Harbour, Auckland, New Zealand (36° 50′ S., 174° 35′ E.). The occurrence was originally recorded by Bartrum (1941) as ‘beach limestone’ found at two places of the island's shore. The beach-rock consists of a grain-supported fabric of poorly sorted, well-rounded, alkali-olivine basalt pebbles and granules, subangular to sub-rounded fresh olivine sand and abraded sand- and gravel-sized bioclasts in a colourless to pale yellow-green aphanocrystalline matrix of motukoreaite. Additional detritals include quartz, feldspar, and sedimentary rock fragments. Stereoscan examination of the surface of pieces of the cement prised from the beach-rock showed a box-work of plate-like crystals with a hexagonal form in which individuals measured about 3×3×0·02 microns (fig. 1).Wet-chemical analysis of a separate of the cement containing some 5 % quartz and traces of calcite and goethite gives SiO2 5·55, Al2O3 17·87, Fe2O3 0·73, CaO 0·92, MgO 22·98, MnO 0·70, ZnO 0·56, Na2O 0·71, K2O 0·10, CO2 9·32, SO3 10·00, H2O+ 19·62, H2O- 10·35, sum 99·41 %. The unit-cell formula using obtained unit-cell constants and measured specific gravity 1·43) is (Na0·73K0·07)∑0·80(Mg18·13Mn0·32Zn0·21)∑18·66Al11·15(CO3)6·22(SO4)3·97 (OH)51·1927·20H2O. Of several idealized formulae that may be proposed NaMg19Al12(CO3)6.5 (SO4)4(OH)54·28H2O is preferred.

Paleomagnetic study of satyavedu sandstones of cretaceous age from Andhra Pradesh, India

1970 ◽  
Vol 81 (1) ◽  
pp. 177-191 ◽  
Author(s):  
G. S. Mital ◽  
R. K. Verma ◽  
G. Pullaiah
Keyword(s):  
Andhra Pradesh ◽  
Paleomagnetic Study
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