نتایج جستجو برای: volcanics

تعداد نتایج: 398  

2001
B. E. HOBBS

One of the characteristic features of Ordovician tectonism in the east Lachlan Fold Belt is the occurrence of calcalkaline to shoshonitic basalts, which have been recognised as part of an intraoceanic arc environment (Glen et al. 1998), consistent with early tectonic interpretations (Oversby 1971; Scheibner 1973). Aside from typical traceelement abundances of intraoceanic arcs, critical evidenc...

2013
R. D. Powell T. R. Naish L. A. Krissek G. H. Browne L. Carter E. A. Cowan Gavin B. Dunbar R. M. McKay G. B. Dunbar T. I. Wilch

ANDRILL completed its first season in 2006-07 drilling AND-1B through the McMurdo Ice Shelf (MIS) to a depth of 1,285m below the sea floor, a record for Antarctic margin drilling, with 99% recovery. The alternating glacial-interglacial sediment packages interbedded with volcanics provide a uniquely detailed record of Antarctic glacial and climatic change through the Neogene. This paper summariz...

2007

Regional scale geological maps are still not available for many remote parts of the Earth. All geological maps contain two fundamental pieces of information: a) lithological data: a list of the various rock types present, and b) structural data: geometrical information that describes the spatial relationships of the various rock units. For the purposes of regional scale geological mapping the s...

Journal: :International Journal for Research in Applied Science and Engineering Technology 2021

2013
Zi-Fu Zhao Li-Qun Dai Yong-Fei Zheng

Findings of coesite and microdiamond in metamorphic rocks of supracrustal protolith led to the recognition of continental subduction to mantle depths. The crust-mantle interaction is expected to take place during subduction of the continental crust beneath the subcontinental lithospheric mantle wedge. This is recorded by postcollisional mafic igneous rocks in the Dabie-Sulu orogenic belt and it...

2008
R. Friedman

Key to this dis cov ery was the rec og ni tion of a group of Palaeozoic, sub ma rine vol ca nic rocks, named the Mount Attree volcanics, which had pre vi ously been mapped as part of the Lower Ju ras sic Telkwa For ma tion (Woodsworth et al., 1985). The Lower Telkwa vol ca nic rocks are not con sid ered pro spec tive for VHMS de pos its be cause they formed in a subaerial, compressional en vi r...

2003
Jean-Pierre Williams David A. Paige Craig E. Manning

[1] High-resolution images of the walls exposed in Valles Marineris reveal variations in appearance and degree of layering indicating various lithologies comprise the Tharsis plateau. The layered wall rock has been proposed to result from effusive flood basalt volcanism or interbedded sediments and volcanics. We present observations of unlayered rock that indicate layering extends to a greater ...

Journal: :Australian Journal of Earth Sciences 2021

Paleomagnetic studies in the Lachlan Orogen have indicated rotation of elements within it, but evidence for is limited and has significant statistical uncertainty. This study presents a detailed paleomagnetic investigation, assisted by X-ray analysis magnetic mineralogy middle Cambrian to lower Silurian sedimentary igneous rocks Victoria New South Wales. Four demagnetisation behaviours (types A...

2012
lUCy mINeR

The tectonic evolution of southern Alaska is defined by a long history of subduction, accretion, and coastwise transport of terranes along the North American margin (e.g. Plafker et al., 1994). Cowen (1982, 2003) and Haeussler et al. (2003) propose two competing hypotheses for the formation and transport history of the Mesozoic-Tertiary Chugach-Prince William terrane that extends for at least 2...

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