andesitic


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andesitic

(ˌændɪˈzɪtɪk)
adj
relating to, or containing, andesite
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This was followed by a 103-meter interval with sections of finely disseminated chalcopyrite and pyrite stringers in andesitic volcanoclastic rocks consistently chlorite-sericite altered, featuring approximately 5-15% quartz veins.
In its application the firm said: "The stone quarried at Harden was formed approximately 390 million years ago, when magma from deep underground was forced up into the surrounding andesitic rocks, forming a thick blister-like intrusion of mica-porphyrite, which is now commonly called Harden red.
6 m hosted in lithic tuff and continued in andesitic tuff with ~1% pyrite to 38.
The rocks of Noorabad ophiolite consist of peridotites, serpentinites and pegmatite gabbros as mantle sequence, whereas crustal sequences are composed of locally layered gabbros, isotropic gabbros, sheeted dike complex, basaltic to andesitic lavas and sedimentary rock (radiolarites and late cretaceous pelagic limestones) (Fig.
All Hat property drill holes passed through Late Triassic age Stuhini formation andesitic flows and tuffs and coeval iron-rich gabbroic intrusive rocks and all rocks, with the exception of a few apparently much younger dykes, are variably altered with development of chlorite, magnetite and, less frequently, biotite.
The claims are underlain by three different geological horizons: the andesitic basalts of the Obatogamau Formation across the central portion, flanked to the north and south by more-felsic pyroclastic formations.
They started with a lighter andesitic lava that can form in the presence of water, and were then overlaid with heavier basaltic lava that makes up the visible surface of the Martian crust.
680 Ma Stirling Group consists primarily of andesitic to basaltic lapilli tuff with interbeds of tuffaceous arenite and laminated siltstone.
Host rocks are intruded by andesitic dykes, both pre- and post-mineralization.
All four diamond drillholes totalling 1,125m intersected wide intervals of strongly propyllitic- to phyllic-altered andesitic volcanic rocks with widespread disseminated and vein-style pyrite +/- lesser sphalerite-galena-chalcopyrite mineralisation.
Iron sand is product of a process of change in the form from andesitic and basaltic volcanic rocks, which are rich in iron.
In 1988 Galeras showed signs of unrest and erupted explosively in 1989; an andesitic lava dome was emplaced during September-November 1991, and explosive activity took place again during 1992-1993.