These rocks have high to very high vein densities and are intensely altered exhibiting propyllitic, sericitic, and potassic assemblages nearing the mineralizing plutonic rocks
The Mira terrane is composed of mainly volcanic and plutonic rocks
that form linear northeast-southwest trending belts separated by regional-scale faults and younger sedimentary cover sequences (Fig.
1), which comprises three amphibolite-facies high-strain zones separated by sheets of syn-kinematic plutonic rocks
(Lissenberg and van Staal 2002).
The main plutonic rock
types are granite and gabbro/diorite.
Although gravity measurements are sparse in this area, gravity values are higher in the northern part of the study area, and tail off in the southeastern highlands, compatible with an interpretation of a thrust fault transporting a thin veneer of basement rocks over younger sedimentary rocks with no root of plutonic rocks
in Baddeck River-St.
Stendal (2006): U-Pb dating of plutonic rocks
involved in the nappe tectonics in southern Cameroon; Consequence for the Pan-African orogenic evolution of the central African fold belt Journal of African Earth Sciences, 44, 479-493
It is excavated over both plutonic rocks
(granite) and metamorphic rocks (gneiss, schist, calcic silicate rock) with a more recent geological structure rising in Tertiary Alpine Orogeny.
Lake Mead snakes through the mountains between Las Vegas and the Grand Canyon, straddling the state line between Arizona and Nevada, and the surrounding territory is a geological candy shop of Tertiary basin-fill sedimentary rocks and volcanic and plutonic rocks
, boundaries, structural relief, strike-slip faults, lateral tectonic transport, and other features.
As the Saaremaa zone crosscuts the post-orogenic plutonic rocks
, it can be considered as formed during postorogenic and anorogenic faulting phases.
2], is often blue but may be white or pink, occurs in both volcanic and plutonic rocks
of the nepheline syenite family.
The anisotrophy and heterogeneity of coarse-grained plutonic rocks
tend to create large variations in the degree of weathering, even on the same rock outcrop or stone.
With new technology, they (today's prospectors) can identify granitic, plutonic rocks
and determine all the plutonic rocks
of particular age that seem to have mineralization around them," Madonna says.
These observations, recent seismic refraction studies at the East Pacific Rise (see "Tomographic Imaging of Spreading Centers," Oceanus Winter 1991/92), and petrological studies of volcanic and plutonic rocks
from mid-ocean ridges have led to a new concept of what ridge-crest magma chambers look like.
It contains terrigenous sedimentary rocks, mafic to ultramafic volcanic rocks and plutonic rocks
metamorphosed from the greenschist facies to the lower amphibolite facies.
The degree of migmatization increases toward the centre of the gneiss, away from the exposed contacts with the surrounding plutonic rocks