They are pecked or abraded on heavily jointed and fractured gabbro and granophyre
igneous rock surfaces that have weathered into massive linear piles.
Dickin and Exley (1981) reported an age of 59 3[+ or -]0 07 Ma for the youngest Cuillin centre intrusion, the Coire Uaigneich Granophyre
generally is present in syenogranite samples.
Haggan continues, "The highest gold values in these drill holes are associated with quartz veining and strong hydrothermal alteration of the intrusive granophyre
Chemical composition of ten samples (one granophyre
, three gabbros, one mafic dyke, three felsic dykes and two rhyolites) of the Sierra de San Miguel Complex was analyzed.
The primary unit is an Archean aged volcano-sedimentary (greenstone) sequence, which is intruded and partially assimilated by granophyre
bodies, which are of tonalitic to granodioritic composition; a later suite of mafic and ultramafic intrusives complete the package.
The sample consists of light grey, sparsely porphyritic, aphanitic rhyolite with potassium feldspar, and lesser amounts of quartz and granophyre
Most of the area within the 1830 head dyke is on acid granophyre
- a stone which appears buff to white depending on the weather conditions.
The Lady of the Lake Complex comprises a layered suite of rocks ranging in composition from mafic, pegmatoidal norite and gabbros to granophyre
, and bears geologic similarities to both the Stillwater and Bushveld complexes.
and hybrid pipes in dolerite layer of Slieve Gullion.
For instance, the grey, greenish or bluish gabbro and granophyre
of the arid Pilbara region in Australia bears a whitish weathering zone which in turn is concealed under a ferromanganeous skin (of rock varnish or a similar deposit; Bednarik 1977; 1979).