Granophyre refers to fine-grained granitic material, commonly though not always with graphic intergrowths. In the Skaergaard, granophyre occurs in three forms: transgressive granophyre dikes, granophyre patches in gabbroic pegmatite, and as interstitial granophyre in the gabbros, common in UZb and UZc.
Transgressive granophyre dikes. These dikes transgress (cut across) other units, as one might expect for dikes. As I understand it, these granophyre dikes have strongly evolved Sr isotopic compositions that indicate that they are partial melts from the adjacent Archean gneisses, and do not represent late differentiates from the Skaergaard.
Two "transgressive granophyre" dikes. These dikes are transgressive (cut the other rocks), and made of a fine-grained granitic rock (granophyre) of mostly quartz, alkali feldspar, brown hornblende, and biotite. Isotope systematics strongly suggest that this material, as distinct from granophyre associated with some of the mafic pegmatites, is a partial melt from the Archean gneisses surrounding the Skaergaard pluton. Thin section here.
Photograph of basalt inclusions in a larger dike of transgressive granophyre. The Granophyre crosscuts a basalt dike here. The basalt dikes are characteristically highly fractured and so supply numerous xenoliths to the granophyre.
Granophyre in gabbroic pegmatite. This type of macroscopic granophyre was seen by me only in UZc, one of the most differentiated parts of the Skaergaard, where they represent a significant fraction of the pegmatite volume (1 to 10%). They may represent segregated granitic liquid, perhaps even immiscible liquid.
A mafic pegmatite in UZc: white plagioclase, black oxides, and rusty olivine and pyroxene (or former pyroxenoids) with a fine-grained, gray granophyre filling much of the interior.
The same pegmatite as in the photo above in a less granophyre-rich part. This shows the contact with the host gabbro at the bottom. Note the irregularity of the contact.
Interstitial granophyre in the gabbros. This stuff is generally found as microscopic patches of fine-grained granitic material interstitial to larger plagioclase and other cumulate minerals. It probably represents in situ granitic liquid residua.
Photograph of the sandwich horizon candidate rock 1. It is composed of plagioclase, olivine, oddly patchy pyroxene, and granophyre patches. Thin section here.