What is the slightly more mafic variety of granite?

Granodiorite is considered the slightly more mafic variety of granite because it contains a higher proportion of dark-colored minerals, such as biotite and hornblende, while still being primarily composed of quartz and feldspar. Granite, in contrast, is typically lighter in color and features a higher content of light minerals, mainly white or pink feldspar and quartz, which gives it a more felsic composition.

Granodiorite typically has a composition that is intermediate between granite and diorite, which allows it to have those slightly darker and more mafic characteristics. This makes it a distinct rock type in the granite family, showcasing a transition in mineral content that reflects the differences in magma formation and cooling processes.

In terms of the other options, basalt is a volcanic rock with much higher mafic content than granodiorite, while gabbro is also a mafic intrusive rock that has a significantly different composition compared to granite and granodiorite.