Named for Golden Gate Canyon drainage. Type area extends from mouth of Golden Gate Canyon to about 4,500 ft north along mountain front to NE1/4 sec 20, T3S, R70W, Golden quad, Jefferson Co, CO in Southern Rocky Mountain region. Called interlayered amphibolite and biotite-plagioclase-quartz gneiss in earlier reports. Consists primarily of thin-banded, non-ptygmatically folded amphibolitic gneiss containing occasional thin lenses of fine-grained quartzite lenses in lower and middle part. Basal 200 to 300 ft is locally tactitic. Concordant and discordant pegmatites occur throughout. Approximately 4,500 ft thick along mountain front, but thins to west and northwest. Contact with underlying Junction Formation (new) is an unconformity. Contact with overlying Cedar Gulch Formation (new) is gradational. Geologic map. Cross section. Precambrian age.

Source: GNU records (USGS DDS-6; Denver GNULEX).

Is one of several units defined in a narrow belt along east-central Front Range, near Golden, Jefferson Co, CO in the Southern Rocky Mountain region. Of doubtful use elsewhere. Assumed direction of stratigraphic sequence is debatable. Belongs with pre-1,700 m.y. metamorphic complex, or of Precambrian X age.

Source: GNU records (USGS DDS-6; Denver GNULEX).