Browse Items (21 total)

  • Collection: (PH) Powderhorn (Iron Hill) Carbonatite Suite -- Gunnison County, SW Colorado

PH-20 Hand Sample - Horizontal.
Iron rich Carbonatite.

PH-19 Hand Sample.
Hand Sample:

All weathered faces of the rock show heavy traces of oxidation.

PH-18 Hand Sample - Horizontal.
Dark gabbro dike separating ijolite and uncompahgrite

PH-17 Hand Sample - Horizontal.
Hand Sample:

Rock is comprised almost entirely K-Feldspar.

PH-16 Hand Sample - Horizontal.
Hand Sample:

The rock is largely comprised of a very fine grained light green matrix with large (1 x 3 cm) black equant galena crystals. It's pretty magnificent.

PH-15 Hand Sample - Front View.
Hand Sample:

Three hand samples from different facies were collected to represent this sample. Out of two of the largest samples one is a dark fine grained rock while the other is coarse grained. Both contain large (5-8 mm) clusters of biotite.

PH-14 Hand Sample.
Hand Sample:

Large (1 cm-2 cm) dark grey to translucent quartz crystals comprise the matrix of the rock. Melilite minerals propagate consistently paralell to one another throughout the rock.

PH-13 Hand Sample.
Hand Sample:

Coarse grained pyroxenite showing heavy traces of oxidation on every weathered face of the rock. Large clusters (5-8 mm) of biotite appear throughout the rock.

PH-12 Hand Sample.
Chert sample found in a Carbonatite.

Hand Sample:

Pink to light brown chert sample that contains small (< 1 mm diameter) vesicles. Very thin quartz veins propagate through the sample in no preferred orientation.

PH-11 Hand Sample.
Light brown to almost off-white fine grained Carbonatite. Delicated Barite appears in very thin layers on one side of the rock.

PH-10 Hand Sample.
Fenitized porphyroblastic Gneiss.

Hand Sample:

Entirely coarse-grained rock except for 2 cm wide dark fine grained band. Obvious traces of oxidation appear on all sides, dominating the most weathered sides of the rock.

PH-9 Hand Sample.
Coarse gabbro, extracted from the southern dike of two east-west dikes N of Deldardo Creek.

Hand Sample:

Evenly distributed dark, light, and white colored coarse-grained (1 mm) crystals. Obvious traces of oxidation from some metallic mineral…

PH-8 Hand Sample.
Hand Sample:

Rock is comprised predominately of a dark fine grained matrix. Some specimens have minor amounts of pink K-feldspar. Clusters of biotite (~1 cm in diameter) appear on one face of the rock.

PH-7 Hand Sample.
Hand Sample:

Composed entirely of Ilmenite.

PH-6 Hand Sample.
Recently exhumed ijolite from shallow bulldozer cut.

Hand Sample: Shows traces of iron oxidation in isolated areas. Small (> 0.5 mm in diameter) nodules, with the appearance of small sand grains appear in clusters on one face of the rock (not…

PH-5 Hand Sample.
White Carbonatite. Found on Southwest side of the main rock unit body on North side of Beaver Creek about 1/4 mi.

PH-4.
Nepheline Syenite. Thin, dark vein runs through the center body of the rock.

PH-3.
Nepheline syenite that outcrops on west side of trail at about 9200 ft. on east side line of section.

PH-2.
Fenitized Gneiss. Gneiss discovered in direct contact with pyroxenite in prospect trench on ridge, about 500 ft. west of PH-1.. .

Pyroxenite
Coarse pyroxenite, with traces of nepheline. This is the freshest pyroxenite that was found. It occurs near the nepheline syenite body in the eastern part of the complex.