Browse Items (15 total)

  • Spatial Coverage is exactly "Powderhorn, CO"

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-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-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…

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

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

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

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.
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