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…

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.
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