Browse Items (1651 total)

Antigorite, magnetite, ankeritic carbonate, diopside, tremolite. A very marked subsequent foliation nearly completely obliterates a previous initial foliation.

Grossular-andradite garnet, diopside, chlorite, sodic pyroxene, vesuvianite, titansphene, opaques. Traces of primitive gabbroid structure with diablastic development of the newlyformed phases and pseudomorphs of sodic pyroxene on primary pyroxenes.…

Relics of augitic clinopyroxene, albite, actinolite, chlorite, clinozoisite, and sphene. Relics of the clinopyroxene of the original dolerite are in part substituted by chlorite and actinolite in a granoblastic and metablastic matrix of albite,…

Carbonates (calcite and dolomite), chlorites, garnets, diopside, epidote, serpentine, amphiboles. Very variable compositions in same hand specimen. The rock derives from metamorphism of oficalcitic rocks developed at very high pressures and medium…

Sodic pyroxene, glaucophane, lawsonite, chlorite. Pseudomorphs of sodic pyroxene and glaucophane,chlorite on original augitic pyroxenes; pseudomorphs of lawsonite and glaucophane on original plagioclase.

Albite, Na-amphiboles (from Mg-riebeckite to glaucophane, epidote, aegirinic pyroxene, chlorite, ilmenite, tspesphene, apatite, lawsonite. Pseudomorphic relations of the metamorphic paragenesis on the substituted primary phases. Sometimes lawsonite…

OCR PDF of supplemental information for the Anorthosite-Charnockite Metamorphic Suite-Adirondack Mountains, New York collection.

OCR PDF of supplemental information for the Panoche Pass, California collection.

This specimen consists of 50-60% andesine, 20-30% quartz, and minor pyroxene and hornblende. Associated with this lithology are 2-6 inch layers of pyroxene-plagioclase granulite and amphibolite. It is believed that the Royal Mountain Member gneiss…

This lithology is characterized by 1-4 inch long megacrysts of microperthite in a groundmass of quartz, oligoclase, hornblende, orthopyroxene, garnet, and oxide. Although the contacts of this unit are everywhere conformable, the rock is believed to…

This specimen is typical of the saturated gabbros of the Adirondacks. The plagioclases are generally in the range of Anâ‚„â‚€ and the orthopyroxenes average close to En₆₀. Antiperthite is locally developed. Scattered grains of ilmenite and garnet…

This calcite marble is typical of most Adirondack metacarbonates. In the majority of instances, original dolomite has reacted to yield calcsilicates. Also present in these specimens are small, serpentinized droplets which may originally have been…

Pods and lenses of green diopsidite commonly occur along with the marbles. They are often composed of over 90% diopside.
Thin section contains diopside.

This specimen is similar to the famous garnet deposits at Barton Mines at Gore Mountain. The garnets at Gore Mountain can attain diameters of 3 feet. At the Speculator road cut, garnet of 8-10 inches in diameter have been found, but smaller examples…

The Sacandaga Formation consists of a well layered series of dark granulites (AD-12) and leucogneisses (AD-13). Orthopyroxene is generally present in greater quantity than clinopyroxene. It is not known whether these rocks are metasedimentary or…

This specimen displays an unusual and distinctive lithology that occurs primarily in lower, marble-rich units (for example, the Cedar River Formation).
Thin section shows quartz, K-feldspar and clinopyroxene.

This specimen is typical of the olivine metagabbros that occur throughout the Adirondacks. These rocks are of great petrologic interest for they contain classic examples of garnet coronas and spinel-clouded plagioclase. Note the preservation of…

This coarse-grained specimen is typical of the massive, homogeneous anorthosite that occurs within the Marcy Massif and underlies the High Peaks region of the Adirondacks. The anorthosite from Route 3 is best represented by analyses 5-L and 8, Table…

This specimen is typical of the 5-10 foot thick coarse grained layers of glassy quartzites that comprise this formation. In most instances the quartzites are about 90% quartz. Feldspar and garnet are encountered locally. This is presumed to be the…

This charnockite is similiar to most of the Adirondack charnockites that occur interlayered with other metastratified units. Like its analogues, the Canada Lake charnockite shows conformable realationships with enveloping units. Mineralogically,…