Browse Items (1651 total)

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Contains secondary products of alteration including serpentine, talc, chlorite, carbonates, and iron oxides

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Macroscopic: Mesocratic fibrolitic double micaceous pinstripped gneiss. High reflectivity denotes a high concentration of foliated micas. Migmatized texture indicates of the rock indicates incipient melting. Microscopic: This sample contains…

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Rock Sample:
The rock is dark green throughout, with a mineral forming white specks. The white mineral does not react with hydrochloric acid. The texture is very rough, and the rock's edges are sharp. Large flat phenocrysts (~ ≤10mm). The…

This is dolerite from the "Dragon's Back" dyke, from the farm Romance. It is the youngest dolerite body in the area and contains biotite and hornblende. Emplacement of this dolerite took place at a much deeper crustal level than the gabbros. It has…

Doleritic basalt with metamorphic overimprinting in prehnite-pumpellyite facies.
Primary minerals: plagioclase, titanaugite, ilmenite, olivine.
Metamorphic paragenesis: albite, pumpellyite, prehnite, sphene, chlorite.

Hand Sample: Holocrystalline, phaneritic, porphyritic, diorite with quratz crystals up to 3mm in diameter set in a field of smaller light gray, and dark gray crystals. Some small oxidized pyrite crystals. Very weathered on two sides to orange yellow…

Hand Sample: Porphyritic (or coarse-grained phaneritic) diorite with coarse-grained white plagioclase laths up to 1cm and some black mineral. Weathering to rust-orange color.

Much of the plagioclase has been altered to epidote and sericite, hornblende occurs as long prismatic crystals arranged in sprays

Mostly plagioclase and biotite