HAWAI‘I ROCKS (and minerals)

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HAWAI‘I ROCKS (and minerals)

description

HAWAI‘I ROCKS (and minerals). olivine. Oceanite (from Mauna Loa) – a basalt with >40% mafic phenocrysts, and all the phenocrysts are olivine. Ankaramite (from Hual ālai) – a basalt with >40% mafic phenocrysts, and those phenocrysts consist of olivine and pyroxene. pyroxene. olivine. - PowerPoint PPT Presentation

Transcript of HAWAI‘I ROCKS (and minerals)

Page 1: HAWAI‘I ROCKS (and minerals)

HAWAI‘I ROCKS

(and minerals)

Page 2: HAWAI‘I ROCKS (and minerals)

Oceanite (from Mauna Loa) – a basalt with >40% mafic phenocrysts, and all thephenocrysts are olivine.

olivine

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Ankaramite (from Hualālai) – a basalt with >40% mafic phenocrysts, and those phenocrysts consist of olivine and pyroxene

olivine

pyroxene

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Pyroxene crystals, weathered out of ankaramite lavas, East Maui SW rift zone

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Outer, weathered surface of ankaramite from Rarotonga, Cook Islands

pyroxene

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Freshly broken surface of ankaramite from Rarotonga, Cook Islands

pyroxene

olivine

amygdule(former vesicle, nowfilled with some sortof secondary mineral)

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Vesicular basalt (from Kohala) with lots of little clusters of plagioclase feldspar phenocrysts (and a few olivine phenocrysts).

plagioclase feldspar

olivine

vesicle(frozen bubble)

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Very fine-grained (almost glassy) basalt, from Wai‘anae

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Gabbro (from Wailau, Moloka‘i)plagioclase feldsparpyroxene

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Granite (from Mojave desert, California)plagioclase feldspar

quartzpotassium feldspar

biotite, or maybe hornblende

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Obsidian, from near Mono Lake, California

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Pumice from Pu‘u Wa‘awa‘a, Hualālai

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Calcareous sandstone (from near Ko Olina, O‘ahu)

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Fragment of pāhoehoe lava showing the rapidly-chilled (and therefore glassy) outersurface, and the more slowly-cooled (and therefore crystalline) interior