hawai‘i rocks (and minerals). oceanite (from mauna loa) – a basalt with >40% mafic...

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HAWAI‘I ROCKS (and minerals)

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Page 1: HAWAI‘I ROCKS (and minerals). Oceanite (from Mauna Loa) – a basalt with >40% mafic phenocrysts, and all the phenocrysts are olivine. olivine

HAWAI‘I ROCKS

(and minerals)

Page 2: HAWAI‘I ROCKS (and minerals). Oceanite (from Mauna Loa) – a basalt with >40% mafic phenocrysts, and all the phenocrysts are olivine. olivine

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

olivine

Page 3: HAWAI‘I ROCKS (and minerals). Oceanite (from Mauna Loa) – a basalt with >40% mafic phenocrysts, and all the phenocrysts are olivine. olivine

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

olivine

pyroxene

Page 4: HAWAI‘I ROCKS (and minerals). Oceanite (from Mauna Loa) – a basalt with >40% mafic phenocrysts, and all the phenocrysts are olivine. olivine

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

Page 5: HAWAI‘I ROCKS (and minerals). Oceanite (from Mauna Loa) – a basalt with >40% mafic phenocrysts, and all the phenocrysts are olivine. olivine

Outer, weathered surface of ankaramite from Rarotonga, Cook Islands

pyroxene

Page 6: HAWAI‘I ROCKS (and minerals). Oceanite (from Mauna Loa) – a basalt with >40% mafic phenocrysts, and all the phenocrysts are olivine. olivine

Freshly broken surface of ankaramite from Rarotonga, Cook Islands

pyroxene

olivine

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

Page 7: HAWAI‘I ROCKS (and minerals). Oceanite (from Mauna Loa) – a basalt with >40% mafic phenocrysts, and all the phenocrysts are olivine. olivine

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

plagioclase feldspar

olivine

vesicle(frozen bubble)

Page 8: HAWAI‘I ROCKS (and minerals). Oceanite (from Mauna Loa) – a basalt with >40% mafic phenocrysts, and all the phenocrysts are olivine. olivine

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

Page 10: HAWAI‘I ROCKS (and minerals). Oceanite (from Mauna Loa) – a basalt with >40% mafic phenocrysts, and all the phenocrysts are olivine. olivine

Gabbro (from Wailau, Moloka‘i)plagioclase feldsparpyroxene

Page 11: HAWAI‘I ROCKS (and minerals). Oceanite (from Mauna Loa) – a basalt with >40% mafic phenocrysts, and all the phenocrysts are olivine. olivine

Granite (from Mojave desert, California)plagioclase feldspar

quartzpotassium feldspar

biotite, or maybe hornblende

Page 12: HAWAI‘I ROCKS (and minerals). Oceanite (from Mauna Loa) – a basalt with >40% mafic phenocrysts, and all the phenocrysts are olivine. olivine

Obsidian, from near Mono Lake, California

Page 13: HAWAI‘I ROCKS (and minerals). Oceanite (from Mauna Loa) – a basalt with >40% mafic phenocrysts, and all the phenocrysts are olivine. olivine

Pumice from Pu‘u Wa‘awa‘a, Hualālai

Page 14: HAWAI‘I ROCKS (and minerals). Oceanite (from Mauna Loa) – a basalt with >40% mafic phenocrysts, and all the phenocrysts are olivine. olivine

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

Page 15: HAWAI‘I ROCKS (and minerals). Oceanite (from Mauna Loa) – a basalt with >40% mafic phenocrysts, and all the phenocrysts are olivine. olivine

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