Dissolution of olivine during natural weathering

摘要: Abstract Naturally weathered olivine occurring as phenocrysts in Hawai’ian volcanic rocks from several centers and regolith/outcrop settings, tectonized olivines metadunite bodies the southern Appalachian Blue Ridge, are all similarly corroded by natural weathering. Conical (funnel-shaped) etch pits occur individual pits, base-to-base pairs of cone-shaped or en echelon arrays. Etch-pit shapes orientations smallest etch-pit arrays visible conventional scanning electron microscopy resemble even smaller features previously reported transmission microscope investigations Etch samples with chemical and/or mineralogical evidence weathering, associated with, proximal directly connected to, fractures exposed outcrop surface, therefore formed weathering not inherited pre-weathering aqueous alteration (e.g., serpentinization, iddingsitization) these parent rocks. Many devoid products. Natural is surface-reaction-limited. Similarity corrosion forms naturally multiple igneous metamorphic parent-rock suggests that weathers same manner regardless its specific crystallization/recrystallization history, eruption/weathering/exposure ages olivine’s host rock, local regolith history.