Weathering and transport of chromium and nickel from serpentinite in the Coast Range ophiolite to the Sacramento Valley, California, USA

摘要: Abstract A soil geochemical study in northern California was done to investigate the role that weathering and transport play regional distribution mobility of geogenic Cr Ni, which are both potentially toxic carcinogenic. These elements enriched ultramafic rocks (primarily serpentinite) soils derived from them (1700–10,000 mg per kg 1300–3900 mg Ni soil) Coast Range ophiolite. Chromium have been transported eastward into western Sacramento Valley as a result, valley is (80–1420 mg kg−1) (65–224 mg kg−1) compared median values U.S. 50 15 mg kg−1, respectively. Nickel source present serpentine minerals (lizardite, antigorite, chrysotile) more easily weathered Cr, primarily resides highly refractory chromite ([Mg,Fe2+][Cr3+,Al,Fe3+]2O4). Although majority minerals, etching dissolution these presence Cr- Ni-enriched clay development nanocrystalline Fe (hydr)oxides evidence significant fractions transferred labile phases.