Nickeliferous laterites in southwestern Oregon and northwestern California

The fate of chromium and nickel in subalpine soils derived from serpentinite

“…Serpentinitic parent materials are located in many areas of the world and are of great interest to researchers, particularly in the helds of agronomy, botany, environmental chemistry, plant genetics, soil science, and toxicology. Serpentinitic ecosystems have been studied mainly from an agronomic, botanical or ecological point of view; however, pedological investigations are rare (Rabenhorst et al 1982;Brooks 1987 (Hotz 1964;Schellmann 1964 For personal use only.…”

Contributions to commodity geology research

“…In contrast, other samples were collected with a hand auger and, because of the limitations of this device, seldom penetrated more than 2 to 3 m of laterite. In eight cases, this amount of penetration was sufficient to sample profiles that exhibited all the features found in the more completely exposed pits as well as to show the same features that have been described for other laterites in this region (Hotz, 1964;Ramp, 1978). Samples collected from these eight locations as well as those taken from the exploration pits provide the material discussed in this report.…”

“…Saprolite is present in other deposits but generally does not contain significant amounts of gamierite-type mineralization. The reason for the apparent restriction of higher grade nickel ores to the Riddle area is not clear, but Hotz ( 1964) speculates that rocks associated with this deposit may have had a longer weathering history. As a result of its higher nickel grades, the deposit near Riddle was the first to be developed.…”

“…Most probably occurred during the Miocene formation of the Klamath peneplain (Diller, 1902). Some weathering, however, was much younger, as shown by the occurrence of laterite on Pleistocene terraces (Hotz, 1964;Moring, oral commun., 1986). Subsequently, most laterites have been uplifted and dissected so that many now occur on plateaus or as cappings on ridges and saddles and as transported debris on sides of hills and in valleys.…”

“…The saprolite zone grades into greenish-brown weathered peridotite and then into fresh peridotite or serpentine (Hotz, 1964;Ramp, 1978). In some laterites, nickel occurs in the lower saprolitic zone as a solid solution replacement of magnesium in a variety of secondary magnesium silicates (mostly serpentine, talc, and chlorite).…”