Biogeochemical sampling in the Mahd Adh Dhahab District, Kingdom of Saudi Arabia

Ebens, Richard J.; Shacklette, Hansford T.; Worl, Ronald G.

Abstract:

A biogeochemical reconnaissance of the Mahd adh Dhahab district, Kingdom of Saudi Arabia, confirms the ability of deep-rooted Acacia trees to reflect bedrock concentrations of some trace elements. The analytical values for lead, zinc, selenium, and cadmium in ash of tree branches are significantly higher in samples from areas of known mineralization (13 sites) than in samples from areas of no known mineralization (12 sites). Geometric mean concentrations of these elements in the two areas (mineralized; nonmineralized), quoted as parts per million in ash, are lead (122; 28), zinc (713; 443), selenium (1.2; 0.6), and cadmium (1.4; 0.5). The range of molybdenum values in ash from the two areas is similar, but a cluster of four sites in an area classified as nonmineralized corresponds to an area where the U.S. Geological Survey reported anomalous molybdenum values in rock in 1965. Results for other elements were either equivocal (mercury, tellurium, silver) or showed no correspondence to the two areas. Mean values for barium, manganese, potassium, and sodium are significantly higher in areas of no known mineralization, but we conclude that this reflects a difference in country rock major-element chemistry rather than the effect of ore-forming processes. The pattern of trace-metal values in Acacia ash is present whether the sampled tree grows on bedrock, on talus, or on residual or modern alluvium. This fact suggests that the trace-element chemistry of the trees reflects bedrock geochemistry and implies that Acacia biogeochemistry could be applied as a prospecting tool in areas where bedrock is not well exposed.

Genre:

USGS Numbered Series

ProdID:

40180

Citation Author:

Ebens, Richard J.; Shacklette, Hansford T.; Worl, Ronald G.

Citation Contributing Office:

Citation Datum:

Citation Day:

Citation Edition:

Citation Editor:

Citation End Page:

Citation Issue:

Citation Keywords:

Citation Language:

ENGLISH

Citation Larger Work Title:

Citation LatN:

Citation LatS:

Citation LonE:

Citation LonW:

Citation Month:

Citation No Pagination:

Citation Number Of Pages:

Citation Online Only Flag:

Citation Phsyical Description:

1 map ;47 x 56 cm. +1 text (i, 16 p. : map ; 28 cm.)

Citation Projection:

Citation Public Comments:

Citation Publisher:

Citation Series:

Open-File Report

Citation Series Code:

OFR

Citation Series Number:

83-330

Citation Search Results Text:

Biogeochemical sampling in the Mahd Adh Dhahab District, Kingdom of Saudi Arabia; 1983; OFR; 83-330; Ebens, Richard J.; Shacklette, Hansford T.; Worl, Ronald G.

Citation Start Page:

Citation Volume:

Citation Year:

1983

Type:

citation/reference

Text:

Biogeochemical sampling in the Mahd Adh Dhahab District, Kingdom of Saudi Arabia; 1983; OFR; 83-330; Ebens, Richard J.; Shacklette, Hansford T.; Worl, Ronald G.