Relationship of Redox-Sensitive Trace Elements in Soils and Plants to Petroleum Production in Railroad Valley, Nevada

Ronald W. Klusman, Mahyoub A. Saeed

Surface geochemical exploration methods for petroleum are based essentially on the observation that lighter hydrocarbons contained in oil and gas fields migrate toward the surface of the earth through structures such as faults and fractures. The hydrocarbons leaking toward the surface create a slightly reducing zone directly above the deposit, which in turn affects the mobility of redox-sensitive trace elements in the soil. This in turn affects trace element uptake by native plants of the area. Previous workers have found non-methane hydrocarbons leaking from the Eagle Springs and other fields in Railroad Valley, Nevada. The Eagle Springs field is about 1.5 km wide and 3 km long. Sagebrush and surface soils were sampled over an area of 5 km by 5 km at 500-m intervals. A D PA-extract of the soil samples and nitric acid digestion of the plants were analyzed for 17 trace elements by inductively coupled plasma emission spectrometry.

The distribution of redox-sensitive trace elements forms halo patterns around the Eagle Springs field. An evaluation of the use of trace elements in soils and plants as a surface exploration technique will be presented. Determination of the impact of soil contamination of plants and correcting for this allow use of plant materials in surface geochemical exploration. These methods provide a low-cost tool for complementing other exploration data in the Basin and Range environment.

AAPG Search and Discovery Article #91038©1987 AAPG Annual Convention, Los Angeles, California, June 7-10, 1987.