Abstract

A number of induced and remanent magnetic measurements have been performed on 55 cubic samples, each 8 cm3, from a single segment of Athabasca Oil Sand core. Samples are representative of four major lithofacies types, which have been classified in the following manner: facies A—laminated, bitumen-free sediments; facies B—bioturbated (laminae are biologically disrupted to some degree), bitumen-free sediments; facies C—bioturbated sediments with moderate bitumen content; and facies D—massive sand, bitumen-rich sediments. Samples of facies D are divided into subfacies D1 and D2, based upon extremely high percentage values of anisotropy of magnetic susceptibility (AMS) observed for D2 samples. Magnetic fabric ranges progressively from undisturbed in samples of facies A to anomalous, considered highly disturbed, for samples of facies D2. Only samples of facies D record a stable remanent magnetization and, since the magnetic fabric is anomalous, it is inferred that the remanent magnetism may also be anomalous. It is concluded that zone D2 may result from locally high concentrations of authigenic magnetic minerals such as maghemite or siderite. Such D2 zones may prove to be useful stratigraphic markers in bitumen-saturated samples in which sedimentary structures are usually obscure.

You do not currently have access to this article.