Beidellite and Associated Clays from the Delamar Mine and Florida Mountain Area, Idaho

Abstract

Abstract--There has been much interest in the rare specimen of beidellite from the Black Jack Mine, Florida Mountain, Idaho. A variety of aluminous clays exists along veins such as the Black Jack vein, in rhyolite and latite flows, and in near-surface ash beds, often containing less than 1.0% MgO and 0.5% Na20. Associated clays include beidellite, illite, kaolinite, 10-A halloysite, dickite, nacrite, rectorite and a tarasovite-like mineral. The predominant clay is mixed-layer illite-beidellite. The beidellites have A120 ~ contents ranging from about 28 to 33%, and predominantly Ca and K as interlayer cations. The typical beidellite dehydroxylation temperatures of about 595 ~ readily differentiate the beidellite from montmorillonite, which has a dehydroxylation temperature in the range of 735 ~ A modified differential thermal analysis (DTA) method is given for readily estimating the interlayer cation populations of smectites, including Mg ++ and A1 § § § cations. Chemical analyses and layer charges of 11 beidellites from mines around the Black Jack Mine are given. The beidellites have an American Society for Testing and Materials (ASTM) classification of CH, qb value, internal friction angle of about 8 ~ and an expansion pressure of about 9 kgf/cm 2 (88.3 kPa), similar to that of nontronite.

Fe3+-Rich Montmorillonite-Beidellite Series in Ayvacik Bentonite Deposit, Biga Peninsula, Northwest Turkey

“…The similarities in XRD data between Ayvaclk, the Black Jack Mine, Idaho and DeLamar Mine, Idaho (Post et al, 1997) beidellites are shown in Table 1.…”

“…Most iron-rich, high-charge beidellites in verti- (Weir and Greene-Kelly, 1962) and DeLamar Mine, Idaho (Post et al, 1997 (Badraoui et al, 1987;Badraoui and Bloom, 1990). They also reported that during weathering, soil mica is transformed first to vermiculite and then to beidellite, preserving the tetrahedral character of the charge.…”

“…Most of the host rock has been altered by weathering and hydrothermal alteration (Cupp, 1989). Beidellite was found along a primary vein, which dips steeply along a northerly trend and consists of a thin, highly altered basalt dike containing discontinuous clay seams on the east side and deposits of silver and gold on the west side (Post et al, 1997). The objective of this work is to document parentrock alteration and to identify and characterize the Fe3+-rich montmorillonite-beidellite series.…”

Investigation of dioctahedral smectite hydration properties by modeling of X-ray diffraction profiles: Influence of layer charge and charge location

“…Compared to SWy-1 montmorillonite studied by Ferrage et al (2005b) (Post et al 1997 For all samples, size fractionation to < 1 µm was obtained by centrifugation. Then, ion exchange was achieved with 1 mol.L -1 aqueous solutions of CaCl 2 , for SAz-1 only, and SrCl 2 , with three steps of saturation followed by three washing steps, as described by Ferrage et al (2005b).…”

“…The near complete swelling of layers following EG solvation is observed for montmorillonite and for population A of beidellite. In contrast, for beidellite increasing layer charge from the mean layer charge may produce vermiculite-like layers, discrete illite layers or irreversibly collapsed K-beidellite layers when potassium is present as assumed for SbId-1 (Post et al 1997). However, heterogeneous structures where layers have different hydration/swelling abilities is not a priori characteristic of smectite with layer charge originating in the tetrahedra, although such interstratified structures probably occur more frequently in beidellite compared to montmorillonite.…”