HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Abstract Full Text Free Full Text (PDF) Free Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in ISI Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (7) Citing Articles via Google Scholar Google Scholar Articles by Jolicoeur, S. Articles by Bouchard, M. Search for Related Content PubMed Articles by Jolicoeur, S. Articles by Bouchard, M. GeoRef GeoRef Citation Agricola Articles by Jolicoeur, S. Articles by Bouchard, M.

Kaolinite and Gibbsite Weathering of Biotite within Saprolites and Soils of Central Virginia

^a Institut des Sciences de l'Environnement, Univ. du Québec à Montréal, C.P. 8888, succursale Centre-ville, Montréal, QC, Canada H3C 3P8, present address: Univ. de Moncton, Moncton, Nouveau-Brunswick, Canada E1A 3E9
^b CAMPARIS, Laboratoire de Minéralogie-Cristallographie, Univ. de Paris 6, 4 Place Jussieu, 75252 Paris, France
^c Univ. du Québec à Montréal, C.P. 8888, succursale Centre-ville, Montréal, QC, Canada H3C 3P8

View larger version (51K): [in a new window]   Fig. 1 Location map. Geological boundaries after Bartholomew and Lewis (1984). Greyed area: outline of the Blue Ridge Mountains and of the Piedmont foot-hills. Dark codes indicate saprolite-soil profiles presented in this paper. White codes indicate additional saprolite-soil profiles presented in Jolicoeur et al. (1995)

View larger version (159K): [in a new window]   Fig. 2 Photomicrographs. Pseudomorphs after biotite in saprolite and soils of central Virginia. (1) C4 saprock sheared biotite. (2) C4 saprolite. Kaolinite pseudomorph after biotite. Under crossed polarizers. (3) M2 saprolite. Biotite–vermiculite–kaolinite–gibbsite pseudomorph. (4) M2 saprolite. Gibbsite and kaolinite pseudomorph after biotite. Under crossed polarizers

View larger version (11K): [in a new window]   Fig. 3 X-ray diffraction diagrams from sorted biotite and related clay minerals pseudomorphs. (A) C4 saprolite. Transparent biotite mica flakes; (B) C4 saprolite. Pseudomorph after biotite; (C) G1 saprolite. Pseudomorph after biotite. M–V = mixed layer mica–vermiculite, K = kaolinite. Peak values in angströms

View larger version (6K): [in a new window]   Fig. 4 Microprobe analyses. (A) biotite pseudomorphs geochemical evolution in C4 weathering profile (Si–Al–Ca + Na + K system); (B) biotite pseudomorphs geochemical evolution in M2 weathering profile (Si–Al–Ca + Na + K system). K = kaolinite. Numbered data points refer to numbered analyses in Table 1

View larger version (153K): [in a new window]   Fig. 5 Scanning electron microscopy photomicrographs. Pseudomorphs after biotite in M2 saprolite. (1) Weathering products in coating and interlayer sites. (2) Prismatic weathering products in coating site. (3) Topotaxial tubular halloysite developing at edges of biotite 001 planes. (4) Kaolinite–gibbsite pseudomorph after biotite

View larger version (10K): [in a new window]   Fig. 6 Scanning electron microscopy–energy-dispersive x-ray analyzer analyses from biotite weathering products in M2 saprolite. (A) Qualitative chemical analysis of prismatic weathering products in coating sites (same site as in Fig. 5, Photo 2); (B) Qualitative chemical analysis of prismatic weathering products perpendicular to 001 planes in kaolinite and gibbsite pseudomorph after biotite (same material as in Fig. 5, Photo 4)

View larger version (20K): [in a new window]   Fig. 7 X-ray diffraction diagrams from sorted biotite and related clay minerals pseudomorphs. (A) M4 saprolite. Slightly weathered biotite; (B) M2 nonsaprolite residuum. Transparent biotite mica flakes; (C) M4 Typic Hapludult Bt horizon. Pseudomorphs after biotite; (D) M2 saprolite. Clayey white volume (same material as Fig. 5, Photo 4, and Fig. 6b). Q = quartz, M = mica, K = kaolinite, G = gibbsite, Go = goethite. Peak values in angströms