Origin of the Woodstown, New Jersey, Macro-Kaolinite

Wayne C. Isphording and William Lodding
Department of Geology, University of South Alabama, Mobile, Alabama, and Rutgers, The State University, New Brunswick, New Jersey

Abstract: A kaolin bed in which many of the individual kaolinite platelets exceed 0·2 mm in size occurs in the immediate vicinity of the base of the middle-Miocene Kirkwood Formation, near Woodstown, New Jersey. These platelets appear to have resulted from breakdown of pre-existing illite and montmorillonite coupled with concurrent epitaxial growth and diagenetic growth of primary kaolinite. The alteration of the clay minerals is thought to be a product of upward leaching (dialysis) by groundwaters in the underlying Vincentown Sand. This is further evidenced by abnormally high percentages of clay-size kaolinite in the clays that lie above the Vincentown Sand but beneath the macro-kaolinite horizon. Growth of the macro-kaolinite was facilitated by face-to-edge sedimentation and the resultant high permeability of the stratum.

Clays and Clay Minerals; August 1968 v. 16; no. 3; p. 257-264; DOI: 10.1346/CCMN.1968.0160308
© 1968, The Clay Minerals Society
Clay Minerals Society (www.clays.org)