A Caltech Library Service

Core Softening in Cavernously Weathered Tonalite

Conca, James L. and Rossman, George R. (1985) Core Softening in Cavernously Weathered Tonalite. Journal of Geology, 93 (1). pp. 59-73. ISSN 0022-1376.

PDF - Published Version
See Usage Policy.


Use this Persistent URL to link to this item:


Tonalite exhibiting cavernous weathering at Catavina, Baja California, was investigated to determine the factors which contribute to differential hardness within the rock. Soft cores have a high degree of chemical weathering as indicated by kaolinite content. Hematite formed from the leaching of biotite occurs in coatings on rock surfaces, but the hardening effect of the coating is insignificant compared to the core-softening of the interior. The hardness, measured by an abrasion resistance hardness tester, is inversely correlated with kaolinite content in the tonalite. A one-dimensional water flow model was developed for core-softened. cavernously weathered boulders. It indicates that during infiltration and dessication the moisture flux is greatest through the cavern interior wall because of changes in the hydraulic conductivities induced by core softening. Therefore, the cavern interior wall should have the greatest weathering rate in the boulder.

Item Type:Article
Related URLs:
URLURL TypeDescription
Rossman, George R.0000-0002-4571-6884
Additional Information:© 1985 by The University of Chicago. Manuscript received April 30. 1984; revised August 6, 1984. We would like to thank Rosemarie Cubba and Peter Larson for assisting us in the field, and Robert P. Sharp and Ronald F. Scott for insightful comments and discussion. This research was supported in part by grants from Sigma Xi and the National Science Foundation (EAR 82-12590).
Funding AgencyGrant Number
NSFEAR 82-12590
Other Numbering System:
Other Numbering System NameOther Numbering System ID
Caltech Division of Geological and Planetary Sciences4058
Issue or Number:1
Record Number:CaltechAUTHORS:20130710-113109762
Persistent URL:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:39286
Deposited By: Tony Diaz
Deposited On:16 Jul 2013 21:28
Last Modified:26 Nov 2019 11:15

Repository Staff Only: item control page