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Metamorphism at the Contact of the Cable Stock, Montana


Allingham, John Wing (1954) Metamorphism at the Contact of the Cable Stock, Montana. Master's thesis, California Institute of Technology. doi:10.7907/A9ME-5365.


A study of metamorphic rocks is integrated with the areal geology in the vicinity of the Cable stock, a granodiorite intrusive surrounded by Paleozoic carbonate rocks. Detailed geology of the zones of most intense metamorphism at the intrusive contact is described. Isochemical thermal metamorphism was followed by metasomatic addition of material and accompanied by various stages of alteration. Silicic magnesian limestones altered to diopside-grossularite marble by the introduction of iron. The addition of iron, little magnesia, and alumina altered the marble to a diopside-grandite tactite. Additional iron was deposited as magnetite and accompanied widespread dedolomitization and alteration. Rocks near the intrusive contact were replaced by epidote, mica, and scapolite. Areas of intense metamorphism occur at the granodiorite contact. Metamorphism is localized in areas of intense folding, fracturing, and shearing. The basic border of the stock indicates assimilation of calcareous rocks by the granodiorite; the transfer of calcium across the contact resulted in the development of pargasite, diopside, and scapolite. Deformation of the sediments was preceded and, in part, accompanied by forceful intrusion of the granodiorite.

Item Type:Thesis (Master's thesis)
Subject Keywords:Geology
Degree Grantor:California Institute of Technology
Division:Geological and Planetary Sciences
Major Option:Geology
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Campbell, Ian (advisor)
  • Jahns, Richard H. (advisor)
Thesis Committee:
  • Unknown, Unknown
Defense Date:1 January 1954
Record Number:CaltechETD:etd-12042003-160709
Persistent URL:
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:4771
Deposited By: Imported from ETD-db
Deposited On:11 Dec 2003
Last Modified:07 Jun 2023 22:48

Thesis Files

PDF (Allingham_jw_1954.pdf) - Final Version
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