Mineralogy and ore textures at the Iron Mountain mine, St. Francois County, Missouri
- Univ. of Missouri, Rolla, MO (United States)
The Iron Mountain mine, located in the St. Francois Mountains of southeast Missouri, approximately 80 miles southwest of St. Louis, Missouri, has been the third largest iron producer in Missouri. It is one of six known major iron deposits in the Southeast Missouri Iron Metallogenic Province. The deposit is in the form of a unique inverted cup-shaped body, and it is hosted by volcanic flows of Middle Proterozoic age. The iron mineralization occurred during Precambrian time as shown by the presence of pebbles of iron ore in the overlying Cambrian sediments. A study has been initiated based on drill core samples and data donated to the Missouri Geological Survey. Drill cores from more than 1,000 exploratory holes are available. Core samples from selected drill holes are being studied using various analytical, petrographic, ore microscopic, and geochemical methods. Hematite and, to a lesser extent, magnetite are the main ore minerals. The most abundant gangue minerals are andradite, quartz, calcite, actinolite, apatite, epidote, and chlorite. The ore occurs in two modes: massive veins and as matrix between brecciated host rock. Some of the veins exhibit crustiform ore and gangue mineral textures. Host rock alteration is uncommon, and in most places the contact with the ore is quite sharp. The objectives of this study are to examine the ore and gangue mineralogy, determine the causes of brecciation, utilize ore textural information to evaluate the relative roles of hydrothermal and magmatic processes in the origin of the deposit, and explore the relationships between the Iron Mountain deposit and, other iron deposits in Missouri, and assess how the deposit fits in with the Olympic Dam model.
- OSTI ID:
- 5075501
- Report Number(s):
- CONF-9303210-; CODEN: GAAPBC
- Journal Information:
- Geological Society of America, Abstracts with Programs; (United States), Vol. 25:3; Conference: 27. annual Geological Society of America (GSA) North-Central Section meeting, Rolla, MO (United States), 29-30 Mar 1993; ISSN 0016-7592
- Country of Publication:
- United States
- Language:
- English
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