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Geology and geophyscis. (Senior Division 2002).

Dudley, M.A., J.L. Nold, and D. Joseph. Department of Earth Science, Central Missouri State University. THE CEDAR HILL DEPOSIT, IRON COUNTY, MO--A PROTEROZOIC OOLITIC SEDIMENTARY BANDED IRON FORMATION. At the Cedar Hill iron deposit north of Pilot Knob, MO, hematite ores are contained within rhyolitic volcanic breccias of the Proterozoic St. Francois Mountains terrane. These hematite ores show excellent thin bedding and lamination. These ores are alternating laminations of fine grained hematite and oolitic hematite, both with interstitial quartz., i.e., the ores are siliceous taconite banded iron formations. The oolitic nature of some of the laminations leads us to the conclusion that the bedded hematite ores are of undoubted sedimentary origin and not of hydrothermal replacement origin. In addition to the interbedded fine grained and oolitic ores, some of the iron is present as coarse, crosscutting specular hematite, filling fractures and breccia interstices, and apparently is of late hydrothermal origin. As sociated with this late specular hematite is abundant red jasperoid, perhaps the result of hot spring activity. The bedded ores are, in places, considerably disturbed as a result of volcanic or tectonic processes. Minor magnetite is present and some has been partly converted to hematite as martite. Minor pyrite is also present.

The laminated fine grained hematite ores at Cedar Hill are very similar in appearance to the ores at Pilot Knob Hematite. No oolites have been found at Pilot Knob Hematite but the similarity of the Pilot Knob ores to the fine grained ores at Cedar Hill which are undoubtedly of sedimentary origin, strongly supports our past assertions that Pilot Knob Hematite is of sedimentary origin and not of hydrothermal replacement origin.

Reese, J.F. Department of Geology and Geography, Northwest Missouri State University. USING SPACE PHOTOS TO OBSERVE EARTH'S DYNAMIC SURFACE. Photographs of Earth from Space are excellent observational data that document large-scale earth-system processes and interactions as well as natural environmental changes and hazards. In essence, these photos show Earth's spheres operating on enormous scales. Photos of reefs, atolls, and algal/planktonic buildups demonstrate a biosphere intimately connected with the hydrosphere and geosphere. Those of deltas show sediment input into the hydrosphere. Canyon landscapes and glaciated terrains as viewed from Space reveal modification of the geosphere by the hydrosphere. Photos of weather patterns and circulation systems depict dynamic linkage between atmosphere and hydrosphere. Photos of volcanoes and dust blows illustrate contrasting inputs of material into the atmosphere. Lake-level fluctuations documented from Space indicate short-term environmental changes. Tectonic ele ments such as mountain belts, volcanic arcs, rifts and faults, however, are linked to slower internal Earth processes and are clearly shown on photos. Impact crater photos reveal landscape modification by extraterrestrial agents. All of these photos portray complex yet clear interrelationships between Earth's spheres at scales best viewed from Space.
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Author:Wronkiewicz, David
Publication:Transactions of the Missouri Academy of Science
Geographic Code:1U4MO
Date:Jan 1, 2002
Words:466
Previous Article:Geography. (Senior Division 2002).
Next Article:Physics. (Senior Division 2002).
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