Geometry of the Pleistocene Rock Bodies and Erosional Surfaces Around Ames, Iowa

Five rock bodies and four major erosional surfaces are recognized in the subsurface; these are a lower till Kansan(?), a middle till Tazewell(?), a middle silt, an upper till (Cary), and a complexly interconnecting sand and gravel body. Erosion surfaces occur at the top of each rock body. The lower till is confined to the Squaw Buried Valley where it reaches a maximum thickness of 100 feet. The middle till averages 40 feet in thickness but ranges from 100 feet in buried valleys to absent over bedrock topographic highs. The middle silt is largely confined to the Squaw Buried Valley where it reaches thicknesses of 60 feet. The Cary till mantles the area, reaching thicknesses of over 100 feet in bedrock valleys and thinning to less than 25 feet over bedrock uplands. The distribution of the rock bodies suggests that the Squaw Buried Valley ceased to be the major drainage after Kansan (?) deposition and that the amount of pre-Tazewell (?) erosion was sufficient to remove all Kansan (?) drift from the uplands. The discontinuous distribution of the middle silt and Tazewell (?) till on the bedrock uplands indicates that erosion by the Cary glacier removed much of these rock bodies. The shape of the modern landscape mimics the shape of the buried bedrock valleys, though the relief in the area decreased from over 100 feet in pre-Kansan times to around 50 feet in pre-Cary times. The comparison of depositional landforms on the Cary surface to the till thicknesses suggests that washboard moraines. transverse features and circular features become dominant with progressively greater till thicknesses

Cooperative research in coal liquefaction

Significant progress was made in the May 1990--May 1991 contract period in three primary coal liquefaction research areas: catalysis, structure-reactivity studies, and novel liquefaction processes. A brief summary of the accomplishments in the past year in each of these areas is given

Measurement of Physical and Chemical Changes Induced During Weathering of A Carbonate Rock Unit

Changes which occurred during weathering of the Iowa Falls Member of the Mississippian Hampton Formation at Iowa Falls, Iowa were investigated quantitatively. The physical properties measured were: a) compressive strength, b) pore sized distribution, c) porosity and d) permeability. Chemically determined calcite and dolomite contents are related to the physical changes by utilization of an extensive sample sequence. The following changes are shown to be associated with the weathering process: 1) pore space and the degree of its interconnectedness increases with weathering, 2) calcite and dolomite are leached out during weathering, and 3) the rate of removal of calcite is twice that of dolomite

Groundwater Flow Patterns of the Ames Aquifer

Extensive field studies have indicated that the Ames aquifer (at Ames, Iowa) approximates a confined horizontal aquifer of uniform thickness and height. The aquifer is partly fed through the channel beds of two surface streams, the Skunk River and Squaw Creek. Part of the boundary of the Ames Aquifer is formed by a till layer that can be considered impervious. Pumping tests have indicated that the Skunk River and Squaw Creek maintain nearly a constant head distribution along the boundaries of the aquifer while the aquifer is pumped. A theoretical solution is presented that yields the well discharge, the hydraulic head at every point in the flow region, and the stream function when the aquifer is pumped by one completely penetrating well