STANDARD PROCEDURES FOR EVALUATION OF QUATERNARY MATERIALS IN IOWA

G.R. Hallberg (Editor)


Iowa Department of Natural Resources, Geological Survey Bureau,
Technical Information Series 8, 1978, 109 p.

INTRODUCTION


The Quaternary or unconsolidated materials constitute a very important resource to the State of Iowa. These glacial wind-blown, and stream-laid sediments cover approximately 97% of the land-surface in Iowa and range in thickness from a few inches to over 600 feet. These are the parent materials for the rich agricultural soils which are the backbone of Iowa's economy. They also constitute an economic resource for the aggregate, brick and tile, and construction material industries. With the widespread nature and great thickness of the Quaternary deposits they also are a major factor in most engineering works. The alluvial deposits and various kinds of buried horizons form important sources of water. Just as important as this, is the role that the various unconsolidated deposits play in influencing water movement into Iowa's important bedrock aquifers. Related to water movement and quality, is the problem of waste disposal. Most waste material in Iowa is disposed of in landfills in Quaternary glacial deposits or loess.

As our resources become more heavily used, the questions of proper resource management become more critical. To fully understand the nature of engineering and hydrologic properties and problems in these unconsolidated materials, and for proper understanding and management of the soils developed on these materials it is imperative that their stratigraphy be as fully understood as possible.

To meet this need the Iowa Geological Survey in cooperation with various local, state, and federal agencies and university personnel, most notably the U.S. Geological Survey, Water Resources Division, and the various members of the Iowa Cooperative Soil Survey program, and the Nebraska Conservation and Survey Division, has been conducting investigations into the stratigraphy and related applied properties of Quaternary materials. The stratigraphic relations of these materials are quite complex, and for the purposes of correlating the stratigraphy it is necessary to characterize the properties of the materials so that they may be distinguished from site to site. For the purpose of our investigations the techniques employed have had to meet two basic requirements:

1. That they are inexpensive and relatively simple (don't take too much time) but consistent; so that large numbers of samples can be processed;
2. That they can be used on samples from drill cuttings or cores as well as outcrop; in other words, the analyses must be usable on a small volume of material.

Many techniques have been tried and/or evaluated and discarded. The various procedures outlined here are the standard procedures that have been and continue to be employed in nearly all detailed investigations carried out by the Iowa Geological Survey. They are presented here for evaluation by those who use the data and hopefully so that these techniques might be used by others working on Quaternary deposits in Iowa. Many other techniques have been used (for example - magnetic susceptibility analyses and multi-element chemical analyses), however, to form a common data base for evaluation it is important that standard techniques be employed with these other analyses. Hopefully, various workers can integrate their approaches so that an expanded and compatible data base emerges for all concerned with the resources of Iowa's Quaternary deposits.