Research Objectives

"To see the world in a grain of sand..." William Blake, Auguries of Innocence

When William Blake penned this line, he wasn't thinking about geology, but his phrase reveals a great deal about this project. Sand is typically comprised of 2-3 common minerals and another ~20 less common to scarce minerals (plus hundreds of rare minerals). The identity, proportions and total amounts of the less common minerals are widely used in academic, governmental and industrial geologic investigations to interpret climate, rates of erosion, general physiographic setting, rates of sediment accumulation, and basin-water chemistry and to correlate rock bodies over long distances.

The relative abundance of each of the ~20 less common minerals in any particular sand layer is affected by a variety of factors, the most important of which are:
1) the mineral composition of the source area supplying the sand grains;
2) chemical alteration of the minerals in the source area prior to eventual erosion and transportation to their depositional site;
3) chemical alteration of the minerals in the depositional area prior to consolidation of the loose sand grains into solid sandstone; and
4) sorting based on size, shape, and density of the different minerals during transport from source area to depositional site due to differences in the flow characteristics of streams, rivers, ponds, etc.

This research project addresses the fourth of these factors: how different environments result in measurably different mineral assemblages, even when supplied by the same source area. The project involves analyzing and correlating geologic environment (for example, low-energy stream, below wavebase marine shoreline, high-energy river, etc.) with mineral composition. Consequently, there are two major investigative components to the study:
1) interpretation of the environment of deposition, and
2) determination of the identity, proportions, and total amounts of the less common (but diagnostic) minerals.