LITHOLOGICAL AND STRUCTURAL ANALYSES OF CLASTIC DIKES WITHIN THE INDIAN PEAK-CALIENTE CALDERA COMPLEX

In Enterprise, Utah, there are clastic dikes cross cutting ignimbrites and volcaniclastics from the Indian Peak-Caliente Caldera Complex that have not been documented or studied. The purpose of this research is to answer the following three questions; what are the compositions of the clastic dikes, what was the order of events that led to the emplacement of the clastic dikes, and how do their orientations relate to the regional tectonic setting? To do this, I mapped the locations and orientations of the prominent dikes, described their lithologies in hand sample, created thin sections to analyze at the microscopic scale, and completed a paleostress analysis using stereonets.

These clastic dikes run through a small portion of the numerous ignimbrites and volcaniclastic formations from the 36-18 Ma Indian Peak-Caliente Caldera Complex. The clastic dikes strike in two different orientations which crosscut each other. The first generation, which is crosscut by the second, is oriented about N54E 8NW, and the second generation is oriented about N52W 87NE. These two orientations have their own unique characteristics. Generation one contains pumice particles of various sizes within a pink, ash-sized matrix. These dikes also have a thin mud coating along the outer edges. Generation two seems to be mostly mud. Many of the larger dikes are layered from a very fine grained to a fine grained mud. A few of these dikes also have volcaniclastic material within them. The differences between these sets of dikes seem to indicate multiple events and different depositional styles. It also seems to be a local phenomenon due to the small extent where these are found.

Although this is a work in progress, I expect to have a finished result by the end of the year. This will consist of the compilation of my research and answers to the questions previously stated. The goal of this research is to improve general knowledge of the Enterprise, Utah area and the formation of clastic dikes within ignimbrites and volcaniclastic rocks.