Geology

The geology of the Middle and Upper Paleolithic sites is being investigated by Susan Mentzer and Paul Goldberg. Considerable titing of the geological beds that contain UCI and UCII caves has occurred and is typcial in the tectonically active and extensively faulted region. In addition t geomorphological documentation of the locale, the technique of soil micromorphology is being used to identify changes in the mineralogy and texture of the sediment in the stratigraphic layers.  A close collaboration is being undertaken between the zooarchaeological and the geoarchaeological analyses to better understand the local environmental conditions that prevailed during the occupation of the UCI and UCII cave sites. Specifically, the faunal and sedimentary records are being compared for changes that may indicate an environmental signal related to fluctuations in climate and sea level.

Archaeological micromorphology is the study of intact archaeological sediments at high magnifications, using techniques derived from geological petrology and soil science. Oriented blocks of intact sediment are collected from exposed archaeological profiles in the field. Samples often target the contacts between two layers, a representative example of one particular layer or an archaeological feature such as a hearth. The wrapped sediment blocks are labeled and shipped to the University of Arizona where they are dried in an oven and impregnated with a mixture of polyester resin and styrene catalyzed with MEKP. Once hardened to a solid block, the blocks are oven-cured, sliced with a rock saw, and selected areas trimmed to fit 2x3 inch petrographic thin sections. The trimmed blocks are sent to a thin section preparation lab, where they are glued to slides and ground to a thickness of 30 microns. These sections are then examined at variable magnification and under plane polarized light, cross polarized light and oblique incident light using both a petrographic stereographic microscope and a standard petrographic microscope. Finally, the sections are viewed at low and high magnification using a petrographic microscope equipped with a blue light source, which enables fluorescence microscopy.

The goals of the micromorphological analyses at Üçağızlı I and II include identification of the minerals and archaeological micro-materials using their optical properties; (2) evaluation of grain size distribution and degree of rounding that may reveal sediment sources, and transport and depositional processes; (3) confirming or disconfirming boundaries between lithological layers that had been identified in the field, and relating them to specific processes such as erosion; (4) identification of possible microlayering within a site; (5) evaluation of specific textures and microstructures that may indicate post-depositional alterations such as bioturbation and soil formation; (6) identifying areas of post-depositional dissolution and weathering as indicated by voids in the matrix, visible recrystallization or in situ formation of secondary minerals; and (7) isolation of anthropogenic sediments that have specific compositions and structures. 

Back to Top