Dyanna Czeck

Assistant Professor

354 Lapham Hall
(414) 229-3948
dyanna@uwm.edu

PhD: University of Minnesota
BS: University of Iowa

Specializations: Structural Geology

Research:

My emphasis in structural geology links naturally deformed rocks with processes of deformation using a variety of tools: field work, thin section analysis, mathematical models, physical analogue models, and geophysical techniques. In deformed ductile rocks, resultant fabrics provide a record of the deformation history. Therefore, understanding the processes of fabric development is an important step in deciphering the history of deformed terranes and solving the fundamental problem of how earth materials respond to tectonic forces. By learning in detail how rocks deform, we can best characterize the dynamics of crustal materials. I am especially interested in addressing fundamental questions concerning rheology and deformation processes as mechanisms for production of structural fabric and the way in which fabrics vary due to lithologically controlled rheology contrasts at a variety of scales, from individual mineral grains to the terrane scale.

Some Present work:

Deformation in the Ottertail Pluton: Superior Province, Ontario:

One example of ductile deformation partitioning due to lithological contrasts has arisen from my work in the Superior Province, a terrane consisting of greenstone belts, sedimentary sequences, and plutons. We are looking at a large granitic body within a deformation zone and have determined that it behaved very differently during deformation than the surrounding rocks. We are using a variety of strategies: A) a field study of deformation fabrics within the pluton, B) a petrographic description of the pluton in order to describe mineralogical variations and potential rheological variations, and C) an Anisotropy of Magnetic Susceptibility study of internal pluton fabrics.

Syntectonic Dikes and Veins- unravelling a strain history in the Rainy Lake region, Ontario:

I am working on a collaborative project with Dr. Jordi Carreras and Dr. Elena Druguet from the University of Barcelona in the Superior Province near Rainy Lake. We are looking at the complex field geometries formed with multiple intrusions during a prolonged deformation event. We have made photomosaics of boudined and folded veins and dikes and plan to use the geometries to unravel the deformation history.

The Baraboo Quartzite, cleavage refraction, and rheological contrasts:

This is a collaborative project with Dr. Carol Ormand at Wittenberg University. Within the Baraboo Quartzite of south-central Wisconsin, there are interbedded shaly layers. We are looking in detail at the cleavage refraction associated with the layering and correlating that refraction with the mineralogical or fabric differences we see in the rocks.

Rheology and Conglomerates:

Due to natural variations in the response to strain, heterogeneous deformed rocks such as conglomerates provide natural laboratories to observe rheologically-controlled deformation. In some respects, conglomerates are a smaller scale version of the pluton problem and deformation partitioning we studied with the Ottertail pluton. Polymictic conglomerates (those with clasts having a range of compositions), in particular, are ideal to study rheologically-controlled deformation. By exploiting the natural rheological contrasts within the conglomerates, we hope to address the processes of deformation partitioning within rheologically heterogeneous rocks. I am currently planning a collaborative project with Dr. Basil Tikoff and Eric Horsman at UW-Madison to address this problem.

For Further Information