Research

1. Research project objectives

Deformation bands (DB) are small scale tectonic features. The detailed study of their kinematic and microstructural properties can reveal regional scale deformation mechanisms, the relative timing of their deformation and burial conditions. Results of hitherto performed worldwide studies show that DB are a perfect tool for structural history reconstructions. Deformation bands have also been reported from several nappes in the Polish segment of the Outer Carpathians. Unfortunately, studies on DB have only rarely been undertaken there. Moreover, the only extensive studies of DB in the Outer Carpathians were restricted to the Magura Nappe and were performed 20 years ago. Therefore, taking into account the recent considerable progress in studies on DB and the introduction of new analytical techniques such as X-Ray microtomography and permeability measurements, a very promising opportunity has arisen to explore the topic in a novel approach.

DB have also been reported from the Silesian Nappe. The recent observations of the author of the project show that DB are widespread within the nappe, in the Bieszczady Mts. region. The results of pilot studies by the present author, performed along a single profile, show that DB occur there within several map-scale folds and show different properties, indicating differentiated burial conditions during their origin. Therefore, there is a need to extend the research area in order to find the regional trends and relationships. The observed DB’s also display a different relationship to the host strata orientation. As a result, for the explanation of regional differentiation in DB development, it is necessary to study DB in a larger area. Apart from their contribution to regional geology, the topic of DB types and their X-ray computed microtomography expressions has not been tackled to date, and thus this provides the opportunity to complete this gap and make a universal contribution regarding the nature of these structures as well.

Moreover, there is a tempting opportunity to simultaneously undertake a new approach to paleostress reconstructions. The author’s recent advances in methodological aspects regarding porous spaces in a microstructural approach using the aforementioned X-ray tomography have demonstrated the possibility of deriving detailed micro-scale, 3D characteristics of porous spaces. It has been demonstrated that the architecture of porous spaces results from deformation processes. These processes can be identified and, most importantly, reconstructed based on a quantitative approach to geometry and the spatial arrangement of pores. It appears that since the internal structure of rocks shows a strong correlation with permeability properties, the deformation processes should be recorded in permeability anisotropy as well. Hence, an opportunity arises from the possible outcome of the novel study approach and a combination of other methods. This may lead to improvements in terms of knowledge regarding the influence of deformation processes on the conduit properties of rocks and the origin of deformation structures, as well as a proposal for a new method for paleostress reconstructions.

Therefore, the project has two main objectives:

1. determination of the origin of DB, and thus regional scale deformation mechanisms with regard to the burial conditions, and,

2. proposing a microtectonic method for paleostress reconstructions based on porous space geometry and permeability anisotropy.

Research project methodology: It is planned to carry joint study including field, laboratory and computational studies. Their synergy will allow for comprehensive approach to cover the goals. The field part consists of collecting structural measurements and samples. Analysis of collected structural data will be supplemented with digital terrain model (LiDAR) analysis. Laboratory part consists of traditional petrographic analyzes performed on thin sections with a use of transmitted light microcopy, electron microscopy and cathodoluminescence. It will be followed by modern techniques comprising the use of digital image analysis techniques of corresponding cylindrical plug sample 3D images obtained with X-Ray microcomputed tomography scanning and permeability measurements.