Title

Preliminary analysis of penetrative strain fabrics from the Carboniferous Namarian Basin; County Claire; Western Ireland

Poster Number

2

Lead Author Major

Global Studies and Geology

Format

Poster Presentation

Faculty Mentor Name

Kurtis Burmeister

Faculty Mentor Department

Earth and Environmental Sciences

Abstract/Artist Statement

Preliminary results of a three-dimensional normalized Fry analysis of grain scale strain suggest that strata within Namurian Basin have accumulated very low magnitudes of penetrative strain. The five samples analyzed were collected along a south (nearest to a collisional mountain belt) to north (towards the undeformed interior) along the Loop Head Peninsula. All samples contain very low strain magnitudes (es values of less than 0.2). The southernmost sample is from the Ross Formation at Killbaha Bay, and is the only sample that contains a weak constrictional strain fabric likely produced by tectonic convergence. Remaining samples were collected from the Ross (at Ross Bay and Bridge of Ross) the Tullig (at Killard Bay), and Killkee Formations (at Quilty) have well developed flattening strain fabrics that are likely associated with deposition and compaction. Analyses were conducted using three, mutually perpendiciular petrographic thin sections prepared from orientated samples. Photomicrographs of these thin sections were digitized using the EllipseFit software package (Vollmer, 2015). The EllipseFit program determines grain centers and uses the distances between adjacent gains to calculate the ellipticity, orientation, and magnitude of rock fabrics. The results of rock fabric analysis are best communicated with Flinn and Hsu diagrams, which illustrate the degree of flattening, plane, or constrictional strain in each sample.

Location

DeRosa University Center, Ballroom

Start Date

25-4-2015 2:00 PM

End Date

25-4-2015 4:00 PM

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Apr 25th, 2:00 PM Apr 25th, 4:00 PM

Preliminary analysis of penetrative strain fabrics from the Carboniferous Namarian Basin; County Claire; Western Ireland

DeRosa University Center, Ballroom

Preliminary results of a three-dimensional normalized Fry analysis of grain scale strain suggest that strata within Namurian Basin have accumulated very low magnitudes of penetrative strain. The five samples analyzed were collected along a south (nearest to a collisional mountain belt) to north (towards the undeformed interior) along the Loop Head Peninsula. All samples contain very low strain magnitudes (es values of less than 0.2). The southernmost sample is from the Ross Formation at Killbaha Bay, and is the only sample that contains a weak constrictional strain fabric likely produced by tectonic convergence. Remaining samples were collected from the Ross (at Ross Bay and Bridge of Ross) the Tullig (at Killard Bay), and Killkee Formations (at Quilty) have well developed flattening strain fabrics that are likely associated with deposition and compaction. Analyses were conducted using three, mutually perpendiciular petrographic thin sections prepared from orientated samples. Photomicrographs of these thin sections were digitized using the EllipseFit software package (Vollmer, 2015). The EllipseFit program determines grain centers and uses the distances between adjacent gains to calculate the ellipticity, orientation, and magnitude of rock fabrics. The results of rock fabric analysis are best communicated with Flinn and Hsu diagrams, which illustrate the degree of flattening, plane, or constrictional strain in each sample.