@article{MeereMulchroneMcCarthyetal.2016, author = {Meere, Patrick A. and Mulchrone, Kieran F. and McCarthy, Dave J. and Timmerman, Martin Jan and Dewey, John F.}, title = {Prelithification and synlithification tectonic foliation development in a clastic sedimentary sequence}, series = {Geology}, volume = {44}, journal = {Geology}, publisher = {American Institute of Physics}, address = {Boulder}, issn = {0091-7613}, doi = {10.1130/G37587.1}, pages = {291 -- 294}, year = {2016}, abstract = {The current view regarding the timing of regionally developed penetrative tectonic fabrics in sedimentary rocks is that their development postdates lithification of those rocks. In this case, fabric development is achieved by a number of deformation mechanisms, including grain rigid body rotation, crystal-plastic deformation, and pressure solution. The latter is believed to be the primary mechanism responsible for the domainal structure of cleavage in low-grade metamorphic rocks. In this study we combine field observations with strain studies to characterize considerable (>50\%) Acadian crustal shortening in a Devonian clastic sedimentary sequence from southwest Ireland. Despite these high levels of shortening there is a marked absence of the domainal cleavage structure and intraclast deformation that are expected with this level of deformation. Fabrics in these rocks are predominantly a product of rigid body rotation and repacking of extraformational clasts during deformation of a clastic sedimentary sequence before lithification was complete.}, language = {en} } @misc{MeereMulchroneMcCarthyetal.2016, author = {Meere, Patrick A. and Mulchrone, Kieran F. and McCarthy, David J. and Timmerman, Martin Jan and Dewey, John F.}, title = {Prelithification and synlithification tectonic foliation development in a clastic sedimentary sequence}, series = {Geology}, volume = {44}, journal = {Geology}, publisher = {American Institute of Physics}, address = {Boulder}, issn = {0091-7613}, doi = {10.1130/G38103Y.1}, pages = {E397 -- E397}, year = {2016}, language = {en} } @article{EnnisMeereTimmermanetal.2015, author = {Ennis, Meg and Meere, Patrick A. and Timmerman, Martin Jan and Sudo, Masafumi}, title = {Post-Acadian sediment recycling in the Devonian Old Red Sandstone of Southern Ireland}, series = {Gondwana research : international geoscience journal ; official journal of the International Association for Gondwana Research}, volume = {28}, journal = {Gondwana research : international geoscience journal ; official journal of the International Association for Gondwana Research}, number = {4}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1342-937X}, doi = {10.1016/j.gr.2014.10.007}, pages = {1415 -- 1433}, year = {2015}, abstract = {The Upper Devonian Munster Basin of southern Ireland has traditionally been viewed as a post-orogenic molasse deposit that was sourced from the Caledonides of central Ireland and subsequently deformed by the end Carboniferous Variscan orogenic event. The basin fill is composed of super-mature quartz arenite sandstone that clearly represents a second cycle of deposition. The source of this detritus is now recognized as Lower Devonian Dingle Basin red bed sequences to the north. This genetic link is based on the degree of similarity in the detrital mica chemistry in both of these units; micas plot in identical fields and define the same trends. In addition, the two sequences show increased textural and chemical maturity up-sequence and define indistinguishable Ar-40/Ar-39 age ranges for the detrital mica grains. Partial resetting of the Ar ages can be attributed to elevated heat flow in the region caused by Munster Basin extension and subsequent Variscan deformation. The combined evidence from southwest Ireland therefore points to a Caledonian or possibly Taconian primary source area that initially shed detritus into the Lower Devonian Dingle Basin which was subsequently recycled into the Upper Devonian Munster Basin following mid-Devonian Acadian basin inversion. (C) 2014 International Association for Gondwana Research. Published by Elsevier B.V. All rights reserved.}, language = {en} } @article{MeereMulchroneTimmerman2013, author = {Meere, Patrick A. and Mulchrone, Kieran F. and Timmerman, Martin}, title = {Shear folding in low-grade metasedimentary rocks - reverse shear along cleavage at a high angle to the maximum compressive stress}, series = {Geology}, volume = {41}, journal = {Geology}, number = {8}, publisher = {American Institute of Physics}, address = {Boulder}, issn = {0091-7613}, doi = {10.1130/G34150.1}, pages = {879 -- 882}, year = {2013}, abstract = {Shear folding, which is also referred to as slip folding, involves shear along planes that are oriented approximately parallel to the axial plane of the fold structure. These planes, which are typically axial-planar cleavage planes, facilitate high-angle reverse slip leading to fold limb rotation and amplification. This study builds on recent advances in our understanding of the role of weak fault zones in facilitating slip on misoriented faults; i.e., faults at a high angle to the maximum principal tectonic stress (sigma(1)). Analysis of folded marine sedimentary rocks from the Variscan of southern Ireland provides unambiguous microstructural evidence for reverse shear on chemically weakened cleavage domains. Significant silica loss in these cleavage domains, and as a consequence marked mechanical weakening, is seen as the primary cause for the reverse slip associated with the shear folding of these sedimentary rocks.}, language = {en} }