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Do smoothly curving, spiral-shaped inclusion trails signify porphyroblast rotation?

1992; Geological Society of America; Volume: 20; Issue: 1 Linguagem: Inglês

10.1130/0091-7613(1992)020 2.3.co;2

1943-2682

T.H. Bell, A. Forde, Nicholas Hayward,

Rock Mechanics and Modeling

Research Article| January 01, 1992 Do smoothly curving, spiral-shaped inclusion trails signify porphyroblast rotation? T. H. Bell; T. H. Bell 1Department of Geology, James Cook University, Townsville, Queensland 4811, Australia Search for other works by this author on: GSW Google Scholar A. Forde; A. Forde 1Department of Geology, James Cook University, Townsville, Queensland 4811, Australia Search for other works by this author on: GSW Google Scholar N. Hayward N. Hayward 1Department of Geology, James Cook University, Townsville, Queensland 4811, Australia Search for other works by this author on: GSW Google Scholar Author and Article Information T. H. Bell 1Department of Geology, James Cook University, Townsville, Queensland 4811, Australia A. Forde 1Department of Geology, James Cook University, Townsville, Queensland 4811, Australia N. Hayward 1Department of Geology, James Cook University, Townsville, Queensland 4811, Australia Publisher: Geological Society of America First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (1992) 20 (1): 59–62. https://doi.org/10.1130/0091-7613(1992)020 2.3.CO;2 Article history First Online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation T. H. Bell, A. Forde, N. Hayward; Do smoothly curving, spiral-shaped inclusion trails signify porphyroblast rotation?. Geology 1992;; 20 (1): 59–62. doi: https://doi.org/10.1130/0091-7613(1992)020 2.3.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract Smoothly curving, spiral-shaped inclusion trails may form in porphyroblasts during the overprinting of near-orthogonal foliations in schists that are relatively quartz rich and, in general, graphite poor. The smooth curvature results from the combined effects of (1) the protection from progressive shearing provided by projecting crystal faces and (2) greater competency and generally wider zones of progressive shearing in these rock types than in ones that are less quartz rich and more graphtic. Therefore, lack of truncations or abrupt changes in compositional zoning profiles and the presence of smoothly curving, spiral-shaped inclusion trails do not necessarily signify that the porphyroblast containing them rotated as it grew. This has considerable significance for shear-sense determinations in deformed and metamorphosed rocks. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.