Metamorphic plumbing system in Proterozoic calc-silicates, Queensland, Australia
1987; Geological Society of America; Volume: 15; Issue: 9 Linguagem: Inglês
10.1130/0091-7613(1987)15 2.0.co;2
ISSN1943-2682
Autores Tópico(s)Methane Hydrates and Related Phenomena
ResumoResearch Article| September 01, 1987 Metamorphic plumbing system in Proterozoic calc-silicates, Queensland, Australia Nick Oliver; Nick Oliver 1Department of Earth Sciences, Monash University, Clayton, Victoria 3168, Australia Search for other works by this author on: GSW Google Scholar Vic Wall Vic Wall 1Department of Earth Sciences, Monash University, Clayton, Victoria 3168, Australia Search for other works by this author on: GSW Google Scholar Geology (1987) 15 (9): 793–796. https://doi.org/10.1130/0091-7613(1987)15 2.0.CO;2 Article history first online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Nick Oliver, Vic Wall; Metamorphic plumbing system in Proterozoic calc-silicates, Queensland, Australia. Geology 1987;; 15 (9): 793–796. doi: https://doi.org/10.1130/0091-7613(1987)15 2.0.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 A calc-silicate–rich terrain in northwest Queensland exhibits spectacular examples of heterogeneous fluid/rock interaction attending regional amphibolite facies metamorphism and deformation. Large areas of pristine calc-silicate rocks show evidence for internal buffering of fluid composition and low fluid/rock ratios (F/R), as inferred from δ18O and δ13C signatures typical of metamorphosed marine carbonates, the progress of calc-silicate reactions, and scapolite compositional variations between layers. In contrast, high-variance assemblages are developed in pretectonic intrusive rocks, as well as in metasomatic zones in calc-silicates around their margins. Scapolitized metadolerites, albitized calc-silicates, and large calcite pods and veins with 18O- and 13C-depleted values are typical of these regions and indicate localized throughput of predominantly externally derived fluid, at high F/R, accompanying the metamorphic peak. Major competency contrasts between meta-intrusive and calc-silicate rock types influenced stress and strain patterns around the igneous bodies, which in turn controlled fracture permeability and the focusing of the metamorphic fluid. The relatively brittle behavior of the meta-intrusive rocks favored the development of small-scale fracture permeability and consequent pervasive alteration of these bodies. Calcite vein systems and intensely albitized calc-silicate breccias are localized in shear zones and dilatant areas around the meta-intrusions, either where shear stresses were high or where all stresses were low, resulting in shear and tensile failure, respectively. Thus, permeability enhancement and the development of major fluid pathways during regional metamorphism of the terrain are systematically related to variations in the stress field accompanying deformation. Similar factors may strongly influence the channeling of fluids during metamorphism of other terrains. 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.
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