Unroofing of active metamorphic core complexes in the D'Entrecasteaux Islands, Papua New Guinea

Abstract

Research Article| October 01, 1992 Unroofing of active metamorphic core complexes in the D'Entrecasteaux Islands, Papua New Guinea E. J. Hill; E. J. Hill 1Victorian Institute of Earth and Planetary Sciences, Department of Earth Sciences, Monash University Clayton, Victoria 3168, Australia Search for other works by this author on: GSW Google Scholar S. L. Baldwin; S. L. Baldwin 2Research School of Earth Sciences, Australian National University, GPO Box 4, Canberra, A.C.T. 2601, Australia Search for other works by this author on: GSW Google Scholar G. S. Lister G. S. Lister 1Victorian Institute of Earth and Planetary Sciences, Department of Earth Sciences, Monash University Clayton, Victoria 3168, Australia Search for other works by this author on: GSW Google Scholar Author and Article Information E. J. Hill 1Victorian Institute of Earth and Planetary Sciences, Department of Earth Sciences, Monash University Clayton, Victoria 3168, Australia S. L. Baldwin 2Research School of Earth Sciences, Australian National University, GPO Box 4, Canberra, A.C.T. 2601, Australia G. S. Lister 1Victorian Institute of Earth and Planetary Sciences, Department of Earth Sciences, Monash University Clayton, Victoria 3168, 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 (10): 907–910. https://doi.org/10.1130/0091-7613(1992)020<0907:UOAMCC>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 MailTo Tools Icon Tools Get Permissions Search Site Citation E. J. Hill, S. L. Baldwin, G. S. Lister; Unroofing of active metamorphic core complexes in the D'Entrecasteaux Islands, Papua New Guinea. Geology 1992;; 20 (10): 907–910. doi: https://doi.org/10.1130/0091-7613(1992)020<0907:UOAMCC>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 Metamorphic core complexes in the D'Entrecasteaux Islands are forming as a result of active extension at the western end of the Woodlark Basin spreading center. High-grade metamorphic rocks exist in the cores of gneissic domes, including eclogites formed at minimum depths of 45-75 km (i.e., 13-21 kbar). High temperatures were maintained during uplift of basement rocks from 13-21 kbar (T ≈ 730-900 °C) through 7-11 kbar (T ≈ 570-730 °C) to ∼5-6 kbar (T ≈ 730 °C). Subsequent rapid cooling (>>100 °C/m.y.) of the basement occurred between 1 and 2 Ma (on the basis of 40Ar/39Ar geochronology). The core-zone rocks were transected by kilometre-scale, amphibolite-facies ductile shear zones active at depths of 25-35 km. Extensive intrusion of granodiorite plutons occurred, and the age of granodiorite intrusions constrains late-stage shear-zone activity to ∼2 Ma and younger. Unroofing was accomplished by faults and shear zones bounding the gneiss domes, juxtaposing them against ultramafic rocks and sedimentary deposits. Surface uplift continues today and has led to topographic elevations of up to 2.5 km. 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.