| Title | Isotopic and geochemical constraints on the age and origin of granitoids from the central Mawson Escarpment, southern Prince Charles Mountains, East Antarctica |
| Author | Boger, S.D.; Maas, R.; Fanning, C.M. |
| Author Affil | Boger, S.D., University of Melbourne, School of Earth Sciences, Melbourne, Victoria, Australia. Other: Australian National University, Australia |
| Source | Contributions to Mineralogy and Petrology, 155(3), p.379-400, . Publisher: Springer International, Heidelberg - New York, International. ISSN: 0010- 7999 |
| Publication Date | Mar. 2008 |
| Notes | In English. 93 refs. GeoRef Acc. No: 288147 |
| Index Terms | Antarctica--Prince Charles Mountains; absolute age; alkaline earth metals; Antarctica; dates; dikes; diorites; geochemical anomalies; geochemistry; granites; igneous rocks; intrusions; isotope ratios; isotopes; Lambert Complex; lithostratigraphy; Mac Robertson Land; magmatism; major elements; Mawson Escarpment; metals; metamorphic rocks; metasedimentary rocks; Nd-144/Nd-143; neodymium; nesosilicates; Ordovician; orthosilicates; Paleoproterozoic; Paleozoic; petrology; plutonic rocks; Precambrian; Prince Charles Mountains; Proterozoic; rare earths; silicates; Sr-87/Sr-86; stable isotopes; stratigraphic units; strontium; syntectonic processes; tonalite; trace elements; trondhjemite; U/Pb; upper Precambrian; yttrium; zircon; zircon group |
| Abstract | Granitoids from the central Mawson Escarpment (southern Prince Charles Mountains, East Antarctica) range in age from Archaean to Early Ordovician. U-Pb dating of zircon from these rocks indicates that they were emplaced in three distinct pulses: at 3,519±20, 2,123±12 Ma and between 530 and 490 Ma. The Archaean rocks form a layer-parallel sheet of limited extent observed in the vicinity of Harbour Bluff. This granitoid is of tonalitic-trondhjemitic composition and has a Sr-undepleted, Y-depleted character typical of Archaean TTG suites. #2ENd and TDM values for these rocks are -2.1 and 3.8 Ga, respectively. Subsequent Palaeoproterozoic intrusions are of granitic composition (senso stricto) with pronounced negative Sr anomalies. These rocks have #2ENd and TDM values of -4.8 and 2.87 Ga, indicating that these rocks were probably melted from an appreciably younger source than that tapped by the Early Archaean orthogneiss. The remaining intrusions are of Early Cambrian to Ordovician age and were emplaced coincident with the major orogenic event observed in this region. Cambro-Ordovician intrusive activity included the emplacement of layer- parallel pre-deformational granite sheets at approximately 530 Ma, and the intrusion of cross cutting post-tectonic granitic and pegmatitic dykes at ca. 490 Ma. (mod. journ. abst.) |
| URL | http://hdl.handle.net/10.1007/s00410-007-0249-x |
| Publication Type | journal article |
| Record ID | 85071 |