TY  - JOUR
A1  - Möller, Andreas
A1  - Hensen, Bastiaan J.
A1  - Armstrong, Richard A.
A1  - Mezger, Klaus
A1  - Ballévre, Michel
T1  - U-Pb zircon and monazite age constraints on granulite-facies metamorphism and deformation in the Strangways Metamorphic Complex (central Australia)
N2  - The age of Proterozoic granulite facies metamorphism and deformation in the Strangways Metamorphic Complex (SMC) of central Australia is determined on zircon grown in syn-metamorphic and syn-deformational orthopyroxene-bearing, enderbitic, veins. SHRIMP zircon studies suggest that M1-M2 and the correlated periods of intense deformation (D1-D2) are part of a single tectonothermal event between 1,717-2 and 1,732-7 Ma. It is considered unlikely that the two metamorphic phases (M1, M2) suggested by earlier work represent separate events occurring within 10-25 Ma of each other. Previous higher estimates for the age of M1 granulite metamorphism in the SMC (Early Strangways event at ca. 1,770 Ma) based on U-Pb zircon dating of granitic, intrusive rocks, are not believed to relate to the metamorphism, but to represent pre-metamorphic intrusion ages. Conventional multi-grain U-Pb monazite analyses on high-grade metasediments from three widely spaced localities in the western SMC yield 207Pb/235U ages between 1,728-11 and 1,712-2 Ma. The age range of the monazites corresponds to the SHRIMP zircon ages in the granulitic veins and is interpreted to record monazite growth (prograde in the metasedimentary rocks). The data imply a maximum time-span of 30 Ma for high-grade metamorphism and deformation in the SMC. There is, thus, no evidence for an extremely long period of continuous high- temperature conditions from 1,770 to ca. 1,720 Ma as previously proposed. The results firmly establish that the SMC has a very different high-grade metamorphic history than the neighbouring Harts Range, where upper amphibolite facies metamorphism in the Palaeozoic caused widespread growth or recrystallization of monazite.
Y1  - 2003
UR  - http://www.springerlink.com/app/home/ content.asp?wasp=nnkjymtwwjhb0ylpgw97&referrer=contribution&format=2&page=1&pagecount=18
ER  - 
TY  - JOUR
A1  - Schmidt, Alexander
A1  - Mezger, Klaus
A1  - O'Brien, Patrick J.
T1  - The time of eclogite formation in the ultrahigh pressure rocks of the Sulu terrane Constraints from Lu-Hf garnet geochronology
JF  - Lithos : an international journal of mineralogy, petrology, and geochemistry
N2  - Eclogites from the main borehole of the Chinese Continental Scientific Drilling project yield highly precise Lu-Hf garnet-clinopyroxene ages of 216.9 +/- 1.2 Ma (four samples) and 220.5 +/- 2.7 Ma (one sample). The spatial distribution of the rare earth elements in garnet is consistent with the preservation of primary growth zoning, unmodified by diffusion, which supports the interpretation that the Lu-Hf ages date the time of formation of garnet, the major rock forming mineral in the eclogites. The preservation of primary REE-zoning, despite peak metamorphic temperatures around 800-850 degrees C. indicates that the Lu-Hf chronometer is perfectly suitable to date garnet-forming reactions in high grade rocks. The range of Lu-Hf ages for eclogites in the Dabie-Sulu UHP terrane point to episodic rather than continuous growth of garnets and thus punctuated metamorphism during the collision of the North China Block and the Yangtze Block. The U-Pb ages and Hf-isotope systematics of zircon grains from one eclogite sample imply a protracted geologic history of the eclogite precursors that started around 2 Ga and culminated in the UHP metamorphism around 220 Ma.
KW  - Lu-Hf
KW  - Eclogite
KW  - Garnet
KW  - Geochronology
KW  - Ultrahigh-pressure
Y1  - 2011
U6  - https://doi.org/10.1016/j.lithos.2011.04.004
SN  - 0024-4937
VL  - 125
IS  - 1-2
SP  - 743
EP  - 756
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Wenzel, T.
A1  - Oberhänsli, Roland
A1  - Mezger, Klaus
T1  - K-rich plutonic rocks and lamprophyres from the Meissen Massif (northern Bohemian Massif) : Geochemical evidence for variably enriched lithospheric mantle sources
Y1  - 2000
ER  - 
TY  - JOUR
A1  - Kroner, Alfred
A1  - Oberhänsli, Roland
A1  - Mezger, Klaus
A1  - Teklay, M.
T1  - Geochemistry, Pb-Pb single zircon ages and Nd-Sr isotope composition of Precambrian rocks from southern and eastern Ethiopia: implications for crustal evolution in east Africa
Y1  - 1998
ER  -