U–Pb SIMS dating of synkinematic granites: timing of core-complex formation in the northern Anatolide belt of western Turkey

Secondary ion mass spectrometry (SIMS) U–Th–Pb dating of magmatic zircon from the synkinematic Egrigoz and Koyunoba granites and a leucogranite dyke dates core-complex formation in the northern Anatolide belt of western Turkey at 24–19 Ma. The granites intrude into the footwall of the Simav detachment and are strongly elongated in the NNE direction parallel to tectonic transport on the detachment. Although large parts of the granites are undeformed, localized mylonitic to ultramylonitic deformation occurs directly beneath the Simav detachment and preserves evidence of progressive deformation from ductile to brittle conditions. Oscillatory zoned rims of long-prismatic zircon from the Egrigoz…

Has the East African Orogen Played Any Role in the Formation and Breakup of the Supercontinent Rodinia and the Amalgamation of Gondwana? New Evidence from Field Relationship and Isotopic Data

Structural and thermal history of poly-orogenic basement: U-Pb geochronology of granitoid rocks in the southern Menderes Massif, Western Turkey

Ion microprobe U-Pb dating of granitoid rocks from key structural outcrops of the Menderes Massif in western Turkey provides an important constraint to the thermal and deformational history of a structurally complex metamorphic belt within the Alpine chain. Crystallization ages of two granite protoliths, derived from the weighted means of rim ages and the ages of homogeneous prismatic zircon grains, are 541 +/- 14 Ma and 566 +/- 9 Ma, whereas the cores of zoned pyramidal and short-prismatic zircon grains range from Palaeoproterozoic to Neoproterozoic in age. These ages indicate that amphibolite- to gramilite-facies metamorphic rocks in much of the Menderes Massif were deformed, metamorphose…

Detrital footprint of the Mozambique ocean: U–Pb SHRIMP and Pb evaporation zircon geochronology of metasedimentary gneisses in eastern Madagascar

Abstract The southern East African Orogen is a collisional belt where the identification of major suture zones has proved elusive. In this study, we apply U–Pb isotopic techniques to date detrital zircons from a key part of the East African Orogen, analyse their possible source region and discuss how this information can help in unravelling the orogen. U–Pb sensitive high-mass resolution ion microprobe (SHRIMP) and Pb evaporation analyses of detrital zircons from metasedimentary rocks in eastern Madagascar reveal that: (1) the protoliths of many of these rocks were deposited between ∼800 and 550 Ma; and (2) these rocks are sourced from regions with rocks that date back to over 3400 Ma, with…

Continental Construction in Central Asia (IGCP-592): Scientific Results and Meetings in 2012

IGCP-Project #592 (2012-2015) "Continental construction in Central Asia", funded by UNESCO-IUGS, was launched in April 2012. The Project focuses on tectonic and magmatic aspects of formation of continental crust in the Central Asian Orogenic Belt and their comparison with actualistic examples from the western Pacific. This report summarizes related scientific results and meetings. In total, in 2012 the Project organized, and/or participated in the organization of, six international conferences and workshops, three of which were accompanied by training schools for young scientists and special training courses. At the present time, more than 250 scientists from 27 countries expressed their in…

Proterozoic Tectonostratigraphy and Paleogeography of Central Madagascar Derived from Detrital Zircon U‐Pb Age Populations

Abstract Detrital zircon U‐Pb ages determined by SHRIMP distinguish two clastic sequences among Proterozoic metasedimentary rocks from central Madagascar. The Itremo Group is older: zircon data, stromatolite characteristics, and carbon isotope data all point to a depositional age around 1500–1700 Ma. The Molo Group is younger, deposited between ∼620 Ma (the age of the youngest zircon) and ∼560 Ma (the age of metamorphic overgrowths on detrital cores). Geochronologic provenance analysis of the Itremo Group points to sources in East Africa as well as local sources in central and southern Madagascar but provides no evidence for a detrital contribution from northern and eastern Madagascar nor f…