Nd, Pb, Hf isotope characteristics and provenance of glacial granitic pebbles from Late Ordovician diamictites in the Taurides, S Turkey

Outcrops of the Late Ordovician glacio-marine deposits in Tauride Anatolide Platform contain rare rounded/sub-rounded glacially transported granitic pebbles. Recently determined crystallization ages of the granitic fragments by LA-ICP-MS U-Pb zircon dating fall in two groups, 575 to 600 Ma and 700 to 965 Ma. Crystallization ages are in the range of juvenile magmatic rocks in the Arabian Nubian Shield except one sample implying pre-0.87 Ga magmatic activity. All dated granitic pebbles geochemically show arc-related compositions and juvenile isotopic systematics (whole rock _ƐNd_(T), Pb-Pb and zircon _ƐHf_(T) isotopic data). Marginal arc type sources fit well with the geochemical and isotopic data of the granitic pebbles of 700 and 800 Ma that have juvenile Hf-T_DM and older Nd-T_CR modal ages. However, A-type affinity of three samples, ranging from 575 to 600 Ma show that they might have been derived from mixing of juvenile mantle and older crustal sources having older Hf-T_DM and Nd-T_CR modal ages. A 965 Ma granitic fragment has the oldest Hf-T_DM and Nd-T_CR model age(s) implying involvement of pre-Neoproterozoic crustal source(s) in its genesis. These results collectively suggest that the glacio-marine successions in the Tauride Anatolide Platform were eroded from Neoproterozoic granitic/meta-granitic/meta-granodioritic rocks in the northern Nubian Shield (Egypt) and were then transported to the Tauride-Anatolide Platform by the glacial sheets during Late Ordovician time.