This study suggests that multiple etches are required when a complete spectrum of ages in a zircon suite is desired.We present here bulk sediment major element chemistry, Nd and Sr isotope ratios, and detrital apatite fission-track (AFT) and U-Pb zircon ages to characterize the provenance of the southwestern Taklimakan Desert (northwest China) and the...The Almora–Dadeldhura klippe in the Kumaun–Garhwal andwestern Nepal Himalaya is the witness and largest representative of these crystalline klippen, south of MCT.Here, we investigate the post-emplacement kinematics and exhumation history of the Almora klippe.The Ayder granitoid (46.4 ± 1.0 Ma) is the result of middle- to late-Eocene post-collisional magmatism related to slab break-off.The Halkalıtaş quartz diorite (43.7 ± 2.3 Ma) and the Güllübağ monzonite (38.1 ± 0.9 Ma) document a middle- to late-Eocene episode related to post-collisional extension. Wolf-Christian Dullo (IFM-GEOMAR) are kindly thanked for their constructive comments which improved the manuscript.The Kaçkar batholith in the Turkish eastern Pontides comprises several intrusive units with distinctive textural, mineralogical and geochemical characteristics.Their titanite and zircon fission-track ages confirm that the different lithodem units result from consecutive igneous episodes, establish their emplacement sequence and, together with geochemical data, help to relate them to their geodynamic context.
Here we address the latter issue using WUSEM, an...South of the Mazatag Ridge a significant eolian deposit accumulated ~500 yr ago, but this has been deflated in more recent times.Comparison of the modern river data with those previously measured from Cenozoic foreland sedimentary rocks shows that no sediment similar to that of the modern Yarkand River is seen in the geologic record, which is inferred to be younger than 11 Ma, and probably much less. 17 Ma, somewhat after that of the Pamir and Songpan Garze of northwestern Tibet, dated to before 24 Ma.The data reveal the advantages of dense sampling, spanning a maximum range of elevations.
Apart from the increased precision on the mean, redundant sampling allows to shift the basis for interpretation from a priori assumptions to a posteriori numerical criteria when using geochronometers with low to moderate closure temperatures, including apatite, titanite and zircon fission-tracks but also K–Ar (Ar–Ar) biotite, muscovite and K-feldspar.
The Çamlıkaya granitoid (112.4 ± 1.6 Ma) was emplaced during an immature-arc magmatic episode of early Cretaceous age.