The Neogene Browning on Central Asia

The Neogene de-greening of Central Asia

Authors:

Caves et al

Abstract:

There remains substantial debate concerning the relative roles of tectonics and global climate in driving the evolution of climate in Central Asia. Today, interior Asia—including the Taklamakan, Gobi, and Ordos Deserts—is exceptionally arid and is surrounded by distinct rainfall boundaries, such as those generated by the Asian monsoon systems to the east and south and those generated by high topography to the north and west. Determining how and why these boundaries have varied over the Neogene is hindered by the lack of a single proxy that can be broadly applied through space and time. We construct isoscapes of pedogenic carbonate δ13C (δ13Cc) over the Neogene in Asia by combining a compilation of 2236 published measurements with new data from three localities in northern Central Asia. Pedogenic carbonate δ13C records local aridity—excepting localities impacted by C4 grasslands and during large changes in atmospheric pCO2—through variations in soil respiration, depth of carbonate formation, and the effect of water stress on plant δ13C. Together, these effects reflect changes in both primary productivity and mean annual precipitation. Throughout the Neogene, we find consistent and exceptionally high δ13Cc in interior Asia with a ring of lower δ13Cc that demarcates higher precipitation. This persistent ring of lower δ13Cc corresponds in the south and east with the influence of the Asian monsoon systems; in the west and north, it reflects both orographic rainfall due to uplift of the Tian Shan and to moisture delivery by the mid-latitude westerlies. Finally, δ13Cc and, hence, aridity increases regionally in the latest Neogene, reflecting the effects of Northern Hemisphere glaciation and cooling. This widespread "de-greening" would have increased regional albedo and modified basin-scale water balances, resulting in greater dust fluxes due to reduced vegetative cover and precipitation.

Paleogene Oyster Shell Mg/Ca as Palaeotemperature Proxy

Mg/Ca in fossil oyster shells as palaeotemperature proxy, an example from the Palaeogene of Central Asia

Authors:

Bougeis et al

Abstract:

Fossil oyster shells are well-suited to provide palaeotemperature proxies from geologic to seasonal timescales due to their ubiquitous occurrence from Triassic to Quaternary sediments, the seasonal nature of their shell growth and their relative strong resistance to post-mortem alteration. However, the common use to translate calcitic oxygen isotopes into palaeotemperatures is challenged by uncertainties in accounting for past seawater δ18O, especially in shallow coastal environment where oysters calcify. In principle, the Mg/Ca ratio in oyster shells can provide an alternative palaeothermometer. Several studies provided temperature calibrations for this potential proxy based on modern species, nevertheless their application to palaeo-studies remains hitherto unexplored. Here, we show that past temperature variability in seawater can be obtained from Mg/Ca analyses from selected fossil oyster species and specimens. High-resolution Mg/Ca profiles, combined with δ18O, were obtained along 41 fossil oyster shells of seven different species from the Palaeogene Proto-Paratethys sea (Central Asia) found in similar as well as different depositional age and environments providing comparison. Suitable Mg/Ca profiles, defined by continuous cyclicity and reproducibility within one shell, are found to be consistent for specimens of the same species but differ systematically between species, implying a dominant species-specific effect on the Mg/Ca signal. Two species studied here (Ostrea (Turkostrea) strictiplicata and Sokolowia buhsii) provide an excellent proxy for palaeoclimate reconstruction from China to Europe in Palaeogene marine sediments. More generally, the protocol developed here can be applied to identify other fossil oyster species suitable for palaeoclimate reconstructions.

Therizinosaurs From Upper Cretaceous Uzbekistan

Therizinosauroidea (Dinosauria: Theropoda) from the Upper Cretaceous of Uzbekistan

Authors:

Sues et al

Abstract:

Skeletal remains of indeterminate therizinosauroid dinosaurs are present in the Cenomanian Khodzhakul Formation and common in the Turonian Bissekty Formation of Uzbekistan. At least two taxa are present in the Bissekty Formation based on different frontal and humerus morphotypes. Phylogenetic analysis based on a dataset with 348 morphological characters and including all known therizinosaurian taxa places the Bissekty taxa as derived non-therizinosaurid therizinosauroids. The Bissekty therizinosauroids are more derived than Alxasaurus elesitaiensis in the extensive pneumatization of the postcranial axial skeleton, the absence of teeth in the anterior portion of the dentary, the weak development or even absence of pits for the collateral ligaments on the manual phalanges, and the subtriangular medial aspect of the distal end of the humerus, with the entepicondyle positioned well medial to the ulnar condyle. They are less derived than Therizinosauridae in the presence of a basisphenoid recess, the absence of pneumatic openings on the anterior caudal vertebrae, the distal end of metacarpal III not being ginglymoid in dorsal view, and the separation of the femoral head from the neck of that bone by a raised ventral rim.

Military Assistance & its Sources in Central Asia in the Future

As the drawdown of foreign forces from Afghanistan has accelerated in the run-up to their withdrawal by the end of 2014, attention has come to focus on the extent to which military equipment will be left behind for the use of the Central Asian states.

Over the past decade, Russia and the United States have been the main sources of military assistance to Central Asian states, while other countries have played much smaller roles. The USA is in the process of reducing its assistance to the region as it completes its withdrawal from Afghanistan. Russia is likely to remain the main source of military and security assistance for most Central Asian states.

External military assistance to Central Asian states is unlikely to have a serious negative impact on regional stability and security. Internal instability is the most serious threat that these states are likely to face. Steps will have to be taken to ensure that future assistance does not enhance the ability of internal security forces to harm civilians. This can be accomplished by focusing on training programmes over the provision of military equipment.

This is a summary from the work of Dmitry Gorenburg @ Russian Military Reform. At his site there are links to the working paper and policy paper. I suggest you take a look there.

How the Russian Military is Preparing for Central Asia's Potential Future Instability

The most recent issue of the Moscow Defense Brief has an interesting article by Maksim Shepovalenko on “Russian Preparations for Reduced Foreign Military Presence in Afghanstan.” It starts with the usual line on how the Taliban could spread instability to Central Asia if it came to power after the coming withdrawal of ISAF, which is an argument that I and others have found to be exaggerated at times. The threat of Islamist infiltration of Central Asia is often used by Central Asian and Russian governing elites to justify their security policies in the region, whereas most Islamist groups in the region are now far more focused on developments in Afghanistan itself and in parts of Pakistan. Islamist groups external to the region are primarily focused on fighting in Syria and, to a lesser extent, Iraq. So the greater threat to Central Asia comes from internal instability, such as the violent protests that have regularly shaken Kyrgyzstan in recent years, conflicts among the Central Asian states (as highlighted by the recent border conflict between Kyrgyzstan and Tajikistan), and the possibility of fighting resulting from a succession crisis in Uzbekistan or Kazakhstan. But although it doesn’t say anything new on the nature of the threat facing Central Asia, the MDB article does gets interesting once it starts to talk about the capabilities of Russian forces in or near Central Asia.

link.