Reconciling Himalayan midcrustal discontinuities: The Main Central thrust system

The occurrence of thrust-sense tectonometamorphic discontinuities within the exhumed Himalayan metamorphic core can be explained as part of the Main Central thrust system. This imbricate thrust structure, which significantly thickened the orogenic midcrustal core, comprises a series of thrust-sense faults that all merge into a single detachment. The existence of these various structures, and their potential for complex overprinting along the main detachment, may help explain the contention surrounding the definition, mapping, and interpretation of the Main Central thrust. The unique evolution of specific segments of the Main Central thrust system along the orogen is interpreted to be a reflection of the inherent basement structure and ramp position, and structural level of exposure of the mid-crust. This helps explain the variation in the timing and structural position of tectonometamorphic discontinuities along the length of the mountain belt

Empirical constraints on extrusion mechanisms from the upper margin of an exhumed high-grade orogenic core, Sutlej valley, NW India

The Early–Middle Miocene exhumation of the crystalline core of the Himalaya is a relatively well-understood process compared to the preceding phase of burial and prograde metamorphism in the Eocene–Oligocene. Highly deformed rocks of the Greater Himalayan Sequence (GHS) dominate the crystalline core, and feature a strong metamorphic and structural overprint related to the younger exhumation. The Tethyan Sedimentary Series was tectonically separated from the underlying GHS during the Miocene by the South Tibetan Detachment, and records a protracted and complex history of Cenozoic deformation. Unfortunately these typically low-grade or unmetamorphosed rocks generally yield little quantitative pressure–temperature�time information to accompany this deformation history. In parts of the western Himalaya, however, the basal unit of the Tethyan Sedimentary Series (the Haimanta Group) includes pelites metamorphosed to amphibolite facies. This presents a unique opportunity to explore the tectono-thermal evolution of crystalline rocks which record the early history of the orogen. Pressure–temperature�time–deformation (P–T�t–d) paths modelled for two Haimanta Group pelitic rocks reveal three distinct stages of metamorphism: (1) prograde Barrovian metamorphism to 610–620 °C at c. 7–8 kbars, with garnet growing over an early tectonic fabric (S1); (2) initial decompression during heating to 640–660 °C at c. 6–7 kbars, with development of a pervasive crenulation cleavage (S2) and staurolite and kyanite porphyroblast growth; (3) further exhumation during cooling, with minor retrograde metamorphism and modification of the pervasive S2 fabric. Monazite growth ages constrain the timing of initial garnet growth (> 34 Ma), the start of D2 and maximum burial (c. 30 Ma), and the termination of garnet growth (c. 28 Ma). Muscovite Ar/Ar ages indicate cooling through c. 300 °C at c. 13 Ma, from which we derive an initial exhumation rate of c. 1.3 mm year? 1 for the Haimanta Group. The underlying GHS was exhumed at a rate of 2.2 to 3 mm year? 1 during this time. The difference in exhumation rate between these two units is considered to reflect Early Miocene displacement on the intervening South Tibetan Detachment. Slower exhumation (c. 0.6 mm year? 1) of both units after c. 13 Ma followed the cessation of major displacement on this structure, after which time the Haimanta Group and the GHS were exhumed as one relatively coherent tectonic block

The metamorphism and exhumation of the Himalayan metamorphic core, eastern Garhwal region, India

[1] Geothermobarometric together with micro- and macro-structural data indicate ductile flow in the metamorphic core of the Himalaya in the Garhwal region of India. Peak metamorphic pressure and temperature increase dramatically across the Main Central Thrust (MCT) from ~5 kbar and ~550°C in the Lesser Himalayan Crystalline Sequence (LHCS) to ~14 kbar and ~850°C at ~3 km above the MCT in the Greater Himalayan Sequence (GHS). Pressures within the GHS then decrease upsection to ~8 kbar while temperatures remain nearly constant at ~850°C up to the structurally overlying South Tibetan Detachment (STD). The GHS exhibits sheath fold geometries are indicative of high degrees of ductile flow. Overprinting ductile structures are two populations of extensional conjugate fractures and normal faults oriented both parallel and perpendicular to the orogen. These fractures crosscut major tectonic boundaries in the region such as the MCT and STD, and are found throughout the LHCS, GHS, and Tethyan Sedimentary Sequence (TSS). The thermobarometric and metamorphic observations are consistent with a form of channel flow. However, channel flow does not account for exhumational structures that formed above the brittle-ductile transition. To explain all of the features seen in the metamorphic core of the Garhwal region of the Himalaya, both the theories of channel flow and critical taper must be taken into account. Channel flow can explain the exhumation of the GHS from the middle crust to the brittle-ductile transition. The most recent extensional deformation is consistent with a supercritical wedge

A922 Sequential measurement of 1 hour creatinine clearance (1-CRCL) in critically ill patients at risk of acute kidney injury (AKI)

Meeting abstrac

Robust image analysis with sparse representation on quantized visual features

10.1109/TIP.2012.2219543IEEE Transactions on Image Processing223860-871IIPR

A next-generation liquid xenon observatory for dark matter and neutrino physics

The nature of dark matter and properties of neutrinos are among the most pressing issues in contemporary particle physics. The dual-phase xenon time-projection chamber is the leading technology to cover the available parameter space for weakly interacting massive particles, while featuring extensive sensitivity to many alternative dark matter candidates. These detectors can also study neutrinos through neutrinoless double-beta decay and through a variety of astrophysical sources. A next-generation xenon-based detector will therefore be a true multi-purpose observatory to significantly advance particle physics, nuclear physics, astrophysics, solar physics, and cosmology. This review article presents the science cases for such a detector

Post-humanitarianism: humanitarian communication beyond a politics of pity

This article offers a trajectory of humanitarian communication, which suggests a clear, though not linear, move from emotion-oriented to post-emotional styles of appealing. Drawing on empirical examples, the article demonstrates that the humanitarian sensibility that arises out of these emerging styles breaks with pity and privileges a short-term and low-intensity form of agency, which is no longer inspired by an intellectual agenda but momentarily engages us in practices of playful consumerism. Whereas this move to the post-emotional should be seen as a reaction to a much-criticized articulation between politics and humanitarianism, which relied on ‘universal’ morality and grand emotion, it is also a response to the intensely mediatized global market in which humanitarian agencies operate today. The article concludes by reflecting on the political and ethical ambivalence at the heart of this new style of humanitarian communication, which offers both the tentative promise of new practices of altruism and the threat of cultural narcissism