Seismic images of crust and upper mantle beneath Tibet: evidence for Eurasian plate subduction.

Seismic data from central Tibet have been combined to image the subsurface structure and understand the evolution of the collision of India and Eurasia. The 410- and 660-kilometer mantle discontinuities are sharply defined, implying a lack of a subducting slab beneath the plateau. The discontinuities appear slightly deeper beneath northern Tibet, implying that the average temperature of the mantle above the transition zone is about 300 degrees C hotter in the north than in the south. There is a prominent south-dipping converter in the uppermost mantle beneath northern Tibet that might represent the top of the Eurasian mantle lithosphere underthrusting the northern margin of the plateau.

Partially Molten Middle Crust Beneath Southern Tibet: Synthesis of Project INDEPTH Results

INDEPTH geophysical and geological observations imply that a partially molten midcrustal layer exists beneath southern Tibet. This partially molten layer has been produced by crustal thickening and behaves as a fluid on the time scale of Himalayan deformation. It is confined on the south by the structurally imbricated Indian crust underlying the Tethyan and High Himalaya and is underlain, apparently, by a stiff Indian mantle lid. The results suggest that during Neogene time the underthrusting Indian crust has acted as a plunger, displacing the molten middle crust to the north while at the same time contributing to this layer by melting and ductile flow. Viewed broadly, the Neogene evolution of the Himalaya is essentially a record of the southward extrusion of the partially molten middle crust underlying southern Tibet.

Computerised dietary calculations: an interactive approach updated.

Five dietary interactive programs have been written based on the 4th edition of McCance and Widdowson's 'The composition of foods' (Paul & Southgate, 1978) to which additional recipes and foods, including products used in therapeutic diets, have been added. The programs are DIET1 for calculating the nutrient content of a meal, recipe or list of foods; DAILYD for calculating the nutrient intake for a day, meal by meal; EXCHNG for calculating the weights of any selected foods required to obtain any chosen weight of any selected nutrient; DIETAD which gives the code numbers and nutrient composition of foods which have been added; INFOD1 which gives the nutrient composition of any food on the file. The use of these programs is described and an example using DIET1 is given.