Structure of intertidal and subtidal benthic macrofauna in the northeastern region of Todos os Santos Bay (TSB), northeast Brazil, was investigated during a period of two years. Relationships with environmental parameters were studied through uniand multivariate statistical analyses, and the main distributional patterns shown to be especially related to sediment type and content of organic frac...

Isotopic data were collected on lower crustal xenoliths to constrain the Mexican lower crust as source material for the mid-Tertiary Sierra Madre Occidental, which is one of the largest silicic volcanic piles known. The xenoliths are predominantly pelitic gneisses and marie orthogneisses that were brought to the surface on the eastern edge of the Sierra Madre Occidental by recent alkalic basalt...

The conditions at which monazite and allanite were produced and destroyed during prograde metamorphism of pelitic rocks were determined in a Buchan and a Barrovian regional terrain and in a contact aureole, all from northern New England, USA. Pelites from the chlorite zone of each area contain monazite that has an inclusion-free core surrounded by a highly irregular, inclusion-rich rim. Texture...

The Achemmach region is located 40 km to the SW from Meknes city and 6 NE frm Hammam mine. It part of Paleozoic massif Central Morocco. studied area formed by two rock-types: (i) a meta-sedimentary sequence composed Middle Visean limestone shale-sandstone withflyschoid Upper Visean-Namurian age, (ii) magmatic rock series represented volcanic rocks (pillow-lavas), hypovolcanic (dolerites) olivin...

the cheshin meta-calcareous rocks (permo triassic) in southeast hamedan outcrop in association with a variety of pelitic schists and hornfels rocks. the intrusion of the alvand batholith (jurassic age) into pelitic and calcareous host rocks has produced metamorphic rocks in the hamedan area (cheshin village). on the basis of the dominance of calcite/dolomite, silicate and ore minerals, the calc...

In continental arcs the extension of geothermal gradients derived from shallow crustal levels to depth predicts widespread melting at pressures that are inconsistent with seismic studies. Numerical models of low-pressure metamorphism in continental arcs suggest that these extrapolations are problematic because magmatic advection is the dominant mechanism of heat transport in these terranes rath...