Neutron activation analysis was employed in a survey of weathering abilities of rock surface microorganisms. A yeast isolated from an amphibolite of a megalithic grave was found actively to concentrate, in media and in or on cells, iron and other elements when grown in the presence of ground rock. This was demonstrated by comparing a spectrum of neutron-activated amphibolite powder (particle si...

SUMMA R Y. In the Dahomeyan of the western Accra Plains marie gneisses, amphibolites, and orthoamphibolite dykes in granitic gneiss occur. During the latest recrystallization, metamorphic conditions ranged (north to south) from oligoclase--epidote amphibolite subfacies through andesineepidote amphibolite subfacies to at least the medium or upper part of the amphibolite facies. Chemical analyses...

The Nahal Yael basin is underlain chiefly by schist, amphibolite, and granite. Thin (generally < 1 m thick), grussy colluvium which covered the lower portions of granitic hillslopes in the late Pleistocene has now been stripped completely, causing marked contrasts in outcrop morphologies, even where there is no contrast of fracture density or petrologic characteristics. Formerly mantled slopes ...

Introduction The lowest known portion of the Poorman Formation as determined from diamond drilling and mapping is the Yates Unit. It largely comprises amphibolite, but also contains interbedded volcaniclastics, calc-silicate beds, metachert, and carbonate-rich semipelitic rocks. This unit is exposed at the surface in the Blacktail Gulch area north of Lead and continues down-plunge to the southe...

Lithium concentrations and isotopic compositions in the country rocks (amphibolites and schists) of the Tin Mountain pegmatite show systematic changes with distance to the contact. Both Li and δLi decrease dramatically along a ∼10m traverse from the pegmatite into amphibolite, with Li concentration decreasing from 471 to 68ppm and δLi decreasing from +7.6 to −19.9. Rubidium and Cs also decrease...

Amphibolite blocks from an Archaean (2.9 Ga) trondhjemite-agmatite complex in the Lewisian at Gruinard Bay have a varied trace element and R E E content. Whilst some of the variability is attributable to element mobility during high-grade metamorphism and subsequent trondhjemite magmatism, it is for the main part considered to be a primary feature of the amphibolites. The observed trace element...

Thermobarometry suggests that ultrahigh-pressure (UHP) to high-pressure (HP) rocks across the Western Gneiss Region ponded at the Moho following as much as 100 km of exhumation through the mantle and before exhumation to the upper crust. Eclogite across the c. 22 000 km study area records minimum pressures of c. 8–18 kbar and temperatures of c. 650–780 C. One orthopyroxene eclogite yields an UH...

[1] The Nordfjord area of western Norway hosts one of the best known provinces of ultrahigh-pressure (UHP) rocks in the world, yet the nature of the transition from the UHP rocks into surrounding amphibolite-facies crust has remained unclear. New thermobarometry of phengiteand kyanite-bearing eclogites shows that this transition is unbroken by major structures: the pressure and temperature grad...