Unconventional hydrocarbon reserves substantially surpass those of conventional resources and therefore are extremely economically attractive. However, exploration and production of unconventional reserves is challenging. This paper demonstrates that one can observe significant induced polarization effects in shale reservoir rocks, which can be used in exploration for unconventional reserves. T...

Hydrocarbon wells drilled vertically through longwall coal pillars are vulnerable to severe deformation and potential failure as a result of underground coal mining. The lithology of the host rocks play a critical role in well stability. In this study, a two dimensional finite element method is employed to investigate the horizontal shear offset, vertical delamination, and compression at the we...

This paper presents a wavelet based method of analysis of experimentally recorded weak electric signals from marble specimens which have undergone successive abrupt step loadings. Experimental results verify the existence of “memory effects” in rocks, as far as the current emission is concerned, akin to the “Kaiser effect” in acoustic emissions, which accompany rock fracturing. Macroscopic sign...

The polar desert is one of the most extreme environments on Earth. Endolithic organisms can escape or mitigate the hazards of the polar desert by using the resources available in the interior of rocks. We examined endolithic communities within crystalline rocks that have undergone shock metamorphism as a result of an asteroid or comet impact. Specifically, we present a characterization of the h...

The Isua greenstone belt (Fig. 1) contains the oldest known, relatively well preserved, metavolcanic and metasedimentary rocks on Earth. The rocks are all deformed and many were substantially altered by metasomatism, but both the deformation and metasomatism were heterogeneous. Transitional stages can be seen from relatively well preserved primary volcanic and sedimentary structures to schists ...

Osmium isotope compositions and concentrations of Re, platinum group elements (PGE), and Au were determined for host peridotites (serpentinites and harzburgites) and hydrothermally altered ultramafic wall rocks associated with Mother Lode-type hydrothermal gold-quartz vein mineralization in the Alleghany district, California. The host peridotites have Os isotope compositions and Re, PGE, and Au...

The role of the subducting lithospheric slab in the genesis of mantle-derived (primitive) magmas is investigated through a study of volcanic rocks formed in the tectonically strike-slip–dominated western Aleutian arc. Two types of chemically and petrologically distinctive primitive andesites have been found among the Miocene– late Pleistocene–age volcanic rocks in the western Aleutians. These a...

Two-dimensional measurement of radiation produced by natural irradiation of granitic rocks was performed by the use of an imaging plate, which is a storage film coated with photostimulated phosphor (BaFBr:Eu2+). Radiation images of small volume specimens, such as thin sections were obtained with the imaging plate. Irradiation images of granitic rocks are inhomogeneous and the intensity of photo...

Introduction The special issue of this journal (Nov. 2000) that was devoted to “Some Great Ideas for Geoscience Courses,” included nine ideas under the heading “Earth materials.” Six of those papers involved classification (Thomas and Thomas, 2000; Dowse, 2000; Reynolds and Semken, 2000; Harper, 2000; Christman, 2000; Niemitz, 2000). Classification of rocks and minerals is obviously a necessary...

ONE petrological approach to upper mant le studies is to determine which ultramafic rocks represent mantle material. Ultramafic rocks occur in a variety of field and petrographic associations : in recent reviews, Wyllie [1967b, 1968] outlined eleven petrographic associations, some with subdivisions. In this summary, it is convenient to consider these in four larger groups: (1) layered, stratifo...