The Big Jim complex is a concentrically zoned ultramafic to felsic plutonic complex which intruded the pelitic Chiwaukum schist. Most of the major plutonic rock types (from websterite through hornblendite, gabbronorite, hornblende gabbro and diorite, to granodiorite) enclose harzburgite and metaperidotite xenoliths similar to foliated metaperidotite lenses included in the Chiwaukum schist. The ...

The Lewisian complex of northwest (NW) Scotland has long been correlated with intercontinental Palaeoproterozoic belts of the North Atlantic region but uncertainty about the age and origin of the supracrustal rocks of the Loch Maree Group (LMG) and the apparent lack of subduction-related intrusive rocks have precluded interpretations of a similar tectonic setting for the Lewisian. We present in...

The Erongo subvolcanic center in Namibia is the largest composite, bimodal complex in the Mesozoic Etendeka igneous province of Namibia. This study of 40Ar/39Ar and high spatial resolution U^Pb zircon dating demonstrates that emplacement of the various igneous units at Erongo took place within a time span equivalent to or shorter than geochronologically resolvable age differences (ca. 2 Ma), an...

Determining the timing, magnitude, and location of deformation due to the Indo-Asian collision is widely acknowledged as an important step in understanding how the lithosphere responds during continental collision. A puzzling result of geological investigations of the Lhasa Block over the past 2 decades has been the apparent lack of significant Tertiary deformation there. Perhaps the most impor...

Abstract Tonalite-trondhjemite-granodiorite (TTG) suites are the dominant component of Earth's first continents, but their origins debated. The trace element concentrations these rocks conventionally linked to source depths and inferred geodynamic settings with implicit assumption that TTG compositions source-controlled. Alternatively, variable may be caused by fractional crystallization in plu...

The Sierra de Guasayán (Eastern Sierras Pampeanas, Argentina) is formed by low to medium grade metamorphic rocks intruded Cambrian metaluminous (La Soledad quartz-diorite), slightly peraluminous (Guasayán, El Escondido and Martirizado granodiorite plutons), strongly (Alto Bello granodiorite) granitoids of the Pampean magmatic arc. Chemical compositions amphibole, plagioclase, biotite, titanite ...

Although the quest for Earth's oldest rock is of great importance, identifying the youngest exposed pluton on Earth is also of interest. A pluton is a body of intrusive igneous rock that crystallized from slowly cooling magma at depths of several kilometers beneath the surface of the Earth. Therefore, the youngest exposed pluton represents the most recent tectonic uplift and highest exhumation....