Mica and hornblende K‐Ar Ar‐Ar data are presented from each of the three crustal components Himalayan collision zone in North Pakistan: Asian plate, Kohistan Island Arc, Indian plate. Together with U‐Pb Rb‐Sr published elsewhere these new (1) date age suturing along Northern Suture, which separates Asia, at 102–85 Ma; (2) establish that basic magmatism Kohistan, postdates predates 60 Ma, later granite spanned a range 60–25 (3) show uplift amounts within greater toward Nanga Parbat syntaxis...

New field mapping and structural data, combined with published geochemical from the Kohistan arc in NW Himalaya, enable a re-evaluation of stratigraphy. Key lithological units their relationships are more clearly defined, permitting construction revised magmatic-tectonic history for arc. The oldest transitional oceanic-type basalts, which form basement to subduction related sequence. Arc-type gabbroic sheets plutons intrude oceanic basalts: together these Kamila Amphibolite Belt....

The world-class Loulo mining district (15.5 Moz resource), in the Birimian terrane of western Mali, contains a range mineralogically diverse styles orogenic gold mineralization. is distinguished by As-rich orebodies as at Yalea, well tourmaline-bearing, Fe-rich, Gara. New fluid inclusion and stable isotope data presented here constrain nature hydrothermal fluids responsible for these different types mineralization, point towards role multifluid sources (metamorphic magmatic) formation...

Research Article| May 01, 1994 Mechanisms of continental growth in extensional arcs: An example from the Andean plate-boundary zone John Grocott; Grocott 1School Geological Sciences, Kingston University, Kingston-upon-Thames KT1 2EE, United Kingdom Search for other works by this author on: GSW Google Scholar Michael Brown; Brown 2Department Geology, University Maryland, College Park, Maryland 20742 R.David Dallmeyer; Dallmeyer 3Department Georgia, Athens, Georgia 30602 Graeme K. Taylor;...

Abstract A synthesis of the available tectonic, structural, magmatic and geochronologic data from Afghanistan western Pakistan suggests that collision between Indian Plate Afghan Block (a collage blocks assembled during Cimmeride orogeny), took place Pliocene. Prior to this, thinned margin Plate, together with transitional oceanic crust which separated Block, was overlain by a wedge Tertiary clastic sediments deposited in large flexural basin included what is now Katawaz as well Sulaiman...

Loulo is a world-class orogenic gold mining district in the Birimian terrane of western Mali. Orebodies are located along second or higher order shears associated with Senegal-Mali shear zone, mineralization largely linked to transtensional event. The mine camp divided into two distinct styles deposit on basis differing geologic characteristics. One group typified by Gara deposit, whereas other Yalea deposit. Both hosted similar rock types (calcareous graywackes and calciticdolomitic...

In North Chile, Jurassic-Cretaceous arc magmatism is represented by several narrow belts of plutons and two separate volcanic sequences. New $$^{40}Ar/^{39}Ar$$ mineral ages confirm five distinct episodes magma emplacement as plutonic complexes (c. 202-188 Ma, c. 160-153 142-138 130-127 106-103 Ma). Conjugate dike sets were emplaced immediately before periods plutonism, each episode prior to 127 Ma was located successively eastward, inboard from the subduction boundary, features interpreted...

Early Tertiary, coesite-bearing eclogites crop out in the internal zones of Indian Plate Kaghan Valley North Pakistan. Field and geochronological data suggest that UHP metamorphism, at c . 46 Ma, accompanied subduction leading edge continental India beneath Kohistan. A new U–Pb rutile age 44.1 ± 1.1 Ma can be interpreted as either a growth or cooling age, given uncertainty closure temperature for Pb, but clearly documents very short-lived metamorphic peak, with occurring between 44 40 Ma....

ABSTRACT South of the Main Mantle Thrust in north Pakistan, rocks northern edge Indian plate were deformed and metamorphosed during main southward thrusting phase Himalayan orogeny. In Hazara region, between Indus Kaghan Valleys, metamorphic grade increases northwards from chlorite zone to sillimanite a typically Barrovian sequence. Metamorphism was largely synchronous with early phases deformation. The subsequently imbricated by late north‐dipping thrusts, each higher hanging wall than...

India collided with a northern Kohistan-Asian Plate at about 50 Ma ago, the time of ocean closure being fairly accurately defined from syntectonic sediments as well effect on magnetic stripes Indian Ocean floor. Since collision, Asia has over-ridden India, developing wide range thrust scrapings top Plate. Sections through imbricated sedimentary cover suggest minimum displacement over 500 km during Eocene to recent plate convergence. This requires Kohistan region north be underlain by...

The Greater Himalayan Sequence in India and Nepal records crustal thickening processes that took place during following the onset of India-Asia collision (ca. 54–50 Ma). These resulted late Eocene–early Miocene kyanite- sillimanite-grade regional metamorphism, Oligocene–Miocene anatexis, which formed migmatites leucogranites. We present new U-Pb monazite data for gneisses Neoproterozoic to Cambrian Tanawal Formation Pakistan Himalaya, have metamorphic ages 482.4 ± 7.9 Ma 464.5 4.0 Ma,...

The intra-oceanic Kohistan island arc was initiated during the Cretaceous as a result of northward movement Indian Plate. conventional assertion that erected above north-dipping subduction zone has been challenged by an alternative hypothesis, which suggests built south-dipping zone. This hypothesis is based partly on apparent presence ‘Dupal’ signature in mafic rocks arc, and occurrence boninites exposed northern part arc. signature, with enhanced levels radiogenic lead, found only...

Abstract Regional metamorphic rocks in the Pakistan Himalaya include both UHP coesite eclogite-facies and MP/T kyanite–sillimanite-grade Barrovian rocks. Age data show that peak metamorphism of was c. 47 Ma. 40 Ar– 39 Ar hornblende cooling ages date post-peak through 500 °C by Ma, some 20 Ma earlier than for central eastern Himalaya. Typically these have been explained obduction Kohistan arc onto Indian plate at about 50 India–Asia collision. We suggest instead Pakistani sequence could be...