At the southernmost part of Tierra del Fuego a few outcrops and erratic boulders of alkali basaltic rocks with ultramafic enclaves have been studied. Alkali basalt plugs or pipes hitherto identified are scarce, and host rocks are constituted by slates that belong to Mesozoic deposition. The petrography, texture and composition of the basalt and xenoliths were investigated by petrographic micros...

the pyroxene composition of basaltic rocks from the coloured series and exotic blocks in the neyriz area are discussed. comparison has been made with equivalent rocks from oman. the clinopyroxene compositions are in cognation with trace and rare-earth element analyses which definately confirm the occurrence of three different trends in basic lavas: i-depleted tholeiite, 2-transitional basalt, 3...

The pyroxene composition of basaltic rocks from the Coloured Series and Exotic blocks in the Neyriz area are discussed. Comparison has been made with equivalent rocks from Oman. The clinopyroxene compositions are in cognation with trace and rare-earth element analyses which definately confirm the occurrence of three different trends in basic lavas: I-Depleted tholeiite, 2-Transitional basal...

the nayband strike-slip fault forms the western margin of the micro-continental lut block in eastern iran. neogene and quaternary mafic volcanic rocks collected near tabas, along the northern part of the fault (nnf; 15 ma), and further to the south, along the middle part of the fault (mnf; 2 ma), are within-plate sodic-series alkali olivine basalts with high tio2 and up to >16% normative nephel...

Petrologic analysis of the lunar surface is critical for determining lunar formation and evolution. Here, we report the first global petrologic map that includes the five most important lunar lithological units: the Ferroan Anorthositic (FAN) Unit, the Magnesian Suite (MS) Unit, the Alkali Suite (AS) Unit, the KREEP Basalt (KB) Unit and the Mare Basalt (MB) Unit. Based on the petrologic map and...

there are three different basic dykes in the northeast of golpayegan area, central part of sanandaj-sirjan zone (ssz) including: mylonitic gabbros (group 1), alkali dioritic-basanitic dykes (group 2) and alkali monzogabbroic to monzodioritic dykes (group 3). group 2 and 3 cut post-collisional rocks and are related to after subduction processes of neo-tethys. geochemistry characteristic of studi...

Studies of the origin of magmas in subduction zones, particularly in the Japanese island arc, have been significantly advanced by petrological, geochemical, geophysical and experimental studies during last 50 years. Kuno's original model(1)) for magma generation in the Japanese island arc, that tholeiite magmas are formed at relatively shallow levels in the mantle on the Pacific Ocean side wher...

Microprobe analyses of Ca-rich pyroxenes crystallized in the melting ranges of a magnesian alkali basalt, a transitional basalt, an olivine tholeiite, a tholeiitic andesite, and an augite leucitite at pressures between 8 and 45 kb show complex variation. Ca-poor pyroxene precipitated only from the alkali basalt at pressures between 14 and 18 kb. Pyroxene falling near the Di-Hed join in the pyro...