[1] Spectral interpretation that silicic rocks are widespread on Mars implies that Earth’s differentiated crust is not unique. Evaluation of observations bearing on the composition of the Martian crust (Martian meteorite petrology and a possible crustal assimilant, analysis of Mars Pathfinder rocks, composition of Martian fines, interpretation of spacecraft thermal emission spectra, and inferre...

Atmospherically corrected thermal infrared spectra of large regions of the Martian surface from the Mars Global Surveyor Thermal Emission Spectrometer (MGS TES) previously have been interpreted to represent two general spectral classes. One class represents a basalt to basaltic andesite composition, and the other class represents a basaltic andesite to andesite composition. We have performed ne...

Shallow water sedimentary units are generally considered scarce in Archean greenstone belts. We describe an unusual quartz arenite-subaerial andesite association within the Archean Hisovaara greenstone belt, a fragment of the Parandovo-Tikshozero belt within the Karelian craton of the Baltic Shield. The Hisovaara greenstone belt consists of several lithotectonic assemblages: (1) a komatiite-tho...

Numerous important Miocene and early Pliocene epithermal Au-Ag deposits are present in the northern Great Basin. Most deposits are spatially and temporally related to two magmatic assemblages: bimodal basaltrhyolite and western andesite. These magmatic assemblages are petrogenetic suites that reflect variations in tectonic environment of magma generation. The bimodal assemblage is a K-rich thol...

The Wadi Hodein area contains a wide variety of late Precambrian igneous and metamorphic rocks, represented by gneisses, serpentinites, metagabbros, metasediments, metavolcanics, metagabbro-diorite, granodiorite and granitoids. The Wadi Hodein metavolcanics (WHV), including G. Khashab and G. El Anbat, represent one of the significant metavolcanic suites in the southern part of the Nubian Shield...

In the southeast of bam, there is a collection of volcanic rocks with andesite, basalt and trachy andesite composition. The texture of these rocks are often porphyritic with microlithic, porphyric cavity, and sometimes glomerulophorphuri, sore throat trachytic. Main minerals include Olivine, Clinopyroxene, Plagioclase and secondary minerals including opaque minerals, Iodenzyte, secondary Biotit...

Thirty oriented fresh block samples were collected from ten suitable sites of the outcropping andesite rock formation to study their Petrographical characteristics and Magnetic properties. The analysis of these rocks around Khairmalia shows that the magnetite crystals are fresh and are in perfect shape. These crystals are present in sufficient quantity i.e. measured as 10 to 20% in various rock...