The Indian Peak volcanic field is representative of the more than 50,000 km3 of ashflow tuff and tens of calderas in the Great Basin that formed during the Oligocene-early Miocene "ignimbrite flareup" in southwestern North America. The field formed about 32 to 27 Ma in the southeastern Great Basin and consists of the centrally positioned I n d i Peak caldera complex and a surrounding blanket of...

Wellsch Valley tephra, near Swift Current, southwestern Saskatchewan, and Galt Island Medicine Hat, southeastern Alberta, have been referenced in the literature since 1970s, but little is available on their physical chemical attributes – necessary information if they are to be recognized elsewhere. This study seeks remedy this situation. Both a calc-alkaline rhyolitic composition with hornblend...

qaleh-zari is a fe-oxide cu-ag-au vein type deposit located 180 km south of birjand, in eastern iran. host rocks are mainly tertiary calc-alkaline to k-rich calc-alkaline with transition to shoshonitic andesite and andesitic basalts, but in the central part shale and sandstone of jurassic age. andesitic rocks from the western region of qaleh-zari were dated to 40.5 ± 2 ma. four trends of faults...

biotite samples from different units of boroujerd granitoid complex (bgc) of the sanandaj-sirjan zone, western iran, have beenanalyzed by electron microprobe for major elements. biotite analyses from three units of quartzdiorite, granodiorite and monzograniteof bgc have their own distinct non-overlapping compositional fields in the annite – siderophyllite – phlogopite – eastonitequadrilateral (...

Pleistocene basaltic lava flows, consisting of trachybasalt and basaltic trachyandesite, cover an area north-northwest of Shahre-Babak in southeastern Iran. The whole rock chemistry indicates that the lavas are dominantly alkaline and mildly calc-alkaline. Variation diagrams of SiO2 with major and trace elements are consistent with fractional crystallization processes involving olivine, pyroxen...

New geochemical data were presented for the mafic (basalts and gabbros) ultramafic (dunites, serpentinites pyroxenites) rocks from Mawat ophiolite exposed in Zagros suture zone northeastern Iraq. The mantle section of is composed serpentinized peridotites, harzburgites, dunites, chromitites pyroxenite dykes. crustal layered amphibole-rich gabbros, pegmatitic gabbros as well basalts minor felsic...

Abstract West Sumatera is a region that has an abundance of natural resources in the form iron sand, one which area Pasia Jambak Beach, Padang. Beach type beach rumps and sandy beaches, grayish-brown sand rough grains on its surface. Iron could be formed due to weathering rocks materials found around coast, such as old ships others. This study aims see rock origin composition magnetic mineral e...

Numerous post-ophiolite intrusions exposed into the late Cretaceous–Paleocene Sabzevar ophiolite belt, northeast Iran. The intrusions consist of calc-alkaline intermediate to felsic rocks with metaluminous to peraluminous in nature and adakitic affinities. Based on U-Th-Pb dating on separated zircons by SHRIMP Ⅱ, the emplacement age of these rocks into the ophiolite zone is constrained to ~45 M...