In this study the formation of polygenetic High Tatra granitoid magma is discussed. Felsic and mafic mixing mingling processes occurred in all batches composing pluton are documented by typical textural assemblages, which include: microgranular enclaves (MME), clots, felsic quartz-plagioclase-titanite ocelli, biotite-quartz poikilitic plagioclase crystals, chemically zoned K-feldspar phenocryst...

Granitic rocks related to 1.18 to 1.13 Ga anorthosite-mangerite-charnockitegranite plutonism stitch three terranes in the southwestern Grenville Province (Adirondack Highlands–Morin terrane, Frontenac terrane, Elzevir terrane). Because of the refractory nature of zircon (Zrn), analysis of oxygen-isotope ratios of dated igneous zircon from these rocks allows calculation of δ18O values of origina...

JULY 2005, GSA TODAY ABSTRACT The subduction factory processes raw materials such as oceanic sediments and oceanic crust and manufactures magmas and continental crust as products. Aqueous fluids, which are extracted from oceanic raw materials via dehydration reactions during subduction, dissolve particular elements and overprint such elements onto the mantle wedge to generate chemically distinc...

Lava dome eruptions commonly display fairly regular alternations between periods of high activity and periods of low or no activity. The time scale for these alternations is typically months to several years. Here we develop a generic model of magma discharge through a conduit from an open-system magma chamber with continuous replenishment. The model takes account of the principal controls on f...

Supereruptions violently transfer huge amounts (100 s-1000 s km(3)) of magma to the surface in a matter of days and testify to the existence of giant pools of magma at depth. The longevity of these giant magma bodies is of significant scientific and societal interest. Radiometric data on whole rocks, glasses, feldspar and zircon crystals have been used to suggest that the Bishop Tuff giant magm...

Felsic magma commonly pools within shallow mushroom-shaped magmatic intrusions, so-called laccoliths or cryptodomes, which can cause both explosive eruptions and collapse of the volcanic edifice. Deformation during laccolith emplacement is primarily considered to occur in the host rock. However, shallowly emplaced laccoliths (cryptodomes) show extensive internal deformation. While deformation o...

Clinopyroxene phenocrysts and microphenocrysts in potassic and sodic Eosen alkaline volcanic rocks from the northern Lahrud (NW Iran) record various stages in the crystallization and evolution history of the alkaline melt as well as its origin. The rock series hosting the clinopyroxene phenocrysts is phonolitic tephrite and tephritic phonolite composition. Theses rocks generally show porphyriti...

In the Variscan Western Tatra granites hybridization phenomena such as mixing and mingling can be observed at the contact of mafic precursors of dioritic composition and more felsic granitic host rocks. The textural evidence of hybridization include: plagioclase-K-feldspar-sphene ocelli, hornblende- and biotite-rimmed quartz ocelli, plagioclase with Ca-rich spike zonation, inversely zoned K-fel...