Incompatible element

About: Incompatible element is a research topic. Over the lifetime, 2420 publications have been published within this topic receiving 154052 citations.

Tholeiitic and alkali basalts from the Mid-Atlantic Ridge at 43 ° N

Abstract: Tholeiitic basalts dredged from the Mid-Atlantic Ridge (MAR) axis at 43 ° N are enriched in incompatible trace elements compared to the ‘ normal’ incompatible element depleted tholeiites found from 49 ° N to 59 ° N and south of 33 ° N on the MAR. The most primitive 43 ° N glasses have MgO/FeO*= 1.2 and coexist with olivine (Fo90–91) and chrome-rich spinel. The tholeiitic basalts from the MAR 43 ° N are distinct from the strongly incompatible trace element depleted tholeiities found elsewhere in the Atlantic, and have trace element features typical of island tholeiities and MAR axis tholeiites from 45 ° N. Petrographic, major, and compatible trace element trends of the axial valley tholeiites at 43 ° N are consistent with shallow-level fractionation; in particular, evolution from primitive liquids with forsteritic olivine plus chrome spinel as liquidus phases to fractionated liquids with plagioclase plus clinopyroxene as major crystallizing phases. However, each dredge haul has distinctive incompatible trace element abundances. These trace element characteristics require a hetrogeneous mantle or complex processes such as open system fractional crystallization and magma mixing.

Petrogenesis of Early Neogene Magmatism in the Northern Puna; Implications for Magma Genesis and Crustal Processes in the Central Andean Plateau

Abstract: of UOLM-2 and MM group rocks. Assuming the same endNew compositional data and petrogenetic models are presented for member compositions, the modelling suggests genesis of the MM pre-Upper Miocene volcanism in the northern Puna of Argentina magmas at higher pressure than the UOLM-2 centres ([10 kbar (22°S–24°S). Two phases of volcanism produced small dome vs 7 kbar), which may reflect the influence of crustal thickening in complexes of mainly silicic andesite to low-SiO2 rhyolite. The the plateau region by the mid-Miocene. The felsic dome complexes Upper Oligocene–Lower Miocene phase (UOLM, 20–17 Ma), of this study are compositionally similar to the large-volume, calderaproduced two distinct groups of rocks. The UOLM-1 group is sourced felsic ignimbrites that dominated volcanism in the region metaluminous and mainly andesitic, with isotopic compositions like from 10 to 2 Ma and our results suggest that there is no fundamental those of the recent arc ( Sr/SrT >0·706; NdT −3). The difference in magma genesis between them. The differences in the UOLM-2 group is more silicic and peraluminous, and has isotopic volumes and the mode of eruption reflect changes in the stress and compositions indicating a substantial crustal contribution ( Sr/ thermal regime with time. SrT >0·713; NdT −8). The Mid-Miocene phase (MM: 15–12 Ma) produced rocks similar in composition to those of the UOLM-2 group ( Sr/SrT >0·710; NdT −7) but with higher incompatible element contents. Ratios of Ba/Nb and Zr/