Petrology of high pressure clinopyroxenite series xenoliths,Mount Carmel,Israel |
| |
| Authors: | David W Mittlefehldt |
| |
| Institution: | (1) Department of Geology and Mineralogy, Ben-Gurion University of the Negev, 84120 Be'er Sheva, Israel;(2) Present address: SN4/Ex. Planet., NASA/Johnson Space Center, 77058 Houston, TX, USA |
| |
| Abstract: | The Mount Carmel xenolith suite is composed of a series of garnet granulites of probable lower crustal origin, and a high pressure clinopyroxenite series. The clinopyroxenite series is petrologically diverse with the most common lithologies being garnet-clinopyroxenite, clinopyroxenite, garnet-amphibole-clinopyroxenite, amphibole-clinopyroxenite, amphibole-mica-clinopyroxenite plus megacrystalline nodules of clinopyroxene, garnet, amphibole and mica. Orthopyroxene is extremely rare (1 sample) and olivine is absent in the clinopyroxenite series xenoliths. The clinopyroxenite series is divided into three rock associations based on textures, mineralogy, mineral chemistry and equilibration temperatures: the metaclinopyroxenite, the magmatic garnet-clinopyroxenite and the amphibole-mica-clinopyroxenite associations. Many of the xenoliths contain late phases, largely amphibole, as microphenocrysts in glass and altered glass that was intruded into the xenoliths. Each of the three associations plus the late phases represents the crystallization products of one or more magma batchs. Garnet-clinopyroxene geothermometry and phase relations for alkaline basalts allow estimates of theP/T conditions of equilibration to be made for some of the xenoliths. The metaclinopyroxenites were equilibrated at 1.5–3 GPa and 990–1,115° and the magmatic garnet-clinopyroxenites were equilibrated at 2–3 GPa and 1,160–1,190°. The Mt. Carmel xenoliths are samples from the depth range 50–95 km and fall in the sampling gap between xenoliths typical of alkali basalts (d<60 km) and those typical of kimberlites (d> 90 km). |
| |
| Keywords: | |
| 本文献已被 SpringerLink 等数据库收录！ |
|
