Petrography and Mineral Chemistry of the Almanden Garnet, and Implication for Kelyphite Texture in the Miocene Alkaline Basaltic Rocks North East Jordan ()
ABSTRACT
The Miocene alkali
basaltic rocks cover the northeastern part of Jordan, within Harrat Al-Shaam
plateau. The volcanic concentrated along the Dead Sea boundary and spread
around the north east of Jordan area, and was considered as interplat volcanic
field in Jordan. The volcanic basalt is associated with xenoliths fragmental
rocks or xenocryst minerals. Nine samples were collected from the study area
and analyzed for XRD, XRF and SEM. These samples presented the xenoliths rocks
and minerals existing in the study area. This study is focused on the garnet
and pyroxene xenoliths minerals in Tulayl Al-Hasna area within Ufayhim
Formation. Hand samples are characterized by coarse aggregates of garnets up to
(2 cm in diameter) with dark brown to red color, and highly fresh fractures.
Also, the pyroxene (<1.5 cm) with gray to dark green color, and the olivine
(range 3 - 4 mm) are pale green to dark green and pale yellowish color. In thin
sections, plagioclase phenocryst in the garnet presented corona texture. In
addition, garnet surrounded by orthopyroxene refers to kelyphite texture. There
are two types of kelyphite texture fibers and radial as shown in Scanning
Electron Microscope photomicrograph. The mineralogical analyses of garnet for
X-Ray Diffraction are composed of almandine, pyrope and majorite. The existence
of minerals reflects the high pressure and temperature of the upper mantle
origin. The chemical analysis showed the average composition of garnet as
follow (Alm 42.78, Pyro 41.04, Gross 16.18), pyroxene (Wo 16.90, Fs 20.37, En
62.73). This referred to presentation of the following elements Mg, Fe and Ca
in the garnet. As a result, the basaltic garnet xenoliths were from shallow
lithosphere mantle origin.
Share and Cite:
Yaseen, I. (2014) Petrography and Mineral Chemistry of the Almanden Garnet, and Implication for Kelyphite Texture in the Miocene Alkaline Basaltic Rocks North East Jordan.
International Journal of Geosciences,
5, 222-237. doi:
10.4236/ijg.2014.52024.