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 (
Highlights
Almandine garnet is considered as a relatively rare mineral in the volcanic alkali basalt
Experimental studies of [3,4,5,6,7,8] show that Ca- rich (Ca > 4 wt%) and (Mn < 4 wt%) almandine crystallize from hydrous andesitic magmas at relatively high pressure (>7 kbar) and temperature at 900 ̊C - 950 ̊C. [5] suggested that the grassular and spessartine contents of almandine are sensitive to pressure and temperature conditions
Other type of corona texture are mad in orthopyroxene surrounded to the garnet crystal (Figure 5), this texture refer to second type of kelyphites texture
Summary
Almandine garnet is considered as a relatively rare mineral in the volcanic alkali basalt. The rarity may be due to under the restricted condition, such as garnet which can be formed in hydrous mantle sources, with high-pressure crystallization from hydrous Al-rich magma [1], and geodynamic setting tensional stress field, which rapidly ascending garnet bearing melts. According to [2] almandine can be liquid or near liquid mineral in silica magma at high pressure (9 - 18 Kbar). The grassular content of garnet increases with increasing pressure, whereas a higher Mn content stabilizes garnet at shallower depths, if (Mn > 4 wt%) almandine can be crystallized from silica liquids at ≤5 kbar [1]. Primary Ca bearing almandine in volcanic rocks has been rapid ascent of host magma by a tensional stress field [9,10]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
