TITLE:
Characterization and Origin of the Miocene Mudawwara-Quwayra Basaltic Dike, Southern Jordan
AUTHORS:
Hani Alnawafleh, Khaled Tarawneh, Khalil Ibrahim, Khitam Zghoul, Awad Titi, Rami Rawashdeh, Khaled Moumani, Ahmad Masri
KEYWORDS:
Jordan, Basalt, Dike, Miocene, Geochemistry
JOURNAL NAME:
International Journal of Geosciences,
Vol.6 No.8,
August
25,
2015
ABSTRACT: Petrographic,
mineralogical and geochemical investigations were carried out on representativesamples from the Mudawwara-Quwayra
Dike (MQD) in southernJordan. The MQD intruded Paleozoic and Cretaceous rocks
as sub-vertical basaltic plugs, striking NW-SE along a fault zone and extending
for more than 100 km. The MQD forms irregularly positive features, and is
represented by symmetrical, elliptical, elongated or circular hills. It
comprises thin basaltic layers intercalatedwith
pyroclastics and inclusions of different size and lithology, including
limestone, sandstone, phosphate, quartzite, and marble. Petrographically, the
rock exhibits phyric, porphyritic, vitrophyric and locally glomerophyritic
textures manifested by plagioclase, clinopyroxene and rareolivine and set in a matrix of
plagioclase, pyroxene, brown glass and opaque phases. Clinopyroxeneand olivine phenocyrsts show
disequilibrium textures such as reaction/resorbed rims in theforms of corroded ends. The
paragenetic sequence shows that olivine is the first phase to be crystallized
and coexisting with pyroxene at sometime, while pyroxene continues
crystallization. Plagioclase might have crystallized in contemporaneous later
than the pyroxene. The MQD rocks are classifiedas basalt and exhibit a narrow range
of silica with a unique subalkaline affinity. This is mostprobably attributed to assimilation of
the abundant siliciclastic inclusions by the ascending magma. Emplacement of
the MQD is attributed to regional phase of magmatism in Jordan and Saudi
Arabia, which is probably the peripheral extension of a large magmatic event
widely exposed in the Red Sea realm.