TY - JOUR
T1 - Pulsed emplacement under the Uyaijah granite ring structure, eastern Saudi Arabia—results from 3D gravity-magnetic inversion
AU - Mukhopadhyay, Manoj
AU - Saibi, Hakim
AU - Elawadi, Eslam
AU - Al-Arifi, Nassir
N1 - Funding Information:
M.M. is supported by ISPP #0039, Vice-Rectorate for Graduate Studies and Research, King Saud University, Riyadh, Saudi Arabia. H.S. is financially supported by the UAEU (Research Office) to purchase GEOSOFT software (G00003204).
Funding Information:
We used Generic Mapping Tools (Wessel and Smith, 1998) to draw Figure 1. The authors thank Dr. M. Bersi (Ferhat Abbas University, Algeria) for helping in drawing Fig. 2.
Publisher Copyright:
© 2021, Saudi Society for Geosciences.
PY - 2021/11
Y1 - 2021/11
N2 - The Uyaijah ring structure (URS), situated within the Precambrian Kushaymiyah Igneous Complex (KIC) at the eastern edge of the Arabian Shield, consists of three large laccoliths: two granitic and one granodioritic, intruded by late mafic dikes. The transverse fault zone (TFZ), belonging to the Najd Fault System of Saudi Arabia, transects the URS along its major axis. The digital elevation map for the URS is first correlated with surface geology to clarify the effects of faulting on the elevation of the pluton. Next, the complete (terrain-corrected) Bouguer anomaly (CBA) map for the URS, based on 145 gravity stations, is examined to investigate the source of the URS through 3D-gravity inversion modeling. A pronounced CBA “low” (< 50 mgal amplitude) occupies the central part of the URS; this is interpreted as the lower density root of the pluton. Three-dimensional gravity inversion modeling traces the source magmatic body through sections at 2–10 km below sea level; this model is largely complemented by results from the 3D magnetic inversion of the RTP aeromagnetic anomalies. The gravity-magnetic inversion indicates that the pluton root zone lies below the SW of the URS at ~ 10-km depth; this value is significantly different from previous depth estimates of ~ 4.75 km. The root zone is noticeably offset by the TFZ. These results suggest a genetic relationship between pluton expansion and updoming, dyking, and faulting that probably reaches down to the base of the upper crust, involving pulsed emplacement.
AB - The Uyaijah ring structure (URS), situated within the Precambrian Kushaymiyah Igneous Complex (KIC) at the eastern edge of the Arabian Shield, consists of three large laccoliths: two granitic and one granodioritic, intruded by late mafic dikes. The transverse fault zone (TFZ), belonging to the Najd Fault System of Saudi Arabia, transects the URS along its major axis. The digital elevation map for the URS is first correlated with surface geology to clarify the effects of faulting on the elevation of the pluton. Next, the complete (terrain-corrected) Bouguer anomaly (CBA) map for the URS, based on 145 gravity stations, is examined to investigate the source of the URS through 3D-gravity inversion modeling. A pronounced CBA “low” (< 50 mgal amplitude) occupies the central part of the URS; this is interpreted as the lower density root of the pluton. Three-dimensional gravity inversion modeling traces the source magmatic body through sections at 2–10 km below sea level; this model is largely complemented by results from the 3D magnetic inversion of the RTP aeromagnetic anomalies. The gravity-magnetic inversion indicates that the pluton root zone lies below the SW of the URS at ~ 10-km depth; this value is significantly different from previous depth estimates of ~ 4.75 km. The root zone is noticeably offset by the TFZ. These results suggest a genetic relationship between pluton expansion and updoming, dyking, and faulting that probably reaches down to the base of the upper crust, involving pulsed emplacement.
KW - 3D gravity and magnetic inversion models
KW - Bouguer anomaly
KW - Plutonic root zone
KW - Pulsed emplacement of granite magma
KW - Uyaijah ring structure
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U2 - 10.1007/s12517-021-08647-2
DO - 10.1007/s12517-021-08647-2
M3 - Article
AN - SCOPUS:85117720601
SN - 1866-7511
VL - 14
JO - Arabian Journal of Geosciences
JF - Arabian Journal of Geosciences
IS - 21
M1 - 2199
ER -