Geochemical and isotopic constraints on island arc, synorogenic, post-orogenic and anorogenic granitoids in the Arabian Shield, Saudi Arabia

Robinson, Frank A.; Foden, John; Collins, Alan S.

doi:10.1016/j.lithos.2015.01.021

Cited by 58 publications

(59 citation statements)

References 60 publications

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“…As illustrated in figure 2, anorogenic trace elements have values similar to those of postorogenic suites. These age groups both have A-type whole-rock geochemistry (Robinson et al 2015) and unsurprisingly show extensive mingling with zircon geochemistry. Most importantly, the most evolved anorogenic geochemistry is consistently separated from older IA1 Syn zircons ( fig.…”

Section: Resultsmentioning

confidence: 98%

“…These cycles represent different tectonic processes in Arabian Shield evolution and produced a diverse range in granitoid mineralogy. According to recent whole-rock geochemical classification by Robinson et al (2015), the island arc and synorogenic phases are I-type granitoids that are generated in subduction settings from MORB-like or arc tholeiitelike mafic parents. The postorogenic magmatism that appears at the termination of orogenic sutures (e.g., Nabitah Suture) is also classified as I-type.…”

Section: Arabian Shield Geologic Settingmentioning

confidence: 99%

“…However, these suites also include aegirine-bearing Atype granites. As suggested by Robinson et al (2015), the postorogenic granites are generated from contaminated island arc tholeiite (IAT) and MORB-like basic magmas in lower crustal zones followed by fractionation. Anorogenic suites are also A-type granites, but they are derived from a distinct heavy rare earth element (HREE)-enriched source and are interpreted to be emplaced in back-arc settings and associated with lithospheric delamination.…”

Section: Arabian Shield Geologic Settingmentioning

confidence: 99%

“…Anorogenic suites are also A-type granites, but they are derived from a distinct heavy rare earth element (HREE)-enriched source and are interpreted to be emplaced in back-arc settings and associated with lithospheric delamination. Taking this diversity into account, this study will maintain the island arc, synorogenic, postorogenic, and anorogenic phases defined by Robinson et al (2014) and use these as a systematic way to present the zircon geochemistry from 19 samples and support the tectonic models discussed in Robinson et al (2015). The geochronological and geochemical properties of these samples are summarized in table 1.…”

Section: Arabian Shield Geologic Settingmentioning

confidence: 99%

“…Zircon geochemical data are presented from the four discrete granite evolution stages outlined by Robinson et al (2014): (1) the island arc stage (∼845 Ma), (2) the synorogenic stage (∼715-700 Ma), (3) the postorogenic stage (∼640-600 Ma), and (4) the late anorogenic stage (!600 Ma). The zircon geochemistry in this study is linked with prior wholerock data from Robinson et al (2015) with the aim of identifying trace element discriminators that support the progressive changes in granitic sources during the accretion and cratonization of the ANS. An additional tool used in this study is provided by the morphology of zircon.…”

Section: Introductionmentioning

confidence: 99%

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Zircon Geochemical and Geochronological Constraints on Contaminated and Enriched Mantle Sources beneath the Arabian Shield, Saudi Arabia

Robinson

Foden

Collins

2015

The Journal of Geology

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A B S T R A C TArabian Shield granitic zircon geochemistry provides insight into the petrogenetic processes involved in generating one of the planet's largest tracts of juvenile Neoproterozoic crust. New zircon geochemistry supports previous U-Pb and whole-rock data that defined four magmatic groups: (1) ∼870-675 Ma island arc and synorogenic I-type granitoids (IA1Syn), (2) ∼640-585 Ma I-and A-type granitoids from the Nabitah and Halaban Suture (NHSG), (3) ∼610-600 Ma postorogenic perthitic (hypersolvus) A-type granitoids (POPG), and (4) !600 Ma anorogenic aegirine-bearing perthitic (hypersolvus) A-type granitoids (AAPG). The low Nb (∼1-300 ppm) and intrasuite rare earth element variation in IA1Syn and NHSG zircons indicates that these suites are derivatives of contaminated mantle followed by fractionation. AAPG suites, however, have higher Nb content (∼10-400 ppm) and are derived from limited crust-enriched mantle interaction. Each of the IA, Syn, and NHSG suites have discrete granite subsuites distinguished using zircon morphology and geochemistry whose U-Pb ages in each case form three groups. The IA subgroups are ∼867, ∼847, and ∼829 Ma; the Syn subgroups are ∼730, 716, and 696 Ma; and the NHSG subgroups are ∼636, ∼610, and ∼594 Ma. This apparent subevent repetition suggests some form of magmatic pulsing in the Arabian Shield. It is suggested that IA1Syn suites reflect typical volcanic arc granite settings and incremental subduction/accretion of eastward-migrating oceanic fragments of the East African Orogen. The appearance of ∼636 Ma A-type magmatism within suture zones (NHSG) is possibly derived from a long-lived (∼50 m.yr.) melting, assimilation, storage, and homogenization (MASH) zone resulting from an ∼640 Ma slab tear. These A-types are distinguished from more-enriched anorogenic (!600 Ma) A-types, possibly associated with lithospheric delamination.

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Section: Resultsmentioning

confidence: 98%

Section: Arabian Shield Geologic Settingmentioning

confidence: 99%

Section: Arabian Shield Geologic Settingmentioning

confidence: 99%

Section: Arabian Shield Geologic Settingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Zircon Geochemical and Geochronological Constraints on Contaminated and Enriched Mantle Sources beneath the Arabian Shield, Saudi Arabia

Robinson

Foden

Collins

2015

The Journal of Geology

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A discussion on the tectonic implications of Ediacaran late- to post-orogenic A-type granite in the northeastern Arabian Shield, Saudi Arabia

et al. 2017

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The transition from late‐orogenic to post‐orogenic magmatism following major orogenic episodes such as the Neoproterozoic to Cambrian East African Orogen (EAO) is an important, yet not well‐understood geological event marking the cessation of subduction‐controlled magmatism between buoyant lithospheric fragments. Forming the northern part of the EAO in the Arabian‐Nubian Shield are three granitic suites that successively intruded the same northeastern area and post‐date the ~640 Ma major orogenic episode: (1) 620–600 Ma alkali feldspar (hypersolvous) granite with alkaline/ferroan/A‐type geochemistry, (2) 599 Ma granite cumulates (some garnet‐bearing) with calc‐alkaline/magnesian affinities, and (3) 584–566 Ma alkali feldspar (hypersolvous) granite (aegirine‐bearing) with a distinctive peralkaline/ferroan/A‐type signature. Combining whole‐rock geochemistry from the southern and northern Arabian Shield, suites 1 and 2 are suggested to be products of late‐orogenic slab tear/rollback inducing asthenospheric mantle injection and lower crustal melting/fractionation toward A‐type/ferroan geochemistry. Suite 3, however, is suggested to be produced by post‐orogenic lithospheric delamination, which replaced the older mantle with new asthenospheric (rare earth element‐enriched) mantle that ultimately becomes the thermal boundary layer of the new lithosphere. Major shear zones, such as the 620–540 Ma Najd Fault System (NFS), are some of the last tectonic events recorded across the Arabian Shield. Data presented here suggest that the NFS is directly related to the late‐orogenic (620–600 Ma) slab tear/rollback in the northeastern Shield as it met with opposing subduction polarity in the southern Shield. Furthermore, this study infers that east and west Gondwana amalgamation interacted with opposing convergence reflected by the NFS.

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U–Pb Zircon Geochronology and Geochemistry of Some Plutonic Rocks from the Afif Terrane of Saudi Arabia, Arabian Shield: Implications for Crustal Evolution

Harbi

2019

Regional Geology Reviews

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Geochemical and isotopic constraints on island arc, synorogenic, post-orogenic and anorogenic granitoids in the Arabian Shield, Saudi Arabia

Cited by 58 publications

References 60 publications

Zircon Geochemical and Geochronological Constraints on Contaminated and Enriched Mantle Sources beneath the Arabian Shield, Saudi Arabia

Zircon Geochemical and Geochronological Constraints on Contaminated and Enriched Mantle Sources beneath the Arabian Shield, Saudi Arabia

A discussion on the tectonic implications of Ediacaran late- to post-orogenic A-type granite in the northeastern Arabian Shield, Saudi Arabia

U–Pb Zircon Geochronology and Geochemistry of Some Plutonic Rocks from the Afif Terrane of Saudi Arabia, Arabian Shield: Implications for Crustal Evolution

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