TY - JOUR
T1 - Crustal evolution and recycling in the Northern Arabian-Nubian Shield
T2 - new perspectives from zircon Lu-Hf and U-Pb systematics
AU - Morag, Navot
AU - Avigad, Dov
AU - Gerdes, Axel
AU - Belousova, Elena
AU - Harlavan, Yehudit
PY - 2011/4
Y1 - 2011/4
N2 - This paper presents laser-ablation (MC)-ICP-MS single-zircon Hf isotopic data coupled with U-Pb geochronology from a unique rock inventory in southern Israel, recording ca. 300m.y. of Neoproterozoic crustal evolution in the northern Arabian-Nubian Shield (ANS). The early, island-arc magmatic cycle in this area is recorded by detrital zircons from arc-derived metasediments, dated between 870 and 760Ma, and by ca. 790 and 740Ma orthogneisses. Zircon e{open}Hf(t) values from these rocks are all positive, supporting previous isotopic evidence for the overall juvenile nature of northern ANS crust. Nonetheless, detrital zircons from the metasedimentary units display a wide range of e{open}Hf(t) values between +1 and +13. The lower values in this range suggest some contribution from an older crustal component. The involvement of pre-Neoproterozoic crustal component is also indicated by the occurrence of rare zircons with pre-Neoproterozoic ages and/or negative e{open}Hf(t) values in younger (post-collisional) magmas that intrude the arc sequence. Arc accretion was followed by a period of ∼60m.y. of relative igneous tranquility interrupted only by the emplacement of local basic dike swarm at ca. 705Ma. Average zircon e{open}Hf(t) value of +10 found in one of these dikes indicates a depleted mantle source possibly implying a mid-Neoproterozoic extensional phase. The later, post-collisional magmatic cycle marks the transition of the accreted arc complexes into a mature continental crust. It consists of voluminous 680-600Ma granitoid plutons of calc-alkaline affinity, and subordinate 610-580Ma intrusions of alkaline affinity. Average zircon e{open}Hf(t) values in these post-collisional rocks are all positive and range between +6 and +9, compatible with both mantle source and juvenile crust reworking.
AB - This paper presents laser-ablation (MC)-ICP-MS single-zircon Hf isotopic data coupled with U-Pb geochronology from a unique rock inventory in southern Israel, recording ca. 300m.y. of Neoproterozoic crustal evolution in the northern Arabian-Nubian Shield (ANS). The early, island-arc magmatic cycle in this area is recorded by detrital zircons from arc-derived metasediments, dated between 870 and 760Ma, and by ca. 790 and 740Ma orthogneisses. Zircon e{open}Hf(t) values from these rocks are all positive, supporting previous isotopic evidence for the overall juvenile nature of northern ANS crust. Nonetheless, detrital zircons from the metasedimentary units display a wide range of e{open}Hf(t) values between +1 and +13. The lower values in this range suggest some contribution from an older crustal component. The involvement of pre-Neoproterozoic crustal component is also indicated by the occurrence of rare zircons with pre-Neoproterozoic ages and/or negative e{open}Hf(t) values in younger (post-collisional) magmas that intrude the arc sequence. Arc accretion was followed by a period of ∼60m.y. of relative igneous tranquility interrupted only by the emplacement of local basic dike swarm at ca. 705Ma. Average zircon e{open}Hf(t) value of +10 found in one of these dikes indicates a depleted mantle source possibly implying a mid-Neoproterozoic extensional phase. The later, post-collisional magmatic cycle marks the transition of the accreted arc complexes into a mature continental crust. It consists of voluminous 680-600Ma granitoid plutons of calc-alkaline affinity, and subordinate 610-580Ma intrusions of alkaline affinity. Average zircon e{open}Hf(t) values in these post-collisional rocks are all positive and range between +6 and +9, compatible with both mantle source and juvenile crust reworking.
UR - http://www.scopus.com/inward/record.url?scp=79952624714&partnerID=8YFLogxK
U2 - 10.1016/j.precamres.2011.01.004
DO - 10.1016/j.precamres.2011.01.004
M3 - Article
AN - SCOPUS:79952624714
SN - 0301-9268
VL - 186
SP - 101
EP - 116
JO - Precambrian Research
JF - Precambrian Research
IS - 1-4
ER -