TY - JOUR
T1 - Geochronological and geochemical constraints on Late Cryogenian to Early Ediacaran magmatic rocks on the northern Tarim Craton
T2 - implications for tectonic setting and affinity with Gondwana
AU - Xiao, Yang
AU - Wu, Guanghui
AU - Vandyk, Thomas Matthew
AU - You, Lingxia
PY - 2019/3/1
Y1 - 2019/3/1
N2 - The Tarim Craton provides a geologic record of both the fragmentation of the Rodinian supercontinent and the subsequent assembly of Gondwana. However, the timing and interactions of these radically different tectonic processes remains contested. A critical part of this debate revolves around the late Cryogenian-Ediacaran igneous rocks along the Craton’s northern margin, specifically, whether they record super-plume related Rodinian breakup or Gondwanan orogeny. To address this issue, we present zircon U-Pb-Hf isotopic data and whole rock geochemistry from late Cryogenian to early Ediacaran granitoids of the northern Tarim Craton. U-Pb zircon ages reveal three magmatic periods along the northern Tarim margin: ca. 660 –640 Ma, 635 –625 Ma and 620 –600 Ma, associated with small scale felsic and mafic magmas. These granitoids have an A2-type affinity and are enriched in alkalines, but are depleted in Nb, Ta, Sr, P and Ti. Elemental data and generally negative εHf(t) values (-13.96 to 1.65) suggest that they were mainly derived from partial melting of enriched, subduction-modified lithospheric mantle triggered by upwelling of the asthenospheric mantle along the active continental margin of northern Tarim. We suggest that the Tarim Craton travelled as an isolated plate for much of the late Neoproterozoic, near the outer part of Rodinia and subsequently Gondwana. During this time it was affected by localized and periodic subduction-related intrusion and eruption. However, within the samples of this study, there is no U-Pb-Hf isotopic and whole rock geochemical evidence to support either super-plume related rifting (i.e. Rodinian breakup) or Pan-African orogeny (i.e. Gondwanan assembly).
AB - The Tarim Craton provides a geologic record of both the fragmentation of the Rodinian supercontinent and the subsequent assembly of Gondwana. However, the timing and interactions of these radically different tectonic processes remains contested. A critical part of this debate revolves around the late Cryogenian-Ediacaran igneous rocks along the Craton’s northern margin, specifically, whether they record super-plume related Rodinian breakup or Gondwanan orogeny. To address this issue, we present zircon U-Pb-Hf isotopic data and whole rock geochemistry from late Cryogenian to early Ediacaran granitoids of the northern Tarim Craton. U-Pb zircon ages reveal three magmatic periods along the northern Tarim margin: ca. 660 –640 Ma, 635 –625 Ma and 620 –600 Ma, associated with small scale felsic and mafic magmas. These granitoids have an A2-type affinity and are enriched in alkalines, but are depleted in Nb, Ta, Sr, P and Ti. Elemental data and generally negative εHf(t) values (-13.96 to 1.65) suggest that they were mainly derived from partial melting of enriched, subduction-modified lithospheric mantle triggered by upwelling of the asthenospheric mantle along the active continental margin of northern Tarim. We suggest that the Tarim Craton travelled as an isolated plate for much of the late Neoproterozoic, near the outer part of Rodinia and subsequently Gondwana. During this time it was affected by localized and periodic subduction-related intrusion and eruption. However, within the samples of this study, there is no U-Pb-Hf isotopic and whole rock geochemical evidence to support either super-plume related rifting (i.e. Rodinian breakup) or Pan-African orogeny (i.e. Gondwanan assembly).
U2 - 10.1080/00206814.2019.1581847
DO - 10.1080/00206814.2019.1581847
M3 - Article
SN - 0020-6814
SP - 1
EP - 18
JO - International Geology Review
JF - International Geology Review
ER -