Supporting Information for "Low δ18O and δ30Si TTG at 2.3 Ga hints at an intraplate rifting onset of the Paleoproterzoic supercontinent cycle" submitted to JGR-Solid Earth. The Supporting material includes three parts: A PDF file as the table of contents, including detailed methods and references, Supplementary Figures S1-S2 with figure captions and references, and captions for Supplementary Tables S1 to S8. Supplementary Figures S1-S2 are uploaded separately. All analytical data are provided in Supplementary Tables S1 to S8 separately as excel files, with corresponding captions and references.
<p>Investigations on the late Neoproterozoic to early Paleozoic sedimentary strata of western South China and northern Indochina reveal a provenance affinity between the two, which was mainly derived from the local western part of South China. The newly discovered provenance featured differently from that of the typical Indian-Australian Gondwana siliciclastic source. Basin types and sedimentation histories of the two sedimentary basins in western South China and northern Indochina are also comparable. Furthermore, previous studies discovered the geochronological, petrological and geochemical similarities of the early Paleozoic magmatic rocks between these two regions, suggesting a connection between the two during the subduction of the proto-Tethys ocean towards the northern Gondwana and the accretion of Asian continents onto the Gondwana mainland. Utilizing all such geological information, we speculate in this study that South China and Indochina were probably in the neighbourhood on the northern Gondwana margin when the Gondwana semi-supercontinent was assembled. Specifically, Indochina was likely located to the southwest of South China during the late Neoproterozoic to early Paleozoic. Apart from sedimentation, neither Indochina nor the western part of South China got much deformational and metamorphic impaction from the collision between South China and northern Gondwana during that time.</p>
Abstract The proto-Andean margin of Argentina consists of several suspect terranes, the origins of which are disputed. The Cuyania (greater Precordillera) suspect terrane was originally interpreted to be of southeast Laurentian affinity, but more recently a southwestern Gondwanan provenance has been argued. Both potential source regions comprise Mesoproterozoic rocks, but we show they are isotopically distinct, using previously published zircon Lu-Hf data. Detrital zircon εHf data from southwestern Gondwana (Namaqua-Natal belt) show no correlation with new zircon U-Pb and Lu-Hf data from Cuyania, suggesting that Gondwana was not the source of these sediments. Rather, detrital zircons from Cambrian strata in Cuyania yield Mesoproterozoic zircons with depleted εHf that correlate to the Grenville margin of Laurentia, and a ca. 535 Ma zircon population sourced directly from rift-related rocks of the Ouachita Embayment, thus recording rifting and drifting of Cuyania from Laurentia. By contrast, zircons from Middle to Late Ordovician strata of Cuyania record a larger range of εHf values, correlated with Western Sierras Pampeanas Mesoproterozoic basement inliers of Argentina. These synorogenic clastic deposits record the Ordovician arrival of Cuyania at the proto-Andean margin of Gondwana. The new data require the terrane boundaries of Cuyania to be redefined, thereby excluding Western Sierras Pampeanas basement inliers. The results verify the Laurentian microcontinent model for the origin of Cuyania.
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