Provenance Record of Late Mesoproterozoic to Early Neoproterozoic Units, West Hainan, South China, and Implications for Rodinia Reconstruction

Abstract

Unraveling the character and source of late Mesoproterozoic‐early Neoproterozoic sedimentary sequences is crucial in constraining Rodinia reconstructions. We carried out an integrated geochemical, zircon U‐Pb geochronological and Lu‐Hf isotopic study of the Shilu Group and the overlying Shihuiding Formation in Hainan, South China. These two successions are chemically mature and dominated by siliceous components. The Shilu Group was mainly derived from felsic arc lithologies whereas the Shihuiding Formation was from recycled sedimentary materials and records a transition from convergent to passive margin settings during the late Mesoproterozoic‐early Neoproterozoic in Hainan. Detrital zircons from the Shilu Group and Shihuiding Formation yield similar age populations, with maximum depositional ages of ~1,100–1,000 Ma and ~900 Ma, respectively. The Shilu Group matches well with the Kunyang Group outcropped in the Yangtze Block in depositional age, detrital zircon age populations and Lu‐Hf isotopic compositions, and geochemical characteristics, whereas the Shihuiding Formation exhibits significantly different detrital age populations from the Wanquan Group in the Cathaysia Block. This indicates that Hainan was linked to the Yangtze Block rather than the Cathaysia Block in the late Mesoproterozoic‐early Neoproterozoic. The Shilu and Kunyang groups have similar detrital age patterns to the late Mesoproterozoic to early Neoproterozoic strata in northwest India and are distinct from their equivalents in west Laurentia, suggesting an external location of Hainan‐Yangtze in Rodinia.

Precambrian Tectonic Affinity of Hainan and Its Evolution from Columbia to Rodinia

“…Metamorphic zircons of 1300-1000 Ma are widely exposed in the metasedimentary rocks, gneisses, and magmatic rocks of the Baoban Complex but are largely absent within the Shilu Group (layers 3-6) [37-39,70,77] (Figure 2), which indicates that these sedimentary and magmatic rocks experienced metamorphism during 1300-1000 Ma. Abundant detrital zircon U-Pb data for layers 3-6 of the Shilu Group constrain the maximum depositional age of the mid-upper Shilu Group to approximately 1100 Ma [60,70,71]. All of these results support that the mid-upper Shilu Group is a depositional system distinctively different from the metasedimentary rocks in the Baoban Complex.…”

“…It can be seen that the disagreement mainly focuses on the age of each component unit of the "Baoban Group" and the relationship between them. With the continuous improvement of analytical methods and in-depth research, an increasing number of researchers have gradually realized that the "Baoban Group" mainly consists of supracrustal rocks and later intruded granitic and metamafic rocks and named it the "Baoban Complex" [37][38][39]52,60,70,71]. The supracrustal rocks are divided from bottom to top into the Gezhencun and Ewenling formations, and they were intruded by gneissic granitoids and amphibolites.…”

“…Sedimentary detritus from layers 3-6 of the Shilu Group are of low maturity, relatively enriched in high field strength elements and rare earth elements, and deficient in transition elements (e.g., Sc and Co) [71], implying their origination dominantly from felsic igneous rocks. This inference further indicates their deposition on active continental margins [78][79][80].…”

“…The Shihuiding Formation is a suite of siliciclastic clastic rocks that are unmetamorphosed and less deformed [81]. In contrast to the Shilu Group, it has a higher quartz content, is enriched in SiO 2 , and depleted in CaO, Na 2 O, and TiO 2 with more remarkable differentiation between light and heavy rare earth elements [71,82], implying that it should originate dominantly from recycled sediments. Furthermore, it yields an additional age peak at ~1390 Ma and a slightly younger maximum depositional age of ~930 Ma [40,71] (Figure 3).…”

The affinity of microcontinents in northern East Gondwana in the Silurian: Hainan Island response to the closure of the Proto-Tethys Ocean

“…Previous studies have shown that the complex magmatic During the Mesoproterozoic-Neoproterozoic Grenvillian Orogeny (1.3-0.9 Ga), the residual fragments of the Columbia supercontinent that were not completely disintegrated converged to form the Rodinia supercontinent (Fig. 7b) (Cawood, 2020;Zhang et al 2020b;Wu et al 2023). The Grenvillian Orogeny (1.3-0.9 Ga) is extensively recorded in both Laurentia and Gondwana (Fig.…”