Neoproterozoic tectono-thermal history of the Himalayan Terrane: a four-stage evolution hypothesis

The tectono-thermal evolution of the Neoproterozoic Himalayan terrane remains controversial, largely due to a lack of systematic review and comparative analysis. By integrating previous magmatic studies, the paradigms of arc–back-arc system, and our current understanding, we envisage that the Himalayan terrane was likely situated along the northwestern margin of Rodinia, where it experienced a key episode of geological evolution from ca. 930 to 760 Ma, which comprises four progressive stages (I to IV): Stage I (ca. 930–840 Ma): formation of an Andean-type orogen in response to the subduction of the Mirovoi Ocean beneath the periphery of Rodinia; Stage II (ca. 840–810 Ma): early back-arc subsidence and rifting due to lithospheric thinning and extension; Stage III (ca. 810–790 Ma, postulated): establishment of a back-arc spreading centre driven by strong extension and sufficient mantle upwelling; Stage IV (ca. 760 Ma): development of a normal mid-ocean ridge resulting from full-rate spreading and substantial upward counterflow of asthenosphere. This hypothesis may shed new light on the geodynamic framework of the Neoproterozoic Himalayan terrane. Nevertheless, more robust and diagnostic magmatic evidence is required to validate this synthetic model.