How did the peripheral subduction drive the Rodinia breakup: Constraints from the Neoproterozoic tectonic process in the northern Tarim Craton

Abstract

The peripheral or exterior subduction is known to drive the breakup of Rodinia; however, the geodynamic driving mechanism remains controversial, which may result from the slab retreat or the slab avalanche-induced superplume impingement. We report here new constraints on the Neoproterozoic tectonic process whether the northern Tarim Craton at the NW margin of Rodinia was subduction- or mantle plume-dominated that further sheds light on how the peripheral subduction drove the Rodinia breakup. A tectonic transition from the Cryogenian arc and backarc rift to the Ediacaran passive margin characterized northern Tarim, as indicated by the distinct detrital zircon geochronological, geochemical, and structural-sedimentary features between the Ediacaran and Cryogenian sequences. This rejects the mantle plume-dominated evolution, but supports a Neoproterozoic evolving subduction process at the northern Tarim margin, where an advancing subduction (830–780 Ma) evolved into a retreating subduction (<780 Ma) in response to the retreat of the subducting Pan-Rodinia oceanic slab. The retreat-induced backarc rifting resulted in the opening of the northern Tarim rift between 760 and 740 Ma and the Cryogenian to Ediacaran tectonic transition. The peripheral subduction along the northern Tarim margin had thus caused no rifting before 780 Ma, which was also impossible to induce the >780 Ma rifting events in the supercontinent interior. These findings imply a composite peripheral subduction-driving mechanism for the Rodinia breakup. The slab retreat probably occurred as the dominant breakup driving force at the supercontinent margins, with less impact to the supercontinent interior; however, another geodynamic driver such as the deep subduction-induced plume impingement may account for the interior rifting and breakup. In addition, a zircon U-Pb age of 636 ± 2 Ma obtained from tufflava constrains the Tereeken diamictite to correlate with the Marinoan glaciation that further indicates a rapid and globally synchronous termination of the Neoproterozoic “Snowball Earth”.