Evolution of the Earth’s Middle Age (mesoproterozoic): Insights from North China Craton

The Earth’s Middle Age represents a prolonged phase characterized by environmental, evolutionary, and lithospheric stability, also known as the ‘Boring billion’ or ‘Balanced billion’, in contrast to the dramatic changes in preceding (Orosirian) and succeeding (Cryogenian) Periods. It is also marked by episodic global magmatism and rifting, alongside the evolution of the first two supercontinents, Columbia and Rodinia. While the uniqueness of this era is veiled in doubt, its evolution and subdivision are widely discussed. The North China craton preserves well-documented stratigraphic records spanning intervals of ca. 1.8-1.78 Ga (e.g., the Xiong’er Group), ca. 1.7-1.3 Ga (e.g., the Changcheng, Jixian and Daijian Systems) and ca. 1.1-0.9 Ga (e.g., the Huaibei Group), as well as multiple stages of rift-related magmatism, notably during ca. 1.8-1.6 Ga, 1.4-1.2 Ga and 0.9-0.8 Ga. The sedimentation and magmatic activities can be linked to the assembly and prolonged tenure of the Columbia supercontinent from ca. 1.8-1.4 Ga and its breakup at ca. 1.4-1.2 Ga, followed by the assembly and tenure of the Rodinia from ca. 1.2-0.9 Ga and its breakup at ca. 0.9-0.8 Ga. The onset of the Earth’s Middle Age is characterized by both the peak of the large igneous province activities and the accretionary orogenesis between ca. 1.79-1.62 Ga (the Statherian), during which continuous plume activity and accretionary processes shaped the formation of Earth’s first supercontinent. While minor oxidation and carbon excursion events in the Mesoproterozoic and early Neoproterozoic strata indicate environmental perturbations, the identification of the first of five intermittent negative inorganic carbon excursions, the Majiatun excursion at ca. 0.95 Ga, signals the termination of the Earth’s Middle Age much earlier than previously proposed (e.g., at ca. 0.82 or 0.72 Ga), prior to the initial stage of the breakup of Rodinia. During ca. 1.62-0.95 Ga, the incomplete breakup of Columbia and the subdued assembly of the Rodinia supercontinent define the prolonged lithospheric stability. Based on the evolution of the Earth’s Middle Age recorded in the North China craton and global comparisons, we propose two key temporal boundaries—ca. 1.79 Ga as the onset of the Mesoproterozoic Era and ca. 0.95 Ga as its termination—thereby defining the Mesoproterozoic Era as Earth’s Middle Age. This presentation outlines our interim understanding of Earth’s Middle Age of the Deep Earth Probe and Mineral Resources Exploration - National Science and Technology Major Project (2025ZD1005300).