Origin, Accretion, and Reworking of Continents

Capitanio

Proc. Natl. Acad. Sci. U.S.A.

et al. 2022

Continental, orogenic, and oceanic lithospheric mantle embeds sizeable parcels of exotic cratonic lithospheric mantle (CLM) derived from distant, unrelated sources. This hints that CLM recycling into the mantle and its eventual upwelling and relamination at the base of younger plates contribute to the complex structure of the growing lithosphere. Here, we use numerical modeling to investigate the fate and survival of recycled CLM in the ambient mantle and test the viability of CLM relamination under Hadean to present-day mantle temperature conditions and its role in early lithosphere evolution. We show that the foundered CLM is partially mixed and homogenized in the ambient mantle; then, as thermal negative buoyancy vanishes, its long-lasting compositional buoyancy drives upwelling, relaminating unrelated growing lithospheric plates and contributing to differentiation under cratonic, orogenic, and oceanic regions. Parts of the CLM remain in the mantle as diffused depleted heterogeneities at multiple scales, which can survive for billions of years. Relamination is maximized for high depletion degrees and mantle temperatures compatible with the early Earth, leading to the upwelling and underplating of large volumes of foundered CLM, a process we name massive regional relamination (MRR). MRR explains the complex source, age, and depletion heterogeneities found in ancient cratonic lithospheric mantle, suggesting this may have been a key component of the construction of continents in the early Earth.

Section: Discussionmentioning

confidence: 81%

mentioning

confidence: 99%

Accretion of the cratonic mantle lithosphere via massive regional relamination

Capitanio

Proc. Natl. Acad. Sci. U.S.A.

et al. 2022

“…Such a similar structure was also revealed beneath the Yellowstone volcano (e.g., Seats & Lawrence, 2014; Stachnik et al., 2008; Thybo & Artemieva, 2013; Waite et al., 2006). In addition, relatively minor modification of the crust may occur in the continental margins due to thermo‐mechanical‐magmatic erosion (e.g., R. Zhu et al., 2021).…”

Section: Discussionmentioning

confidence: 99%

Pn Anisotropic Tomography of Hainan Island and Surrounding Areas: New Insights Into the Hainan Mantle Plume

Lu¹,

Lei²,

Zhao

et al. 2022

JGR Solid Earth

The Hainan and surrounding areas in the Eurasian plate are one of the most active and complex regions in the western Pacific subduction system, surrounded by the Indo-Australian plate, the Philippine Sea plate and the Pacific plate (Figure 1). The Pacific and Philippine Sea plates are subducting westward, the Indian plate is subducting eastward, whereas the Indo-Australian plate is subducting northward (Bird, 2003). The interactions between these plates may have significantly influenced mantle convection under this region, which leads to intensive seismicity and intraplate volcanism (Figure 1). The Indo-Eurasian collision resulted in a sinistral strike-slip Red River fault zone (e.g., Bird, 2003;Tapponnier et al., 1982;Xia et al., 2015;Yin, 2010) (Figure 1). Since the Oligocene, the opening of the South China Sea (SCS) has activated the faults in the Leiqiong area, and changed the tectonic stress field from compressive to extensional. As a result, the volcanic activity in this area had continued until the Holocene (e.g., Z.

“…Water content and fluid accessibility are important factors that control the extent and process of continental modification (Zhu et al., 2021). Large amounts of water and fluids are carried into the upper mantle as the plate subduction (e.g., Cai et al., 2018; Hirschmann, 2006).…”

Section: Discussionmentioning

confidence: 99%

3D Crustal and Upper Mantle Model of East‐Central China From a Joint Inversion of Surface and Body Waves and Its Tectonic Implications

2021

The major geological units in East-Central China include the North China Craton (NCC), the South China Block (SCB), and the Qinling-Dabie-Sulu orogen formed by the collision of the NCC and SCB (Figure 1). During the Late Paleozoic to Triassic, as the Paleo-Tethys Ocean closed, the SCB collided with and subducted under the NCC (e.g., S. Li et al., 1993;Meng & Zhang, 2000;Y. F. Zheng et al., 2003). During the Jurassic to Early Cretaceous, influenced by the subduction and retreat of the Paleo-Pacific plate, East China developed extensive magmatic activities, which is strongly associated with the destruction of the NCC (Zhu & Xu, 2019), the intensive post-collision magmatism in the Dabie and Sulu orogen (Z. F. Zhao et al., 2013), and the rich mineral resources in the Middle-Lower Yangtze River Metallogenic Belt (Lü et al., 2015). During the Late Cretaceous, East China was in a period of tectonic quiescence. Until the Cenozoic, the Pacific plate began to subduct and retreat, resulting in a large-scale eruption of Cenozoic continental basalts in East China (Y. Xu et al., 2018;. Additionally, the far-field impact of the India-Eurasia plate collision during the Cenozoic also needs to be considered.