Early Cretaceous tectonics across the North Pacific: New insights from multiphase tectonic extension in Eastern Eurasia

摘要: Abstract How deep mantle processes affected plate interactions and the dynamics of deformation on both sides Paleo-Pacific has been a first order scientific challenge. The ubiquitous Early Cretaceous multiphase tectonic extensional structures in eastern Eurasia (EE) show marked contrasts to episodic compressional western North America (WNA), which provides convincing arguments linking shallow processes. Recent studies tectonics EE have shown that continent is characterized by multiple phase extension weak compression, forming several major provinces vast area ca. 3000 km × 3000 km. peak occurred at 135–120 Ma, addition episodes pre- (160–145 Ma) post-peak (120 Ma-) stages. Kinematic analysis reveals an identical NW-SE-oriented field for their formation. In addition, synextensional magmatism sourced from ancient juvenile crust or lithospheric was episodically active peaked 160, 125 100–80 Ma, respectively. Particularly, magmatic flare-up origin 125 ± 5 Ma China. contrast, WNA Cordillera displays prolonged compression beginning ~170 Ma (Jurassic). Tectonic involved Nevadan, Sevier Laramide orogenies 175 Ma, 125 Ma 80 Ma, respectively, form orogenic system. During Nevadan orogeny intensive convergence 154 150 Ma contributed continental arc magmatism. orogen thin-skinned thrust sheets while dominated slab dip oceanic subduction basement-core uplifts Archean foreland. Significant sinistral strike-slip shearing ~140–125 Ma documented Cretaceous. Widespread crustal shortening emplacement batholiths (magmatic flare-up) were contemporaneous with accretion high pressure-low temperature (blueschist) Franciscan Complex 125–100 Ma during orogeny. constitute part retreating (Paleo-) Pacific-Eurasia system, along resulted advancing Farallon-North Stratified convection needed, however, when taking evolution margins mid-ocean range as integral system evolving globe. Shallow-mantle plates, Andean-type zones Ocean early stage subduction. Possibly 160 Ma on, eastward flow occurred, induced migration systems. As result, west-dipping slabs became steepened, stagnated subsequently folded transition zone, east-dipping Farallon flattened, its penetrated zone. resultant systems continuously drove (or Izanagi) plate, Paleo-Pacific-Farallon ridge. consequence, phases interior tectono-magmatic activities margin WNA.