page_title: Eastern Block of the North China Craton
section_title: Subduction
hierarchical_section_title: Eastern Block of the North China Craton / Tectonic evolution / Paleoproterozoic / Subduction
caption_attribution_description: English: A series of evolutionary diagrams demonstrates the subduction and continent-continent collision of Eastern Block and Western Block. Trans-North China Orogen was formed and North China Craton was assembled.
context_page_description: The Eastern Block of the North China Craton is one of the Earth's oldest pieces of continent. It is separated from the Western Block by the Trans-North China Orogen. It is situated in northeastern China and North Korea. The Block contains rock exposures older than 2.5 billion years. It serves as an ideal place to study how the crust was formed in the past and the related tectonic settings.
  Geologists are able to deduce the past environments and tectonic events by studying geological records like rocks and geological structures. The oldest components of the Eastern Block were first formed more than 4 billion years ago. It later experienced numerous geological events between 3.8 and 1.85 billion years ago, including recurring volcanic eruptions and metamorphic events. Therefore, most of the rocks were reworked and highly metamorphosed with changes in minerals and texture. Due to the sparse exposure of pre-Neoarchean rocks, only the tectonic settings of the rocks generated from 2.7 to 1.85 billion years ago are thought to be understood. These settings include a Large Igneous Province event, mantle plume activity, continental collisions, rifting and subductions of plates.
context_section_description: Other than the subduction and collision on the eastern side of the Eastern Block, subduction also happened at the western margin. The subduction lasted from 2.55 to 1.85 billion years ago. It closed the ocean between the Eastern and Western Blocks of the North China Craton and formed the Trans-North China Orogen.
  The subduction took place 2.55–2.47 billion years ago. It led to the partial melting of the lower crust and mantle wedge. It produced a large amount of magma, which formed granitoids, greenstone, mafic and felsic volcanic rocks. As subduction continued, the region next to the arc spread and formed a back-arc basin. Thus, magma flowed upward. There were granitic intrusions and mafic dyke intrusions 2.35–1.92 billion years ago. The mafic dykes were later metamorphosed as mafic granulites and amphibolites. Eventually, the whole ocean sank under the Eastern Block. The Eastern and Western Blocks were brought together at approximately 1.8 billion years ago. It formed the Trans-North China Orogen and led to the assembly of the North China Craton. The collision of blocks may be related to the global assembly of the Columbia supercontinent.
caption: A series of evolutionary diagrams demonstrates the subduction and continent-continent collision of Eastern Block and Western Block. Trans-North China Orogen was formed and North China Craton was assembled.[1][70]
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