A new concept of continental construction in the Central Asian Orogenic Belt: (Compared to actualistic examples from the Western Pacific)

Abstract

A new concept of continental construction based on four main terms: (1) crustal growth, (2) crustal formation, (3) continental growth and (4) continental formation is presented here. Each of these terms reflects a certain process responsible for the formation of what we call now "continental crust". This concept is applied to the Central Asian Orogenic Belt (CAOB), which is a global major accretionary orogen formed after the closure of the Paleo-Asian Ocean, and to its actualistic analogues - orogenic belts and accretionary complexes of the Western Pacific. The main focuses of the paper are the state of activities in the study of the CAOB, the theoretical basics of the new concept of continental construction, its challenges, prospects and social impacts, main methods of investigation. The main issues of the paper are what has been done in this field of geoscience, which questions remained unaddressed and which problems should be solved. The most important challenges are: (a) dominantly Phanerozoic formation of the CAOB continental crust versus its dominantly Archean growth; (b) to what extent the CAOB continental crust was juvenile or recycled; (c) whether magmatic arcs or Gondwana-derived terranes were accreted to the Siberian, Kazakhstan, Tarim and North China cratons; (d) what was the balance between continental formation and tectonic erosion based on modern examples from the Western Pacific; (e) what social benefits (mineral deposits) and geohazards (seismicity and volcanism) can be inferred from the study of orogenic belts formed in place of former oceans.