​​​​​Orogenic Architecture and Crustal Growth 

from Accretion to Collision

IGCP 662
Results expected
General Results:
1) In basic science
      This project will undertake first comparative studies on the crustal composition, architecture and metallogenesis between the CAOB (a typical accretionary orogen) and the Tethyan belt (a typical collisional orogen), and outline their differences and similarities. The results of isotopic (whole-rock Nd, Hf-O in-zircon) mapping will be provided, and different types of crustal provinces will be delineated for well-studied regions of the CAOB, the Tethyan belt and other orogens.
      In addition, we shall try to propose a new conceptual or theoretical framework for understanding orogenesis, continental growth and their relationships. A new model for (semi-) quantitative description of orogenic development during the Wilson cycle may be established.
      Finally, new advances or possible new models for metallogenesis during different phases of orogen development and a deeper understanding of the relationship between orogenic processes and metallogenesis may be proposed.
2) In applied sciences and technology
      This project will try to develop semi-quantitative markers or parameters to define and distinguish between orogen types and their evolution. We shall use the technique of regional isotopic mapping to look for such markers or parameters as, for example, the ratio of juvenile vs. ancient continental crust. We shall also attempt to use and test the new method of mapping xenocrystic/inherited zircons of igneous rocks to trace deep crustal compositions, especially ancient compositions (e.g., Zhang et al., 2016; 2017).These methods will help to delineate juvenile and ancient continental crustal provinces (e.g., Wang et al., 2009; 2015; Yang et al., 2017; Kröner et al., 2014; 2017; Safonova, 2017), and this may also be a new approach to semi-quantitatively assess continental growth. These methods can later be used to investigate and understand other orogens.
      In addition, this project will establish a database for zircon ages, whole-rock and Hf-O in-zircon isotopes of igneous rocks and ore deposits of the above orogens and their mineral deposits. This database will be open to all researchers, and will provide a platform for international collaborative research.
3) In respect of benefit to society
      This project will enhance collaboration in the geosciences between developing and developed countries and establish good relationships between geologists of these countries. Many female and male young scientists will take part in the project and will obtain the opportunity to participate in international actives. This will help them to improve their knowledge in the geosciences and their status in education and society. This project will also enhance the training of graduate students and other qualified persons.
      The exchange of research ideas, methodologies, and results between research groups from developing and developed countries will be helpful to improve scientific knowledge and to create new concepts and ideas for basic research. New ideas and a deeper understanding of the setting and formation characteristics of ore deposits related to orogenic processes will be helpful in the search for, and exploitation of, natural resources.

Results expected in each year
      To establish a feasible work plan and develop a website for the new IGCP Project. To undertake fieldwork and sampling in some key regions, such as the Chinese Altai, Junggar, Great Xing’an Range in the southern CAOB, and the Gangdise terrane in the eastern Tethyan belt, as well as in important metallogenic belts in both orogens. Based on previous investigations, to complete preliminary isotopic (whole-rock Nd, Hf-O inzircon) mapping in key regions. To establish a database of zircon ages as well as wholerock and Hf-O in-zircon isotopes for igneous rocks and ore deposits of the key regions. To prepare examples and case studies for field investigations and isotopic mapping.
      To continue fieldwork in important areas in the CAOB, the Tethyan belt (including the Zagros Mts. in Iran) and other orogens. To obtain analytical results on samples collected in 2018. To interpret data obtained through field and laboratory work and from the literature and to establish a database. To complete isotopic mapping for the regions mentioned above. In addition, to undertake tectonic field investigations in the CCOS as well as the North American Appalachians and Australian Lachlan orogens, and to conduct isotopic mapping for the western Qinling-Kunlun segment of the CCOS. To undertake several
isotopic cross-sections in the North American Appalachians and Australian Lachlan orogens. To outline similarities and differences in crustal composition and architecture as well as metallogenesis in some typical areas of these different orogens. To continue updating the database.
      To invite and give financial support to female and young geologists to take part in the workshop and field activities of the project. To help train young geologists and postgraduate students.
      To reinforce fieldwork in important areas and to interpret data obtained by field and laboratory work as well as collected from the literature. To provide the results of isotopic mapping and delineation of different-type crustal provinces for major parts of the CAOB, the Tethyan belt and other orogens (e.g., Kunlun-Qinling-Dabie segment of the CCOS). To demonstrate the results of comparative studies on crustal composition and architecture as well as metallogenesis between the CAOB and Tethyan orogen in detail. To summarize similarities and different features in metallogenesis of accretionary and collisional orogens. To continue updating the database. International publications on orogenesis and continental growth. Open the database to scientific community.
      To continue comparative studies of the CAOB, Tethyan, CCOS, and other orogens (e.g., the North American Appalachian orogen, Lachlan orogen in eastern Australian), and find out their probable differences in orogenic architecture and crustal compositions, particularly the differences in the proportions of juvenile vs. ancient crust. To continue updating and opening the database. A special issue publication in Lithos or Tectonophysics
      To establish a new concept and theoretical framework on orogenesis and continental growth and particularly their inter-relationships in terms of crustal composition and architecture. To propose and establish a set of markers or parameters to (semi-) quantitatively describe the orogenic development during a Wilson cycle. To propose new models for metallogenesis related to different phases of orogen development. To finalize and open the database to the scientific community.