Reconstruction of Early Paleozoic trench-arc-basin system in Duobaoshan area, Heilongjiang Province, China

Reconstruction of trench-arc-basin system such as Duobaoshan island arc belt, an important Cu-Mo polymetallic metallogenic zone in NW Heilongjiang Province, China, is crucial for both our understanding of the geological setting of ore-forming processes and future resource prospecting. According to the latest stratigraphical, petrological, field structural, geological mapping and geochronolgical studies, the formation age and stratigraphic sequence of the ore-bearing Duobaoshan and Tongshan formations were reestablished, i. e., the Duobaoshan and Tongshan formations are formed in Latest Cambrian to Early Ordovician and Early to Middle Ordovician, respectively. The redefined relationship between the Tongshan Fm. (upper) and the Duobaoshan Fm. (lower) indicated that a huge resource prospecting potential of Duobaoshan Fm. should be existed in the depth. Furthermore, we reestablished the Early Paleozoic stratigraphical system of Duobaoshan island arc belt based on above studies. There s an Early Paleozoic subduction-accretionary complex zone along Duobaoshan-Sanka region of NW Duobaoshan belt and forearc, interarc and backarc basins, and volcanic arcs between them to the SE, composing a Paleozoic trench-arc-basin system of Duobaoshan belt. An Early Paleozoic ancient oceanic basin was proposed at Duobaoshan-Sanka region which initiated a SE subduction from Ordovician. Thus, the advantageous metallogenic areas of the magmatic arcs are the parts that next to subduction-accretionary complex zone. This conclusion contributes to our realization of ore forming setting and geological condition of Duobaoshan polymetallic metallogenic belt. © 2022 Science Press. All rights reserved.