Workshop on the Establishment of a Geological Model of ...

topographic feature in the south, where the furrows are less and shallower. The isolated seamounts are scattered
like a string of beads, which extends NEE, and stretches in the same direction as the faults NEE across the whole
area.
The Western Region
Seamounts and seamount chains are the main topographic features in the western region, which extends
approximately eastwards. There are intermountain basins and furrow areas between the seamount chains. The
whole region has five seamount chains, with heights that are generally about 500 to 1,000m. The topography of
the intermountain basins and furrow areas is relatively smooth, and undulates less than 100m. The slope is
generally less than 2 o .
Figure 2: Chart of 3D topography in the western region of the China pioneer area
The results of a deep‐tow survey show that in the eastern and western regions there are many abrupt
furrows and sills, with heights varying from several meters to tens of meters. These abrupt sills and furrows will be
topographical obstructions to mining.
Tectonic characteristics
The east and west regions of the Chinese pioneer area are located in the western part of the Clarion‐
Clipperton Fracture Zone (CCFZ) between the Clarion and Clipperton fractures of the East Pacific basin. The
basement of the CCFZ is the oceanic crust consisting of basalt, which is the product of the spreading of the East
Pacific Rise. The thickness of the sediment layer ranges from tens of metres to several hundred metres, and
gradually decreases from the west to the east.
The sediment layer on the basalt is controlled generally by the original topography of the basement.
According to the results of the Deep Sea Drilling Project and the identification of lineation magnetic
anomalies, the age of the basement is lower Campanian of Late Cretaceous in the west, and the Paleocene in the
east. Obviously, the age of formation of the west was earlier than that of the East, so that the water depth in the
west is greater than in the east (Beiersdorf, H., 1992).
The tectonic activity in the western region was mainly volcanism. The fractures by faulting have formed the
passageway of volcanism, which constructed the seamounts and seamount chains in the various scales along the
transform fractures. The tectonic activities in the east were quite different from that in the west, and were mainly
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