Shrimp rock dating
INTRODUCTIONThe NW-SE Ubendian Belt of SW Tanzania is bordered by the Tanzania Craton to the northeast and the Bangweulu Block to the southwest ().
The Ubendian Belt consists of high-grade metamorphic rocks of sedimentary and igneous origin, including granulites, migmatite, amphibolites, biotite gneisses, schists, quartzites, eclogites and marble.
Similar-aged porphyritic monzogranites are also found in North China and South Korea, and their origin is considered to be related to a post-tectonic extensional event of regional extent.
The last phase of Precambrian magmatism recognized in North Korea is Grenvillian-aged, represented by the hornblende-bearing granite that yields a SHRIMP zircon age of 1195 ± 4 Ma, and is considered to be the source rock of the adjacent Yushulazi Group (North China) that contains numerous 1.1-1.2 Ga old detrital zircons.
In both the LGF and MMF, the mineralization is restricted to the sulphide-bearing quartz veins in major shear zones and the link between the gold mineralization event and the emplacement of felsic intrusions remain inconclusive .