Characterization and Origin of Dolomite Associated with Hydrothermal Iron Ore in Paleozoic limestone, Kinta Valley

Dolomite occurring in association with hematite in the Kinta Valley, particularly in
Kek Lok Tong (KL T), Gunung Rapat and Gunung Panjang (GP), Tambun commonly
displays a curved or "saddle" crystal shape. Based on preliminary observations, the
dolomite is believed to be hydrothermal in origin. However, this assumption needs to
be supported by chemical analyses. XRD analysis was conducted to verifY the
dolomite mineralogy. Samples were sent to the University of Miami for stable
(carbon and oxygen) isotope analysis to determine the environment of the dolomite
formation. XRF analysis was conducted to measure concentrations in major and trace
elements in the dolomite.
The isotopic analysis shows that the a180 values for the dolomite are highly
depleted, ranging from -18.4%0 to -16.3-f/00 and the a13C values are slightly
positive, ranging from 0.63%0 and 1.15°/00.Compared with other analyzed
hydrothermal dolomite like dolomite in Western Canada, Guilin, and Southern
Cantabrian Zone Spain, the a180 values ranging from -13.9 %o to -3.5°/oo and a13C
values ranging from -2."floo to 5.2°/00.KLT, Gunung Rapat and GP, Tambun
dolomite is relatively within above range except slightly depleted in the a180 values.
In addition to that, according to Taury Smith (2004), hydrothermal dolomites
typically have depleted li180 values which are between -2 to -20%o .From the XRF
analysis, the dolomite shows the non stoichiometric ratio of CaC03 and MgC03 .The
concentration for iron and manganese are quite high ranging from 11 OOppm to
34400ppm for iron and 7200ppm to 13100ppm for manganese. The two metals most
enriched in hydrothermal vent fluids are iron and manganese (Holland and Turekian,
2010). Other minerals also have been identified such as silicon, titanium, aluminum,
sulfur, phosphorus, potassium, molybdenum, cerium, yttrium, antimony, rubidium,
thorium, vanadium, nickel, arsenic, niobium, chromium, uranium, plumbum, zinc
and copper. The concentration for the valuables metal like argentum, platinum and
aurum is very low so much so that they can be considered negligible.