Geochemical Analysis for Sedimentary Mineralization in Western Emerald belt, Gabriel Felipe Nino Vasquez and Sheng-Rong Song Department of Geosciences, National Taiwan University

INTRODUCTION METHODS AND RESULTS CONCLUSIONS

Legend 2.PETROGRAPHY km 1. FIELD TRIP Alluvial deposits 0 5 Luna Formation Formation 1 Cross Cutting Plastic deformation, and Qz with waved extintion, Carbonate recrystalization, d13C_PDB/d18O_PDB Fault fractures and Veins fractured veins breciation and deformation twims Emerald Mine 4

2

0 -14 -12 -10 -8 -6 -4 -2 0 3 2 Coscuez -2 Monteblanco Cunas

La Pita d13C_PDB 2 1 mm. -4 Españoles Puerto Sanin -6 Masatos

-8 Productive carbonates identification 3. 4 -10 d18O_PDB

* All the samples show a sedimentary / metamorphic origin. Fibrous Geode Orthorhombic * GROUP 2 that produces more than any other area shows higher d18O values, which means that the composition Emeralds in Colombia are generated mainly in black , and are located in the Eastern d13C_PDB/d18O_SMOW (‰) of the fluid is not exactly the same. The For Original fluid (315°C) fluid in this area is more evolved and Cordillera in two parallel belts separated by approximately 130 Km: Western belt 2 reactive (WB) and Eastern belt (EB). The geological, mineralogical and tectonic features from these * Productive veins show higher d18O and 0 belts are quite similar. 20 22 24 26 28 30 32 lower d13C values. -2 La Pita Coscuez * This proxyes result important for -4 Monteblanco Previous researchers concluded that Emeralds in Colombia come from hydrothermal Cunas emerald exploration in the Colombian -6 Espanoles Western Emerald Belt. sedimentary processes without any magmatic influence , which would be an unique Puerto Sanin deposit around the world. They suggested that the source of Cr, V and Be is the host rock -8 Masatos (Giuliani et al. 1994). -10

-12 d18O_PDB Emerald minerallization in the WB are founded in multidirectional veins and breccias hosted by the black shale in paragenesis with carbonates (calcite, dolomite, ankerite), 36 samples from 7 different mines along the WE were collected . All of them are carbonates deposited in BIBLIOGRAPHY albite, pyrite, chalcopyrite, quartz, etc. G. GIULIANI Á C. et al., (1998). Oxygen isotope systematics of emerald: relevance for its originand geological signicance. Mineralium Deposita, Pp 513-519. veins, breccia and from the Muzo formation. Different Parameters like: Crystal habit, paragenesis, ROLLINSON, H., (1996). Using geochemical data: evaluation, presentation, interpretation. Longman (ed.). Pp. 352. L. Mantila et al., (2007) investigación petrográfica y geoquímica de las sedimentitas del cretácico inferior (k1) y sus manifestaciones hidrotermales asociadas; location and productive history were considered in order to define productive and non productive veins planchas 169, 170, 189, 190 (cordillera oriental): implicaciones en la búsqueda de esmeraldas.