The corridor of mineralization in the California gold district, in the Santander Department of Colombia

In the Santander Massif of Eastern Cordillera Colombia, intense Pliocene to Holocene sulfide-rich gold mineralization occurs in a six kilometers long section La Baja fault zone, where it crosses partially migmatized gneisses and intrusions Triassic-Cretaceous quartz monzonites granites. These intrusives are mineralogically texturally similar neosome migmatites that they intrude. The as medium large veins small veins, veinlets disseminations intrusives. type, volume metal grades dependent on local structure, chemical composition degree reactivity host rocks. Thicker higher-grade Mascota-type occur chemically favorable magnetite-hornblende migmatites, deposited after phases silicification, brecciation along foliation Gigante-type shear splays fault, marked by shearing mylonitization. Lower-grade, flat-banded appear leucocratic quartz-feldspar gneiss related migmatites. mineralizing fluids ascended planes, invaded fractures oblique them. all deposits, free form, electrum tellurides, accompanied copper silver.