Geology & Land
The information regarding the Company’s Venezuelan properties contained herein should be considered in context of our October 21, 2009 news release "Gold Reserve Files International Arbitration Against Venezuelan Government."
Mineralization on the Brisas Property
Brisas is a large resource of low-grade disseminated gold and copper mineralization of Precambrian greenstone type. The mineralization is hosted in a fine-grained volcanic rock that was deposited in a water-filled basin as sediment. The copper and gold mineralization was introduced into the rocks during deposition of the host and subsequently modified by metamorphism and tropical weathering.
Surface assessment
Surface exposures of weathered rock are limited to the walls of small flooded pits, rare weathered outcrops and areas cleared by past surface mining activity. Intense weathering produced saprolites to a depth of 60 meters making drilling the primary tool used to define subsurface geology. The rocks encountered in drilling include oxide saprolite, sulfide saprolite and the hard or unweathered bedrock. Andesite tuff units defined in the hardrock include a series of vitric tuffs, lapilli tuffs and crystal tuffs. Based on megascopic and microscopic features, the andesite tuffs are interpreted to have been deposited in shallow water. All the rock units have been metamorphosed to greenschist facies. The andesite tuffs have been intruded by a series of basic dikes and sills and a large monzonite stock. The stock is confined to the east edge of the property.
Geologic structure of the property
Geologic correlation has identified a stratigraphic sequence from top to bottom of: 1) a thick unit of vitric tuff; 2) a two hundred meter thick unit consisting of mixed lapilli tuffs, crystal tuffs and vitric tuffs characterized by rapid vertical and lateral textural changes, 3) a series of thicker, more consistent crystal tuffs, vitric tuffs and lapilli tuffs. The structure of the property is very simple. The tuffs dip shallowly to the west and strike north-south. Very little faulting has been identified and those faults identified are the sites of the basic dikes. Movement along these faults is minimal and often there appears to be no movement at all.
Ore grade mineralization is stratabound and strataform within the 200-meter thick unit characterized by rapid vertical and horizontal changes. Mineralization follows this unit down from the surface and is open at depth. In addition, the deposit is open to the southwest. Three basic types of mineralization exist. Oxide mineralization, restricted to the oxide saprolites, is gold only and makes up about four percent of the total mineralization. Massive sulfide mineralization, as both laminated sulfides and quartz-tourmaline-sulfide breccia pipes, has been identified on the surface and from drilling.
The Blue Whale is an example of this type of mineralization. It contains relatively high-grade copper and gold mineralization. The Blue Whale makes up only a small percentage of the total deposit. The majority of the mineralization is disseminated sulfide mineralization in discrete pyrite grains within the tuffs and as narrow restricted quartz-carbonate-pyrite veinlets. These veinlets often contain visible gold. The disseminated mineralization can be further subdivided into a copper-gold-pyrite mineralization and a pyrite-gold mineralization. The sulfide saprolite and the underlying weathered rock unit are unoxidized and contain typical disseminated sulfide mineralization. The copper-gold-pyrite mineralization dominates the northern portion of the deposit while the gold-pyrite mineralization dominates the southern portion of the orebody. Alteration within the deposit includes massive carbonate often associated with epidote and chlorite. The character of the mineralization and the alteration is consistent with typical gold-in-greenstone type deposits found elsewhere in the world's greenstone-granite terrenes.