Exposed veins as gossans outcroppings of silver and gold are the main source of eroded minerals from most of the area's mineralized fault zones across Nevada. In pre-Tertiary time there was very little forceful water movement to concentrate gold placer. What water movement did occur scattered the gold placer across the topography, into pre-glaciered gully formations, ancient stream beds and ganged into basins.
Majority of the placer gold from the Quaternary age was formed by erosion during an earlier, better watered, stage of erosional cycle. The gold placer was laid down in gulches and occurred in channels along bedrock and in terrace gravels and slope washes on the sides of canyons.
The high-grade gravels are located in channels at bedrock near the head of most alluvial fans. Here the gold placer in size, degree of roundness, and fineness, gold-silver ratio, of the placer gold and the lithology of the gold-bearing gravels indicate that the gold in different gulches and alluvial fans were derived from lode sources close to discovered individual gold placers.
Gold nuggets became scattered across the topography by forces of several orgins and later became covered by pre-ancient volcanic activity and awash by fine-grained igneous basalt debris. Later, eons later, several ancient seas came and went and contributed to the scattering of those pre-dawn Quaternary gold nuggets.
Large gold nuggets are being found in Nevada. The gold nugget shown below weights 42 oz. and was detected 38 inches deep in a northern section of NEVADA; July 1998.
Large nuggets found in NEVADA are usually lode gold. This makes this 3 pound-plus nugget, shown below, a highly unusual find.