continental formations developed a sea coast existed between the archipelago that is the Andies Mts and the main continent of South America . Machado ridge was under water for a very long time perhaps even during the time of the super continents  . 

As the 2 land masses drifted toward one another the land rose and drained the huge sea to the North .  As this process devloped the inland sea gradually became shallower/narrower at the bottom end . 

The drift put enough pressure on a buried plate to buckle the earth creating our Anticlyne and caused fractures that allowed gold laiden fluids to rise .  This process would have occurred over maybe 150 mill years with several fracturing events . Each time hot fluids carrying more ore to deposit on the cooler rocks .

The ridge as we see it today has been exposed for maybe 50 - 75 mill years . The rock is very hard and resistent to weathering . Not a lot of soil or erosion has happened  in all those years .

Because the rock seams are nearly standing on end there are lots of nooks and crannies for eroded gold to collect . This implies that an amount of eroded ore will be found on surface .

This is an artistic interpretation for entertainment purposes only .