Editing Death Valley National Park (section)

===Basement and Pahrump Group===
Little is known about the history of the oldest exposed [[rock (geology)|rock]]s in the area due to extensive [[metamorphism]] (alteration of rock by heat and pressure). [[Radiometric dating]] gives an age of 1,700&nbsp;million years for the metamorphism during the [[Proterozoic]].<ref name="Wright1997p611"/> About 1,400&nbsp;million years ago a mass of [[granite]] now in the Panamint Range intruded this complex.<ref name="Wright1997p631">{{harvnb|Wright and Miller|1997|p=631}}</ref> Uplift later exposed these rocks to nearly 500&nbsp;million years of erosion.<ref name="Wright1997p631"/>

The Proterozoic sedimentary [[formation (geology)|formations]] of the [[Geology of the Death Valley area#Pahrump Group|Pahrump Group]] were deposited on these basement rocks. This occurred following uplift and erosion of any earlier sediments from the Proterozoic basement rocks. The Pahrump is composed of arkose [[conglomerate (geology)|conglomerate]] (quartz clasts in a concrete-like matrix) and [[mudstone]] in its lower part, followed by [[Dolomite (rock)|dolomite]] from [[Carbonate rock|carbonate]] banks topped by [[algal mat]]s as [[stromatolite]]s, and finished with basin-filling sediment derived from the above, including possible [[glacial till]] from the hypothesized [[Snowball Earth]] glaciation.<ref>{{harvnb|Wright and Miller|1997|pp=631–632}}</ref> The very youngest rocks in the Pahrump Group are [[basalt]]ic lava flows.