Physical and Geological Setting
At 4,300 m to 4,400 m above sea level, the Pumacocha valley is a typical Andes ‘puna’ – high, treeless, and surrounded by 5,000 m peaks. The valley is traversed by a dirt road serving active and abandoned mines nearby, and is dotted with stone huts used by locals tending flocks of sheep, llamas and alpacas. At the head of the valley is Laguna Pumacocha, a small lake which along with its catchment area sits atop Miocene age granodiorite. Where the lake's outfall stream meets near-vertically bedded Cretaceous age Jumasha limestones, it has carved a short, shallow canyon containing several abandoned and one active sinkpoint where the entire stream disappears underground. Underlying the limestone is the Lower Cretaceous Pariatambo Formation.
A small concrete canal, intended to keep the lake outfall on the surface by diverting it around the canyon, is in poor shape and normally does not function at all. When local repairs occur, the active sinkpoint (SP1) becomes enterable, but considerable water then leaks into the abandoned sinks (SP2 and SP3).
On a regional scale, the long, irregular band of limestone containing Sima Pumacocha and several other caves runs roughly south-southeast to north-northwest. The Pumacocha waters sink at an elevation of 4,375 m above sea level, and are thought to resurge in the Rio Alis valley some 14km to the north at an elevation of about 3,300 m above sea level.
Read more about this topic: Sima Pumacocha
Famous quotes containing the words physical, geological and/or setting:
“The real stumbling-block of totalitarian régimes is not the spiritual need of men for freedom of thought; it is men’s inability to stand the physical and nervous strain of a permanent state of excitement, except during a few years of their youth.”
—Simone Weil (1909–1943)
“The crystal sphere of thought is as concentrical as the geological structure of the globe. As our soils and rocks lie in strata, concentric strata, so do all men’s thinkings run laterally, never vertically.”
—Ralph Waldo Emerson (1803–1882)
“Teaching Black Studies, I find that students are quick to label a black person who has grown up in a predominantly white setting and attended similar schools as “not black enough.” ...Our concept of black experience has been too narrow and constricting.”
—bell hooks (b. c. 1955)