Sima Pumacocha - Physical and Geological Setting

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:

    I have often been reproached with the aridity of my genius; a deficiency of imagination has been imputed to me as a crime; and the Pyrrhonism of my opinions has at all times rendered me notorious. Indeed, a strong relish for physical philosophy has, I fear, tinctured my mind with a very common error of this age—I mean the habit of referring occurrences, even the least susceptible of such reference, to the principles of that science.
    Edgar Allan Poe (1809–1849)

    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)

    A happy marriage perhaps represents the ideal of human relationship—a setting in which each partner, while acknowledging the need of the other, feels free to be what he or she by nature is: a relationship in which instinct as well as intellect can find expression; in which giving and taking are equal; in which each accepts the other, and I confronts Thou.
    Anthony Storr (b. 1920)