The Precambrian Shield Essay

1990 Words Nov 12th, 2015 null Page
In the Precambrian Shield there are no continuous aquifers and ground water is only found in the fractured and weathered zones of Precambrian rock. These various aquifers are located primarily in gneiss and granite. The Precambrian shield only makes up a small portion of eastern Bolivia. Aquifers in this province are generally shallow at depth less than 90 meters and due to this many of the aquifers are biologically contaminated near populated areas (Roebuck et al. 2004). Majority of the ground water that is used in this area come from alluvial aquifers located near the Rio Paragua (Roebuck et al. 2004). Within the Gran Chaco and Beni Plains there are several groundwater sources in Quaternary age alluvial aquifers and sedimentary and igneous aquifers. The Chaco-Beni Plains consists of the largest single groundwater reservoir in Bolivia (Roebuck et al. 2004). Aquifers in the Chaco plain are usually located 90-110 meters deeper compared to aquifers in the Beni Plains. Due to this area being mostly plains, access to these aquifers to set up wells is in theory not difficult but due to Bolivia’s lack of an advanced network, this makes it difficult to get wells set up easily. In the Subandean zone the aquifer is usually found at a depth of around 100 meters and aquifers range from Quaternary age to Paleozoic aged rocks. Mineral and thermal springs are a small source of freshwater for the Subandean zone. These springs are found commonly in Devonian or Silurian aged rock…

Related Documents