Full Title: Geology of the Lake Titicaca Region, Peru and Bolivia
Author: Norman D. Newell
The basin of Lake Titicaca in the high plateau of the Central Andes lies across the border between Peru and Bolivia. This memoir based mainly on the author's observations during approximately 1 year in the field describes in reconnaissance detail the geology of the basin. The area is complex and forms a geological province distinct from adjoining Andean areas to the south and northwest. A general areal map covering about 58,000 square kilometers was prepared (scale 1:500,000) and a small area of some 200 square kilometers was mapped in detail (1:30,000) at Pirin, highest oil field in the world, northwest of Lake Titicaca. Significant observations have been documented in numerous measured stratigraphic sections and structural profiles. The sedimentary sequence aggregates more than 20,000 meters exclusive of a nearly unknown Lower Paleozoic succession (Cambrian, Ordovician and Silurian) on the east flanks of the Andes north of Lake Titicaca. The studied sequence includes dominantly marine rocks of the Lower and Middle Devonian (3,000 meters), Lower Permian (1,800 meters), Upper Jurassic (1,200 meters), mixed marine and continental Cretaceous (4,000 meters), Lower Tertiary continental clastics (7,000 meters), and younger Tertiary and Quaternary volcanics (4,000 meters). The volcanic rocks are divisible into two series, (1) a thick sequence of older folded and faulted rocks, and a younger group of essentially horizontal beds contemporaneous in origin with the great volcanoes of the Western Cordillera. Six orogenic cycles are inferred from the stratigraphic record. These were (1) near the close of the Paleozoic (?), (2) in the Late Jurassic, (3) near the close of the Medial Cretaceous, (4) near the close of the Late Cretaceous, (5) in the Miocene (?), and (6) in the Pliocene. The present elevation of the Andes is the result of Pleistocene- Recent epeirogenesis…
Published: 3/28/1949
Pages: 111
Product Category: EBooks