The origin of oriented lakes: evidence from the Bolivian Amazon

Lombardo, Umberto; Veit, Heinz (2014). The origin of oriented lakes: evidence from the Bolivian Amazon. Geomorphology, 204, pp. 502-509. Elsevier Science 10.1016/j.geomorph.2013.08.029

Text 1-s2.0-S0169555X13004340-main.pdf - Published Version Restricted to registered users only Available under License Publisher holds Copyright. Download (1MB)

The presence of hundreds of rectangular and oriented lakes is one of the most striking characteristics of the Llanos de Moxos (LM) landscape in the Bolivian Amazon. Oriented lakes also occur in the Arctic coastal plains of Russia, Alaska and Canada and along the Atlantic Coastal Plain from northeast Florida to southeast New Jersey and along the coast of northeast Brazil. Many different mechanisms have been proposed for their formation. In the LM, Plafker's (1964) tectonic model, in which subsidence results from the propagation of bedrock faults through the foreland sediments, is the most accepted. However, this model has not been verified. Here, we present new results from stratigraphic transects across the borders of three rectangular and oriented lakes in the LM. A paleosol buried under mid-Holocene sediments is used as a stratigraphic marker to assess the vertical displacement of sediments on both sides of the alleged faults. Our results show that there is no vertical displacement and, therefore, that Plafker's model can be ruled out. We suggest that, among all the proposed mechanisms behind lake formation, the combined action of wind and waves is the most likely. The evidence from the LM provides new hints for the formation of oriented lakes worldwide.

Interest & Impact

Downloads

8 since deposited on 05 Sep 2014
0 in the past 12 months

Citations

5 Citations in Web of Science ®
6 Citations in Scopus

Search

in Google Scholar™

Services

Actions (login required)

Edit item

Actions (login required)

Edit item