Presentation Type

Poster

Abstract

The pre-ice age Bell River basin of North America was comparable in size to the modern day Amazon basin of South America. In Miocene time, it drained most of Canada and one third of the North American continent before being defeated by tectonics, volcanism, and glaciation. Beginning about 2.5 million years ago, continental glaciers re-routed the paths of the tributaries in Canada, leaving behind only traces of this once massive river basin in headwater valleys in the Rocky Mountains and in a giant river delta in the Labrador Sea. The contemporary Amazon River basin provides an analog for estimating fluvial parameters of the ancient Bell River system. Both systems had headwaters in high mountains and canyons, then drained across flat, continental-scale basins, and emptied into the Atlantic Ocean through broad continental rift zones. Both have large deltas and long submarine turbidity channels. Comparing the Amazon's delta, tributaries, stream gradients, and sediment loads to the remnants of the Bell River system could support a model for pre-ice age North American drainage. This could then augment studies of tectonic displacements in the western interior, for example, uplift of the Great Plains and Rocky Mountains, effects of Yellowstone volcanism, and faulting in the Great Basin.

Category

Physical Sciences

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Apr 11th, 11:00 AM Apr 11th, 12:00 PM

The Amazon River Basin as an Analog for the Pre-Ice Age Bell River Basin of North America

The pre-ice age Bell River basin of North America was comparable in size to the modern day Amazon basin of South America. In Miocene time, it drained most of Canada and one third of the North American continent before being defeated by tectonics, volcanism, and glaciation. Beginning about 2.5 million years ago, continental glaciers re-routed the paths of the tributaries in Canada, leaving behind only traces of this once massive river basin in headwater valleys in the Rocky Mountains and in a giant river delta in the Labrador Sea. The contemporary Amazon River basin provides an analog for estimating fluvial parameters of the ancient Bell River system. Both systems had headwaters in high mountains and canyons, then drained across flat, continental-scale basins, and emptied into the Atlantic Ocean through broad continental rift zones. Both have large deltas and long submarine turbidity channels. Comparing the Amazon's delta, tributaries, stream gradients, and sediment loads to the remnants of the Bell River system could support a model for pre-ice age North American drainage. This could then augment studies of tectonic displacements in the western interior, for example, uplift of the Great Plains and Rocky Mountains, effects of Yellowstone volcanism, and faulting in the Great Basin.