Fortymile River, Yukon River Tributary (IMAGE) Utah State University Caption Broad surfaces called terraces preserve ancient river floodplains and landscape history up to hundreds of meters above the Fortymile River, a tributary of the Yukon River, in eastern Alaska. Researchers from the USGS, the University of Vermont, Purdue University and Utah State University publish definitive support that increases in sediment deposited to oceans from river erosion coincide with dramatic changes in glacial cycles. Credit USGS Usage Restrictions Credit author License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.