Abstract
Cosmogenic 26Al and 10Be in sediments washed into Mammoth Cave, Kentucky, record the history of 3.5 m.y. of water-table position, governed by incision and aggradation of the Green River, a tributary of the Ohio River. Upper levels of the cave formed during a period of slow river incision and were later filled with sediment due to river aggradation at 2.3–2.4 Ma. A brief surge of river incision ca. 2 Ma was followed by river stability and cave-passage formation at a lower level. Rapid incision through 15 m of bedrock ca. 1.5 Ma was prompted by repositioning of the Ohio River to its present course along an ice-sheet margin. Renewed incision ca. 1.2 Ma and aggradation at 0.7–0.8 Ma correlate with major ice advances in the Ohio River basin. Measurements of 26Al and 10Be also indicate that sandstone-capped uplands have maintained slow erosion rates of 2–7 m/m.y. for the past 3.5 m.y., despite accelerated Pleistocene river incision rates of ∼30 m/m.y.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
