Earth Sciences Commons^™

Effects Of Quaternary Climate Change On Tributary Sedimentation And Geomorphology In Eastern Grand Canyon, Benjamin D. Dejong

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Climate variability has had a dramatic impact on eastern Grand Canyon tributaries over the past ~100 ky. This is readily observed in the Lava Chuar and Comanche catchments, which host well preserved colluvial remnants and river terraces that resulted from several climate-induced cycles of aggradation and incision. This study investigates these climate responses using surveying, sedimentology, and luminescence geochronology methods to investigate the mechanisms and timing of their deposition.

The survey data demonstrate that the concavity of terrace treads is lower than modern drainages. The sedimentology suggests the prevalence of stream-flow reworking of debris flow deposits and portrays an expected …

Climatic Differences And Similarities Between Indian And East Asian Monsoon Regions Of China Over The Last Millennium: A Perspective Based Mainly On Stalagmite Records, Ming Tan

International Journal of Speleology

Cave sediments, especially stalagmites, have been providing absolute dated climate records that can extend from the present to over 500,000 years ago. Based on the reconstructed temperature time series, a comprehensive overview of the climatic differences and similarities between the Indian and the East Asian Monsoon regions of China over the last millennium is presented. Evidence from accurately dated and high-resolution records including stalagmites, ice cores and tree rings show that there was a “Medieval Warm Period” (around 1000 to 1400 AD) in north and east China where climate is dominated by the East Asian monsoon; whilst no such interval …

Geology, Geography, And Humans Battle For Dominance Over The Delivery Of Fluvial Sediment To The Coastal Ocean, James P.M. Syvitski, John D. Milliman

VIMS Articles

Sediment flux to the coastal zone is conditioned by geomorphic and tectonic influences (basin area and relief), geography (temperature, runoff), geology (lithology, ice cover), and human activities (reservoir trapping, soil erosion). A new model, termed “BQART” in recognition of those factors, accounts for these varied influences. When applied to a database of 488 rivers, the BQART model showed no ensemble over‐ or underprediction, had a bias of just 3% across six orders of magnitude in observational values, and accounted for 96% of the between‐river variation in the long‐term (±30 years) sediment load or yield of these rivers. The geographical range …