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Full-Text Articles in Physical Sciences and Mathematics
Evidence Of Erosional Self-Channelization Of Pyroclastic Density Currents Revealed By Ground-Penetrating Radar Imaging At Mount St. Helens, Washington (Usa), Andrew C. Gase, Brittany D. Brand, John H. Bradford
Evidence Of Erosional Self-Channelization Of Pyroclastic Density Currents Revealed By Ground-Penetrating Radar Imaging At Mount St. Helens, Washington (Usa), Andrew C. Gase, Brittany D. Brand, John H. Bradford
Geosciences Faculty Publications and Presentations
The causes and effects of erosion are among the least understood aspects of pyroclastic density current (PDC) dynamics. Evidence is especially limited for erosional self-channelization, a process whereby PDCs erode a channel that confines the body of the eroding flow or subsequent flows. We use ground-penetrating radar imaging to trace a large PDC scour and fill from outcrop to its point of inception and discover a second, larger PDC scour and fill. The scours are among the largest PDC erosional features on record, at >200 m wide and at least 500 m long; estimated eroded volumes are on the order …
Floodplain Deposits, Channel Changes And Riverbank Stratigraphy Of The Mekong River Area At The 14th-Century City Of Chiang Saen, Northern Thailand., Spencer H. Wood, Alan D. Ziegler, Tharaporn Bundarnsin
Floodplain Deposits, Channel Changes And Riverbank Stratigraphy Of The Mekong River Area At The 14th-Century City Of Chiang Saen, Northern Thailand., Spencer H. Wood, Alan D. Ziegler, Tharaporn Bundarnsin
Geosciences Faculty Publications and Presentations
Riverbank stratigraphy and paleochannel patterns of the Mekong River at Chiang Saen provide a geoarchaeological framework to explore for evidence of Neolithic, Bronze-age, AD 5th Century Yonok and AD 14-16th Century Lan Na Cultures. Typical bank stratigraphy charted on the Thailand side is imbricate cobble gravel overlain by 5-10 m of reddish-brown sandy silt. The silt section is composed chiefly of ½ to 2-m thick layers of massive silt without paleosols interpreted as near-channel floodplain and gently-inclined levee deposits laid down by episodic, infrequent, large floods. The surface soil is dark-brown clay loam (La Na time. Brick ruins of 14-16th …