SGER: The Owens River as a TIltmeter for Long Valley Caldera: Exploratory Dating of its Oxbow Sediments Using Tephrochronology

SGER：欧文斯河作为长谷火山口的倾斜计：利用岩石年代学对其 Oxbow 沉积物进行探索性年代测定

• 批准号: 9116688
• 负责人: John Reid
• 金额: $ 0.49万
• 依托单位: Hampshire College
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1991
• 资助国家: 美国
• 起止时间: 1991-09-01 至 1992-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9116688&HistoricalAwards=false
• 关键词: SGER; Owens; River; TIltmeter; Long

The Owens River at Long Valley follows the caldera's moat around the N and E sides of the resurgent dome and shows geomorphic evidence that its course has been modified by uplift of the dome over a period of time considerably longer than the last ten years. In most of its lower 15km, the river consists of two parallel meander belts separated by a nearly planar interfluvial surface (200-300m wide) that shows no trace of recent river activity. The two belts display essentially identical meander amplitude and wavelength, but are not the same age. The older meander belt, now carrying a small underfit stream, invariably lies closer to the dome than the main flow in the new outboard channel, and sits some 30-60 cm higher in elevation. The river apparently jumped into the new channel after some period of lateral tilting. Projection of the interfluvial surface to the axis of the some suggests that total uplift of 15 to 35 meters may have occurred. In the lowermost six km of its course, the Owens River floodplain shows as many as six identifiable meander belts of different age (some lying outboard and other lying well inboard of the modern channel) that appear to record events of subsidence as well as resurgence. Knowing the absolute ages of the river's occupancy of each of these meander belts may provide us an estimate of the timing of the resurgence and subsidence of the dome. We are particularly interested to know whether eruptive activity in the Mono Craters and Inyo Craters north of the caldera has been tied in a temporal way to the migratory behavior of the Owens River channel, and thus possible to the resurgence and subsidence of the crate floor.

长谷的欧文斯河沿着火山口的护城河流淌 在复活的圆顶的N和E侧周围， 有证据表明，它的路线已被修改的隆起圆顶 比过去十年长得多 在下游15公里的大部分地区，河流由两条平行的河流组成。 曲流带被几乎平坦的河间面分隔开 （200- 300米宽），没有显示最近河流活动的痕迹。 的 两个带显示出基本相同的曲流幅度， 波长相同，但年龄不同。 古老的曲流带， 携带一个小的不足流，总是位于更接近 圆顶比主流在新的舷外通道，并坐在一些 海拔高30-60厘米。 这条河显然跳进了 经过一段时间的横向倾斜后，新的通道。 投影 一些河流的轴的河间表面表明， 可能总共上升了15到35米。 在 欧文斯河洪泛区最低处6公里处显示， 多达六个不同年龄的可识别的曲流带（一些 位于现代海峡外侧，其他位于现代海峡内侧） 似乎记录了下沉和复苏的事件。 知道了河流占据这些地方的绝对年龄 曲流带可以为我们提供一个时间的估计， 穹顶的复苏和下沉 我们特别 想知道莫诺陨石坑的喷发活动 火山口北部的因约火山口 欧文斯河河道的迁移行为，因此， 可能导致板条箱地板的复苏和下沉。