Diatoms and Cosmogenic Isotopes as Tracers of West Antarctic Ice Sheet History and Processes

[9980364]谢勒该奖项为南极西部冰盖当前和过去的地面冰下沉积物的分析提供了三年的支持。硅藻和10Be不仅可以作为过去冰川消融条件的证据，还可以作为加州理工学院冰川学家从冰流B、C、D和流间脊下回收的活塞岩心微地层变化的沉积示踪剂。类似的分析也将在罗斯冰架南部和靠近冰锋的罗斯海南部的沉积物岩心上进行。硅藻是很好的沉积示踪剂，因为与大多数沉积颗粒不同，它们有已知的初始条件（原始大小、形状、大约年龄和起源环境）。目前的研究包括使用Iverson等人（1998）开发的环剪装置，从实验室研究中对罗斯海硅藻的粉碎进行定量分析。初步分析表明，硅藻断裂的独特模式可能为估计海洋金刚石的载荷和剪切提供指导，这可能对解释过去的冰盖结构具有重要意义。

9980364SchererThis award provides support for three years for analysis of sediments from beneath current and past grounded ice of the West Antarctic ice sheet. Diatoms and 10Be will be used not only for evidence of past deglacial conditions, but also as sedimentary tracers of microstratigraphic variability in piston cores recovered by Caltech glaciologists from beneath ice streams B, C and D, and inter-stream ridges. Similar analyses will be performed on sediment cores recovered from beneath the southern Ross Ice Shelf, and the southern Ross Sea near the ice front. Diatoms make excellent sedimentary tracers because, unlike most sedimentary particles, they have known initial conditions (original size, shape, approximate age, and environment of origin). The current study includes quantitative analysis of comminution of Ross Sea diatoms, from laboratory studies, using the ring-shear device developed by Iverson et al. (1998). Preliminary analyses suggest distinctive patterns of diatom breakage that could lead to guidelines for estimating load and shearing of marine diamictons, which may have important implications for interpreting past ice sheet configurations.