کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
9524865 1635614 2005 10 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
The genesis of the northern Kettle Moraine, Wisconsin
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات فرآیندهای سطح زمین
پیش نمایش صفحه اول مقاله
The genesis of the northern Kettle Moraine, Wisconsin
چکیده انگلیسی
Interpreting past glacial dynamics from the glacial record requires that the depositional environments of glacial sediments and landforms be understood. In the case of interlobate deposits, models that incorporate various components of pro, supra and subglacial deposition have been developed and tested in the northern Kettle Moraine (nKM), Wisconsin; a large interlobate deposit that formed between the Green Bay and Lake Michigan lobes of the Laurentide Ice Sheet during the last deglaciation. In this paper, we interpret a new genesis for the nKM using sediment analysis and distribution along with landform distribution. In Sheboygan County, the nKM consists of two steep-sided, high-relief, hummocky ridges separated by a low elevation and low-relief central axis. Gravel in the bounding hummocky ridges is well-sorted and well-rounded. Some bedding is collapsed. Large, isolated moulin kames are restricted to the axis area and composed of relatively poorly sorted, more angular gravel and diamicton. The distribution of these different sediments and landforms are explained by the accumulation of supraglacial debris that insulated the ice below the axis of the nKM, while the melting of cleaner ice on either side formed channels on the ice surface. As deglaciation proceeded, a substantial thickness of well-rounded, stream-deposited sand and gravel accumulated on ice in the bounding channels. Eventual collapse of this sediment formed the two hummocky ridges. Poorly sorted debris along the axis fell and slid into moulins and larger collapse areas in the ice. Thus, differential debris insulation and ice ablation controlled the mainly supraglacial deposition of this part of the nKM.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Geomorphology - Volume 67, Issues 3–4, 30 April 2005, Pages 365-374
نویسندگان
, , , ,