Middle Stage Early Lake Erie

middle stage of lake erie. based on herdendorf, 2013. blue full extent of prehistoric lake light blue waters of lake huron on modern lake area.

about 10,000 ybp water levels began level off. @ 7,500 ybp elevation 145 metres (476 ft). continued rise, slowing next 2,000 years. period has been called “middle lake erie”. 25 metres (82 ft) below current lake level. alternative level @ 30 metres (98 ft) has been proposed through radiocarbon dates.

it believed decreased precipitation , increased evaporation of set changes created isostatic uplift.) xerothermic or hypsithermal interval existed approximately 5,000 years (10,300 5,300 ybp). uplift continued, north bay outlet rose , upper basin entered stage of lake nipissing. 5,400 ybp. lake erie remained isolated, continued rise. middle stage ended around 5,300 ybp when drainage lake nipissing again diverted through port huron outlet. increase in water, growing humidity in climate, , increased water levels created large delta in western basin @ mouth of ancestral detroit river. remaining depositional features in lake erie (i.e.; buffalo ridge, norfolk moraine, conneaut bank, , presque isle bank) flooded. these underwater obstacles, altered water circulation patterns. forming new surface features, including long point, ontario , presque isle, pennsylvania.

the lake st. clair delta formed during time, (5,000-3,600 ybp). lacustrine clays under delta have been radiocarbon dated @ 7,300 ybp. deltal began during lake nipissing time