Background. Aseptic meningitis is an illness characterized by serous inflammation of the linings of the brain (i.e., meninges), usually with an accompanying mononuclear pleocytosis. Clinical manifestations vary, with headache and fever predominating.
Lake Superior 1  ... is the largest freshwater lake in the world by surface area and the third largest by volume (Lake Baikal in Siberia and Lake Tanganyika in East Africa contain more water). 2  could hold all the water in the other Great Lakes, plus THREE MORE Lake Eries. 11,000 years ago: Glacial Lake Duluth, the precursor to Lake Superior, forms as the ice sheet retreats northeastward. 2  The lake's torrential outflow near present-day Duluth carves the St. Croix River Valley and feeds the Mississippi River.
Mid-Continent Rift Saint Lawrence Rift These rifts are responsible for the great depths of Lakes Superior and Ontario Deep valleys formed as tectonic plates pulled apart Valleys are now deepest regions of these two lakes Midcontinent Rift 1.1 to 1.2 billion years ago two previously fused tectonic plates split apart and created the Midcontinent Rift. A valley was formed providing a basin that eventually became modern day Lake Superior. Rocks rich in copper and silver in Michiganâs UP Saint Lawrence Rift