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Periglacial Landscapes of Central PA Driving Tour

Date(s) - Sun Mar 29, 2015
8:00 am - 5:00 pm

I-99 park and ride lot


All-day driving tour led by Dr. Mark Bonta on Sunday, March 29 that begins and ends at the I-99 park-and-ride lot in Tyrone, visiting several spots in the Nittany anticline and in Bald Eagle valley. Leave at 8:00 A.M. and return at 5:00 P.M. Total number of miles driven per vehicle will be about 150 round-trip from Tyrone; short walks at some spots. Contact Mark in advance ([email protected]) to receive a packet containing field trip map, photos, and descriptions of features; he will also bring a few extra packets along on the trip. Bring picnic lunch and snacks.

Description: During the last million years, and as recently as 12,000 years ago, central Pennsylvania experienced periglacial climates as cold as those of present-day Greenland, thanks to nearby continental glaciers. Ancient landscape features associated with pervasive cold and intense cycles of freeze and thaw, as well as rapid global warming, are ubiquitous in the valleys and hill slopes of the region. We will visit a representative sample of these features and discuss parallels with what is happening in the Arctic today. In addition to widespread felsenmeer and boulder trains, we will examine solifluction lobes, thermokarst gullies, debris fans, grèzes litées, and other geomorphological features. During much of the trip, we will parallel the presumed waterline of proglacial Lake Lesley, viewing and discussing evidence for and against a jökulhlaup (glacial lake outburst flood) down the Juniata some 750,000 years ago.

Lake Lesley from Pennsylvania Glaciation, First Phase