Erosion & Deposition by Ice 2/22/2019 Erosion & Deposition by Ice Show ice age video clip. 2/22/2019
2 Types of Glaciers Continental Alpine Cover large areas, like continents Due to cold global climates Alpine Cover mountain tops and sides Due to Orographic effect 2/22/2019
GLACIERS - VALLEY AND CONTINENTAL 2/22/2019
Glaciers Form when snow accumulation is greater than snow melting Cause a build up of ice Glacial movement is similar to streams (fastest in center) Create "U" shaped valleys with nearly vertical walls and flat bottom 2/22/2019
2/22/2019
2/22/2019
Glaciers in North America over the past 2.0 x 106 years Ice covered most of New York several times in the “recent” past Most recently about 11,000 – 15,000 ybp. 2/22/2019
2/22/2019
The last major glacial period 2/22/2019
Erosion by Glaciers Glaciers remove and carry sediments Ice can be thousands of feet thick and thus very powerful. Surface materials (like soil) are easily removed. Sediments at the bottom of the ice act like sandpaper and scour the bedrock. Continental and alpine glaciers have different erosional (and depositional) characteristics. 2/22/2019
2/22/2019
2/22/2019
2/22/2019
Glaciers Create features like striations 2/22/2019
2/22/2019
Glaciers ….glacial polish Where rocks within a glacier grind against bedrock 2/22/2019
Deposition by Glaciers Mixed sized sediment drops vertically as glacier melts Unsorted sedimentation Sediments often scratched (striations) 2/22/2019
Glacial Deposition This sediment is made of a variety of particle sizes 2/22/2019
Deposition by Glaciers The large rocks left behind by glaciers are called glacial erratics Large rocks not broken into small particles Often different in composition than the bedrock upon which they sit 2/22/2019
NY Erratic 2/22/2019
Erratics in our area Based on this image, where did the erratics and other non -native rock in Harpursville come from? 2/22/2019
Deposition by Glaciers 2/22/2019 Deposition by Glaciers Glacial till Unsorted glacial sediment Ranges from clay sized particles to boulders stratified (sorted) sediment consists of glacial sediments carried by meltwater and deposited in an outwash plain • view images to show these features 2/22/2019
Till- Sierra Nevadas 2/22/2019
A wide variety of landscape features are created by glaciation 2/22/2019
These features are most often associated with alpine glaciations: 2/22/2019
2/22/2019
Drumlins- Oval shaped Moraine Drumlin-Cranes Beach MA Drumlins- Oval shaped Moraine 2/22/2019
2/22/2019
Esker- Rivers on ice bore a hole in the ice and flow under the sheet Esker- Rivers on ice bore a hole in the ice and flow under the sheet. Rocky material builds up and the stream bed is left behind as a ridge of rubble. Esker-MN Esker-WI—Note boulders carries by water 2/22/2019
Esker- NE WA 2/22/2019
Kettles- Large block of ice separates and becomes surrounded with debris 2/22/2019
How is a valley created by a glacier similar to and different from a valley created by a stream? 2/22/2019
U Shaped Valleys- Yosemite Valley- 2/22/2019
Hanging Valley- Yosemite Natl Park, CA 2/22/2019
Holgate Glacier 2/22/2019
Glaciers Fusing Yukon Canada Terminus 2/22/2019
Iceberg Calving Terminus 2/22/2019
Portimoreino 2/22/2019
Jones Beach NY is part of an outwash plain 2/22/2019
Glaciers Video Awsome! 2/22/2019
2/22/2019