Glacial Features

July 26, 2018

Most of the natural sediment that makes up Joppenbergh mountain consists of a thin layer of glacial till draped over bedrock. As glaciers move, they change the landscape by breaking up, transporting, and depositing bits of rocks. When the glacier melts, all of the material within the glacier melts out forming glacier till. Till contains a variety of grain sizes from very fine-grained clay to boulders. These sediments are also unsorted meaning the grain sizes are scattered randomly throughout an area. The vast majority of natural soils throughout Joppenbergh are made up of this till.

The sediments on the outcrop trail (shown on the map) are a bit different from the till. The clay in this area represents sediments deposited in a glacial lake formed from meltwater. Unlike till, sediments deposited in still water are typically sorted and layered. A lake environment is a relatively low energy system meaning that larger particles such as gravel get left behind and finer particles such as sand, silt, and clay dominate. Here, there is mostly clay which makes poorly drained soils and tends to form wetlands

 

Back to Interactive map: https://wallkillvalleylt.org/joppenbergh-interactive-map/

 

Cross-section of the glacial lake sediments 

Area where cross-section was cut