How is a glacial drift formed

00:00well this is a jumbled up mixture of

00:04different grain sizes it's it's

00:06heterogeneous unstructured these pebbles

00:10scattered around make it look a little

00:12bit like a fruitcake there's a lot of

00:14sand and there's also finer material I

00:17can feel it in here there's silt and

00:19probably even clay filling in the pore

00:22spaces and look down there there's even

00:26a boulder so what does this unsorted

00:36sediment tell us what kind of

00:39environment was it deposited in well

00:44this Boulder is a clue this is actually

00:46a glacial erratic it looks like it might

00:49be a limestone it's certainly a

00:51different Rock than any of the bedrock

00:53in this area and must have been brought

00:55here by a glacier and in fact unsorted

00:59sediment like this is very common in

01:03glaciated areas

01:05glaciers in the mountains pick up a

01:08variety of grain sizes dirt cobbles and

01:12boulders everything and as they're

01:15moving along they smear some of that

01:17material along the base and produce

01:20something like this also when glaciers

01:24are melting out at the end of their

01:25journey they can produce a mixture of

01:28unsorted grain sizes just like this and

01:31in fact this is what's called glacial