 So I would like to provide you with an example of some glacial facies, and I want to take you to Greenland and in particular this area that I got to go to last year that has some very old rocks and it's an area called Isua, but I also had the opportunity to observe a lot of glacial facies. So I'm going to show you photos from right in this area at the edge of the ice cap, plus some photos we took from the helicopter as we flew to and from Nook to this area. Okay, so this is a view of the ice cap from the helicopter and out in the distance here you're looking into the interior of Greenland. This is the ice and it's flowing over some rocks and it's got all these crevasses in it from the strain. The brown color is from rock and debris and this is the edge of the glacier that's melting back and this area is a marine, be a lateral marine that is composed of diamnetic type. So we can also look at the ice cap end on and so the ice cap again is at the horizon here and the ice is spilling over this area. Parts of it are scoured bedrock as shown here and then parts of it are marine, these grayer areas here and you can see the debris in the ice sheet. So the next image shows a closer up view right here and you can see that there's a lot of debris in the ice itself and as the ice melts it leaves that behind and it's piled up in this lateral marine because it's at the edge of the ice on top of bedrock. And there's a lot of debris here as well. The front of the glacier and ice sheet is on this lake and you can see a few small icebergs in the area there and so the icebergs break off, we often say cab off the front of the glacier and then once they're floating in the water they continue to melt. The next photo is going to show an area that's off to the left side of the screen here and this is an area where the glacier is melting but it's not melting directly into the lake and so it's depositing a lot of sediment and the liquid water is flowing out and forming this braided river and the braided river is sorting out some of those sediments and you can see that the topography and organization of that depositional environment is significantly different than the moraine which is just the debris released from the laminar flow. So here's another view that's a little bit to the north and west. Again the ice cap is at the horizon and there's a lateral moraine coming down here. The front of the ice used to be out at this area in here but it is melted back. This area is melting very quickly and it has these areas with ponds in it here and there are all these ridges each represent a time when the ice probably flowed to that point and maybe pushed some sediment ahead of it and left a ridge of debris and then melted back. One of the things I like about this image is it shows again water, melt water coming down in through here in a braided river and it's flowing into the lake and it's creating this large delta and that delta it was just like any delta going into a lake. It's building outward and a lot of the sediment is accumulating right at the front here. So both when you have a delta from a braided river flowing into a lake and when you have a debris coming in directly from the glaciers you can end up with a particularly steep slope off the side of the delta. So for example in here and you can get turbidates coming off because the slope is so high that it fails and then you end up with a sediment getting deposited further down slope. I mentioned earlier that the glaciers have and form icebergs and so here is an example of one that shows a significant amount of sediment. And so it's floating over the water which has a very low flow speed and the fine grain sediment will just settle from suspension but as the iceberg melts it drops the sediment irrespective of the grain size down into the bottom of the lake creating lone stones or drop stones. The other thing you can see here are these brownish areas represent parts of the water that have a lot of rock flour and that's that mud sized lithic clasts that come from grinding up of the rock in the glaciers. And so most of the sediment below this area will consist of that rock flour that settled out from suspension but it will have these larger clasts from the melting of the icebergs. So if you go back to the till deposits this is looking down from a helicopter and we have a couple of people here for scale and there are large parts of this that are outcrop but a lot of these, all of these boulders that I'm like putting dots in here, different types, there's one over here, over here, these were all dropped by the ice as it melted back. And so when the ice is just straight melting back you end up with this huge mix of sediment, different sizes, different shapes and just a jumble of grains that would form a dyed migtite if it's turned into rock. Now there's a difference in this upper part of the image here, above the line you note that the rocks look much more closely fitted together and you're seeing mostly large rocks whereas here it looks like there's a lot of dirt in between. The difference is that this part has actually experienced some of that melt water flow over it and the very fine particles that get deposited by the glacier just staying in place were actually washed away here and the next picture will show that those boulders also have some rounding to them. So this is looking in the same valley but looking along it and from the ground and what the sediments are really showing is that they have a more uniform grain size, there are still some much larger boulders and then there's some plants have established in this one here but the rocks are relatively rounded, I guess I should probably say they're subangular, a few are very angular, but this rounding relative to the very angular rocks is evidence that these were exposed to transport in a river system sometime in the past. So the reworking by water both sorts the grains at least to some degree and it rounds the grains at least to some degree. Another feature that's very characteristic of glacial deposits or processes is the development of pavements. So there's a mechanical pencil here for scale and this surface here is a smooth pavement from the glacial erosion. Now it's formed on a schist which had a fabric to it already and so some of these color variations in here are related to the actual fabric of the rock but the next image I'll show that some of these ones that are going diagonal and some of the ones that are sort of parallel to the schistosity are actually carved into the rock by the glacial flow. So here's a close up of that same surface again with a pencil for scale and you can see the scratch marks running along here and each one of those represents a place where a rock inside the glacial flow was scraping against the bedrock, smoothing the bedrock and the class that was in the ice. So these very big zones in here are actually called chatter marks and they're from the interaction of very large rocks with the surface below the ice. So we talked a little bit about the rock flower and suspended sediment and I wanted to talk a little bit more about that. So all of the tan area in here is melt water directly from the ice cap and it has a very high proportion of that mud sized rock flower and in contrast this island is bedrock and there's a lake of accumulated snow melt on that and so this isn't fed by the glacial melt itself. This just has some windblown fine sediment but this is what the water would look like if it wasn't being fed by as much rock flower as you get with the melting glaciers. And that water with all the rock flower flows downstream and this is a river that's flowing off to the left and it has this milky look to it because of all that suspended sediment. So the rivers can move all grains smaller than I think these are boulder size. This was taken from the helicopter so it's a little hard to tell but it can when the flow is high it can move these large grains and when the flow is as it is now or flowing much at all it can transport the rock flower. So downstream eventually these rivers flow into fjords or flooded valleys from the marine water and this is an inner tidal zone at low tide and a lot of that rock flower has accumulated on these mud flats. And so one of the interesting things is that usually mud flats have a lot of mud but it's composed of clay minerals. In this case because it's being fed mostly by melting of the Greenland ice cap with glacial processes it has mud sized grains but they're mostly composed of lithic fragments that aren't chemically weathered. And icebergs can get out into that zone and that far. I actually saw some that were grounded on the inner tidal flats and so even in marine waters they can melt and release some of the sediment like you see here. Okay well thanks for watching.