 I'd like to talk about how we interpret the flow speeds from a stratigraphic column and the water depth and how I want it marked for the projects. So I've taken a few selections from the various example stratigraphic columns and I want to just give an example for each one. So if we look at flow speeds, the black here is coal, we have trough cross stratification, planar cross stratification, ripple cross lamination, root cast, and then shale at the top. So if we're just taking this part, the flow speed for a coal which forms often in a marsh is really slow. So I would mark that part of the column as being slow. That's also true for the mud settling out at the top. So those are slow or the slowest in the column. We know that the trough cross stratification comes from sinuous dune crests and the planar comes from straight dune crests and the trough cross stratification occurs at faster flow speeds than the planar and there's also a decrease in grain size. So if we just take this little part of the column, the lowest part represents the fastest flow in the column and as the grain size decreases and we go from dunes to ripple lamination, the flow speed goes down. So could draw something like this, the upper part is about the same. So basically at the base of the channel there might be some erosion there because channels often migrate laterally. So we could draw in the jump in flow speed if we wanted there and then we have plants and mudstone on top that represents another abrupt change in flow speed. So the causes of the abrupt change here at the bottom would be channel migration and at the top it could also be the opposite sort of going from a channel to a floodplain or possibly the mudstone is in an oxbow lake. So it could be floodplain oxbow formation. If we look at the next example, this represents a diamigthite and we have some rippled sands and we have some shale with dropstones in it. So you get diamigthites. These are from ice which I think those of you with a section have interpreted and the ice is very low flow speed and it also has a very low flow to settle mud out from suspension. So I'd accept that either one of these, either the diamigthite or the isolated pebbles and mudstone would be the slowest flow speed. I'm going to make the ice, ice is often really slow moving. So I'm going to say that in this part of the column, the ice is the slowest, but the mudstone is very slow. But then we have these two sandstone beds with some ripples. So that requires a medium flow for those two beds and then it's not quite lined up. There's a little bit of sandstone in here before you go back to the ice. So this could be a representation of the flow speed for this section of the column. If I was just looking at this part, the fastest flow is probably where there are ripples. So you could mark that or not. The ripples show two directions of flow. So this sort of change in flow speed between those, so like all of these spots here, I could say represent tide changes as the cause. And then going up into this one, it would be ice advances. So you end up with that very low flow. If we take a look at this example, we have some beaches, we have some scour marks, we have some storm deposits and ripples in general, and then we have roots at the top. So to form the plants, we have to have the low flow speed. So right at the top represents the lowest flow, often in the sort of breaker zone, which the scour marks represent, we have a very fast flow. This is coarse grained on the beach, so we need to have a fast flow there. So we can make a fast flow for all of this. And as the grain size declines, we go down to a lower flow speed here. So this is a case where the flow speed is a gradational change except right at the top. And we could say this would be a change in environment causing that. You could say specifically what it is, like going from the beach to vegetated dunes or areas like that. But in this case, the flow speed, the grain size change is variable, and so this is variable smoothly so the flow speed is variable in the same sort of way. Okay, here we have some storm deposits, and there's this one bed that's a whole lot coarser. So that's definitely the fastest part of the flow and the speed. In this area, particularly the erosion at the bottom, and the flow speed goes down through time, and to sort of the average storm speed, and there's none of the shale preserved here. So if there was some shale in here, if I draw it in here, then we would have the lowest flow speed with the shale. So we could have two examples. This jump in flow speed and this jump in flow speed are due to a storm, as you can say, sort of peak storm currents and waves. So the storm advances and causes these jumps in flow speed. Now if we get down to some of these where we have hammock-u-cross stratification in some beds, current ripples, wave ripples, some of these are turbidites, some of these are storm beds. I just chose a couple of parts of examples. In these, you don't actually necessarily have to go the shale, I should say the shale represents the lowest flow speed, and then you have these sort of jumps up in flow speed for the various beds. And those represent sort of short-term intervals of faster flows, so you could draw sort of dots or you could draw lines coming out for each one. An alternative could be to draw an average. So you could through here say that the average flow speed is a little bit higher because it has more sand beds, then you go down to mostly mudstone with a few spikes in flow speed coming up representing those sandstone beds, or you could draw it as an average. And these sharp variations in flow speed, in this example we would have some of them are storms, some of them are turbidites coming and going, causing these variations in flow speed. But the water level, the interpretation of this bit of stratigraphy is that it's a river channel. So basically we have a river channel, and then we have the choice of whether this coal is land and the shale is land or flood plain or lake. And in this little bit I don't really know. We will make the coal be on the flood plain and the mudstone for example in a lake. So in this particular case there's a big abrupt shift between the sandstone and the finer grains on either side. So the causes of the abrupt change would be for example migration of the channel, or you could say for the lake, if it's an oxbow lake could say abandonment of the river channel to become a lake. If we look at the next one down, these two directions of flow suggest tidal flow. And then we have some mudstones with isolated pebbles. So those isolated pebbles if they're dropstone require some standing water for those large stones to be transported by glaciers, or by icebergs out into the water. So for those we could say that they're somewhat deeper marine. We come up to a tidal sort of environment, maybe at sea level. And then we have this question about whether this diamig tide is actually deposited on land or in a shallow marine environment. And we don't really have enough information. So like if the glacier extends out over the standing water, it can create a diamig tide. So here we have either sort of shallow marine somewhere in here or land here, right? And we don't really know which one of those it is. There aren't necessarily abrupt changes, but one of the changes in the facies that you could add if it does go all the way to land would be to say ice advances to get that diamig tide. So if we go down into this environment, we can't actually see. So let's see. So at sea level here, so the beach is right very close to sea level. The breaker zone is just a little bit deeper, and then we have the waves going shallow marine here and the plants indicate land. So right at this environmental change, let me draw this a little bit more. We have this abrupt change here, and it doesn't actually go through the river and lake. The lines don't necessarily tell you, but you can say this abrupt change is going from beach to land with the plants. So for the storm deposits, we have some choices here below SWB stands for storm wave base between fair weather wave base and storm weather wave base or shallow marine. So we're obviously above storm weather wave base, but we don't necessarily know just from this section if we're above fair weather wave base or not. So we'd be somewhere in this zone generally. So you could sort of fill it in or provide two lines, whatever you feel like, however you want to show that uncertainty. Now interestingly, the sea level doesn't significantly change when there's a storm versus when there's not a storm because it's a periodic event. And that's the case with these rocks down here, and we're getting a little bit of storm and a little bit of waves. So we know from those that we are above storm wave base, but there's a lot of shale. So we're probably below the fair weather wave base where waves really frequently influence the sediment. So again, you have these events that represent storms, but probably the whole environment down to where we have the wave ripples here is above storm wave base to get those big ripples. When we get to deeper water here, we just have the turbidites, and so we're not seeing any evidence of storms. So there's probably some transition here into an environment that's below storm wave base because there are no storms. We're not seeing any influence of the storms. So that's why I'm interpreting this as going deeper. So it could be deeper water, or it could be that climate has changed and there are fewer large storms. So let's zoom out just a little bit here and look at this overall section. So the difference in flow speeds, the flow speeds can change when you have events, but sea level, those events don't necessarily mean that sea level changes. There are a lot of times when there's uncertainty in the sea level, and you can show that by drawing a couple of lines like I did here, saying it's either land or at sea level, or here where I sort of filled in the whole range, and either of those is okay. And this sort of interpretation of the change in sea levels, one of the things that really helps us reconstruct environments, and it will help with the sequence stratigraphy, which is using sea level changes in different columns, the relative sea level change to understand how to correlate columns across environments in time with sequence stratigraphy. Thanks for watching.