- [Ali] So we're continuing with our sedimentary structures. I sprayed this core down. And by spraying it, now we can see a lot more detail that we were missing the last time. Now what I want you to focus on is this. Okay, you can see this concave down, depression right there. Here's another one. That's again from the saw blade going across the core. But that's not a real feature right there. But this one is. Okay, and that is a swale. So we saw a hummock, which was the mounded feature. You can kind of tell there's another hummock forming there. This thing would probably get it thicker and thicker and come up and down again. So that represents our hummock. That right there is a really nice example. That's right pretty much at the top of the hummock. So what are we talking about every time I say hummock? And that's top of this guy right there. Okay so you can sample it here. Or you can sample it towards the top. If you sample it here, all you're going to see is laminate going like that. On top you'll actually you might actually see a little bit of the curvature so let me give you an example of this first. That's what you see right here. And then right at the top where you have that curve, that's what you're seeing right there. It's very subtle. Now then we have our swales. Okay and the swales are like that. Okay so we're gonna look for that feature. And that's what you see right there. These hummocks and swales are important because they tell use where our storm wave base is. Okay because hummocks and swales will not develop the low storm wave base. And the way we classify classic shorelines, if it's below storm wave base, it's offshore. Okay, so we start picking up these hummocks and swales in the lower shoreface. Sometimes you'll get isolated hummocks in the transition zone. Okay, in case in shale. But it's if it's in all within sandstone like this, you're getting into stuff which is fairly storm nominated. Here you see quick a sharp contact. Alright? Super sharp contact, this stuff right here is medium to fine grain. And the stuff on top is fairly coarse grain. The other thing you see, as you see the largest grains are at the base. And these grains are getting smaller towards the top. That is normal grading. Normal grading means largest grains at the base and they're getting progressively smaller towards the top. So what is normal grading represent? It represents waning flow. Okay, which means flow velocity is decreasing over time. The competence off the flow, to carry grains of a certain size, is also decreasing over time, which is why the grains get smaller towards the top. Usually we get this in channelized successions. Okay so perhaps with as sharp as that contact is this was maybe some sort of full wheel channel that has cut into this marine succession down here. Okay that one possibility. And given that context, we know that this core happens to be from a marginal marine setting. We have another tutorial on deep marine core. And then there when you look at normal grading it represents something slightly different. But it still represents waning flow. Next thing you see quite a bit here are these ripple class. You can tell that there used to be a shale right there. Whatever cut through the shale, picked up pieces and incorporated it, okay. So these are ripple class right there. You normally find these ripple class at the base of a channel. So that's one interpretation for them. Looking in here, you can see very faint, low angle, cross stratification. Examples of cross stratisfication. Now, in here, we got something fairly interesting. You look at this section right here, you can actually see there's a lot of xxx faulting in here. Okay this faulting has nothing to do with tectonics. This is just sin, sedimentary faulting. And it's from soft sediment deformation. This stuff was partially over liquefied. I shouldn't even say partially liquefied. It's just partially consolidated. While more sediment was being dumped and as a result you got a little bit of faulting and this stuff started collapsing, okay? You can see more convoluted bedding. This stuff is all mixed up. More evidence of soft sediment deformation there. There's some more here. Now usually when you see this much soft sediment deformation it can be in a variety of settings. A lot of times along fluvial channels you'll get soft sediment deformation. And let me show you how. So let's assume... Again this is the cut bank. And then this here is the point bar side. This bank could easily collapse. And once it collapses, you get all kind of jumbo material into the channel down here. And then this stuff is soft sediment deformed. Alright that's one way of doing it. Whenever, like I said, you're not gonna be making interpretations in the core lab. Here you're only making observations. You're collecting data, which you'll process later on. So here's a different core. And we're going through it. And what I'm looking for is, perhaps a nice example, of ripples that I will show you guys. More soft sediment deformation here. Some bioturbation. And this section is actually, is actually fluvial. You can see there's some very low angle cross stratification in there. And this cross stratification, it seems to be fairly planar. So this is probably planar cross stratification which represents straight cresidiums. Looking here you can see there's a bit of more curvature along those laminaze so dude that's cross stratification. And that represents sinius cresidiums. This right here is a good example of ripples. You can see that this here is a lead side. This is the south side for the ripples. So the relationship between cross stratification and ripples is just one off decreasing flow velocity in this situation. Sedimentologists talk about sedimentary structures with respect to upper and lower flow regimes. We're gonna talk about that in the slides, not in here. But these are some of the most common sedimentary structures you'll see. You've seen some sort of flaser bedding, you've seen lenticular bedding. hummocky cross stratification, swaley cross stratification, normal grading, and soft sediment deformation. These are some of the most common sediment structure types you will see in marsh or marine to fluvial cores.