Hello and welcome back to Fossils on Friday!
If you remember last week’s post, we began discussing the concept of horizontal deposition, and the implications it has for both geology, and crossbedding. This week we will focus on the concept of horizontal depositon, and how it works.
Remember the analogy I used last week about a river, or beach with waves? The water flows along horizontally, carrying sediment with it. Now, the faster the water moves, the larger the particles of sediment can be. This is important because in some cases, such as Budleigh Salterton, the sediment particles can be very large pebbles!
And in Australia, near Uluru (Ayer’s Rock), the sediment particles are enormous boulders! Wow! The water must have been travelling very fast for it to be able to move something that big!
The speed of the water also determines the total amount of sediment that the water can carry. Faster water can carry more sediment in its flow than slower water. So if you see a large water-laid deposit of rocks with large boulders mixed in, then you know that there was a lot of water, and it was flowing very fast indeed!
There are several experiments that can be done to show how this all works. Creation Research has designed many of these, and ran them in Jurassic Ark, the outdoor Creation Museum in Australia. These will be replicated for the UK museums in the future – so come and visit us when they’re up and running!
In 2018, I spent many hours working with a rocket scientist (yes, he really did design rockets!) called Clem on our ‘Flood Strata Machine – Mark #10’. The results were quite amazing…..
The structure went like this:
The machine consists of a long flume that slopes slightly downwards. At the base on the floor there is a bathtub filled with a mixture of sand and sediment – mineral & quartz sands. There is a ‘venturi pump’ in the bathtub which sucks up sediment and takes it up pipes to the top of the flume.
It’s then washed into the top of the flume, the water & sediment mixture then runs down to the bottom of the flume, and flows out the end. Just like a river.
After a few minutes, something remarkable begins to happen. Sediment begins to build up – but not one-on-top-of-the-other, but horizontally, with sediment forming sideways along the flume!
Using this method, we have been able to replicate every single geological formation and structure seen in the real world – but on a much smaller scale!
For a closer look, watch some of these videos below, and see some of the examples in action:
Here is a longer video of Jurassic Ark in general, but it has a very good segment on the Strata Machines in which you can see very clearly the sediment being deposited sideways, horizontally as it goes along in a flow.
Ok, so – we can see that sediment forms sideways in our flume machines. But is there an example from the real world where this can be seen. The answer is yes – several! But that’s for next week…..
If you want to go into more detail, here is the link to a multi-part report on the strata machine experiments, and what can be learned from them. STRATA EXPERIMENTS