Welcome back everyone :). Let's start on our second topic!
Here we're going to focus on the geologic history of sedimentary rocks, and talk about how to apply your sedimentary geology knowledge to the observations you now know how to make, to start making some of your own interpretations!
Sedimentary geology is a type of story-telling. What features you see in the rock tells you all about the environment in which it was deposited. Here, you will start to make connections between what you are seeing now and what was happening in that spot during formation throughout the geologic timescale.
Before we jump in, let us discuss what we look for in a sedimentary rock. There are few main aspects we look at; It is good idea to write these down in your fieldbook before you get to the field. Sedimentary rock descriptions can be long and it is easy to forget one of these that can be crucial to your understanding.
Sedimentary rock descriptions include:
Color - it is good to note the difference between a weathered and a 'fresh' face
Texture of gains - size, roundness, sorting
Mineral/grain composition - include cement
Bedding - thickness and shape
Fossils
Sedimentary structures - ripple marks, cross bedding, etc
There are typically more, but we will only focus on these descriptions for this trip.
And don't forget your scale!
Let's get to time-traveling!