Can relative dating always be used

In this lesson, we'll learn a few basic principles of stratigraphic succession and see whether we can find relative dates for those strange strata we found in the Grand Canyon.

In order to establish relative dates, geologists must make an initial assumption about the way rock strata are formed. sediments, which are deposited and compacted in one place over time.

Since we assume all the layers were originally horizontal, then anything that made them not horizontal had to have happened after the fact.

We follow this same idea, with a few variations, when we talk about cross-cutting relationships in rock.

Relative dating cannot establish absolute age, but it can establish whether one rock is older or younger than another.

Imagine that you're a geologist, studying the amazing rock formations of the Grand Canyon.

There may be a layer missing in the strata, or a set of sedimentary rock on top of metamorphic rock.

These interfaces between discontinuous layers of rock are called unconformities.

It's called the Principle of Original Horizontality, and it just means what it sounds like: that all rock layers were originally horizontal. As you can imagine, regular sediments, like sand, silt, and clay, tend to accumulate over a wide area with a generally consistent thickness.

It sounds like common sense to you and me, but geologists have to define the Principle of Original Horizontality in order to make assumptions about the relative ages of sedimentary rocks. Say you have a layer of mud accumulating at the bottom of a lake. More sediment accumulates from the leaf litter and waste of the forest, until you have a second layer.

Leave a Reply

Your email address will not be published. Required fields are marked *

One thought on “can relative dating always be used”

  1. Newer Levi's jackets have four pockets: Two breast pockets and two side pockets are on Levi's jackets from the mid 1980s to the 21st century. Her work focuses on topics about cancer, children, chemical dependency, real estate, finance, family issues and other health-related topics.

  2. I’ve been shooting their VX-6 2-12X model and must admit, this is a serious scope for serious hunters. Leupold has added magnification ranges to this series, along with their new Twilight Max light management technology.