Relative dating and radioactive dating
Despite this, the "principle of cross cutting relationships" can be used to determine the sequence of deposition, folds, and faults based on their intersections -- if folds and faults deform or cut across the sedimentary layers and surfaces, then they obviously came after deposition of the sediments.
You can't deform a structure (e.g., bedding) that is not there yet!
The layers of rock are known as "strata", and the study of their succession is known as "stratigraphy".
Fundamental to stratigraphy are a set of simple principles, based on elementary geometry, empirical observation of the way these rocks are deposited today, and gravity.
My thanks to both him and other critics for motivating me.
An early summary of them is found in Charles Lyell's .
In no way are they meant to imply there are no exceptions.
For example, the principle of superposition is based, fundamentally, on gravity.
In order for a layer of material to be deposited, something has to be beneath it to support it.
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Most of these principles were formally proposed by Nicolaus Steno (Niels Steensen, Danish), in 1669, although some have an even older heritage that extends as far back as the authors of the Bible.