If 1 January is on a Friday, it is part of week 53 of the previous year.If it is on a Saturday, it is part of the last week of the previous year which is numbered 52 in a common year and 53 in a leap year. This week’s properties are: If 31 December is on a Monday, Tuesday or Wednesday, it is in week 01 of the next year.
This method is based on the assumption (which nearly always holds true) that deeper layers of rock were deposited earlier in Earth's history, and thus are older than more shallow layers.
The US broadcast calendar counts the week containing 1 January as the first of the year, but otherwise works like ISO week numbering without partial weeks.
Dating techniques are procedures used by scientists to determine the age of an object or a series of events.
Absolute dating methods are used to determine an actual date in years for the age of an object.
Before the advent of absolute dating methods in the twentieth century, nearly all dating was relative.