In many cases, there are independent cues (such as geologic setting or the chemistry of the specimen) which can suggest that such assumptions are entirely reasonable.
However, the methods must be used with care -- and one should be cautious about investing much confidence in the resulting age...
especially in absence of cross-checks by different methods, or if presented without sufficient information to judge the context in which it was obtained.
Isochron methods avoid the problems which can potentially result from both of the above assumptions.
This is an informational tour in which students gain a basic understanding of geologic time, the evidence for events in Earth’s history, relative and absolute dating techniques, and the significance of the Geologic Time Scale.
He was considered to be the brutish ancestor link to man in the evolution chain, the intermediate stage between man and ape.Archaeological geology as a science had to precede the proposal of evolution, as an understanding of the immense age of the earth is necessary to understand evolution.Cuvier established amongst the scientific community the fact of extinction.He considered that the flattened head was caused by repeated powerful blows (his examination was done pre Darwinism 1859).When more finds came to light with what also appeared to be rickets, it was considered far too much of a coincidence and for lack of any other explanation they became relegated to a sub-human category.