Dating layers with no ages us online dating users
Ask yourself how the things that are happening in the world today might end up being recorded in the sediments that are now or soon will be deposited.How would today's sediments appear to a geologist millions of years in the future examining outcrops of sedimentary rock that originated in our time?What would the geologist be able to deduce about the world we live in, based on what was left in the strata?Stratigraphy started to become a formal science due to the work of a man who published under the name Nicolaus Steno in the 17th century.The absolute dating methods proved that the relative dating methods had been correct, and now geologists can say not only state the sequence of geologic time, they can also estimate fairly accurately how many years ago each division in the sequence occurred.
The angular unconformity is the contact between the younger layers of sediment and the older, tilted strata beneath.
To determine the nature of the contact - whether it is an intrusive contact or a nonconformity - further evidence from field investigations would be needed.
Evidence such as angular pieces of conglomerate surrounded by the granitic intrusion, and contact metamorphism of the conglomerate adjacent to the granite, would indicate that the granite is younger and intruded the older conglomerate.
For instance, an orogenic episode (a long geologic episode of mountain building) may finally come to end and the eroded mountains may be buried beneath a new sequence of sediments.
A major unconformity would mark the change from the building up of mountains to the wearing down of those same mountains and the subsequent blanketing of the area with sediments.
An angular unconformity is an unconformity beneath which the strata were tilted or folded before deposition of the younger layers of sediment above the unconformity.