FOSSILS- Evidence from Once-living Organisms. Fossils found in SEDIMENTARY ROCKS. The lower the sediment layer is, the older the fossils of the layer will be.- Law of Superposition As time elapses, more and more sediment layers form to create the layers of sedimentary rocks.
Relative dating places rocks in their proper sequence of formation, e.g. which formed first, second etc.
Although relative dating cannot give us numeric dates for events that took place, it does provide useful information on what event followed or preceded another event.
Relative dating is still very valuable to scientists and still widely used.
The discovery of radioactive dating has supplemented relative dating techniques.
Can you put the events in order?
Half-Life of an element is the TIME it takes for HALF of the atoms present to RADIOACTIVELY decay into a stable element.
-100x more penetrating than alpha
-Neutron changes to one proton, one electron
-Electron is emitted from nucleus
-2 protons, 2 neutrons
-Emitted from the nucleus
-no charge or mass
-results in only lost energy
-Emitted in Photons
-most dangerous form
PARENT = C-14
DAUGHTER = N-14
Eurobrontes (dinosaur footprints)
A baby mammoth has been uncovered in the permafrost of north-west Siberia. Approx. 9,000 years old.
Skull of horned and
From the Dominican Republic, Miocene epoch (23.8 to 5.3 mya)
The 67-million-year-old Tyrannosaurus rex skeleton known as Sue stands on display at Union Station in WashD.C.