Examine the stratigraphic column diagram. Following the law of superposition in geology, older fossils and rocks are found in lower strata than younger fossils and rock layers. Tectonic activity left some areas of land uplifted, and erosional forces from the lake, nearby rivers, and other forms of weathering exposed rock, even older rock layers, as outcroppings in the landscape. This made the fossils easier for researchers to find. The volcanic material in tuff layers also makes it possible to get a more accurate date for the fossils. What is one technique that scientists use to date the fossils they find? Potassium-argon dating is a form of isotopic dating commonly used in archaeology. Scientists use the known natural decay rates for isotopes of potassium and argon to find the date of the rocks.
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The radioactive isotope converts to a more stable isotope over time, in this case decaying from potassium to argon. If scientists find the ratio of potassium to argon, it tells them how long the rocks have been around by how long the isotopes have been decaying. By understanding the dates of these rocks, scientists can deduce the age of the nearby fossils. What difficulties might paleontologists and archaeologists have when trying to find and date fossils? There are many possible answers. One answer based on a common problem encountered by scientists is that fossils are often encased in rocks or are similarly colored, so they blend in with their surroundings. Sometimes, only a small part of a fossil is showing.
They might also be buried. Because of these characteristics, field crews have to carefully examine their surroundings to find possible fossils. Fossils might also be fragile or found in small fragments. Archaeologists have to use their skill and patience to put small pieces back together, like a jigsaw puzzle. Although fossil dating is now more scientifically accurate, it still requires skill and experience as scientists have to make educated guesses based on any evidence and the dating available for the layers surrounding the fossils. The diagram explains that each fossil is given a specific name, such as KNM-ER 6868. Why is a unique fossil name like this important?
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Because each name is a unique identification, this helps scientists keep track of where and in what order fossils are found. Doing this helps paleontologists maintain accurate records and piece together the story of human history. In this example, the prefix KNM-ER tells us the relative location of where this fossil was found this stands for Kenya National Museum—East Rudolf, from the former name of Lake Turkana. The accompanying numbers are chronological, meaning that, in this example, our fossil is the 6,868th fossil found in the area. Skull of a vertebrate, usually referring to the part that encloses the brain. Area where two or more tectonic plates are moving away from each other. Also called an extensional boundary.
Type of mineral used in ceramics, cleaning products, and archaeological dating. Series of faults and other sites of tectonic activity stretching from southwestern Asia to the Horn of Africa. Human beings are the only living hominins. Statement or suggestion that explains certain questions about certain facts. A hypothesis is tested to determine if it is accurate. Atom with an unbalanced number of neutrons in its nucleus, giving it a different atomic weight than other atoms of the same element. Having unstable atomic nuclei and emitting subatomic particles and radiation.
Method of dating material such as rocks that compares the amount of a naturally occuring isotope of an atom and its decay rates. Also called radioactive dating. Rock formed from fragments of other rocks or the remains of plants or animals. Atom with an unbalanced number of neutrons in its nucleus (isotope) that is not radioactive, or decay naturally. Movement of tectonic plates resulting in geologic activity such as volcanic eruptions and earthquakes. Massive slab of solid rock made up of Earth's lithosphere (crust and upper mantle). Also called lithospheric plate.
Atom with an unbalanced number of neutrons in its nucleus (isotope) that is radioactive, or decays by emitting particles from its nucleus. Also called a radionuclide. The audio, illustrations, photos, and videos are credited beneath the media asset, except for promotional images, which generally link to another page that contains the media credit. The Rights Holder for media is the person or group credited.