earth science 12 Flashcards
what is uniformitarianism who made it?
the idea that the physical chemical and biological laws that operate today also did in the past. James Hutton
what is the absolute age of earth(evolutionists)
4.5billion years
what is relative dating
the method in which scientists use to place rocks in chronological order to
what is the law of superposition
*it states that in an undeformed sequence of sedimentary rocks each layer is older than the one above it and younger than the one below it.
principle of cross cutting relationships
states that a fault or intrusion must be younger than any geologic formation through which it cuts.
principle of original horizontally
states that sediment is generally deposited in flat horizontal layers.
what is unconformities
it is when a surface represented a break in the rock record. Nowhere is earths rock record complete.
what are the three types of unconformites
angular unconformity, disconformity, and nonconformity are
angular unconformity
layers of sedimentary rock form over older sedimentary rock layers that are tilted or folded.
disconformity
it is when two sedimentary rock layers are separated by an erosional surface.
nonconformity
in a nonconformity an erosional surface separates older metamorphic or igneous rocks from younger sedimentary rocks.
what are inclusions
inclusions are pieces of an older rock unit found within a younger rock unit.
what are the different types of fossils
petrified fossils, molds and casts, compression fossils, impression fossils, unaltered fossils, unaltered remains and trace fossils.
what is a correlation?
the process of matching rock layers at different locations that formed at the same time and by the same processes.
what are the two ways for fossils to be preserved
the body of the organism must be protected from scavengers, and it must have hard parts like bones shells teeth or plants with wood. fast burial is also another thing.
petrified fossils
fossils that have been turned into rock and minerals
what are molds and casts
molds- form when seashells or other hard parts fall into soft mud or beach sand and compaction and sedimentation happen and molds form.
casts- are created if the hollow spaces of a mold are later filled with minerals.
what are compression fossils
two dimensional organic remains. they form when pressure squeezes out liquids and gases from a buried organism.
what are impression fossils
two dimensional. they dont contain organic matter.
what are unaltered remains
when they are perfectley fossilized with little change.
what are trace fossils
trace fossils are indirect evidence of prehestoric life. they show that animals must have been their before.
what is the fossil record
all the fossils that geologists have found and arranged by their relative ages.
what is fossil succesion
states that fossil organisms tend to be found in the same general order at different locations.
what are index fossils
fossils that are from a species that existed on earth for short periods of time and were widespread geographically. they are best type of fossils for correlation.
fossils and correlation
it is used to correlate rock layers based on fossils they contain
what is fossils and past environment
fossils can help build detailed pictures of the past environments.
what is fossils and evolution
according to evolution the fossil record reveals older rocks (deeper in rock layer) contain fossils of simpler organisms younger rocks (closer to the surface) contain more complex organisms.
what is ecological zonation
certain organisms live in certain locations
what is absolute dating
a method used by geologists to determine the age in years of a rock or other object
what is radioactive decay
is when an unstable nucleus spontaneously breaks apart or decays.
what is beta decay
beta decay occurs when an atom of an unstable isotope decays. one of its neutrons breaks down into a proton and an electron. the electron leaves the atom as a beta particle the nucleus loses a neutron but gains a proton resulting in a new element
what is the atoms made of
has a nucleus made up of protons and neutrons and that the number of neutrons in the atoms of a given element can vary. Different forms of an element are called isotopes.
what is alpha decay
alpha decay is when the isotopes gives off two protons and two neutrons in the form of an alpha particle.
what is a half life
half life of an isotope is the time it takes for half of the unstable atoms in the isotope to decay into stable isotopes.
what is radiometric dating
a method of calculating the absolute ages of rocks and minerals that contian certain radioactive isotopes.
second probelm with radioactive dating
rocks in earth may have been created with apperent age . so maybe when God created rocks he made them old like how when adam was made he was already an adult
what is the first problem with Absolute dating
earth may have changed its rate of radioactive decay.
third problem for absolute dating
individual fossils of one age are buried over milions of years of sediment. this is impossible because it would have rotted before they were fossilized
the fourth and last problem of radioactive decay
examples of major errors in age dating of rocks. rocks said to be 3 billion years old while they were only 200
dating with carbon-14 radiocarbon dating
to date organic materials carbon 14 is used in a method called radiocarbon dating. organic materials are substances that contain carbon and comes from living things. when an organism dies the amount of carbon 14 gradually decreasesas the carbon 14 to carbon 12 in a sample radiocarbon dates can be determines.
radiometric dating of sedimentary rock
to determine the age of sedimentary rock geologists must relate the sedimentary rock to datable masses of igneous rock.
what is the geologic time scale
it is a record that includes both geologic events and major developments in the evolution of life.
what are the four major eons
phanerozoic proterozoic archean and hadean eons
there are three eras in phapnerozoic eon
paleozoic mesozoic and cenozoic era
what are periods
periods subdivide eras
what are epochs
they divide the quaternary and tertiary periods.
what is the precambrian era
the longest era which take up 88% of the earths history. up until 544 million years ago
what was the first experimental flaw
that started with purified materials while in nature there is a lot of impurities
second flaw
they used only safer wavelengths of ultraviolet radioation.
third flaw
they removed the newly formed amino acids from experiment for protecton. in primitave conditions the amino acid would breakd own quickly.
what was darwins natural selection
the process b which organissm with raits that are suite to a certain environment have a better chance of surival than organisms whos traits are not suited to it.
