Macroevolution 1 Flashcards
Fossil
preserved evidence of life from a past geological age, including impressions and mineralized remains of organisms embedded in rocks
Lagerstätten
a site with an abundant supply of unusually well-preserved fossils — often including soft tissues — from the same period of time
Burgess Shale
a Lagerstätte in Canada in which there is a wealth of preserved fossils from the Cambrian period
absolute dating
provide chronological estimates of the age of certain geological materials associated with fossils, and even direct age measurements of the fossil material itself
relative dating
puts geologic events in chronological order without requiring that a specific numerical age be assigned to each event
geologic time scale
a representation of time based on the rock record of Earth
Superposition
an undeformed sequence of sedimentary rocks, each layer of rock is older than the one above it and younger than the one below it
lateral continuity
layers of sediment initially extend laterally in all directions on different layers; help identify the age of rocks and identify geological features that are related despite being separated
original horizontality
Layers of strata are deposited horizontally, or nearly horizontally, and parallel or nearly parallel to the earth’s surface
Cross-cutting
any geologic features that cut across strata must have formed after the rocks they cut through
index fossil
Fossil species that are used to distinguish one layer from another
carbon dating
Radiometric dating technique that uses the decay of 14C in organic material, such as
wood or bones, to determine the absolute age of the material
uranium-lead dating
Radioactive decay of uranium
to lead via two separate decay chains
potassium-argon dating
Radiometric dating technique that uses the decay of 39K and 40Ar in potassium-bearing minerals to determine the absolute age
Precambrian and Phanerozoic
time interval and all rocks that formed prior to the beginning of the Cambrian Period (base of Phanerozoic Eon) at 541 Ma
