Stratigraphy and Geologic Time Flashcards
What is the principle of superposition?
The theory that older rocks are deposited deeper in the earth and that newer rocks are deposited on top.
What type of rock can cut vertically through the other layers?
Igneous Rock
What is stratigraphy?
The science of using the arrangement and composition of rock layers to interpret geological history
What is a formation in geological terms?
A large uninterrupted sequence of rock, made of multiple layers that all share similar properties
What technique is used to date rocks in absolute terms?
Radiometric dating
What is an isotope?
A variant chemical element that has an unusual number of neutrons
How is radiometric dating conducted?
Scientists can measure how many radioactive isotopes are in a rock to determine how old that rock is.
What tool is used during radiometric dating?
Mass spectrometer
What type of rock cannot be radiometrically dated due to its nature?
Sedimentary Rock
What type of fossil deposit is easy to determine the age of?
Volcanic ash fossils
What is the geological time scale?
Standardized series of chronological divisions that parse the Earth’s history into discrete named units.
What is the list largest to smallest of time periods?
Eons, Eras, Periods, Epochs
What is the order of Eons from oldest to newest?
Hadeon Eon, Archean Eon, Proterozoic Eon, and Phanerozoic Eon
What are the eras of the Phanerozoic Eon from oldest to Newest?
The Paleozoic, The Mesozoic, and The Cenozoic
What are the periods of the paleozoic?
The Cambrian period, The Ordovician, the Silurian, the Devonian, the Carboniferous, The Permian
What are the periods of the mesozoic era?
The Triassic, The Jurassic, The Cretaceous
What are the periods of the Cenozoic era?
The Palogene Period, The Neogene Period, The Quarternary Period
Which Era is known as the era of Dinosaurs?
The Mesozoic Era
What was the cause of the permian-triassic mass extinction?
Large number of Volcanic Eruptions in a region that is now Siberia
What was the first group of vertebrates to fly?
Pterosaurs, they aren’t dinosaurs
What was happening geologically during the Triassic?
Pangea was beginning the break apart
During which period did the first ichthyosaurs evolve?
The triassic
What does the name ichthyosaur mean, what were they really?
Fish Lizard, they are reptiles that adapted to live in the water secondarily, consequently they didn’t have gills, but they did have long snouts and conical teeth
What is similar between the plesiosaurs and ichthyosaurs are they related?
They are not related - they are two separate lineages of reptiles that returned to the water to fill those ecological niches
During which period did plesiosaurs evolve?
The late Triassic
What was a pterosaur wing like?
membranous section of skin supported by one elongated finger
What was the group that pterosaurs belonged to called and at which period in time were they common?
They belonged to the group rhamphorynchoids and were common throughout the Late Triassic and Jurassic
What was a common trait of all the first dinosaurs?
They were small and bipedal
What were the most dominant terrestrial herbivores during the Jurassic?
Sauropods
What were the dominant Terrestrial Carnivore in the Jurassic?
Non-coelurosaurian theropods - like allosaurus
Among the Ornithiscians which first appeared within the Jurassic?
First ankylosaurs, ornithopods, ceratopsians, and stegosaurs
Which group of ornithiscians was basically restricted to the jurassic period?
The stegosaurs
During which period did Archeopteryx evolve?
The Jurassic
Which are the best known formations from the Jurassic Period?
The Morrison Formation and the Solnhofen limestone
Which flying reptiles dominated the skies in the Jurassic?
The rhamphorhynchoid lineage called Pterodactyloids
During which period did the first flowering plants begin to evolve?
The early Cretaceous
Which new theropods evolved during the early cretaceous?
spinosaurids and carcharodontosaurids
Which are the most important early cretaceous formations?
The Yixian formation (China), the Wealden Supergroup (England), Cedar Mountain formation (Utah)
Which third secondarily aquatic reptile evolved during the cretaceous?
Mosasaurs
Which time period is considered to be the apex of non-avian dinosaurs?
The late cretaceous
Which coelurosaurian theropods were abundant in the late cretaceous?
tyrannosaurs, ornithomids, therizinosaurs, oviraptosaurs, dromaeosaurids, and troondontids
During which period did the ankylosaurs split into two separate groups?
The late cretaceous
Which were the major dominant herbivores during the late cretaceous?
Ceratopsians and hadrosaurs (northern hemisphere), Titanosaurid sauropods (Southern Hemisphere)
Which is the only period that pachycephalosaurs are known?
The late cretaceous
What was the cause of the end cretaceous mass extinction?
A giant meteor that crashed onto the earth
During which Eon did life first evolve?
The archean eon
During which period did larger life forms evolve?
The Edicarian
What was the period which marked a large evolutionary expansion of marine life?
The Cambrian expansion during the Cambrian Period
From which period does all the major carbon deposites arise from?
The carboniferous period - remember carbon in the name
During which period did humans evolve?
The current period the Quarternary period
