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PALEO 101 > Lesson 9) Statigraphy and Geologic Time > Flashcards

Lesson 9) Statigraphy and Geologic Time Flashcards

Statisgraphic concepts and the scale of Earth History (39 cards)

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1
Q

Principle of Superposition

A

Tendency or rock layers to be chronologically stacked.
- Sediments deposited -> gradual build up
- How things normally work, but can be exceptions:.

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2
Q

Unconformity

A

Flat surface caused by partially melted igneous intrusions that are uplifted and eroded

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3
Q

Statigraphy

A

Science of using arrangement and composition of rock layers to interpret geological history

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4
Q

Formation

A

Large uninterrupted sequence of rock that is made of multiple layers that all share similar properties (eg- composition + grain size) all formed under similar conditions

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5
Q

What is indicated when a rock changes formations?

A

Large scale change occurred in the environment where the rocks were deposited.

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6
Q

Principle of Superposition

A

Allows stratigraphies to infer relative age of rock layers (layer age vs other layer age)
- DOES NOT determine absolute age

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7
Q

Radiometric dating

A

Technique to determine rocks age.

As rock ages, isotopes decay and ratio of isotopes : decay product decreases.
Mass spectrometers can measure the isotope ratio of rock, which can tell how old it is.

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8
Q

Isotope

A

Variant of a chemicalelement that has unusual number of neutrons.
- some are unstable and undergo radioactive decay: energy release, resulting in atoms w/ different compositions (decay products)

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9
Q

What rock can’t be radiometrically dated?

A

Sedimentary
They are not new: they are made of sediments that have already formed and are undergoing radioactive decay already probably.

However: can use volvanic ash layers (within sedimentaries to estimate nearby fossil ages)

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10
Q

What can usually be radiometrically dated?

A

Igneous
Formed anew
- When igneous rock solidifies, it starts out w/ isotope ratio equal to that found in its environment

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11
Q

How can we measure fossils age, if they’re usually found in sedimentary rocks?

A

Radiometric dating + principle of superstition

IF found between two horizontally deposited igneous rock layers— can bracket age

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12
Q

Geologic Time Scale

A

Standardized series of chronological divisions that parses Earth’s history into discrete named units.

Eons > Eras > Periods > Epochs

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13
Q

Hadean eon

A

4.4-4 billions yrs ago

Formation and earl Earth years.
- Surface partially molten and hella volcanoes
- Planet collision which formed moon

By then end, Earth had cooled and hella oceans
- organic molecules form

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14
Q

Archean Eon

A

2-2.5 billion yrs ago

  • Oldest fossils (single-celled organisms)
  • Cynanobacteria made oxygen and stromatolites
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15
Q

Stromatolites

A

Structures formed by cyanobacteria from the Archean Eon
- Lump stones that when cut in half, show layers of secreted sticky limbs trapping sediment particles.

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16
Q

Proterozoic Eon

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A

2.5 billion-541 million years ago

  • FIrst multicellular organisms
  • very poor fossil record as life at this point was BONELESS
    Ediacarian period: Large forms of life (like animals) finally got here bruh
17
Q

Phanerozoic Eon

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A

540-0 millions years ago

Subdivided into 3 eras
- Rapid animal evolution

18
Q

Paleozoic Era

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A

541-252mil years ago

  • Primitive ocean-dwelling invertebrates (me fr)
  • Big ass forests w/ reptiles, amphibians, insects
19
Q

Cambrian Period

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A

541-485 mil years ago

  • Aquatic life diversification (Cambrian explosion)
  • Anomacolaris, arthropods, SpongeBob worms etc
20
Q

Ordovician Period

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A

485-443 mil years ago
- OCEAN ANIMALS RULE!!!!

21
Q

Silurian Period

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A

443-419mil years ago
- predator fish get jaws #looksmaxing
- land plants start flourishing
- millipede anthropods start crawling on ocean floor

22
Q

Devonian Period

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A

419-359 mil years ago
- FIrst forests EVOR!!!
- sharks
- the fishies start venturing onto land

23
Q

Carboniferous Period

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A

359-299 mil years ago
- ambhipians swamps and reptiles

24
Q

Permian Period

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A

299-252 mil years ago

  • PANGAEA FORMS!!!
  • Reptiles evolve into 3 linages which make up every major animal
25
Mesozoic Era
252 - 66 mil years ago “Age of Dinosaurs” - Marine reptiles evolve (first true reptiles, mammals, birds) - First flowering plants
26
Cenozoic Era and its 3 periods
66-0 mil years ago “Age of Mammals” - Grass reveal Periodt!!! **1. Paleocene:** 66-23 mil - Cooling temperatures, mammals + birds diversifying **2. Neogene:** 23-2.6mil - HOMINIDS IN AFRICA **3. Quaternary:** 2.6-0 mil - Ice age - First anatomically modern humans and civilization
27
Triassic Period
252-201 mil years ago - Life slowly recovers from mass extinction of Permian era - first mammals and Dino’s evolve - Pangaea breaks apart - Ichthyosaurs + Plesiosaurs = Pterosaurs
28
Dinosaurs of the Triassic Period?
First Ornithischians: - Pisanosaurus First Theropods: - Herrerasaurus - Eoraptor First sauropodomporphs: - Panphagia Prosaurupods: - Plateosaurus
29
Ichthyosaurs
“Fish Lizard” but aren’t lizards (nor fish) Group of reptiles that took on a fish-like lifestyle and evolved a very fish body form (and returning to sea) - Ancestors: Terrestrial reptiles - Paddle-like front + hind limbs, fin tail, dorsal fin - Long snout w/ conical teeth (piscovore) - BUT: never evolved gills so they still needed to breath air
30
Plesiosaurs
Group of reptiles that a loved secondarily aquatic lifestyle - Large chests + torsos - Broad, paddle iambs - Short tails - Vary in front *eg) elasmosaurus (keep in mind it lived in Cretaceous period)*
31
Pterosaurs
Close relatives of dinosaurs who branched off reptilian family tree at roughly the same time dinosaurs did - FIRST FLYERS - Membranous wings supported by elongated
32
Jurassic Period
201-145mil years ago Dino diversification - Sauropods were dominant terrestrial herbivores - small ornithopods - theropods were dominant terrestrial carnivores - rhamphorhynchoids and pterodactyloids - first birds - first ankylosaurs and ceratopsians (but not diverse yet)
33
Rhamphorhynchoids
Early pterosaurs *eg) stegosaurus*
34
Pterodactyloids
Came from ramphorhynchoids, differing in morphology - short tails - elongated carpels which made wings longer - large head crests as display - ranged in size *eg) pteranodon*
35
Early Cretaceous Period
146-100 mil years ago - first flowers - spinosaurids and charcharodontosaurids - coelurosaurian theropods diversify - iguanodonts get big and many -- sauropods decline - Mosasaurs - stegosaurs get replaced by ankylosaurs - primitive birds abundant (better than archaeopteryx)
36
Mosasaurs
Relatives of modern monitor lizards and snakes - reptiles - tail finds and paddle limbs - BUT bodies were longer than ichthyosaurs and plesiosaurs - most were predatory and big
37
Late Cretaceous Period
100-65 mil years ago - all the famous celebrity Dino’s - coelurosaurian theropods abundant and diverse - ankylosaurs diverge into two: ankylosaurids and clubless nodosaurids - Ceratopsians and hadrosaurs are dominant herbivores (northern) - titanosaurid sauropods are dominant herbivores (southern) - pachycephalosaurs!!! - flower plants evolve <3 - THEN THEY ALL DIE!!!! MASS EXTINCTION!!!!!
38
What were some coelurosaurian theropods that lived
Tyrannosaurs, oviraptorosaurs, dromaeosaurids, oviraptosaurs, therizinosaurs, troodontids
39
How long ago was the Earth formed?
4.6 billion years ago

PALEO 101 (6 decks)

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