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Flashcards in Earth History Deck (30)
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What is angular nonconformity?

Indicates deposition of sediments, tectonic uplift, and deformation, erosion and deposition of new sediments


What are Carbonaecous films?

Thin silhouettes of carbon. Result from high temp and press. as sediments deposit on top. Carbon of organism undergoes chemical change to produce thin carbon film


What are climate proxy records?

Historical records of crop productivity and other phenomena that imply the nature of past climate. Ex: Tree rings


Principle of Superposition

In any sequence of sedimentary strata the order in which the strata were deposited is from bottom to top
A.k.a Older rocks on bottom, younger rocks on top


What are embedded fragments?

The law of included fragments is a method of relative dating in geology. Essentially, this law states that clasts in a rock are older than the rock itself. One example of this is a xenolith, which is a fragment of country rock that fell into passing magma as a result of stoping.


How may volcanoes have helped to cause the relative warmth in the Cretaceous Period?

Increased volcanic activity, may have contributed to more climate warming and sea level rising


How recent did Humans exist?

One hundred thousand years ago


What are index fossils and what are their characteristics?

Fossilized organism remains and can can be used to correlate rock layer.
Must be abundant, widespread, unique and brief period existence


In what period did dinosaurs become completely extinct?

Cretaceous period


In what period did mammals first appear?

Jurassic Period


In what period did reptiles first appear?

Carboniferous period


In what period did the first amphibians appear?

Devonian Period


In what period did the first flowering plants appear?

Cretaceous Period


Principle of Cross-cutting relationships?

That the geologic feature which cuts another is the younger of the two features. It is a relative dating technique in geology.


How does Radioactive dating work?

By measuring the amount of parent and daughter isotope within a rock or mineral and use the ratio of the two to find age of rock


Where are the oldest known rocks on Earth?

Found in the Canadian Shield


What is walking the outcrop?

Outcrop - A section of a rock layer that can be seen at Earth's surface
Walking along the outcrop is used to find out if 2 rock layers are the same. Can be diff. in areas of thick soil or vegetation


What are trace fossils?

Impressions such as bite marks, burrows, tracks and trails in stone. Indirect evidence


What are four factors that could contribute to global warming?

Earth's Motion, Plate Tectonics, Volcano eruptions and sunspots


What are the divisions of the geologic timetable based upon?

A summary of major events from analyzing the rock record. Based on evidence particularly fossil evidence


What are the ways that remains can be persevered as fossils?

Original Remains: Unchanged parts or complete parts of animals and plants. Woolly mammoths found in Alaska and Siberian in permafrost, woolly rhinos in Poland in asphalt. Occur in mud to shale or resin to amber
Replaced Remains: Water can remove soft parts and replace them with minerals
Molds and Casts: Molds are depression of organism in rock and cast are minerals filling mold and solidifying
Trace Fossils: Impressions such as bite marks, burrows, tracks. Indirect evidence
Carbonaceous Films: Thin silhouettes of carbon. Result from high temp and press. as sediments deposit on top. Carbon of organism undergoes chemical change to produce thin carbon film


What are the orders of geological time?

Eons, Eras, Periods, Epochs


What is Petrified wood?

Replaced Fossil. Silica replaces woody structure and preserves wood with rings in tact


What are the two ways that volcano can affect climate?

1) Release sulphur dixoide into atmosphere which creates sulphurous acid
2) Mass releases of CO2


What do fossils of tropical plants in Greenland provide evidence for?

Greenland was once closer to the equator. Proves plate tectonics as something causes climate change


What is Relative dating?

An order of sequence of events as they occured. Can not identify actual dates


What is the earliest known glacier?

Tillite is a rock created from deposits of till cementing together. Some are 2.3 billion years


What gas is abundant now in the atmosphere but not very abundant in Earth's primitive atmosphere?

Hydrogen and Helium, Water Vapour, Carbon Dioxide, Oxygen and Nitrogen


What things would the change in the location of a continent affect?

Wind patterns
Ocean currents
Amount of solar radiation reflected back to space from land and water


What can bipedal movement and brain size be used to distinguish?

Homo Sapiens Sapiens evolutionary process