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PCS Earth Science
Chapter 22 Vocabulary - The Precambrian Earth
| Term | Definition |
|---|---|
| amino acids | building blocks of proteins that were likely abundant on Earth during the Archean |
| asteroid | metallic or silica-rich object, 1 km to 950 km in diameter, that bombarded early Earth, generating heat energy |
| banded iron formation | unique, shallow marine deposits made up of alternating bands of chert and iron oxides that formed due to locally high oxygen levels produced by stromatolites |
| Canadian Shield | name given to the Precambrian shield in North America because much of it is exposed in Canada |
| cyanobacteria | microscopic, photosynthetic prokaryotes that formed stromatolites and changed early Earth's atmosphere by generating oxygen |
| differentiation | process in which a planet becomes internally zones, with the heavy materials sinking toward the center and the lighter materials accumulating near its surface |
| Ediacaran fauna | fossils of multicellular, varied organisms lacking a mouth, anus, and gut that were widely distributed in the shallow oceans of the late Proterozoic and flourished (did well) between 570 and 670 million years ago |
| eukaryote | organisms that is composed of cells that contain nuclei and is generally larger and more complex than a prokaryote |
| hydrothermal vent | hot water, deep sea vent that has the energy and nutrients needed for the beginnings of life |
| Laurentia | ancient continent formed during the Preterozoic that is the core of modern-day North America |
| meteorite | small asteroid or asteroid fragment that fell on earth Earth, generating heat |
| microcontinents | small pieces of continental crust that collided with one another throughout the Proterozoic, forming the cores of the continents |
| Precambrian Shield | continental core of Archean and Proterozoic rock that may be exposed at the surface or buried by sedimentary rocks |
| prokaryote | single-celled organism that lacks a nucleus, is generally small, belongs to the Kingdom Monera, and existed before the Proterozoic |
| red bed | sedimentary rock deposits that contain oxidized iron, providing evidence that free oxygen existed in the atmosphere during the Proterozoic |
| stromatolites | large mats and mounds composed of billions of photosynthesized cyanobacteria that dominated the Proterozoic's shallow oceans |
| Varangian Glaciation | widespread glaciation event in which ice reached nearly to the equator between 700 and 800 million years ago |
| zircon | very stable mineral commonly found in granite that can provide evidence of Earth's crust being at least 4.1 to 4.2 billion years old through radiometric dating |
Created by:
Ms.Sala
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