Science 20 Geology Unit

• **Chapter 1**

  The Abyss of Time
• Precambrian Era


  First major section of geological time. (4.5 billion years - 590 million years ago)
• Outcrop


  Part of a rock formation that appears above the surface of the surrounding land.
• Core


  Innermost layer of Earth. (Solid inner core - liquid outer core)
• Mesosphere


  Part of the mantle beneath the asthenosphere.
• Lithosphere


  Outermost layer of Earth.
• Crustal Plate


  Large piece of continental crust/oceanic crust that floats and slowly moves atop the asthenosphere.
• Plate Tectonics


  Theory that the lithosphere consists of crustal plates that slowly move across Earth's mantle and interact at their boundaries.
• Paleomagnetism


  Study of magnetic properties of rock formed in a past geological era.
• Deep Time


  Multimillion year time frame within which scientists believe the earth has existed, and which is supported by the observation of natural, mostly geological, phenomena.
• Sedimentary Rocks


  Rock formed from compressed layers of pre-existing rock or organic matter.
• Fossil


  Evidence/remains of ancient life preserved in Earth's crust.
• Strata


  Layered bands within sedimentary rock.
• Stromatolite


  Layered structure built by cyanobacteria.
• Cyanobacteria


  Microscopic, photosynthetic, single-celled bacteria.
• Archaea


  Domain of single-celled bacteria.
• Trace Fossil


  Indirect fossilized evidence left by ancient organisms rather than the organisms themselves.
• Law of superposition


  Law stating that higher strata in a sequence of rock layers are younger than lower strata.
• Relative dating


  The process of placing rocks and geological structures in the correct chronological order.
• Stratigraphic sequence


  Sequence of rocks that provides a chronological record of a region's geological history.
• Intrusion


  Body of rock that forms from the invasion of magma into a pre-existing rock formation.
• Index fossil


  Fossil used to determine the relative age of layer in a stratigraphic sequence or to match stratigraphic sequences from different location.
• Absolute age


  The number of years that have elapsed since an event occurred.
• Sedimentary rocks


  Formed*: eroded fragments of other rock types.Where formed*: surface of the Earth under relatively low temperatures.
• Igneous rocks


  Formed*: forms when molten magma from mantle intrudes into the crust/extrudes onto the surface.Where formed*: deep within Earth's crust and mantle under extreme heat.
• Metamorphic rocks

  Formed*: forms when sedimentary or igneous rock are transformed at the molecular level by intense pressure and heat.
• Rock Cycle


  Concept that relates the continual change of rocks from on type to another.
• Radioactivity

  Emissions of energy from the nuclei of unstable atoms as they change to become more stable atoms.
• Radioactivity decay

  Disintegration of an unstable atom, which results in the release of energy in the form of radiation.
• Half-life


  Time taken for half of a radioactive sample to decay.
• Isotope


  Particular variety of an element as defined by its atomic mass.
• ***Chapter 2**

  A tropical Alberta
• Fossilization


  Process by which any trace of the existence of ancient life is preserved within a rock.
• Burgess Shale


  Cambrian-age rock unit found on the side of Mount Wapta in the Canadian Rockies known for its well-preserved fossils.
• Reef


  Submerged ridge of rock, sand, or coral that rises to the water's surface.
• Petroleum trap


  Large quantity of petroleum confined between layers of impermeable rock.
• Drill core


  Cylindrical sample of subsurface rock taken during drilling operations and returned to the surface for analysis.
• Seismic waves


  Waves that travel through Earth as a result of explosions or earthquakes.
• Seismograph


  Instrument that records seismic waves.
• Seismogram


  Record of seismic waves from a seismograph.