All 26 episodes of the series are available as streaming video at the following url:
This semester, an integral part of the Introductory Geology (ES 15) course will be the viewing of the "Earth Revealed" series developed by Annenberg/CPC Project especially for college level Geology instruction.
Videos #7-9 and #12-14
7. Mountain Building
This program erodes the myth of the mountain as a solid, permanent structure. Animations are used to illustrate the process of orogeny (mountain building) through accretion and erosion, as well as the role of plate tectonics, the rock cycle, and how different types of rock are formed in the course of mountain building.
accumulation as continental shelf, superposition, horizontality, then orogeny (mountain building)
craton (shields) are oldest parts of continent
Compressional: anticlines (A-shape upfold), synclines (U-shape downfold), fold axis, reverse fault, thrust fault, mountain belts (fold and thrust belts)
Extension, tensional or divergence: fault block mountains, normal faults, fault scarps
terraines, exotic terraines are often welded on to the edge of a continent
8. Earth's Structures
A visit to the Grand Canyon lays the foundation for this exploration of rock layers and deformation. The program covers sedimentation, major structures, the methods used to examine them, and how petroleum may be trapped inside them. It also looks at tectonic force and the different types of stress involved in the formation of geologic structures.
stress and strain, strike and dip, outcrop, geologic cross section, dome, basin, hanging wall, footwall, oil traps (or "pools" created by rock structure)
Showing actual footage of earthquakes and their aftermath, this program discusses the forces that fuel these massive events. Faults, waves, and the transfer of energy from the epicenter are explained, and histories of the seismograph and Richter scale are presented. The program also describes devices being developed to study — and eventually predict — earthquakes.
stress builds, rock breaks, seismic waves radiate outward from focus
siesmic waves, p-waves (first and fast), s-waves (second and slower), focus- where energy is released, epicenter (above the focus), seismograph, seismogram, s-wave lag (for calculation of distance), location of an earthquake by using distances from 3 different stations
Mercalli scale, intensity 1-X11 based on how one experiences or "feels" quake,
Richter scale is magnitude, exponential scale (30x previous), measures actual release of energy at the focus
tsunami, benioff zone, relation to plate boundaries, seismic risk, building standards, San Andreas Fault, Parkfield Project
10. Geologic Time
To illustrate the immensity of geologic time, the entire span of Earth’s existence is compressed down to a year. The timeline of major geologic events is superimposed onto the year for a condensed view of Earth’s evolution. A relationship between this timeline and that of life on Earth is established, with fossils and radiocarbon dating playing a major role in the discovery.
Hutton, father of Geology, writes that Earth must be much older than the prevailing thought
Pre Cambrian begins with Earth 4.5 billion yrs ago and ends about 600 million yrs ago, difficult to interpret, mountains were formed and eroded, simple life evolved, single cells, give rise to first major oxygen supply which set the stage for multicellular life. Paleozoic begins with the Cambrian explosion of life. Relative dating depends on superposition (youngest on the top), cross cutting relationships (a dike is younger than the surrounding rock) and faunal succession (simple organisms at first, more complex later on in time).
We talked about the bizaar Burgess Shale which consists of some of the first multicellular animals
Absolute dating is through the use of radioactive isotopes. Parent changes into a daughter product (Uranium-Lead) at a very constant rate. Allows us to date the Palisades at 200 my.
11. Evolution Through Time
The fossil record reveals much about the diversity and development of species. This program examines the traces left by early plants, animals, and single-celled organisms and follows the progression of life forms over time. Connections are drawn between atmospheric gases, climate change, rock formation, biological functions, and mass extinctions.
This video was not shown to the class for exam 2
12. Minerals: The Materials of Earth
Minerals have been indispensable to human civilization. This program looks at the variety of minerals, their atomic and crystalline structures, and their physical properties such as hardness and luster. Petrologists’ methods of sectioning rocks are shown, and gems, precious metals, ore excavation, and the value of silicates are discussed.
mineral definition, crystalline structure (both crystal structure and cleavage is related to the orderly arrangement of atoms), chemical composition (CaCO3 is calcite, SiO2 is quartz), cleavage or fracture, moh's hardness scale, know calcite is 3, feldspar is 6, quartz is 7 and diamond is 10, feldspar and quartz, minerals making up granite, quartz most common
mafic minerals are dark and contain iron such as olivine and augite
felsic minerals are light and rich in silicates such as quartz and k-spar
we learned about certain metals that are implaced by hydrothermal processes, hot water carries metals upward from a magma through fissures and cracks
Volcanoes provide clues about what is going on inside Earth. Animations illustrate volcanic processes and how plate boundaries are related to volcanism. The program also surveys the various types of eruptions, craters, cones and vents, lava domes, magma, and volcanic rock. The 1980 eruption of Mount St. Helens serves as one example.
magma, lava, geothermal energy (Iceland), Sialic (felsic), Mafic, intermediate composition, aphanitic= tiny, phaneritic= large, cooling rate and crystal size, porphyry and phenocrysts (crystals in an aphanitic rock such as andesite, vesicles, crater=vent, caldera= explosion or collapse, volcanic gases, sulfer emissions,
Most volcanoes assoc. w/ ocean floor, rifting, also numerous seamounts and guyots (active and inactive volcanoes) scattered across ocean basins
shield volcano (10°) Hawaii (Kilauea, Mon Loa), basalt. mafic, less viscous, very large, rise up from sea floor
pahoehoe (ropey), aa lava (rough, stiff), lava tube
cinder cone volcano (30°) Mt Capulin, NM, Menan Buttes, Idaho, basalt and scoria, small cones, rapid life cycle
composite volcano (intermediate)- Cascades, unpredictable
examples of volcanoes and tectonic environments of each kind, pillow lava, columnar jointing, tuff (ash), obsidian (cools without crystallization), pumice is also a glass, ring of fire (volcanoes boardering Pacific Ocean), pyroclastic flow (superheated gases, ash explosively released), lahars (mud flows especially with melting of glacial ice at the top of a high volcanic peak),
Cascade Mountains and Andes Mountains both related to subduction of ocean plate below continent- generation of a viscous magma (more felsic), tend to prevent release of gases- very explosive
Hawaii hot spot has been especially persistant as a mantle plume (?)
14. Intrusive Igneous Rocks
Most magma does not extrude onto Earth’s surface but cools slowly deep inside Earth. This magma seeps into crevices in existing rock to form intrusive igneous rocks. Experts provide a graphic illustration of this process and explain the types and textures of rocks such as granite, obsidian, and quartz. Once again, plate tectonics is shown to be involved in the process.
intrusive (plutonic), cools slower
extrusive (volcanic), cools faster
obsidian and pumice (glass froth) without crystal structure (no minerals)
mafic: basalt and gabbro have same composition, related to ocean crust
felsic rock: granite and rhyolite are same composition, related to continent
pegmatite and granite compose batholith, extensive roots of folded mountains,
as mts erode, isostacy elevates the batholith- more erosion may eventually expose the batholith which is initially miles below the surface
volcanic neck (Ship Rock)- hardened lava within cone- cone erodes leaving basalt neck
dike is discordant, cross cuts strata (vertical usually)- made of intrusive rock
sill is concordant, horizontal, intrudes between strata, Palisades Sill
laccolith (Devil's Tower)- smaller batholith like structure- intrusive, begins as a sill, then enlarges
Ken Ettlinger teaches ES 15 "Introduction to Geology" at Suffolk County Community College in Riverhead, New York. For questions and comments he can be reached at: email@example.com