8. How does hornfels form? Rock contacts with magma and bakes rock. 9. Know that the type of metamorphic rock relates to how much heat and pressure the rock was exposed to.
The Island of Aruba is the result of lava hardening from a volcano that occurred almost 100 million years ago underwater. Eventually sediments formed new types of rocks, which came to the surface and began the process of island building. On the Island today the north coast is made up of a jagged coastline filled with all sorts of rocks. “Limestone’s are the youngest rocks that make up Aruba and that surround the islands older rocks. Limestone formed after and on top of the older rocks.” (Archaeological Museum Aruba, 3) While limestone is very common rock on Aruba, a white and black speckled plutonic rock called quartzdiorite is also another prevalent part of the landscape.
Andesite is typically light gray to dark gray in color, sometimes almost black. Less abundant than the Andesite is a rock that occurs in two forms. Dacite is a hard, dense, glassy, gray rock. Its glassy appearance distinguishes it from Andesite. The other siliceous rock is Pumice, a light weight, porous rock formed from liquid rock with a great quantity of finely dispersed gas bubbles.
Saint Helen a composite volcano (or stratovolcano), a term for steep sided, often symmetrical cones constructed of alternating layers of lava flows, ash and other volcanic debris. Composite volcanoes tend to erupt explosively pose considerable danger to nearby life and property. Before 1980, snow capped, gracefully symmetrical Mt. Saint Helens was known as the “Fujiyama of America.” Mt. Saint Helens, other active Cascade volcanoes, and those of Alaska form the North
Mt Kosciusko Field Trip Report Geological History of the Australian Alps The geological history of the Australian Alps starts when the majority of east Australia was submerged underwater at around 800 million years ago. At this time there were large sediment layers that covered the sea floor. By around 450 million years ago, the earth began to move underneath the continental plate causing uplifting and folding (Australian Alps National Parks, 2010, Geology and geomorphology of the alpine landscape para.6). Magma rose up through the layers at temperatures reaching up to 1000°C. The magma that reached the sea bed due to weakness in the crust cooled quickly and formed a layer of basalt above the sediments (see diagram 1).
G208: Volcanoes Chapter 7 : Kilauea, Hawaii 1. What is "volcanic tremor"? (page 94, para 2 to page 95) A volcanic tremor is a continuous, low-frequency vibration of the ground. 2. What do earthquake swarms indicate?
How many half-lives have passed since the crystal formed? A) 1 B) more than 1 but less than 2 C) more than 2 but less than 3 D) more than 3 Answer: B 4) Which of the following geologic observations would NOT bear directly on working out the sequence of geologic events in an area? A) inclusions of sandstone in a granite pluton B) a well-exposed dike of basalt in sandstone C) an unconformity between a granite and sandstone D) the feldspar and quartz contents of a granite Answer: D 5) The principle of ________ is the concept that ancient life forms evolved in a definite order and therefore their fossils can help determine the geologic ages of strata. A) superposition B) cross-cutting relationships C) fossil succession D) fossil assemblage Answer: C 6) Which of the following is an essential characteristic of an index fossil? A) The organism lived in a very specific environment or two, such as tropical volcanic islands.
This type of volcano can be recognized by its broad, gentle slopping shape. The lava dome that composes a shield volcano is usually built over a period of time. When this type of volcano erupts it often involves a flow after flow of lava. An example of shield volcano is Mauna Kea, which along with Mauna Loa forms the large island of Hawaii. The largest shield volcano in the solar system is Olympus Mons, on the planet mars.
How do we know that the Earth has a liquid core? Why is the inner core solid even though it is hotter than the outer liquid core? We know that the Earth has a liquid core because of seismic waves. A type of seismic wave known as an "S" wave or Shear wave moves side-to-side in a shearing motion and does not propagate through liquid only through solid. "S" waves are often blocked or reflected by the inner core and it is therefore thought
For example, the origin of puzzling, hilly volcanic deposits near Mount Shasta and Mount Rainier became clear. Gravitational collapse of volcanic flanks is now seen as a normal event at steep-sided volcanoes, even on the ocean floor and on other