GEO Exam #1

asthenosphere

(plastic layer) mantle under lithosphere rock is hotter and flows under pressure

how old is the earth?

4.6billion years ago

How was the geologic time scale constructed?

Based on fossils or other evidence of relative age.

earths core

Composed of metallic iron and nickel • Outer core is molten • Inner core is solid

How is Earth organized?

Earth has an inner and outer core, a mantle, and a crust.

Rocks that crystallize from melts are_____________.

Igneous

What is a Mid-Continent Rift?

In essence, the earth's crust cracks and begins to spread apart. • Continental rifting has occurred repeatedly in the history of the earth. • It leads to the formation of ocean basins and the fracturing of continents.

Which is the shallowest of the Great Lakes?

Lake Erie

Which is the only one of the Great Lakes entirely within the United States borders?

Lake Michigan

What small lake is located between Lake Huron and Lake Erie?

Lake St. Clair

Which is the deepest of the Great Lakes?

Lake Superior

Which of the Great Lakes has the largest surface area?

Lake Superior

The Great Lakes, in order or surface area from largest to smallest, are:

Lake Superior, Lake Huron, Lake Michigan, Lake Erie, and Lake Ontario.

How fast do plates move?

Large continental plates- move less than 2 cm / yr Oceanic continental plates- move 6-20cm / yr

what makes plates move?

Large thermal convection cells and rising thermal plumes from as deep as core-mantle boundary • Cells rise, diverge and spread laterally • Upwelling at mid-ocean ridges and hot spots ★ Descending flow at subduction zones-DRIVER

According to plate-tectonic theory, plates of rigid, elastic __________ move over a weak plastic layer below.

Lithosphere

Rocks that are formed by the crystallization of new minerals in the solid state (i.e. without melting) due to heat and/or pressure are____________.

Metamorphic

What two lakes are considered to be one lake hydraulically with lake levels rising and falling together?

Michigan and Huron

what states and provinces make up the Great Lakes watershed?

Minnesota, Wisconsin, Illinois, Michigan, Ohio, Pennsylvania, Ontario, New York,

Multiple beam SONAR

Multiple beam SONAR To determine depths in a large area multiple beams are used to "paint" the bottom.

Which of the following geological features on Earth's surface exist because of plate tectonics?

Ocean basins Continents Oceanic Island chains Fault lines

Canadian Shields

Shields are very old rock from continents Precambrian rocks in Canada and the northern Great Lakes are referred to as the Canadian Shield • Consist of granites and metamorphic rocks

What river connects Lake Superior and Lake Huron?

St. Mary's River

The Michigan Basin

There is a marked contrast between the old, resistant Precambrian and Cambrian rocks of the western half of the Upper Peninsula and the sedimentary rocks of the rest of Michigan. • The rocks that dominate the Michigan Basin of the lower peninsula are: • Limestones • Sandstones • Shales

It was the natural 'fit' of the continents that initiated Alfred Wegener's interest in the possible 'drift' of the continents.

True

Water continually flows from the headwaters of the Lake Superior basin through the remainder of the system to the Atlantic Ocean.

True

whats a bathymetry

Two types of data are needed for accurate bathymetry. -Typically a Global Positioning System (GPS) is used to determine horizontal position on the lake. -Sonar is used to determine water depth.

A rock is_____________________.

a solid, cohesive aggregate of one or more minerals.

how much water does the Great Lakes hold?

approximately 6 quadrillion gallons of water

Which of the following is an example of an igneous rock?

basalt

how do we know the amount of water in the GL?

bathymetry

Earths crust

continental crust- granitic composition oceanic crust- basaltic composition

Earth's plates ride on circulating currents of hot rock. This process moves the plates and is the product of:

convection

boundary types

convergent divergent transform

Which of the following is the thinnest layer of the Earth?

crust

Lumbering Era

done by French, to build forts, fur trading, etc the industry boomed until the settlers realized that the forests were not inexhaustible

whats inside of the earth

earth consists of concentric layers of different compositions: crust (continental and oceanic) mantle (biggest layer) outer core (molten) inner core (solid)

Alfred Wagner

evidence for continental drift Pangaea

metamorphic

existing rock that changes form due to exposure to high heat, pressure or chemical fluids -marble, slate, quartzite

What was the fur trade?

fur trade was central to early life of Michigan arrived 10,000 yrs ago.

what are the major rock types?

igneous, sedimentary and metamorphic

drainage division

it is the boundary that physically separates the drainage of one drainage basin from another

stages

minerals, mineraloid (glass), rock

rocks

naturally formed, coherent mass of minerals, may include organic debris

lithospheric plates

rigid "plates" moved over a weaker, more plastic layer in the earths upper mantle

igneous

rocks that form by crystalizing from magma -granite, basalt

sedimentary

rocks that form from sedimentary (fragments of rock, minerals, or animal or plant material) at low pressure -sandstone, limestone

minerals

single element or compound naturally formed inorganic solid crystalline structure

earths mantle

upper mantle- composed of olivine lower mantle- similar to upper mantle but has minerals that form only under high pressure

The area of land where all of the water that is under it or drains off of it goes into the same place is called the _________________.

watershed

Principle of Superposition

when rocks were placed, newer ones were placed or formed on top of older rocks

what is the precambrian shield

• A 2.7-billion-year-old plate boundary beneath parts of Ontario and Quebec was found by scientists • Used seismic waves to peer deep into the Earth's crust

How (SOund NAvigation and Ranging) SONAR works

• A sound "ping" is transmitted by an underwater "speaker" • The travel time of the "ping" is measured to determine distance (water depth).

Mid-Continent Rift

• As the dense layers of basalt cooled, they caused the rift valley to • Sediments continued to fill this valley. sink -Later, compression (water coming from all sides) of the region caused uplift causing the layers of basalt at the edge of the rift upward until they were almost vertical in some places forming what is known as the Lake Superior Syncline

major events of the precambrian

• Colliding plates were forming continents by accretion and partial melting as oceanic plates were forced beneath continental plates (subduction). • Large volumes of volcanic rock were formed, then eroded and deposited as sediments on the ocean floor.

Lake Shore Traps

• The exposed layers of the Lake Superior Syncline have weathered over time, creating "Lake Shore Traps" in some areas. • the word "trap" originated from a Swedish term used to describe stacked lava flows that have weathered to form a stair-step pattern