REFERENCE: The Blue Planet An Introduction to Earth System Science. Brian J. Skinner and Barbara W. Murck (2011) Third Edition. John Wiley and Sons Inc.
It is the solid Earth composed primarily of: : Any naturally formed, nonliving, firm coherent aggregate mass of solid matter that constitutes part of a planet. : The irregular blanket of loose, uncemented rock particles that covers the solid Earth. Understanding plate tectonics and the rock cycle is the key to understanding the geosphere's role in the Earth system.
Layers of Different Composition The oceanic crust is composed mainly of basalt, rich in iron and magnesium. The continental crust is composed mainly of granite, rich in aluminum. Although they are both rich in oxygen and silicon, the rocks that compose the oceanic crust are of higher density than the rocks that compose the continental crust.
Tectonics is the study of the movements and deformation of the lithosphere. Such motions involve complicated events, both seen and unseen. The study of the processes by which the lithospheric plates move and interact with one another is called plate tectonics.
In 1508 Leonardo da Vinci discovered fossil seashells high in the mountains of Italy. In the 1800s James Hutton incorporated the idea of uplift and erosion into the concept of the rock cycle. In the 1830s Charles Darwin made important observations in South America that were key pieces to the rock cycle. A final piece of the rock cycle puzzle was answered: What is the force which has lift up the mountains? Answer: Plate Tectonics
World s landmasses were formed together in a single huge continent called: PANGAEA. Pangaea was somehow disrupted and its fragments (the continents of today) slowly drifted to their present position.
This geothermal gradient and convection are responsible for rising hot rocks and side-ways flow, which are the factors that control the positions of ocean basins and continents. Therefore, these processes determine the shape of the Earth's surface. It is hypothesized that convection also occurs in the interior of the Earth due to the geothermal gradient.
The source of the Earth s magnetism lies in the molten outer core. As a result of the Earth s rotation, the molten iron of the outer core flows continually around the solid inner core. The flowing stream of molten iron causes an electrical current in turn creates the magnetic field. Paleomagnetism is the magnetism in rocks that records the directions of ancient magnetic fields at the time of rock formation.
Lava extruding along a midocean ridge forms new oceanic crust. As the lava cools, it becomes magnetized with the polarity of the Earth's magnetic field.
A & B - Divergent C & E - Convergent Subduction D - Convergent Collision F - Transform Fault
Watch the YouTube video called Plate Tectonics
Convergent Margins Himalaya Los Andes Divergent Margins
ten Brink U S et al. Geological Society of America Bulletin 2009;121:1522-1536 2009 by Geological Society of America
Geodesy, also called geodetics, a branch of earth sciences, is the scientific discipline that deals with the measurement and representation of the Earth, including its gravitational field, in a threedimensional time-varying space.
GPS is funded by and controlled by the U. S. Department of Defense (DOD). While there are many thousands of civil users of GPS worldwide, the system was designed for and is operated by the U. S. military. GPS is the only system today able to show us the exact position on the Earth anytime and anywhere. The first GPS satellite was called GPS Block I and it was launched in 1978. The launch of the 24th satellite in 1994 completed the system. All 24 GPS satellites orbit at 11,000 nautical miles above the Earth. Four GPS satellite signals are used to compute positions in three dimensions and the time offset in the receiver clock.
New GPS Technology goes from meters to cm
or even mm
20 mm/yr Mann,et. al., 2002
Involves the firing of a laser (Light Amplification by Stimulated Emission of Radiation) pulse through a telescope at passing satellites and measuring the time taken for the pulses to return to earth.
Watch the YouTube video called The Early Earth and Plate Tectonics