monday december 3, 2012 (discussion and worksheet - introduction to continental drift and plate...
TRANSCRIPT
MondayDecember 3, 2012
(Discussion and Worksheet -
Introduction to Continental Drift and
Plate Tectonics)
The Launch PadMonday, 12/3/12
In which rock layer would you not find
dinosaur fossils?
Why?
Announcements
Happy ??!
Assignment Currently Open
Summative or
Formative?Date Issued Date Due Date Into
GradeSpeed Final Day
Quiz 11 S1 11/9 11/9 11/30 12/14
Quiz 12 S2 11/16 11/16 11/30 12/14
WS - The Phanerozoic Eon: The Mesozoic Era – The Age of Reptiles
F6 11/28 12/7 12/7
WS - The Phanerozoic Eon: The Cenozoic Era – The Rise of Mammals and Flowering Plants
F7 11/29 12/7 12/7
Quiz 13 S3 11/30 11/30
Recent Events in ScienceMore Intense North Atlantic Tropical Storms Likely in the
Future
A study shows that tropical storms that make their way into the North Atlantic, and possibly strike the East Coast of the
United States, likely will become more intense during the rest of this century.
The study itself examines projected changes in the North Atlantic Power Dissipation Index (PDI) using output from 17
state-of-the-art global climate models and three different potential scenarios. The PDI is an index that integrates storm
intensity, duration, and frequency.
Researchers found that the PDI is projected to increase in the 21st century in response to both greenhouse gas increases and reductions in particulate pollution over the Atlantic over
the current century. By relating these results to other findings in a paper we published May 13, 2012 in the
journal Nature Climate Change, they found that, while the number of storms is not projected to increase, their intensity
is.
The results indicate that as more carbon dioxide is emitted, the stronger the storms get, while scenarios with the most
aggressive carbon dioxide mitigation show the smallest increase in intensity,
Read All About It!www.sciencedaily.com/releases/2012/11/121130151651.htm
Introduction
to Plate
Tectonics
Antonio Snider-Pellegrini (no picture available) was a French geographer and scientist who first hypothesized the possibility
of continental drift.In 1858, Snider-Pellegrini published his book, "The Creation and its
Mysteries Unveiled“, in which he proposed that all of the continents were once connected together during the Pennsylvanian Period.
He based this theory on the fact that he had found plant fossils in both Europe and the United States that were identical.
He found matching fossils on all of the continents.
Continental Drift - An Idea Before Its Time
Continental Drift - An Idea Before Its Time
57 years later, German scientist Alfred Wegener proposed his
continental drift hypothesis (1915.)
His work was published as “The Origin of Continents and Oceans.”
The continental drift hypothesis states that a supercontinent called
Pangaea began breaking apart about 200 million years ago.
The continents “drifted” to their present positions.
Pangaea approximately 200 million years ago
Figure 7.2
Evidence Cited by Wegener
Wegener noted the obvious fit of South America and Africa.
Continental Drift - An Idea Before Its Time
Continental Drift - An Idea Before Its Time
Evidence Cited by Wegener
He pointed out that fossils match across
the seas.
Evidence Cited by Wegener
He pointed out that fossils match across
the seas.
Continental Drift - An Idea Before Its Time
Evidence Cited by Wegener
He pointed out that fossils match across
the seas.
Continental Drift - An Idea Before Its Time
Evidence Cited by Wegener
Wegener also discovered that rock types and structures
match the seas.
Continental Drift - An Idea Before Its Time
Evidence Cited by Wegener
There are similar mountain ranges on different continents.
Continental Drift - An Idea Before Its Time
Evidence Cited by Wegener
He noted that ancient climate
evidence matches on the present-day
continents.
Continental Drift - An Idea Before Its Time
The main objection to Wegener’s proposal was the inability to
find a mechanism for continental drift.
Continental Drift - An Idea Before Its Time
The Continental Drift Mechanism Discovered: Plate TectonicsPlate tectonics is the theory that describes the large-scale motions
of Earth's lithosphere.
The model builds on the concepts of continental drift, developed by Wegener during the first decades
of the 20th century.
It was accepted by the geoscientific community after the concepts
of seafloor spreading were developed in the late 1950s and
early 1960s.
The Continental Drift Mechanism Discovered: Plate TectonicsThe concept of plate tectonics is
more encompassing than the idea of continental drift.
Plate tectonics is associated with Earth’s rigid outer shell, called the
lithosphere. Earth’s lithosphere consists of
several “plates”, which are moving very slowly across the mobile
asthenosphere below.The largest of these plates is the
Pacific plate. The plates are mostly beneath the
ocean.
Figure 1.18 (left)
Figure 1.18 (right)
The Earth’s lithosphere is
divided into plates, which move on top
of the asthenosphere.
New crust is created at mid-oceanic ridges.
Plates move apart (diverge) and crash together (converge.)
Plate tectonics, the mechanism for continental drift, is caused by convection in the asthenosphere causing an upwelling through the
lithosphere.
The Earth’s asthenosphere lies just beneath the
lithosphere. The asthenosphere is
hotter and weaker than the lithosphere.
This allows for the motion of the lithosphere over
the asthenosphere
Plate Tectonics
All major interactions among plates occur along their boundaries.
Plate Tectonics
WorksheetIntroduction to
Continental Drift and Plate Tectonics
Reference notes on teacher website dated Monday,
12/3/12.