Which statement about pangea is true

Notice the postion of the continents of Antarctica Far north of its current position , Australia flipped sideways and far west of its current position and the subcontinent of India Hundreds of miles from Asia.

Scientists believe that the North American continent was located much farther south and east of it's position today. In fact, much of North America was in or near the tropics!! How do scientists know this?? They have found fossils from this period of time. These fossils are of tropical plants and animals. The fossils have been found in cold regions like North Dakota and Greenland!!! About million years ago the supercontinent Pangea began to break up. Scientists believe that Pangea broke apart for the same reason that the plates are moving today.

The movement is caused by the convection currents that roll over in the upper zone of the mantle. This movement in the mantle causes the plates to move slowly across the surface of the Earth. About million years ago Pangaea broke into two new continents Laurasia and Gondwanaland. Gondwanaland was made of the present day continents of Antarctica, Australia, South America.

The subcontinent of India was also part of Gondwanaland. Notice that at this time India was not connected to Asia. The huge ocean of Panthalassa remained but the Atlantic Ocean was going to be born soon with the splitting of North America from the Eurasian Plate. How do we know that South America was attached to Africa and not to North America million years ago? Scientists today can read the history of the rock record by studying the age and mineral content of the rocks in a certain area.

The Triple Junction was formed because of a three-way split in the crust allowing massive lava flows. The split was caused by an upwelling of magma that broke the crust in three directions and poured out lava over hundreds of square miles of Africa and South America. The rocks of the triple junction, which today is the west central portion of Africa and the east central portion of South America, are identical matches for age and mineral make up.

And about million years ago some of the earliest dinosaurs emerged on Pangaea, including theropods, largely carnivorous dinosaurs that mostly had air-filled bones and feathers similar to birds.

The current configuration of continents is unlikely to be the last. Supercontinents have formed several times in Earth's history, only to be split off into new continents.

Right now for instance, Australia is inching toward Asia, and the eastern portion of Africa is slowly peeling off from the rest of the continent. Geologists have noticed that there is a quasi-regular cycle in which supercontinents form and break up every to million years, but exactly why is a mystery, Murphy said.

But most scientists believe that the supercontinent cycle is largely driven by circulation dynamics in the mantle, according to a article in the Journal of Geodynamics. Beyond that, the details get fuzzy. While the heat formed in the mantle likely comes from the radioactive decay of unstable elements, such as uranium, scientists don't agree on whether there are mini-pockets of heat flow within the mantle, or if the entire shell is one big heat conveyor belt, Murphy said. Scientists have created mathematical, 3D simulations to better understand the mechanisms behind continental movement.

Santhosh explain how they produced simulations of large-scale continental movements since the breakup of Pangaea million years ago. The models show how tectonic plate motion and mantle convection forces worked together to break apart and move large land masses.

For example, Pangaea's large mass insulated the mantle underneath, causing mantle flows that triggered the initial breakup of the supercontinent. Radioactive decay of the upper mantle also raised the temperature, causing upward mantle flows that broke off the Indian subcontinent and initiated its northern movement.

We can see evidence of magnetic polarity reversals by examining the geologic record. When lavas or sediments solidify, they often preserve a signature of the ambient magnetic field at the time of deposition.

Incredible as it may seem, the magnetic field occasionally flips over! The geomagnetic poles are currently roughly coincident with the Can USGS photos of fossils be downloaded or viewed online? Fossil photos can also be viewed as published plates within many online USGS publications. The best keywords for searches are author names, such as William Cobban, Norm Filter Total Items: Year Published: Divisions of geologic time Bookmark DescriptionThis bookmark presents information that is widely sought by educators and students.

View Citation. Geological Survey, , Divisions of geologic time ver. Year Published: Why Study Paleoclimate? Why Study Paleoclimate? Lindsey, D. Year Published: Divisions of Geologic Time—Major Chronostratigraphic and Geochronologic Units Effective communication in the geosciences requires consistent uses of stratigraphic nomenclature, especially divisions of geologic time.

Geological Survey Geologic Names Committee. Torsvik, T. Santa Barbara, California, U. Year Published: A tapestry of time and terrain Vigil, J. A tapestry of time and terrain; ; I; ; Vigil, J. Year Published: Geologic age: using radioactive decay to determine geologic age At the close of the 18th century, the haze of fantasy and mysticism that tended to obscure the true nature of the Earth was being swept away.

Geologic Survey. Ray, Louis L. Newman, William L. Filter Total Items: 1. Date published: March 21, II Pangea. History, Social Studies, Religious Studies. Played 0 times. Print Share Edit Delete Report an issue. Start a live quiz. Students progress at their own pace and you see a leaderboard and live results. Assign homework. Finish Editing. This quiz is incomplete! To play this quiz, please finish editing it.