Skip to main content

Super continents

                        Super continents

In geology, a supercontinent is the assembly of most or all of Earth's continental blocks or cratons to form a single large landmass. However, some earth scientists use a different definition, "a grouping of formerly dispersed continents", which leaves room for interpretation and is easier to apply to Precambrian times although at least about 75% of the continental crust then in existence has been proposed as a limit to separate supercontinents from other groupings.

Supercontinents have assembled and dispersed multiple times in the geologic past (see table). According to modern definitions, a supercontinent does not exist today. The supercontinent Pangaea is the collective name describing all of the continental landmasses when they were most recently near to one another. The positions of continents have been accurately determined back to the early Jurassic, shortly before the breakup of Pangaea (see animated image). The earlier continent Gondwana is not considered a supercontinent under the first definition since the landmasses of Baltica, Laurentia and Siberia were separate at the time. Supercontinents appear to form by two end-member processes: extroversion, in which the oceanic lithosphere surrounding the supercontinent (exterior ocean) is preferentially subducted (e.g. Pannotia), and introversion in which the oceanic lithosphere formed between dispersing fragments of the previous supercontinent (interior ocean) is preferentially subducted (e.g. Pangea). Extroversion can be explained by “top–down” geodynamics, in which a supercontinent breaks up over a geoid high and amalgamates above a geoid low. Introversion, on the other hand, requires that the combined forces of slab-pull and ridge push (which operate in concert after supercontinent break-up) must be overcome in order to enable the previously dispersing continents to turn inward. As Eurasia moves laterally along the Ring of Fire, it will eventually collide with the Americas, forming a new supercontinent in the next 50 million to 200 million years.

                                   

                 Image via- en.wikipedia.org 

     

     NDKBlogs 

Comments

Post a Comment

Popular posts from this blog

Singapore

 ©thisisblogndk.blogspot.com |  Owned by the owner Ben HeatBlast of thisisblogndk.blogspot.com Singapore, officially the Republic of Singapore, is a sovereign island city-state in maritime Southeast Asia.   Singapore is one of the main tourist attractions in the world due to its amazing structures. Singapore is also one of the most developed countries in the world.
Post a Comment
Read more

Albert Einstein

                                        Albert Einstein Albert Einstein was a German-born theoretical physicist who developed the theory of relativity, one of the two pillars of modern physics. His work is also known for its influence on the philosophy of science.   He is also known for his discovery of the photoelectric effect, for which he won the Nobel Prize for Physics in 1921. Einstein developed a theory of special and general relativity, which helped to complicate and expand upon theories that had been put forth by  Isaac Newton  over 200 years prior.  The maximum  IQ  score assigned by the WAIS-IV, a commonly-used test today, is 160. A score of 135 or above puts a person in the 99th percentile of the population. News articles often put  Einstein's IQ  at 160, though it's unclear what that estimate is based upon.  Einstein's Big Idea home...
Post a Comment
Read more

NDK Astronomy | Mars landing by NASA.

NDK Astronomy                   The mars landing by NASA. Resently 18/2/2021 National aeronutics and space adminstration launched a space rover for the red planet, Mars.  A Mars landing is a landing of a spacecraft on the surface of Mars. Of multiple attempted Mars landings by robotic, unmanned spacecraft, ten have had successful soft landings. There have also been studies for a possible human mission to Mars, including a landing, but none have been attempted.  The most recent landing took place on the 18 of February 2021 by the NASA rover  of 2021, all methods of landing on Mars have used an   aeroshell   and   parachute   sequence for   Mars atmospheric entry   and descent, but after the parachute is detached, there are three options. A stationary lander can drop from the parachute back shell and ride   retrorockets   all the way down, but a   rover   cannot be burdened with r...
Post a Comment
Read more