Journey Vaalbara To Pangaea Proxima
Journey Vaalbara To Pangaea Proxima
Journey Vaalbara To Pangaea Proxima
SUPERCONTINENT CYCLE
PRESENTED BY
GOURAB HALDER
SUVANKAR GOSWAMI
UG
MIDNAPORE COLLEGE(AUTONOMOUS)
WEST BENGAL
THE EARTH IS UNSTABLE AND ITS RELIEF FEATURES
OF FIRST ORDER – CONTINENTS AND OCEAN BASINS ARE
ALSO CHANGING , MOVING , AND REARRANGING THEMSELVES
OVER MILLIONS OF YEARS – AFFECTING EARTH’S CLIMATE AND
BIOLOGY . EVERY FEW HUNDRED MILLION YEARS , THE
CONTINENTS COMBINE TO CREATE MASSIVE , WORLD
SPANNING SUPERCONTINENTS.
HERE’S THE PAST AND FUTURE OF EARTH SUPERCONTINENTS –
1. Gondwana
ORDOVICIAN PERIOD 420 MILLION YEARS AGO
2. Euramerica
UR. ::
RODINIA :
RODINIA ( “THE MOTHERLAND”) IS A
NEO PROTEROZOIC SUPERCONTINENT
THAT WAS ASSEMBLED 1.3-0.9 BILLION
YEARS AGO AND BROKE UP 750-633
MILLION YEARS AGO .
VALENTINE AND MOORES (1970) FIST
RECOGNIZED THIS AS PANGAEA-I AND IT
WAS RENAMED RODINIA BY Mc MENAMIN
& Mc MENAMIN (1990) .
• PANNOTIA
NAMED BY POWELL(1995)
• PANNOTIA (ALL SOUTHERN LAND) ,ALSO
KNOWN AS VENDIAN SUPERCONTINENT
,GREATER GONDWANA , PAN- AFRICAN
SUPERCONTINENT. IT WAS FORMED 650
MILLION YEARS AGO AND BROKE APART 560
MILLION YEARS AGO.
• PANGAEA
• PROPOUNDED BY ALFRED WEGENER (1912-
1922 IN HIS BOOK “ DIE ENTSTEHUNG DER
KONTINENT AND OZEAN”).
BASIC IDEA :
SEA FLOOR SPREADING IS A PROCESS THAT
OCCURS AT MID OCEANIC RIDGES, WHERE
NEW BASALTIC OCEANIC CRUST IS FORMED
THROUGH UPWELLING HOT MOLTEN LAVAS
FROM ASTHENOSPHERE WITH THERMAL
CONVECTIVE CURRENT AND THEN GRADUALLY
MOVES AWAY FROM THE MID-OCEANIC RIDGE
AND THE EXPANDING CRUSTS ARE DESTROYED
ALONG THE TRENCHES.
➢ TRANSFORM FAULT
➢ SUBDUCTION OF GOYT
INTRODUCTION:
THE TERM ‘PLATE’ FIRST USED BY JOHN TUZO WILSON. THEN MACKENZIE AND PARKAR
DISCUSSED IN DETAIL THE MECHANISM ON BASIS OF EULER’S GEOMETRICAL THEOREM IN 1967.
W.J.MORGAN AND LE PICHON ELABORATED THE VARIOUS ASPECTS OF PLATE TECTONICS IN 1968.
FUNDAMENTAL CONCEPT:
PLATE : THE RIGID LITHOSPHERIC SLABS ARE TECHNICALLY CALLED PLATES.
MAJOR PLATES : 6- 7
MINOR PLATES : 20
PLATE TECTONICS : THE STUDY OF WHOLE MECHANISM OF EVOLUTION, NATURE AND MOTIONS OF
PLATES, DEFORMATION WITHIN PLATES AND INTERRACTIONS OF PLATE MARGINS WITH EACH
OTHER IS COLLECTIVELY CALLED AS PLATE TECTONICS.
1. CONVERGENT OR DESTRUCTIVE PLATE
MARGINS
2. DIVERGENT OR CONSTRUCTIVE PLATE
MARGINS
3. CONSERVATIVE OR TRANSFORM PLATE
MARGINS
WORLD DISTRIBUTION OF PLATES AND
RATE OF THEIR MOTIONS
FUTURE EXPECTATIONS (250 MYA LATER)
➢ NOVO PANGAEA :
IT IS A POSSIBLE FUTURE
SUPERCONTINENT . IT ASSUMES CLOSURE OF PACIFIC ,
DOCKING OF AUSTRALIA WITH EASTERN ASIA AND
NORTHWARD MOTION OF ANTARCTICA.
➢ AMASIA :
AMASIA IS A POSSIBLE,
FUTURE SUPERCONTINENT THAT COULD BE FORMED
BY THE MERGER OF ASIA AND NORTH AMERICA. THIS
PREDICTION RELIES MOSTLY ON THE FACT THAT
THE PACIFIC PLATE IS
ALREADY SUBDUCTING UNDER EURASIA AND NORTH
AMERICA, A PROCESS WHICH IF CONTINUED WILL
EVENTUALLY CAUSE THE PACIFIC TO CLOSE.
PANGAEA ULTIMA OR PROXIMA