SELF-ORGANIZED BREAKUP OF GONDWANA

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• SELF-ORGANIZED BREAKUP OF GONDWANA
• by
• JIM SEARS
• UNIVERSITY OF MONTANA
• MAIN CONCLUSIONS
• BREAKUP OF GONDWANA WAS SELF-ORGANIZED TO
  MINIMIZE WORK
• ARGUES AGAINST DEEP MANTLE PLUMES

HEARD ISLAND HOT SPOT
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THE DEEP MANTLE PLUME PARADIGM AN INTEGRAL PART
OF PLATE TECTONICS SINCE J.T. WILSON (1963) AND
W.J. MORGAN (1981)
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STATIONARY HOT SPOT VOLCANOES TAILS OF DEEP
MANTLE PLUMES?
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LARGE IGNEOUS PROVINCES (LIPS) HEADS OF DEEP
MANTLE PLUMES?
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HEADS AND TAILS LINKED BY HOT SPOT TRACKS?
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• PLUMES RANDOMLY GENERATED AT CORE-MANTLE
  BOUNDARY?
• PLUME OUTBREAKS INITIATE CONTINENTAL BREAKUP?

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INDIA
GONDWANA
AUST
AF
ANTARCTICA
NZ
SA
8
CAMP - FERNANDO
ACCEPTED MODEL FOR GONDWANA BREAKUP LAWVER ET AL.
1999
?1999 UTIG
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KAROO-BOUVET
?1999 UTIG
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GALLODAI-MARION
?1999 UTIG
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PARANA-TRISTAN
?1999 UTIG
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RAJMAHAL-KERGUELEN
BANBURY-HEARD
?1999 UTIG
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HOTSPOT CONSTELLATION
?1999 UTIG
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ARABIA
INDIA
AFRICA
AUSTRALIA
ANTARCTICA
FLORIDA
SOUTH AMERICA
N Z

HOWEVER, BREAKUP OF GONDWANA WAS NOT RANDOM - IT
WAS HIGHLY SELF-ORGANIZED
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ETHIOPIAN 38 Ma
DECCAN 65 Ma
RAJMAHAL 110 Ma
CAMP 205 Ma
MARANHAO 200 Ma
GALLODAI 144 Ma
PARANA 134 Ma
KAROO 183 Ma
TRANSKEI
FERRAR 183 Ma
LIMPOBO
LARGE IGNEOUS PROVINCES
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ST HELENA
MARION
CROZET
KERGUELEN
ASCENCION
HEARD
FERNANDO
TRISTAN
BOUVET
GOUGH
GONDWANA HOT SPOT FAMILY
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GODAV ARI
BENUE
TRANSKEI
TACUTU
PERU-PARAGUAY DISCONTINUITY
WEDELL
THESE MAJOR GONDWANA FRACTURE POLYGONS RIGOROUSLY
OBEY EULERS THEOREM FOR CONVEX POLYTOPES
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GONDWANA
NAMELY, TO TILE A SPHERE WITH 12 PLATES, 12
MUST HAVE 5-FOLD SYMMETRY AT PRECISELY-DEFINED
VERTICES OF ICOSAHEDRON
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GONDWANA
REMAINING (N-12) PLATES HAVE 6-FOLD SYMMETRY
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ICOSAHEDRAL ARRANGEMENTS
Eulers formula relating faces (F), vertices (V
), and edges (E) of a convex polytope (F V E
2)
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ICOSAHEDRAL VIRUS HERPES SIMPLEX
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FINITE ELEMENT SOLUTION FOR THOMSON PROBLEM WITH
912 CHARGES ON SPHERE (Altschuler et al., 1997)
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GONDWANA
EDGE LENGTHS AND CENTERS ARE RIGOROUSLY
DEFINED EACH EDGE 2600 KM AT EARTH SCALE
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ANTARCTICA
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PENTAGON RIFT EDGES 2600 KM
2600 KM
2600 KM
2600 KM
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P
GONDWANA
H
H
H
P
H
P
H
PENTAGONS AND HEXAGONS IN EXACT ARRANGEMENT
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P
GONDWANA
H
H
H
P
H
P
H
16 EDGES, gt20,000 KM
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GONDWANA
PATTERN MINIMIZES TOTAL FRACTURE LENGTH AND
THEREFORE MINIMIZES WORK FUNCTION OF STRENGTH OF
GONDWANA SHELL
STRONGER
GONDWANA
WEAKER
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GONDWANA
PATTERN MINIMIZES TOTAL FRACTURE LENGTH AND
THEREFORE MINIMIZES WORK FUNCTION OF STRENGTH OF
GONDWANA SHELL
STRONGER
X
GONDWANA
WEAKER
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• LARGE IGNEOUS PROVINCES
• ERUPTED DIACHRONOUSLY ALONG FRACTURE PATTERN
• DEPENDED ON PLATE TECTONICS TO OPEN
• FRACTURES TO INDUCE DECOMPRESSION MELTING

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• CONCORDANCE OF FAMILY OF HOT SPOTS WITH FRACTURE
  TESSELLATION
• SHOWS HOT SPOTS ARE NON-RANDOM

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YELLOW STRESS TESSELLATION IS DUAL OF FRACTURE
TESSELLATION THEY CROSS ONE ANOTHER
ORTHOGONALLY
HOTSPOTS ON TESSELLATION
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HOOP STRESS ALONG NORTHERN GONDWANA MARGIN NOTE
RADIAL FRACTURES AT MARGIN
HOTSPOTS ON TESSELLATION
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NOTE PERFECT SYMMETRY OF STRESS TESSELLATION
ACROSS GONDWANA HOTSPOTS FAVOR CENTERS
HOTSPOTS ON TESSELLATION
EXPANSION OF GONDWANA LEADS TO FRACTURES
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• FRACTURE SYSTEM INDICATES GONDWANA WAS UNDER
  UNIFORM TENSION

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NOTE SYMMETRY OF STRESS TESSELLATION ACROSS
GONDWANA
HOTSPOTS ON TESSELLATION
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• INITIAL GEOMETRY OF GONDWANA DETERMINED BEST
  ORIENTATION OF TESSELLATION TO ACHIEVE MINIMUM
  FRACTURE LENGTH
• AND THEREFORE LEAST WORK

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AFRICAN GEOID ANOMALY SYMMETRICAL TO FRACTURES
WHEN GONDWANA IS RESTORED TO TRIASSIC POSITION
HOTSPOTS ON TESSELLATION
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GONDWANA SPREAD OUTWARD DOWN GEOID GRADIENT SEE
ANDERSON, 1982
HOTSPOTS ON TESSELLATION
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• GONDWANA STALLED ON MANTLE FRAMEWORK
• INSULATED UNDERLYING MANTLE
• THERMAL EXPANSION OF MANTLE DROVE UPLIFT AND
  UNIFORM TENSION IN GONDWANA
• FRACTURE TESSELLATION OCCURRED AT CLIMAX OF
  UPLIFT, IN EARLY TRIASSIC
• FRACTURES LATER SEPARATED AS REQUIRED BY PLATE
  TECTONICS, DRIVING DECOMPRESSION MELTING