p-t-t paths and their significance. metamorphic field gradient –trend of thermal maxima across...
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P-T-t Paths and Their Significance
Metamorphic Field Gradient –Trend of Thermal Maxima Across Metamorphic Facies
Clockwise P-T-t Path
P-T-t Path Reflecting Crustal Thickening
A Crustal Thickening P-T-t Path
Central Indian Tectonic Zone (Proterozoic)
Early Barrovian P-T-t Path showing effects of later arc-related magmatism and variable uplift/erosion
P-T-t Path for Connemara
Inlier
P-T-t Path of Burial Metamorphism
Field gradient 25 oC/Km
Subduction and exhumation in 10 Ma. Prograde, retrograde stages of a single metamorphic cycle
(1, 2) Gt-hbl thermometry Gt-amph-plag-qtz barometry(3) Jd-Ky isograd (eclogite facies)(4) Plag-Cor isograd (granulite facies)5) Gt-Hbl thermometry, gt-amph-plag-qtz barometry
SHRIMP U-Pb dating of zircon
Alpine orogeny, Rhodope Region, Greece
Liati and Gebauer, 1999
10 oC/Km
30 oC/Km
Clockwise P-T-t Path in a Back-Arc BasinODP Site 976 between Spain and Morocco – Miocene extensional basin
Exhumation in 6 Ma @ 4km/Ma
Alpine Uplift Rates from Geothermobarometry and 40Ar-39Ar Dating
3.6
2.9
1.80.5
mm/an20 Ma
18 Ma
18 Ma13.3 Ma
7.1 Ma
Uplift Rate
Counter Clockwise P-T-t Paths
Counter-clockwise Path –Commonly Occurs Under Granulite Facies Conditions
Counter clockwise P-T-t Path –Archean Granulite Terrane
Proterozoic Metamorphism N. Australia
HPLP
Counter-clockwise Paths in HP and LP Granulite
Terranes
Clockwise P-T-t Path for Granulite Facies, Scotland
Variscan Clockwise and Counter-clockwise
Paths in the Odenwald, Germany