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