Presentation is loading. Please wait.

Presentation is loading. Please wait.

MESOPROTEROZOIC BELT BASIN:

Similar presentations


Presentation on theme: "MESOPROTEROZOIC BELT BASIN:"— Presentation transcript:

1 MESOPROTEROZOIC BELT BASIN:
CRUSTAL-SCALE ANOMALY IN THE NORTHERN ROCKIES J.W. Sears University of Montana, Missoula

2 Belt Supergroup Calgary Kimberly ALBERTA MONTANA Libby Gibbs

3 Chief Mountain klippe Belt/Purcell Upper Cretaceous Lewis Thrust

4

5 Belt Supergroup Calgary Kimberly ALBERTA MONTANA Libby Gibbs

6

7 Gabbro sill reflectors
Cook and Van der Velden, 1995 Km

8

9 130 km 130 km 110 km 80 km 55 km 40 km 35 km

10

11

12

13

14 74 Ma 59 Ma

15 Dry slab overrides wedge of wet sedimentary rock
with high pore pressures in front Strong slab slides on plastic base in rear

16 Rebound of crustal keel drives Paleogene extension,
folds Purcell anticlinorium Restored at 59 Ma Crustal Keel

17 EARTHSCOPE IMPLICATIONS
Inverted Belt Basin forms crustal-scale structure Thick, coherent Belt-Purcell Supergroup constrains upper-crust structure Mafic sill seismic reflectors constrain middle-crust structure Good Moho reflectivity to bound lower crust Strong, well-layered Belt Basin controlled geodynamics of Northern Rockies thrust belt Post-thrust rebound drove extension, formed Purcell anticlinorium - implications for mantle rheology


Download ppt "MESOPROTEROZOIC BELT BASIN:"

Similar presentations


Ads by Google