Contacts can be combinations of… Injection Deformation Melting/in situ reactions Things to consider on Wednesday!
Dome & keel structures in the Barberton granitoid-greenstone terrain Domes: 3.4 & 3.2 Ga gneissic TTG`s Concentric foliation patterns concordant with foliation in the surrounding supracrustals Keels: tightly folded synformal supracrustals with TPC`s. After Anhaeusser et al. (1981) Anhaeusser (2001). 5 km N
Batholiths Plutons associations Definition not too clear Old litterature: « primordial » granitic level, somewhere down. Modern conceptions: associations of individual plutons, each with its shape and structures Probably rather flat as well!
Figure Schematic block diagram of some intrusive bodies. “Vertical” intrusions
An “old” view of a batholith Figure Schematic cross section of the Coastal batholith of Peru. The shallow flat-topped and steep- sided “bell-jar”-shaped plutons are stoped into place. Successive pulses may be nested at a single locality. The heavy line is the present erosion surface. From Myers (1975) Geol. Soc. Amer. Bull., 86,
Figure Diagrammatic cross section of the Boulder Batholith, Montana, prior to exposure. After Hamilton and Myers (1967), The nature of batholiths. USGS Prof. Paper, 554-C, c1-c30. Modern conceptions: flat batholiths