Apennines          
 
Our work in the Northern Apennines of Italy has focused on both structural geology and sedimentology.        
 

Kink folding

Layered rocks commonly have folds with kink and chevron geometry. The interlayered limestones and shales of the Apennines provide a great natural laboratory for the study of kink folding.

   
 
 
Kink and chevron folds developed in Cretaceous pelagic limestones. We were able to show that these kinds of folds form by migration of the axial surfaces.  
 
                                     

Carbonate Platform Evolution

Jurassic rifting of the Apennine carbonate platform resulted in the formation of a series of fault-block carbonate platforms. Our study of these platforms has yielded insights into the growth and drowning of isolated carbonate platforms.

   
                                     
                           
  Monte Bove (2112 m) in the Sibillini Mountains. This is a well-exposed example of one of the small fault-block carbonate platforms in the Northern Apennines. The rocks making up the upper third of the mountain are part of the Jurassic Calcare Massiccio  
                           
         
                   
Monte Rotondo (1900 m), another Jurassic platform in the Sibillini mountains. The gray rock exposed in the middle of the mountain is the platform-facies Calcare Massiccio. The gulleyd surface on the mountain front is the remnant of a Jurassic by-pass margin that was developed on the platform escarpment. The ancient gulleys are best preserved near the left side of the photograph, where the gray Calcare Massiccio abuts the forested slope. This sharp contact corresponds to an active normal fault that juxtaposes Cretaceous rocks on the left against Jurassic Calcare Massiccio on the right.  
                   
   

Alpi Apuane

The Alpi Apuane are a metamorphic core complex in the Northern Apennines. Below the detachment fault are metamorphosed carbonates; above are unmetamorphosed rocks. Peggy Hodgkins (MS 1991) showed that fluid inclusions from quartz and calcite cement in the fault breccia constrain the temperature and depth at which the fault was active.

 
     
  View of the metamorphic rocks forming the core of the Alpi Apuane. Forested hills in the foreground are underlain by unmetamorphosed Mesozoic carbonates in the hanging wall of the detachment fault  
         
     
                     
Dr. Michael Follo ponders the origin of the intense folding within the metamorphosed footwall.        
                     
                                     
                     
  The Alpi Apuane are the source of much of the world's decorative marble. The white on the slopes of the mountains in the background is not snow - it's the by-product of marble mining in the famous Carrara marble district.
                     

Selected Apennines bibliography

Hodgkins, M.A., and Stewart, K.G., 1994, The use of fluid inclusions to constrain fault zone temperature and kinematic history: An example from the Alpi Apuane, Italy: Journal of Structural Geology, v. 16, p. 85-96.

Stewart, K.G., and Alvarez, W., 1991, Mobile-hinge kinking in layered rocks and models: Journal of Structural Geology, v. 13, p. 243-259.

Bice, D.M., and Stewart, K.G., 1990, The formation and drowning of isolated carbonate seamounts: tectonic and ecological controls in the northern Apennines, in Tucker, M.E., Wilson, J.L., Crevello, P.D., Sarg, J.R., and Read, J.F., eds., Carbonate Platforms: Facies, Sequences, and Evolution, International Association of Sedimentologists Special Publication no. 9., p. 145-168.

Stewart, K.G., and Castellarin, A., 1989, Exotic clasts in a Pliocene conglomerate near Pesaro have an Alpine source: Bollettino Societa Geologica Italiana, v. 108, p. 607-618.

Bice, D.M., and Stewart, K.G., 1985, Ancient erosional grooves on exhumed by-pass margins of carbonate platforms: Examples from the Apennines: Geology, v. 13, p. 565-568.

 
 
Copyright © 2003 Kevin G. Stewart
page last modified: August 12, 2003