Quaternary uplift vs tectonic loading: a case study from the Lucanian Apennine, southern Italy

Abstract Uplift rates have been calculated for a large sector of the Lucanian Apennine (“axial zone” of the southern Apennines, Italy), using both geomorphological observations (elevation values, ages and arrangement of depositional and erosional landsurfaces and other morpho-tectonic indicators) and stratigraphical and structural data (sea-level-related facies, fault kinematics and offset estimations). These data have been compared with those derived from clay mineralogy of Mesozoic pelagic successions (Lagonegro units), outcropping in the same sector of the chain, which gave information on tectonic loading. The values of the Quaternary uplift rates of the southern Apennines axial zone vary from a minimum of 0.2 mm / yr to a maximum of about 1.2 mm / yr . Intermediate values (0.5– 0.7 mm / yr ) have been calculated for the other studied areas. Using geomorphological features and late Pliocene to Pleistocene successions involved in the genesis of erosional and depositional landsurfaces, the same rates ( ∼0.6 mm / yr ) have been obtained for a large time span (about 2 Ma ) in the Melandro basin and adjacent Maddalena Mts. Therefore, during the last 2 Ma , the total uplift amount of the axial zone of the Lucanian Apennine is about 1.2– 1.3 km , with local peaks of 1.5 km . On the other hand, the Mesozoic pelagic units experienced a tectonic loading of 4– 5 km , as estimated by means of illite crystallinity (in the range 0.6– 1.1 Δ°2θ ), percentage of illitic layers in illite/smectite mixed layers (60–90%) and white mica polytypes (in the range of 10–35%). The Quaternary uplift and the related erosion rates of the southern Apennines are unquestionably due to strike-slip faulting and, above all, due to extensional tectonics coupled with thermal/isostatic regional raising. The gap of several kilometres derived from the comparison between uplift rates and tectonic loading values may be explained only by different exhumation modalities starting from late Miocene time.

[1]  R. M. Pollastro.  Considerations and Applications of the Illite/Smectite Geothermometer in Hydrocarbon-Bearing Rocks of Miocene to Mississippian Age , 1993 .

[2]  T. Pescatore,et al.  Stratigraphic and structural relationships between Meso-Cenozoic Lagonegro basin and coeval carbonate platforms in southern Apennines, Italy , 1999 .

[3]  M. Schiattarella.  Quaternary tectonics of the Pollino Ridge, Calabria-Lucania boundary, southern Italy , 1998, Geological Society, London, Special Publications.

[4]  A. Amato,et al.  Erosional landsurfaces of the Campano–Lucano Apennines (S. Italy): genesis, evolution, and tectonic implications , 1999 .

[5]  R. Bevins,et al.  Low Grade Metamorphism , 1992 .

[6]  H. J. Kisch.  Illite crystallinity: recommendations on sample preparation, X-ray diffraction settings, and interlaboratory samples , 1991 .

[7]  C. E. Weaver.  Shale-slate metamorphism in southern Appalachians , 1984 .

[8]  D. Peacor,et al.  Clay Mineral Thermometry—A Critical Perspective , 1995 .

[9]  L. Warr,et al.  Interlaboratory standardization and calibration of day mineral crystallinity and crystallite size data , 1994 .

[10]  L. Ferranti,et al.  Radiocarbon dating of active faulting in the Agri high valley, southern Italy , 2000 .

[11]  G. Cressey,et al.  Rapid whole-pattern profile-stripping method for the quantification of multiphase samples , 1996, Powder Diffraction.

[12]  A. Ascione,et al.  Vertical movements on the eastern margin of the Tyrrhenian extensional basin. New data from Mt. Bulgheria (Southern Apennines, Italy) , 1999 .

[13]  Francesca Romana Cinti,et al.  Regional uplift and local tectonic deformation recorded by the Quaternary marine terraces on the Ionian coast of northern Calabria (southern Italy) , 1998 .

[14]  H. Slaymaker.  Geomorphology, human activity and global environmental change , 2000 .

[15]  E. Tondi,et al.  Fault zone characteristics and scaling properties of the Val d’Agri Fault System (Southern Apennines, Italy) , 2000 .

[16]  C. E. Weaver,et al.  Chapter 4 - Illite-Mica , 1984 .

[17]  B. Velde.  The stability of clays , 1992 .

[18]  B. Velde,et al.  Clay Mineral Evolution in the Illinois Basin and its Causes , 1995, Clay Minerals.

[19]  J. Hower,et al.  Clay Mineral Assemblages as Low Grade Metamorphic Geothermometers: Application to the Thrust Faulted Disturbed Belt Of Montana, U.S.A , 1979 .

[20]  E. Dinelli,et al.  Geology and geochemistry of Jurassic pelagic sediments, Scisti silicei Formation, southern Apennines, Italy , 2002 .

[21]  G. D. Price,et al.  The Stability of minerals , 1993 .

[22]  M. Jaboyedoff,et al.  New data on low-grade metamorphism in the Brianconnais domain of the Prealps, western Switzerland , 1996 .

[23]  G. Cressey,et al.  Rapid, Accurate Phase Quantification of Clay-Bearing Samples using a Position-Sensitive X-Ray Detector , 1998 .

[24]  Paolo Scandone,et al.  Studi di geologia lucana: carta dei terreni della serie calcareo-silico-marnosa e note illustrative , 1972 .

[25]  C. Doglioni,et al.  The Western Mediterranean extensional basins and the Alpine orogen , 1997 .

[26]  Eric Eslinger,et al.  Mechanism of burial metamorphism of argillaceous sediment: 1. Mineralogical and chemical evidence , 1976 .