Cenozoic Volcanism in the Mediterranean Area
A review of petrogenesis of Mediterranean Tertiary lamproites: A perspective from the Serbian ultrapotassic province
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Published:January 01, 2007
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CiteCitation
D. Prelević, S.F. Foley, V. Cvetković, 2007. "A review of petrogenesis of Mediterranean Tertiary lamproites: A perspective from the Serbian ultrapotassic province", Cenozoic Volcanism in the Mediterranean Area, Luigi Beccaluva, Gianluca Bianchini, Marjorie Wilson
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In the Mediterranean area, four major lamproitic provinces with uniform geological, geochemical, and petrographic characteristics are recognized: Spain, Italy, Balkans, and Turkey. Mediterranean lamproites are SiO2-rich lamproites, characterized low CaO, Al2O3, and Na2O, and high K2O/Al2O3 and Mg-number. They are enriched by in large ion lithophile elements relative to high field strength elements and in Pb, and show depletion in Ti, Nb, and Ta. The Mediterranean lamproites are characterized by a wide range of 87Sr/86 and 143Nd/144Sri Ndi. Both intra- and interprovince variations are significant. In contrast, the Pb isotope compositions of all Mediterranean lamproite provinces are almost identical, falling within the pelagic sediment field and resembling local upper-crustal sediments and Mesozoic flysch sediments from the Tethyan Ocean.
Using the Serbian lamproites as an example, we develop constraints on the mantle melting processes and geodynamic environment of the whole Mediterranean lamproitic province. Partial melting of refractory mantle material previously enriched in incompatible elements is considered to be the most likely explanation for Mediterranean lamproites. The depleted-mantle component is probably multiply depleted peridotite from above the subducting plate during Mesozoic subduction processes, which preceded collision and orogenesis. The considerable variations of Sr-Nd isotopes are explained as having been produced by vein + wall-rock melting involving metasomatic veins that were out of isotopic equilibrium with the peridotite wall rock during melting. The uniformity of the Pb isotope compositions of all Mediterranean provinces is a result of the presence of a common crustal isotopic end member in their mantle source similar to flysch sediments from the Vardar Tethyan Ocean.
No generic geodynamic scenario can explain lamproites, but neither mantle plume nor subduction is essential for the initiation of the volcanism. Most of the evidence implies postcollisional tectonics, including delamination of lithospheric mantle and/or orogenic collapse, as the major causes for the volcanism.
- alkaline earth metals
- Asia
- Balkan Mountains
- Cenozoic
- chemical composition
- delamination
- Europe
- genesis
- geochemistry
- geodynamics
- Iberian Peninsula
- igneous rocks
- isotope ratios
- isotopes
- Italy
- lamproite
- lead
- lithophile elements
- major elements
- Mediterranean region
- metals
- Middle East
- Nd-144/Nd-143
- neodymium
- partial melting
- Pb-206/Pb-204
- Pb-207/Pb-204
- Pb-208/Pb-204
- plate collision
- plate tectonics
- plutonic rocks
- radioactive isotopes
- rare earths
- Serbia
- Southern Europe
- Spain
- Sr-87/Sr-86
- stable isotopes
- strontium
- subduction
- Tertiary
- Tethys
- trace elements
- Turkey
- ultrapotassic composition
- Vardar Zone
- variations
- volcanism