Please use this identifier to cite or link to this item: http://hdl.handle.net/2122/5732
AuthorsItaliano, F.* 
Martelli, M.* 
Martinelli, G.* 
Nuccio, P. M.* 
TitleGeochemical Evidence of Melt Intrusions Along Lithospheric Faults of the Southern Apennines (Italy): Geodynamic and Seismogenic Implications
Issue Date10-Jun-2000
Series/Report no.105, B6, 2000
URIhttp://hdl.handle.net/2122/5732
Keywordsmelt intrusions
gas geochemistry
tectonic structures
seismicity
Subject Classification04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry 
AbstractSeveral gas emissions, distributed along 200 km of the Southern Apennine axial zone, have been investigated. This portion of the sedimentary chain, which constitutes the accretionary prism of the westward subduction of the Adriatic plate, is subjected to a tensile stress field responsible of high-magnitude earthquakes. The studied emissions are generally CO2-dominated, have 3He/4He ratios in the range of 0.09-2.84 Ra, and display both 3He and 4He outputs in the range of those reported for the Italian active volcanoes Phlegrean Fields and Vulcano. The helium isotope ratios, together with the amount of released gas, indicate that a huge amount of mantle-derived helium is released over all the investigated area. Our geochemical data and the geophysical peculiarities of the region, such as the high heat flow and the low resistivity of rocks below a depth of 15 km, coherently indicate the presence of melt intruded into the crust along lithospheric faults. Magma intrusions along the axial part of the Southern Apennine sedimentary chain are certainly unusual, since volcanism in Central and Southern Italy is concentrated along the perityrrhenian margin of the peninsula. We suggest that melt is promoted by adiabatic uprise of the asthenosphere in the mantle wedge beneath the Apennines and it is subsequently intruded along tensile lithospheric faults, strongly affecting the thermal state of the lower crust. An inter-relation between the geodynamics, the melt intrusions and the genesis of the large earthquakes (up to M = 7.1) in the region is suggested.
Appears in Collections:Papers Published / Papers in press

Files in This Item:
File Description SizeFormat 
JGR_south-Appennines-2000.pdfmain article10.03 MBAdobe PDFView/Open    Request a copy
Show full item record

Page view(s)

124
checked on Apr 30, 2017

Download(s)

31
checked on Apr 30, 2017

Google ScholarTM

Check