کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
6433762 1636754 2014 13 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Mantle-derived CO2 migration along active faults within an extensional basin margin (Fiumicino, Rome, Italy)
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات فرآیندهای سطح زمین
پیش نمایش صفحه اول مقاله
Mantle-derived CO2 migration along active faults within an extensional basin margin (Fiumicino, Rome, Italy)
چکیده انگلیسی


- We performed detailed soil gas and gas flux surveys in the Fiumicino area.
- We acquired a seismic reflection profiles in the same area, along the Tevere River.
- We interpreted the seismic data and analyzed the soil gas samples.
- We detected significant CO2 leakage along the faults mapped in the seismic profiles.

Fluid migration along faults can be highly complex and spatially variable, with the potential for channeled flow, accumulation in capped porous units, fault cross-flow, lateral migration along strike, or complete sealing. Extensional basin margins can be important for such migration, given the associated crustal thinning and decompression that takes place combined with potential geothermal or mantle gas sources. One such example is near the urban area of Rome, situated along the active extensional continental margin of the Tyrrhenian back arc basin and surrounded by Middle-Upper Pleistocene K-rich and arc-related volcanoes. Recent research activities in the area around Fiumicino, a town 25 km to the west of Rome, has highlighted the close spatial link between degassing CO2 and the faults that provide the necessary vertical migration pathways. In particular, detailed soil gas and gas flux surveys have highlighted the release at surface of large volumes of asthenospheric mantle CO2 in correspondence with normal faults observed in a new seismic reflection profile acquired along the Tiber River. Detailed reconstruction of the Pleistocene-Holocene stratigraphy of the area dates fault activity from 20,000 to 9000 years BP. It is proposed that the gas migrates preferentially along the cataclastic tectonic breccias of the faults until it encounters recent, unconsolidated sediments; porous units within this shallow stratigraphy act as temporary secondary traps for the leaking gas, with local gas release at the ground surface occurring where the sealing of the overlying aquitards has been compromised. Degassing and active faults confirm the extensional tectonics affecting the area and the geodynamic scenario of a mantle wedge beneath the western Apennines, associated with ongoing W-directed subduction. Moreover, degassing highlights the potential geochemical and seismic risks for the highly populated urban areas near Rome.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Tectonophysics - Volume 637, 10 December 2014, Pages 137-149
نویسندگان
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