M. Pieri, 1983. "Three Seismic Profiles Through the Po Plain", Seismic Expression of Structural Styles: A Picture and Work Atlas. Volume 1–The Layered Earth, Volume 2–Tectonics Of Extensional Provinces, & Volume 3–Tectonics Of Compressional Provinces, A. W. Bally
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The alluvial Po Plain extends over about 5,000 sq km (1,931 sq mi) in Northern Italy, between the Southern Alpine and the Northern Appenninic borders. Its subsurface structure has been revealed by the petroleum exploration carried out since 1940 by Agip (the Italian State Oil Company) with extensive and detailed seismic reflection surveys, and the drilling of more than 700 exploratory wells.
The known sedimentary sequence consists of a Mesozoic carbonate section overlain by Tertiary and Quaternary clastics, with a total thickness that exceeds 12 km (7.5 mi) in the structurally lowest areas.
In the southern part of the Po Plain, the subsurface structures correspond to the external elements of the Northern Apennines thrusted and folded belt. From west to east, three main folded arcs can be identified: the Monferrato arc (partly outcropping in the western Po Plain and bordered to the South by the South-Piedmont episutural basin), the Emilia arc, and the Ferrara-Romagna arc.North of the folded arc the foreland area includes the Pedealpine Homocline and the Veneto Plain. These are two structural units separated by the Berici-Euganei Hills axis, which corresponds to a transcurrent fault system accompanied by Tertiary volcanic centers.
The subsurface structure of the Po Plain is the result of late Miocene, Pliocene, and Quaternary tectonics associated with the subduction and/or the shortening of basement and involving the compression of the sequence deposited on the northern part of the Apulo-Adriatic block (a sunken continental margin of the Mesozoic Tethys). The southwestern border of the Alps, folded in late Miocene is relatively unaffected by later tectonic phases. Therefore, the southern external alpine folds are buried under the foredeep sediments of the Pedealpine Homocline. The less competent Tertiary clastic section, where shaly layers are common, is frequently detached from the lower carbonate sequence, and disharmonic folding results.