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The south cliff face of the Monte Testo in the Pasubio massif shows a prominent negative flower structure of early Jurassic age, when the Southern Alps experienced an extensional tectonics related to the development of the Adriatic passive margin of the Ligurian ocean. This structure is due to an oblique movement along a NNW-trending fault set experiencing transtension. In the lower part of the slope the Dolomia principale Fm (upper Triassic) crops out. The Dolomia principale is overlain by the well-stratified M. Zugna Fm (Hettangian-Sinemurian) and the Loppio oolitic lms (upper Sinemurian), which corresponds to the white layer poorly stratified. Since this layer is offset by (oblique-) normal faults and the subsequent marly Rotzo Fm (Pliensbachian) shows sharp thickness variations, the tectonic activity responsible for the M. Testo structure can be constrained to be Pliensbachian. In the upper part of the slope the Rotzo Fm shows an increase of the biohermal “Lithiotis” mounds (white layers). PhotoID819

The south cliff face of the Monte Testo in the Pasubio massif shows a prominent negative flower structure of early Jurassic age, when the Southern Alps experienced an extensional tectonics related to the development of the Adriatic passive margin of the Ligurian ocean. This structure is due to an oblique movement along a NNW-trending fault set experiencing transtension. In the lower part of the slope the Dolomia principale Fm (upper Triassic) crops out. The Dolomia principale is overlain by the well-stratified M. Zugna Fm (Hettangian-Sinemurian) and the Loppio oolitic lms (upper Sinemurian), which corresponds to the white layer poorly stratified. Since this layer is offset by (oblique-) normal faults and the subsequent marly Rotzo Fm (Pliensbachian) shows sharp thickness variations, the tectonic activity responsible for the M. Testo structure can be constrained to be Pliensbachian. In the upper part of the slope the Rotzo Fm shows an increase of the biohermal “Lithiotis” mounds (white layers). PhotoID819

Photograph: Dario Zampieri

Reference: Tobaldo M., Zandonai F., Avanzini M., Miorandi R., Zampieri D., 2004. Note illustrative della carta geologica del settore nord occidentale del Monte Pasubio (Trentino, Italia). Studi Trentini di Scienze Naturali – Acta Geologica, v. 79 (2002), 161-180. Zampieri D., Massironi M., 2007. Evolution of a poly-deformed relay zone between fault segments in the eastern Southern Alps, Italy. In: Cunningham D. & Mann P. (eds), Tectonics of Strike-slip Restraining and Releasing Bends, Geol. Soc., London, Special Publication 290, 351-366. Martinelli, M., Franceschi, M., Massironi, M., Rizzi, A., Salvetti, G., Zampieri, D., 2017.An extensional syn-sedimentary structure in the Early Jurassic Trento Platform (Southern Alps, Italy) as analogue of potential hydrocarbon reservoirs developing in rifting-affected carbonate platforms. Marine and Petroleum Geology, 79, 360-371.