The walls and floors of the Minoan settlement of Gournia (Crete) have retained a perpendicular relationship since their construction between 3650 and 2025 BC. Their present orientation indicates that they were tilted in unison in an east‐south‐east direction. This was established by the reconstruction of a representative block, of which the side planes and the base plane were defined by the present orientation of the wall and floor remnants respectively. Stereographic projection methods, derived from geological practice, were used to determine the geometric elements and the orientation of the representative block.
The Bracco ophiolite complex, exposed in the area studied as the Bracco Subunit of the Melange Nappe, is tectonically intercalated between the underlying Canetolo Nappe and the overlying Lavagna Nappe. Detailed structural analysis and mapping in these units reveals a multi-phase deformation history. In the Bracco Subunit and the Lavagna Nappe, this history is characterized by a change, from SW (i.e. ‘Alpine’) directed folding of the ophiolitic basement and its sedimentary cover, to NE (i.e. ‘Apennine’) directed folds and thrusts. The Canetolo Nappe only shows Apennine vergent structures. The Alpine vergent structures are considered to be developed during the Late Cretaceous to Palaeocene in an accretionary wedge associated with an east-dipping subduction zone. The first Apennine directed structures are low-angle extensional faults and cascading folds, indicating that the change to Apennine polarity resulted from gravitational collapse of the accretionary wedge during the Palaeocene to Eocene. Gravitational instability is considered to have resulted from a drastic decrease of subduction rate during the Palaeocene, which has led to extension and uplift of the wedge. The rapid decompression under isothermal to slightly decreasing temperature conditions of the high-pressure terrains in the Voltri Massif concurs well with this tectonic scenario.
Detailed structural, stratigraphical and sedimentological data show that sedimentation in the Late Miocene 'fore-arc' basins of eastern Crete was controlled by two stages of compression separated by a stage of extension. The compressional stages culminated around the Middle/Upper Miocene boundary and around the Miocene/Pliocene boundary, respectively. The 3rd-order sedimentary cycles in the basin fills appear to be in phase with major tectonic events resulting from plate tectonic processes in the Mediterranean region. Apart from an extra, 3rd-order sedimentary sequence in the Ierapetra Basin spanning the Early Tortonian, all other sedimentary sequences identified from the east Cretan basin fills are grossly correlatable with those found in other basins around the Mediterranean and with the global 3rd-order cycles. During the culmination of compression at the Middle/Upper Miocene boundary, sediment transport and basin-fill patterns were directly controlled by folding and reverse faulting due to steepening of the drainage basin relief. The relief-steepening increased the slope's instability and caused rapid infill of available accommodation space with numerous landslides, mass-flow deposits, and fault-scarp derived breccias deposited in rapidly prograding alluvial-fan and fan-delta environments. During the following extensional stage in Tortonian times, slope instability features are rare. Their absence is related to a reduction of the drainage basin relief due to progressive northwards rotation of fault-blocks. The resultant half-graben fills are strongly tabular, with alternating intervals of fine- and coarse-grained clastic sediments indicating alternating periods of deepening and progradation (parasequences). The texture of the half-graben sediments is more mature and grains are better rounded compared with the clastic sediments deposited during the peak of the previous compression. During the compressional stage at the end of the Miocene, sedimentation is controlled again by progressive steepening of the basin relief. This is shown by basin-subsidence analysis and structural data, and is recorded in the basin fill by numerous synsedimentary subaqueous slide and mass-flow deposits. In contrast with the former compressional stage, the supply of terrigenous material is very limited, which may be related to an increasingly dry climate in Messinian times.
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