Abstract The submerged sill in the Strait of Messina, which is located today at a minimum depth of 81 m below sea level (bsl), represents the only land connection between Sicily and mainland Italy (and thus Europe) during the last lowstand when the sea level locally stood at about 126 m bsl. Today, the sea crossing to Sicily, although it is less than 4 km at the narrowest point, faces hazardous sea conditions, made famous by the myth of Scylla and Charybdis. Through a multidisciplinary research project, we document the timing and mode of emergence of this land connection during the last 40 kyr. The integrated analysis takes into consideration morphobathymetric and lithological data, and relative sea-level change (both isostatic and tectonic), resulting in the hypothesis that a continental land bridge lasted for at least 500 years between 21.5 and 20 cal ka BP. The emergence may have occurred over an even longer time span if one allows for seafloor erosion by marine currents that have lowered the seabed since the Last Glacial Maximum (LGM). Modelling of palaeotidal velocities shows that sea crossings when sea level was lower than present would have faced even stronger and more hazardous sea currents than today, supporting the hypothesis that earliest human entry into Sicily most probably took place on foot during the period when the sill emerged as dry land. This hypothesis is compared with an analysis of Pleistocene vertebrate faunas in Sicily and mainland Italy, including a new radiocarbon date on bone collagen of an Equus hydruntinus specimen from Grotta di San Teodoro (23–21 cal ka BP), the dispersal abilities of the various animal species involved, particularly their swimming abilities, and the Palaeolithic archaeological record, all of which support the hypothesis of a relatively late land-based colonization of Sicily by Homo sapiens .

Abstract Craters cross-cut by faults are used as markers to obtain fault geometric and kinematic properties. Assuming that the shape of these craters was originally circular, it is possible to measure the horizontal and vertical components of fault displacement as well as the slip trend. By applying trigonometric relations, slip plunge, displacement magnitude, fault true dip and fault rake can be derived from the observed values. An example application of this method on craters faulted by lobate scarps on Mercury shows that most of these inferred reverse faults have moderate oblique-slip trends. Moreover, the derived dips of thrusts vary over a wide range of angles. Some preliminary results in terms of fault rake compared with fault dip, strike and latitude are presented together with a pilot study to test and discriminate global tectonic models suggested for the evolution of Mercury. The possibility of estimating quantitative fault parameters through remotely sensed data provides significant assistance in the structural characterization of faults on planetary surfaces.

Integrated mapping, fault-kinematic, paleomagnetic, and gravity analyses around the Rhodes Salt Marsh extensional basin, located within the east-west–trending Mina deflection of the central Walker Lane, reveal that from 8.0 to 9.0 km of late Cenozoic displacement was accommodated on a curved array of faults. The dominant slip on the faults systematically varies from left-oblique, to normal, and to right-oblique as fault strike changes from east, to north-northeast, and to north-northwest, respectively. Kinematic consistency of fault slickenline rakes, preservation of displacement budget, and paleomagnetic data from a pluton and volcanic rocks in the fault-system hanging wall indicate that the curved fault geometry is primary and not due to superposition of two fault systems nor to later vertical-axis rotation. Large-magnitude extension was localized at the apex of the curved faults and resulted in the formation of an ~3.0-km-deep prismatic basin beneath Rhodes Salt Marsh. The offset geologic structures and geophysical basin models indicate that hanging-wall displacement diverged around the curved fault array and resulted in finite flattening, with primary and secondary extensional axes oriented west-northwest and north-northeast, respectively. Fault-slip inversion yields two directions of extension consistent with the finite strain axes, and slickenlines with mutually crosscutting relations indicate formation during incremental flattening. Although broadly contemporaneous, extension parallel to the primary and secondary extension axes alternated at periods ranging from months to as much as several hundred thousand years. Large through-going structures sustained extension directions recorded geodetically and seismologically through multiple seismic cycles. In contrast, the alternation between primary and secondary extension directions recorded by a strainmeter suggests that, on small structures contained within fault-bounded blocks, the two extension directions alternated over time scales of as little as 2 yr.

The late Miocene to Pliocene Silver Peak–Lone Mountain extensional complex in the western Great Basin is part of a structural stepover that links dextral transcurrent motion between the Furnace Creek fault system and northwest-striking transcurrent faults in the central Walker Lane. In the Silver Peak Range, the extensional complex is exposed as a west-northwest–trending turtleback structure that consists of a folded detachment fault separating a metamorphic lower-plate assemblage from unmetamorphosed upper-plate rocks. The upper plate preserves structurally attenuated lower Paleozoic carbonate and clastic rocks, upper Oligocene to lower Miocene volcanic rocks, and a synextensional mid-Miocene to Pliocene clastic and volcanic succession. The three-dimensional geometry of fault-bounded extensional basins formed during displacement on the detachment is preserved, and the synextensional units comprise five sequences separated by unconformities. The locus of deposition migrated spatially as dimensions of small basins changed through time. The entire extensional complex is deformed in two generations of late Cenozoic folds. North-northeast–trending folds formed first with axial traces oriented at a high-angle to upper-plate extension, and these are preferentially developed in proximity to thrusts and partially inverted extensional faults. Younger, west-northwest–trending folds parallel the axis of the turtleback structure and involve all lithologic units, several syndepositional high-angle faults, and the basal detachment. Pliocene growth of west-northwest–trending folds marked the end of slip on the exposed parts of the basal décollement and the cessation of deposition in the fault-bounded basins. Today, upper and lower plates of the extensional complex are dissected by north- to northeast-striking normal faults that cut alluvium and cross-cut and locally reactivate earlier Cenozoic structures.