Abstract Damage zones of different fault types are investigated in siliciclastics (Utah, USA), carbonates (Majella Mountain, Italy) and metamorphic rocks (western Norway). The study was conducted taking measurements of deformation features such as fractures and deformation bands on multiple 1D scanlines along fault walls. The resulting datasets are used to plot the frequency distribution of deformation features and to constrain the geometrical width of the damage zone for the studied faults. The damage-zone width of a single fault is constrained by identifying the changes in the slope of cumulative plots made on the frequency data. The cumulative plot further shows high deformation frequency by a steep slope (inner damage zone) and less deformation as a gentle slope (outer damage zone). Statistical distributions of displacement and damage-zone width and their relationship are improved, and show two-slope power-law distributions with a break point at c. 100 m displacement. Bleached sandstones in the studied siliciclastic rocks of Utah are associated with a higher frequency of deformation bands and a wider damage zone compared to the unbleached zone of similar lithology. Fault damage zones in the carbonate rocks of Majella are often host to open fractures (karst), demonstrating that they can also be conductive to fluid flow.

Abstract The Timor Orogen comprises the island of Timor, a narrow offshore area to the north and a wider offshore fold-and-thrust belt to the south. This orogen formed by jamming and subsequent collision of the Banda Sea subduction system by the Australian Plate. The BandaSeis seismic survey has revealed excellent images of the deep-water fold-and-thrust belt. Seismic interpretation of the dataset demonstrated structural and tectonic features not previously described, including regional geological features on the Australian continental crust and two regional NE–SW sinistral strike-slip faults, and a prominent Middle Permian palaeogeographical high (Timor Plateau). Moreover, since the Middle–Late Triassic and Middle Jurassic, the two NE-trending strike-slip faults governed the formation of the West Timor and Cova-Lima sub-basins. The location along the Australian margin plays a dominant role in controlling the structural style and shaping of the Timor Orogen. Vertical loading and the southerly motion of the orogenic wedge are the main driving forces responsible for its building, illustrating a thin-skinned tectonic framework. Thrust faults nucleate in a forward-breaking sequence in the motion of thrust transport, with younger thrusts developing in front of older thrusts. Most of the collisional deformation has been classified into two styles: shallow thin-skinned and deep-seated deformation.

ABSTRACT This study provides a composite record of 87 Sr/ 86 Sr, δ 18 O, and δ 13 C for three sections in the Tethyan Lower Cretaceous Maiolica formation, a pelagic limestone from the Umbria-Marche Apennines of Italy, carefully tied to a magnetostratigraphically and biostratigraphically calibrated time scale. Although the 87 Sr/ 86 Sr record accurately follows the trend of the global marine 87 Sr/ 86 Sr reference curve, individual Sr isotope ratio values are relatively high for their inferred stratigraphic position, with all 87 Sr/ 86 Sr ratios yielding a fairly uniform +0.00007 to +0.0001 discrepancy. This offset likely results from incorporation of excess 87 Sr through isotopic reequilibration with interstitial pore waters during progressive lithification of the calcareous ooze. Although the process occurs principally through dissolution-reprecipitation, buffering the contemporaneous seawater Sr isotopic signature, diffusive communication with the overlying water column and porous sediments will compete with the dissolution-precipitation process, homogenizing pore-fluid concentrations and isotope ratios throughout the sediment column. Because the secular trend in 87 Sr/ 86 Sr throughout the Maiolica time frame is one of constant increase before rebounding to lower 87 Sr/ 86 Sr ratios in the Barremian, the ratios of the Maiolica carbonates are systematically displaced from that of the seawater in which they were deposited toward more radiogenic (higher 87 Sr/ 86 Sr) values. In addition, the carbon and oxygen isotope record of the Maiolica limestone allows identification of the mid-Valanginian Weissert event, characterized by a positive excursion in the δ 13 C and the δ 18 O records. Furthermore, the Weissert event correlates with a positive spike (+0.0001) in 87 Sr/ 86 Sr. Both the Sr and O isotopic peak signals predate the maximum peak in the δ 13 C excursion. This is likely a diagenetic artifact and may support the hypothesis of diffusive communication during lithification of the calcareous ooze.