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The article discusses the late Miocene to early Pleistocene sedimentary rocks in the Fish Creek-Vallecito basin in southern California that records late Cenozoic subsidence and basin filling due to deformation in the San Andreas fault system. Data reportedly show that the section ranges in age from circa 8.0-0.4 million years (Ma). The article states that the onset of sedimentation at circa 8.0-0.4 million years (Ma) preserves the earliest extension or transtension in the area.

The article presents a study on the interactions of tectonic deformation, climate, eustasy and isostasy on forearc basin sedimentation in the Pleistocene sedimentary record of Hawke Bay, New Zealand. Eleven depositional sequences that developed during the last 1.1 million years are reportedly preserved into four controlled basins. The article states that the major uncorformity S5 separates megasequences M1 and M2 and that an overall retrogradational pattern of sequences were identified.

Far-field compressional stresses resulting from arc collisions with the northeast coast of Africa-Arabia propagated across the African plate in the Santonian (ca. 84 Ma), and later similar pulses occurred through much of the Cenozoic. Waves of inversion-related features including folds, thrusts, and igneous activity developed during the compressional events. Structures generated were uneven in intensity and distribution, and were commonly concentrated in existing rifts. Because of the irregular shapes of the North African continental margin and associated inboard basins, Cyrenaica underwent the most severe shortening, although deformation extended eastward from Libya to the Levant. Areas south and southeast of Cyrenaica (the Sirt Basin and the far Western Desert of Egypt) underwent very little shortening because they occupied a regional strain shadow. The eastern region of the Western Desert and Sinai, which were not sheltered by the stress-absorbing Cyrenaica inversion, recorded strong compressional deformation synchronous with that in Cyrenaica. As closure of the Mediterranean continues, Cyrenaica will become an indenter comparable to those of other orogenic belts. The detailed tectonic evolution of individual northeast African basins has depended on their positions in relation to the Cyrenaican strain shadow. No single subsidence and paleostress history reflects the complete regional development of the converging Mediterranean-North African margin. [ABSTRACT FROM AUTHOR]

Recently collected multibeam bathymetry and hydroacoustic earthquake data are used to investigate the recent tectonics of the Explorer-Juan de Fuca Ridge systems, the boundaries between the Pacific and northern Juan de Fuca plates. The bathymetric and seismic evidence presented is consistent with a zone of shear extending well south of the Sovanco Fracture Zone to include the Heck and Heckle seamounts, and potentially as far south as the Springfield Seamounts and Cobb offset along the Juan de Fuca Ridge. This indicates that the triple junction between the Pacific-Juan de Fuca-North American plates may be reorganizing southward to establish at the Cobb offset. [ABSTRACT FROM AUTHOR]

Our results from seismic anisotropy analyses reveal for the first time the complex spatial variability of the characteristics of subsurface tectonic structures associated with ridge propagation. The significance lies in the fact that these variations are found at a locality with few lineaments or fissures at seafloor level. The over- lap region between mid-ocean ridge segments at 9°N on the East Pacific Rise is characterized by aligned cracks that are structurally more closely related to the propagating-ridge segment. These aligned cracks, which are approximately parallel to the ridge segments, provide conclusive observational evidence for establishing the nontransform nature of overlapping spreading centers, especially those with overlap basins covered by volcanic edifices. The aligned cracks of the 9°03′N overlapping spreading center are more similar to the ridge-parallel lineaments observed between overlapping axial-summit collapse troughs than those found at larger overlapping spreading centers. Our results therefore suggest that the lithospheric deformation between overlapping ridge segments depends on ridge offset and that this dependency may be thermally related. [ABSTRACT FROM AUTHOR]