Giant paleo-seafloor craters and mass wasting associated with magma-induced uplift of the upper crust

Giant seafloor craters are known along many a continental margin with recurrent mass-wasting deposits. However, the impact of breakup-related magmatism on the evolution of such craters is barely understood. Using high-quality geophysical datasets, this work examines the genetic relationship among the location of magmatic sills, forced folds and the formation of giant paleo-seafloor craters underneath an ancient mass-transport complex in the Møre and Vøring basins, offshore Norway. The data reveal that forced folding of near-seafloor strata occurred because of the intrusion of several interconnected magmatic sills. Estimates of 1-dimensional uplift based on well data show that uplift occurred due to the intrusion of magma in Upper Cretaceous to Lower Eocene strata. Our findings also prove that subsurface fluid plumbing associated with the magmatic sills was prolonged in time and led to the development of several vertical fluid flow conduits, some of which triggered mass wasting in Neogene to Recent times. The repeated vertical expulsion of subsurface fluids weakened the strata on the continental slope, thereby promoting mass wasting, the selective cannibalization of the paleo-seafloor, and the formation of elongated craters at the basal shear zone of the mass-transport complex. Significantly, the model presented here proves a close link between subsurface magmatic plumbing systems and mass wasting on continental margins.</p

Tectonic evolution of strike-slip zones on continental margins and their impact on the development of submarine landslides (Storegga Slide, northeast Atlantic)

Submarine landslides have affected the mid-Norwegian margin since the Last Glacial Maximum. However, the role of tectonic movements, and most especially fault reactivation, in generating landslides offshore Norway is largely unconstrained. This study uses high-quality three-dimensional seismic and borehole data to understand how landslide development is controlled by faults propagating within the uplifted south Modgunn arch. Variance and structural maps above the south Modgunn arch show that: (1) local scarps of recurrent landslides were formed close to the largest faults, and mainly above strike-slip faults; (2) distinct periods of fault generation were associated with tectonic events, such as the breakup of the northeast Atlantic Ocean, and those events forming the south Modgunn arch; and (3) important fluid-flow features coincide with faults and sill intrusions. In total, 177 faults were analyzed to demonstrate that fault throw values vary from 10 ms to 115 ms two-way traveltime (8 m to 92 m). We propose that the long-term activity of faults in the study area has contributed to fluid migration, weakened post-breakup strata, and controlled the development of submarine slope instability. In particular, strike-slip faults coincide with the locations of several Quaternary landslide scars near the modern seafloor. Similar processes to those documented in Norway may explain the onset of large-scale landslides on other continental margins

Quantitative datasets reveal marked gender disparities in Earth Sciences faculty rank in Africa

As in most disciplines of science, technology, engineering, mathematics and medicine (STEMM), gender disparity is prevalent in the ranking of Earth Sciences faculties at senior and advanced levels. (i.e., Associate and Full Professors). In this study, a robust database was mined, created, and analyzed to assess the faculty compositions of 142 Earth Science departments in 39 countries across Africa. The data were collected from verifiable online resources focusing on ranks and gender ratios within each department. The studied earth science departments cut across universities in northern, southern, central, eastern, and western Africa. Our data revealed that female faculty members are predominantly underrepresented in most of the departments documented and are markedly uncommon in senior positions such as Professors, associate Professors, and senior researchers compared to their male counterparts. On the contrary, female faculty members are predominant in the lower cadres, such as lecturers, teaching, and graduate assistants. The observed male to female ratio is 4:1. At the base of this gender gap is the lower enrolment of female students in Earth Science courses from undergraudate to graduate studies. To achieve gender equality in Earth Science faculty composition in Africa, we recommend increasing female students’ enrollment, mentoring, awareness, timely promotion of accomplished female researchers, and formulation of enabling government policies. More work-related policies that guarantee work-life balance for female earth science academic professionals should be formulated to attract and retain more women into Earth Sciences careers