9. Alteration of Uppermost Lavas and Volcaniclastics Recovered During Leg 152 to the East Greenland Margin

During the last stages of the eruption of syn-rift basalts along the East Greenland Margin, debris flows and/or pyroclastic deposits were emplaced at Ocean Drilling Program Sites 915 and 916. The deposits and the tops of the lava flows at Site 918 were altered by subaerial weathering processes as indicated by downhole changes in mineral and chemical composition, and by the mineral paragenesis. Kaolinite and goethite, which form in acidic waters, are abundant at the tops of the weathering profiles and decrease in abundance downward. They are replaced by a smectite-hematite-opal assemblage at the bases of the weathered profiles. Gibbsite is a minor component in the upper parts of the profiles. Good preservation of parent structure and stratification indicate that only the bases of paleosols are preserved at all sites. The upper parts were probably eroded when these sites subsided below sea level. Abundant gibbsite in marine sediment overlying the paleosols and of middle to late Eocene age is probably derived from the erosion of highly weathered soils formed in a subtropical to tropical climate. A highly weathered basaltic terrane supplied abundant iron oxides in addition to gibbsite, kaolinite, illite/mica, and quartz through fluvially dominated deltaic systems on the shelf through at least the late Eocene. Only small amounts of sediment spilled over into the adjacent Irminger Basin through the Eocene, as indicated by the presence of felsic terrane-derived minerals (quartz, illite, and/or mica). Sedimentation rates were low enough in the Irminger Basin to allow Mn oxide crusts to develop until quartzose turbidites spilled over in the late Oligocene. Gibbsite was not detected in sediment of early Oligocene age and younger, suggesting a regional cooling, increased aridity, and/or leveling of the source area at this time

9. Alteration of Uppermost Lavas and Volcaniclastics Recovered During Leg 152 to the East Greenland Margin

During the last stages of the eruption of syn-rift basalts along the East Greenland Margin, debris flows and/or pyroclastic deposits were emplaced at Ocean Drilling Program Sites 915 and 916. The deposits and the tops of the lava flows at Site 918 were altered by subaerial weathering processes as indicated by downhole changes in mineral and chemical composition, and by the mineral paragenesis. Kaolinite and goethite, which form in acidic waters, are abundant at the tops of the weathering profiles and decrease in abundance downward. They are replaced by a smectite-hematite-opal assemblage at the bases of the weathered profiles. Gibbsite is a minor component in the upper parts of the profiles. Good preservation of parent structure and stratification indicate that only the bases of paleosols are preserved at all sites. The upper parts were probably eroded when these sites subsided below sea level. Abundant gibbsite in marine sediment overlying the paleosols and of middle to late Eocene age is probably derived from the erosion of highly weathered soils formed in a subtropical to tropical climate. A highly weathered basaltic terrane supplied abundant iron oxides in addition to gibbsite, kaolinite, illite/mica, and quartz through fluvially dominated deltaic systems on the shelf through at least the late Eocene. Only small amounts of sediment spilled over into the adjacent Irminger Basin through the Eocene, as indicated by the presence of felsic terrane-derived minerals (quartz, illite, and/or mica). Sedimentation rates were low enough in the Irminger Basin to allow Mn oxide crusts to develop until quartzose turbidites spilled over in the late Oligocene. Gibbsite was not detected in sediment of early Oligocene age and younger, suggesting a regional cooling, increased aridity, and/or leveling of the source area at this time

Initial Transgressive Phase of Leg 144 Guyots: Evidence of Extreme Sulfate Reduction

The initial transgressive phase at the Leg 144 Guyots is characterized by a typical association of sedimentary facies (from bottom to top): in situ weathered volcanic rocks; variegated clays, partly pyritic; gray clay, pyritic, homogeneous, or mottled; black clay, peaty, laminated, or bioturbated; and marine argillaceous limestone. Site 877 at Wodejebato Guyot represents the typical development of the initial transgressive phase. The black clay is rich in organic carbon (up to 40%) and sulfur (up to 25%). The organic matter is dominantly of terrestrial origin, but it has a significant marine, algal input. The variegated clays consist of a red, lower, sulfur-free part and a blue to gray-blue, sulfur-containing upper part. Organic carbon is not observed in this facies. The sulfur occurs as pyrite and organically bound sulfur. The isotope composition of pyrite varies from -50‰ to 0%e, which clearly points to bacterial sulfate reduction as the origin for the high sulfur content. Pyrite formation was limited by availability of reactive iron. Because of the origin of the clays as lateritic weathering products, the amount of reactive iron was high, and pyritization proceeded to high values. The following model is suggested for sulfur enrichment in the sediments at the initial transgressive phase: (1) marine flooding of an organic-rich back-reef mangroval swamp; (2) intense bacterial reduction of marine sulfate within the black clay; and (3) downward diffusion of H2S into the underlying clays, reduction of red iron oxides to blue-gray iron sulfides, and growth of pyrite

Diversity and equality in honours and awards programs – steps towards a fair representation of membership

Honours and awards bestowed by professional societies recognize and reward members who have advanced the goals and values of that society. All too often, however, awards reflect a small network of people who know about the awards and participate in the process. This network works wonderfully for the people lucky enough to be in it, but typically neglects the full range and breadth of scholarship and service within the society. We represent a combined 15C years’ experience on the honours’ committee for a large professional society (the American Geophysical Union) and here offer strategies to increase the representation of honourees.Women represented less than 20%of awardees when we first became committee members in 2008; women represented 50% of awardees in 2019. There is still much to do to ensure that members from other typically underrepresented groups (non-US members, members from underrepresented races/ethnicities) are truly represented and honoured for outstanding science and service. We recommend forming canvassing committees that will scour the literature, conferences, and membership lists for appropriate and otherwise overlooked nominees; providing implicit bias training to selection committees; and ensuring selection committees focus on the criteria for the award rather than non-pertinent, often personal, information, as well as additional strategies that allow us to recognize our worthy colleagues

Paleocene Cyclic Sedimentation in the Western North Atlantic, ODP Site 1051, Blake Nose

Upper Paleocene (zone CP8b) cyclic sediment from Ocean Drilling Program (ODP) Site 1051 on Blake Nose, western North Atlantic, alternates from white carbonate-rich to green carbonate-poor in response to precessional forcing. Compositional differences between the two bed types are minor: mineral and nannofossil composition of the beds vary subtly, but grain size of the terrigenous component and biogenic silica content remain constant. Iron content determined by sediment magnetic susceptibility and iron intensity determined by a core-scanning XRF correlates negatively with carbonate content and are higher in green beds. Kaolinite content of green beds is slightly higher as well. Green beds exhibit lower evenness values than white beds for nannofossil assemblages and are more dominated by the species Coccolithus. Dominance by Coccolithus indicates more mesotrophic conditions over Blake Nose during deposition of the green beds, which correlates with slightly higher iron and kaolinite contents. The absence of change in terrigenous grain size and the absence of any indication of planktonic blooms indicate that there was a minor, most likely eolian, input of iron and kaolinite during deposition of the green beds. The source area was most likely northwest Africa, which supplied iron and kaolinite when source areas deflated under drier conditions. With this scenario, kaolinite is an indicator of drier climate and source area erosion, rather than the warmer and/or wetter conditions under which it forms in soils. During precessional minima or perihelion summer (the opposite of our current configuration), there was an increased range of seasonal temperatures and an increase in the intensity of summer and winter monsoon circulation. As a consequence, there was more rainfall in northern Africa and drier conditions in the continental interiors at mid-latitudes. Green bed deposition occurred during precessional maxima when the North Atlantic was cooler, northwest Africa drier, and the eolian flux to the western North Atlantic slightly increased

Academic Specialties in U.S. Are Shifting; Hiring of Women Geoscientists Is Stagnating

Women have been receiving a greater proportion of the bachelor’s and master’s degrees in the geosciences over the last 10 years, reaching near 40% in 2000 (latest data available), while receiving only 28% of the Ph.D.s that year. Women are now only 20% of assistant professors at Ph.D.-granting institutions, a proportion that has not changed in the last four years. As part of a larger study to find what key barriers continue to prevent larger numbers of women geoscientists from becoming academics, data have been compiled from the National Science Board [NSB, 2002], and the American Geological Instititute\u27s (AGI) Directory of Geoscience Departments [Claudy, 2001] on geoscience specialty by gender

Academic Specialties in U.S. Are Shifting; Hiring of Women Geoscientists Is Stagnating

Women have been receiving a greater proportion of the bachelor’s and master’s degrees in the geosciences over the last 10 years, reaching near 40% in 2000 (latest data available), while receiving only 28% of the Ph.D.s that year. Women are now only 20% of assistant professors at Ph.D.-granting institutions, a proportion that has not changed in the last four years. As part of a larger study to find what key barriers continue to prevent larger numbers of women geoscientists from becoming academics, data have been compiled from the National Science Board [NSB, 2002], and the American Geological Instititute\u27s (AGI) Directory of Geoscience Departments [Claudy, 2001] on geoscience specialty by gender