Young rifts are shaped by combined tectonic and surface processes and climate, yet few records exist to evaluate the interplay of these processes over an extended period of early rift-basin development. Here, we present the longest and highest resolution record of sediment flux and paleoenvironmental changes when a young rift connects to the global oceans. New results from International Ocean Discovery Program (IODP) Expedition 381 in the Corinth Rift show 10s–100s of kyr cyclic variations in basin paleoenvironment as eustatic sea level fluctuated with respect to sills bounding this semi-isolated basin, and reveal substantial corresponding changes in the volume and character of sediment delivered into the rift. During interglacials, when the basin was marine, sedimentation rates were lower (excepting the Holocene), and bioturbation and organic carbon concentration higher. During glacials, the basin was isolated from the ocean, and sedimentation rates were higher (~2–7 times those in interglacials). We infer that reduced vegetation cover during glacials drove higher sediment flux from the rift flanks. These orbital-timescale changes in rate and type of basin infill will likely influence early rift sedimentary and faulting processes, potentially including syn-rift stratigraphy, sediment burial rates, and organic carbon flux and preservation on deep continental margins worldwide.

Sediments deposited along continental margins of the Arctic Ocean presumably host large amounts of methane (CH 4 ) in gas hydrates. Here we apply numerical simulations to assess the potential of gas hydrate dissociation and methane release from the East Siberian slope over the next 100 years. Simulations are based on a hypothesized bottom water warming of 38C, and an assumed starting distribution of gas hydrate. The simulation results show that gas hydrate dissociation in these sediments is relatively slow, and that CH 4 fluxes toward the seafloor are limited by low sediment permeability. The latter is true even when sediment fractures are permitted to form in response to overpressure in pore space. With an initial gas hydrate distribution dictated by present-day pressure and temperature conditions, nominally 0.35 Gt of CH 4 are released from the East Siberian slope during the first 100 years of the simulation. However, this CH 4 discharge becomes significantly smaller ($0.05 Gt) if glacial sea level changes in the Arctic Ocean are considered. This is because a lower sea level during the last glacial maximum (LGM) must result in depleted gas hydrate abundance within the most sensitive region of the modern gas hydrate stability zone. Even if all released CH 4 reached the atmosphere, the amount coming from East Siberian slopes would be trivial compared to present-day atmospheric CH 4 inputs from other sources.

This work is distributed under the Creative Commons Attribution 4.0 International (CC BY 4.0) license. Contents 1 Introduction and operations 5 Lithostratigraphy 9 Structural geology 13 Micropaleontology 16 Geochemistry 18 Physical properties 25 Paleomagnetism 26 Downhole measurements 30 Core-log-seismic integration 33 References

Abstract. Continental slopes north of the East Siberian Sea potentially hold large amounts of methane (CH 4 ) in sediments as gas hydrate and free gas. Although release of this CH 4 to the ocean and atmosphere has become a topic of discussion, the region remains sparingly explored. Here we present pore water chemistry results from 32 sediment cores taken during Leg 2 of the 2014 joint Swedish-Russian-US Arctic Ocean Investigation of Climate-Cryosphere-Carbon Interactions (SWERUS-C3) expedition. The cores come from depth transects across the slope and rise extending between the Mendeleev and the Lomonosov ridges, north of Wrangel Island and the New Siberian Islands, respectively. Upward CH 4 flux towards the seafloor, as inferred from profiles of dissolved sulfate (SO 2− 4 ), alkalinity, and the δ 13 C of dissolved inorganic carbon (DIC), is negligible at all stations east of 143 • E longitude. In the upper 8 m of these cores, downward SO 2− 4 flux never exceeds 6.2 mol m −2 kyr −1 , the upward alkalinity flux never exceeds 6.8 mol m −2 kyr −1 , and δ 13 C composition of DIC (δ 13 C-DIC) only moderately decreases with depth (−3.6 ‰ m −1 on average). Moreover, upon addition of Zn acetate to pore water samples, ZnS did not precipitate, indicating a lack of dissolved H 2 S. Phosphate, ammonium, and metal profiles reveal that metal oxide reduction by organic carbon dominates the geochemical environment and supports very low organic carbon turnover rates. A single core on the Lomonosov Ridge differs, as diffusive fluxes for SO 2− 4 and alkalinity were 13.9 and 11.3 mol m −2 kyr −1 , respectively, the δ 13 C-DIC gradient was 5.6 ‰ m −1 , and Mn 2+ reduction terminated within 1.3 m of the seafloor. These are among the first pore water results generated from this vast climatically sensitive region, and they imply that abundant CH 4 , including gas hydrates, do not characterize the East Siberian Sea slope or rise along the investigated depth transects. This contradicts previous modeling and discussions, which due to the lack of data are almost entirely based on assumption.

The surface free energy of a solid is a material property that influences its interaction with other solids, liquids, and gases. Mineral aggregates are mixed with bitumen in the production of asphalt mixtures, and the interaction of aggregates with bitumen, water, or chemical modifiers affects the overall performance of the mixtures and, in turn, the pavement structure. A comprehensive characterization of the minerals that make up these aggregates can be used to explain the interactions between the aggregates and components used to bind the aggregates including bitumen, water, and chemical additives. This paper combines several techniques to quantify and describe or catalog mineral properties. These properties primarily include surface free energy, specific surface area, and surface carbon content of some of the most common minerals found in aggregates. The paper presents data that exemplify how this information can be used to characterize the moisture-induced stripping potential for bitumen–mineral combinations. Results indicate that a simple energy ratio calculated on the basis of adhesive bond energies from surface free energy measurements of the minerals and the bitumen can predict performance in asphalt mixtures and that a few minerals can form thermodynamically stable bonds with some bitumens that are inherently resistant to stripping.