Intensive study of the Greenland Ice Sheet's (GrIS) subglacial drainage has been motivated by its importance for ice dynamics and for nutrient/sediment export to coastal ecosystems. This has revealed consistent seasonal development of efficient subglacial drainage in the lower ablation area. While some hydrological models show qualitative agreement with field data, conflicting evidence (both field-

Inspired by exhumed subduction shear zones that commonly exhibit block-in-matrix characteristics (mélanges), we create synthetic models with different proportions of strong clasts within a weak matrix and compare them to natural mélange outcrops. Using 2D Finite Element visco-plastic numerical simulations in simple shear kinematic conditions, we determine the effective rheological parameters of such

The simulation of volcanic ash transport and deposition (VATD) for distances within a few kilometres from the vent (proximal region) is challenging owing to a combination of unresolved volcanogenic effects and the impact of the volcano's orography. Due to the urgency of calculations or sometimes lack of access to computational resources or expertise, atmospheric vertical velocity (w) is often underestimated

The discovery of a large putative impact crater buried beneath Hiawatha Glacier along the margin of the northwestern Greenland Ice Sheet has reinvigorated interest into the nature of large impacts into thick ice masses. This circular structure is relatively shallow and exhibits a small central uplift, whereas a peak-ring morphology is expected. This discrepancy may be due to long-term and ongoing subglacial

The Early Phanerozoic witnessed one of the most important events in Earth history - the Cambrian Explosion. There is also a consensus that at roughly the same time oceanic dissolved silicon (DSi) concentrations decreased from close to saturation to somewhere below saturation. Yet the timing and magnitude of the putative DSi decrease, and any relationship with biological innovations, remain poorly known

Calcium silicate perovskite and bridgmanite are two phases believed to coexist throughout the lower mantle, which at some temperature, at least theoretically, dissolve into each other to form a single perovskite solid solution (CaxMg1−xSiO3). This may have large seismic and geochemical implications due to the changes in density, elasticity and element partition coefficients between single and mixed

Global warming will likely perturb carbon storage and cycling throughout many components of the exogenic carbon cycle, but its net impact on the long-term fate of organic carbon stabilized in soils is unclear. Abrupt warming during the Paleocene-Eocene Thermal Maximum (PETM) profoundly altered vegetation and hydrologic patterns globally. To assess the consequences for soil carbon in a mid-latitude

Although Earth's surface motion is well known, the flow field in the underlying mantle is not. Mantle flow is typically calculated on the basis of inferred density variations, and flow directions can also be reflected in seismically observed anisotropy, but those observations leave ambiguity on the depth and direction of the deformation. Anisotropy orientations in East Asia, outside Tibet, have been

Variations in the marine 87Sr/86Sr record are largely driven by riverine export of weathering-derived strontium. Among the large river systems, the Ganga and the Brahmaputra deliver a disproportionately large flux of radiogenic Sr (i.e., high 87Sr/86Sr) to the ocean. Understanding the sources and processes that make these river systems such important contributors of radiogenic Sr to seawater has been

Bioturbation—sediment mixing and ventilation by burrowing animals—provides one of the most prominent examples of how animals shape their surroundings. A critical but longstanding question is when and how in Earth's history bioturbators began to similarly influence marine biogeochemistry. Recent work has proposed that even though the development of well-mixed sediments was a protracted process, the

Heterogeneity in isotopic compositions within the protoplanetary disc has been demonstrated for a number of elements measured in extra-terrestrial materials, mostly based on chondrite meteorite analyses. However, precise 182Hf-182W and 26Al-26Mg ages of iron meteorites, achondrites, and chondrules show that chondrites accreted later than achondrites and therefore do not strictly represent the early

Neoproterozoic carbon isotope excursions are commonly attributed to changes in the global fraction of organic carbon burial associated with climate instability and/or oxygenation. Here we show that carbonate sediment deposited during the ca. 661 – <651 Ma Cryogenian non-glacial interlude between the Sturtian and Marinoan glaciations exhibit lateral offsets in carbonate-carbon isotope values from coeval

In plate tectonic theory a weak asthenosphere is required to facilitate the motions of the rigid plates. Partial melt could weaken the mantle, in turn impacting convection, but to date the existence of persistent melt has remained controversial. A wide range of scenarios has been reported in terms of the location, amount and pathways of melt. Here we use data collected by 39 ocean bottom seismometers

Carbonate clumped isotopes (Δ47) have become a widely applied method for paleothermometry, with applications spanning many environmental settings over hundreds of millions of years. However, Δ47-based paleothermometry can be complicated by closure temperature-like behavior whereby C–O bonds are reset at elevated diagenetic or metamorphic temperatures, sometimes without obvious mineral alteration. Laboratory

The thick sequence of Quaternary sediments preserved within the northern North Sea contains important information about the glacial history, palaeo-oceanographic conditions and slope stability of this region during the last 2.6 million years. The interplay between glacial, fluvial and contouritic processes can be determined from seismic stratigraphic studies. Here, seismic horizon, attribute and geomorphological

The timing, extent and driving mechanisms of burial, uplift and exhumation of the Colorado Plateau, and the carving of the Grand Canyon have been at the center of a long-standing controversy. Here, we develop a new approach to constrain burial and exhumation histories of sedimentary basins from the distributions of ‘clumped’ isotope compositions in carbonate minerals. We apply this approach to constrain

Microbial methanogenesis is a significant component in the global carbon cycle, a driver of greenhouse warming from atmospheric methane, and contributes to natural gas resources. There are several metabolic pathways of methanogenesis, and it is challenging to discriminate between them and quantify their relative contributions in natural settings. Here we measure and compile four rare isotopologues

The first major mass extinction of trilobites occurred at the transition from Cambrian Series 2 (CS2) to Miaolingian (M) and coincided with a large marine transgression and volcanic eruptions of a large igneous province (LIP). Understanding the causal links between these events is important in deciphering environmental changes and life evolution at that time. This paper presents S-Hg-C isotopic and

Magnesium isotopic fractionation during basalt differentiation is commonly thought to be negligible at current levels of analytical precision. However, Mg isotopic variation of ∼0.4‰ (δ26Mg) can be observed in some highly evolved volcanic rocks with MgO contents of <5 wt.%, suggesting that detectable Mg isotopic fractionation may occur during late-stage basalt differentiation. Here we examine this

Ore deposits found in Proterozoic marine sedimentary basins supply much of the world's zinc. Many of the deposits formed contemporaneously with their host sediments when saline brines circulating from deeper in the basin reached the sea floor. Textural, geochemical and isotopic features of these SEDEX (‘sedimentary-exhalative’) deposits and their host sediments indicate that biologically active seeps

Continental margin sediments have been identified as the dominant sink in the marine budget of cadmium (Cd). The isotopic composition of this important output flux is, however, unknown. Here we present, with measurements on the Argentine continental margin, the first observational constraints on the isotopic composition of Cd in modern marine oxic and sub-oxic sediments. We identify two main removal

Eruption onset, style and duration are governed, in part, by the movement and interaction of distinct magma bodies at depth. High-resolution investigation of erupted products can retrospectively inform our understanding of such processes and improve future interpretation of real-time monitoring signals. In 2002-03, Mount Etna (Italy) erupted two elementally and isotopically distinct magmas simultaneously

Recent seismic studies suggested an anisotropic Mantle Transition Zone (MTZ) in areas adjacent to subducted slabs. Wadsleyite is the main anisotropy contributor in the upper MTZ, therefore the interpretation of these seismic observations requires the knowledge of single-crystal elastic moduli (Cijs) and the deformation-induced lattice preferred orientation (LPO) of wadsleyite. Wadsleyite can host up

The expansion of land plants is considered to have played a key role in triggering the Late Paleozoic Ice Age (LPIA), but evidence linking climatic events to terrestrial floral changes is limited. Here, we generated bulk carbonate δ13C, conodont δ18O and 87Sr/86Sr profiles from the lowermost Carboniferous of South China and Vietnam in order to investigate their relationship to contemporaneous land

Granular neoblastic zircon (ZrSiO4) with systematically oriented granules has been proposed as evidence for extreme shock pressures (>30 GPa) and subsequent high temperatures (>1200 °C). It is widely agreed to reflect the solid-state phase transition from zircon to its high-pressure polymorph reidite and subsequent reversion to zircon. This model is based on crystallographic relationships between granules

Ferromanganese nodules and crusts (Fe-Mn deposits) are being widely explored for their significant economic potential and paleoenvironmentally significant archives. Fe-Mn deposits contain abundant Fe-bearing minerals including detrital minerals, biogenic Fe-bearing components, but predominantly amorphous Fe hydroxides (AFH). Particularly, the hydrogenetic Fe that is formed in bottom water should be

The sedimentary basins of Yunnan, Southwest China, record detailed histories of Cenozoic paleoenvironmental change. They track regional tectonic and palaeobiological evolution, both of which are critically important for the development of modern floral diversity in southwestern China and throughout Asia more generally. However, to be useful, the sedimentary archives within the basins have to be placed

Riverine suspended particulate matter (SPM) is essential for the delivery of micronutrients such as iron (Fe) to the oceans. SPM is known to consist of multiple phases with differing reactivity, but their role in the delivery of elements to the oceans is poorly constrained. Here we provide new constraints on the source and composition of reactive phases in SPM from the Mackenzie River, the largest

The transition of ringwoodite to bridgmanite and periclase (the post-spinel transition) is a strong control on the 660 phase discontinuity and the boundary between the transition zone and the lower mantle. The transition zone may contain significant amounts of water and thus the effect of water on the post-spinel transition must be known to correctly determine its properties. In this paper we examine

Today's knowledge about paleomagnetic secular variations in (southern) Africa is extremely limited. Here, we derive paleomagnetic records from independently radiocarbon dated sediment records from three maars in Madagascar: Andraikiba and Amparihibe are terrestrial maars located on the main island of Madagascar and on a small island in the Northwest, whereas Crater Lake is a maar which has an open

The Qaidam Basin in the core area of arid Inner Asia has been considered undergoing continuous aridification over the Cenozoic. However, the Qaidam Basin is marked with expanded lacustrine sedimentation during the Oligocene, which contrasts with the fluvial or deltaic facies stratigraphically below (Eocene) and above (Miocene-present). The Oligocene lacustrine expansion challenges the idea of persistent

It is often assumed that the carbon isotope composition (δ13C) of carbonate minerals records that of the dissolved inorganic carbon (DIC) species with insignificant disequilibrium effect. However, results from field observations and laboratory experiments have shown that the δ13C difference between calcite and solution can vary up to 3‰ even under a similar set of solution composition and temperature

Tropical and subtropical rivers deliver large quantities of terrestrial organic carbon (OCterr) to the ocean, acting as a crucial part of the global carbon cycle, but little is known about the timescale and efficiency of its transport to and in the adjacent coastal sea. Here we examined source-specific biomarker (fatty acids, FAs) contents and isotope compositions in surface sediments in an alongshore

Physical-chemical controls of continental magmatism evolution remain enigmatic. Of prime and controversial nature is the temporal transition from calc-alkaline magmas to alkali basalts, correlated with a switch in tectonic regime from extension to compression. We perform 1D thermo-kinematic modelling to analyze the evolution of the thermo-rheological structure of the lithosphere in such settings using

How the underlying mantle responds to the subduction of an oceanic plate remains controversial. Numerical models demonstrate the presence of 3D flow in the sub-slab mantle with a poloidal component induced by slab entrainment and a toroidal component driven by slab rollback. These flows produce plate–motion–parallel and trench-parallel fast directions of seismic anisotropy, respectively, allowing them

A new rock complex has been discovered from the Tsuwano area of Southwest Japan. This granitic rock complex namely, Tsuwano Complex contains foliated granitic gneiss, massive granitoids, and metaquartzite, forming a distinct unit at the westernmost end of the east-west elongate Maizuru Terrane. The above-mentioned litho-assemblage is characteristically different in appearance from the typical rocks

Marine sediments are typically subject to bioturbation from benthic macrofauna, which disrupt sediments and can have a substantial impact on the amplitude and timing of climate proxy signals recorded in marine sediment cores. This study explores a computational approach to quantify and remove these post-depositional effects from marine climate proxy records. The bioturbation process is modeled as a

Serpentine veins are ubiquitous in hydrated and deformed ultramafic rocks, and have previously been used to track fault kinematics and understand the evolution of environmental conditions during vein formation. However, difficulties in unambiguously identifying and mapping serpentine types at sub-micron to mm scales has limited our understanding of vein precipitation kinetics and growth histories.

The diverse fluid regimes during melting of the metasedimentary crust have been often discriminated on the basis of the composition of anatectic granitoids, with granites indicating fluid-absent melting conditions and trondhjemitic compositions suggesting the addition of external water in the source region. The lack of abundant metasedimentary-derived trondhjemites in the geological record is supposed

The Yutu-2 rover, part of the Chang'e-4 (CE-4) mission to the lunar farside, has been exploring the Von Kármán crater (VK) within the South Pole-Aitken (SPA) gathering data on its geology. The Lunar Penetrating Radar's (LPR) 500 MHz antenna reveals the subsurface structure up to 40 m in depth, which helps to construct models on the evolution of the shallow stratum. This work presents the analysis and

Atmospheric samples and surface seawater collected on a Chinese Antarctic Research Expedition (CHINARE) transect are used to investigate sources and production of nitrate (NO3−) in the atmosphere and its contribution to the surface NO3− pool in the ocean. Most atmospheric NO3− is concentrated on intermediate size particles, and much higher concentrations were observed in the northern hemisphere than

An ice-free greenhouse interval (ca. 660 ∼ 650 Ma) occurred between the global Sturtian (ca. 717 Ma ∼ 660 Ma) and Marinoan glaciation (ca. 650 Ma ∼ 635 Ma) during the Cryogenian. While volcanic CO2 emissions have been suggested as a trigger for this ice-free interval, evidence for volcanism has been lacking. In this study, spikes in both Hg concentration (76 to 366 ppb) and Hg to total organic carbon

Forearc basins preserve the geologic record relating strictly to arc magmatism. The provenance of forearc sediment can be used to differentiate periods of crustal growth, accretion, and destruction, enhanced magmatism, advancing and retreating subduction slabs, delamination, etc. These tectonic systems predict differing degrees of sedimentary reworking of the older forearc units. Additionally, Hf isotopes

Quantifying how land surface height, such as that of the Tibetan region, has changed with time is crucial for understanding a range of Earth processes, including atmospheric dynamics, biotic evolution and tectonics. Elevation reconstructions are highly uncertain and controversial, in part because of assumptions used in their calculation. The largest uncertainties are in the choice of unconstrained

Antarctic ice sheet and climate evolution during the mid-Miocene has direct relevance for understanding ice sheet (in)stability and the long-term response to elevated atmospheric CO2 in the future. Geologic records reconstruct major fluctuations in the volume and extent of marine and terrestrial ice during the mid-Miocene, revealing a dynamic Antarctic ice-sheet response to past climatic variations

The Black Sea underwent dramatic changes in salinity from the last glacial maximum to Holocene as it evolved from a large inland lake to become a part of the global ocean due to post-glacial sea level rise. However, the detailed history of the re-connection of the Black Sea to the Mediterranean and the resulting Black Sea salinity variations have been heavily debated. We take advantage of our recent

A series of catastrophic iceberg and meltwater discharges to the North Atlantic, termed Heinrich events, punctuated the last ice age. During Heinrich events, coarse terrigenous debris released from the drifting icebergs was preserved in deep-sea sediments, serving as an indicator of iceberg passage. Quantifying the vertical flux of ice-rafted debris (IRD) in open-ocean settings can resolve questions

Low molecular weight carboxylate anions such as formate (HCOO−), acetate (CH3COO−) and oxalate (C2O42−) have been shown to play an important role in supporting deep subsurface microbial ecosystems. Their origin whether biological or abiotic is currently highly debated, but surprisingly radiolytic production has rarely been considered, as it is the case for H2. Here, we address this question through

Martian meteorites are the only available samples that can be directly measured to constrain the geological evolution of Mars. It has been suggested that the oxygen fugacity (fO2) of martian shergottite meteorites, which have low (∼7 wt.%) to high-MgO (∼30 wt.%) compositions, correlates with incompatible trace element enrichment (i.e., La/Yb), and 87Sr/86Sr, 143Nd/144Nd, 187Os/188Os and 176Hf/177Hf

The surface of Mercury is dominated by extensive, widespread lava plains that formed early in its history. The emplacement of these lavas was accompanied by the release of magmatic volatiles, the bulk of which were lost to space via thermal escape and/or photodissociation. Here we consider the fate of these erupted volatiles by quantifying the volumes of erupted volcanic plains and estimating the associated

Ice shell dynamics are a critical control on the habitability of icy ocean worlds. Here, we present a systematic study evaluating the effect of temperature-dependent material properties on these dynamics. We review the published thermal conductivity data for ice, which demonstrates that the most commonly used conductivity model in planetary science represents a lower bound. We propose a new model for

The uplift of the Tibetan Plateau in the Cenozoic has greatly affected the tectonics in Asia. But the evolution of the plateau is still unclear. The northeastern Tibetan Plateau is under ongoing expansion and is therefore essential for understanding the tectonic evolution of the plateau. Using data from 675 stations deployed by the ChinArray project, we obtained an anisotropic shear-wave velocity model

The delivery of organic carbon (OC) to the ocean's deepest trenches in the hadal zone is poorly understood, but may be important for the carbon cycle, contain crucial information on sediment provenance and event-related transport processes, and provide age constraints on stratigraphic sequences in this terminal sink. In this study, we systematically characterize bulk organic matter (OM) and OC signatures

Coring, geophysical logging, and in-situ temperature measurements were performed with the MARUM-MeBo200 seafloor rig to characterize gas hydrate occurrences in sediments of the Danube deep sea fan, off Romania, Black Sea. The new drilling data showed no evidence for significant gas hydrate saturations within the sediments but the presence of free gas at the depth of the bottom-simulating reflector

We use ambient-noise-based seismic monitoring to detect an anomalous seismic velocity decrease (∼0.01%) widely distributed in Honshu that arose about 1 year after the 2011 Mw 9.0 Tohoku-Oki earthquake. The anomaly is located along the central quaternary volcanic axis, and it suggests that the changes are related to volcanic processes. After correction for possible external environmental forcing-related

We use core reflected ScS waves sensitive to a broad region of the core-mantle boundary beneath Hawaii to create the first high-resolution map of the Hawaiian ultralow-velocity zone (ULVZ). Positive ScS-S differential times are used to identify regions of strong slow velocity anomalies in the lowermost mantle, and the presence of pre/post-cursors around the main ScS phase confirms the sharp top of

We present a high-resolution in situ study of oxygen and boron isotopes measured in tourmaline from the world-class San Rafael Sn (–Cu) deposit (Central Andean tin belt, Peru) aiming to trace major fluid processes at the magmatic-hydrothermal transition leading to the precipitation of cassiterite. Our results show that late-magmatic and pre-ore hydrothermal tourmaline has similar values of δ18O (from