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Early Pleistocene Marine Isotope Stage (MIS)-31 (1.081 to 1.062 Ma) is a unique interval of extreme global warming, including evidence of a West Antarctic Ice Sheet (WAIS) collapse. Here we present a new 1000-year resolution, spanning 1.110-1.030 Ma, diatom-based reconstruction of primary productivity, relative sea surface temperature changes, sea-ice proximity/open ocean conditions and diatom species absolute abundances during MIS-31, from the Scotia Sea (59° S) using deep-sea sediments collected during International Ocean Discovery Program (IODP) Expedition 382. The lower Jaramillo magnetic reversal (base of C1r.1n, 1.071 Ma) provides a robust and independent time-stratigraphic marker to correlate records from other drill cores in the Antarctic Zone of the Southern Ocean (AZSO). An increase in open ocean species Fragilariopsis kerguelensis in early MIS-31 at 53° S (Ocean Drilling Program Site 1094) correlates with increased obliquity forcing, whereas at 59° S (IODP Site U1537; this study) three progressively increasing, successive peaks in the relative abundance of F. kerguelensis correlate with Southern Hemisphere-phased precession pacing. These observations reveal a complex pattern of ocean temperature change and sustained sea surface temperature increase lasting longer than a precession cycle within the Atlantic sector of the AZSO. Timing of an inferred WAIS collapse is consistent with delayed warmth (possibly driven by sea-ice dynamics) in the southern AZSO, supporting models that indicate WAIS sensitivity to local sub-ice shelf melting. Anthropogenically enhanced impingement of relatively warm water beneath the ice shelves today highlights the importance of understanding dynamic responses of the WAIS during MIS-31, a warmer than Holocene interglacial.

The magnetic anomalies of the Alboran Sea have been modeled along several profiles revealingthe presence of crustal scale, basicigneous intrusionslocated at depths from8 to 14 km. Some ofthem are located under volcanic highs, such as the Djibouti bank,but the most intenseanomalies of central Alboran Seaare related to aNE-SW alignmentof igneous intrusionslocated below the Alboran Channel that runs from the Ibn-Batouta bank to the East Alboran Basin.It is remarkable that these intrusions are northwards displaced with respect to the Alboran Ridge, which is supposed to be the main volcanic high of the Alboran Sea. TheNE-SW elongated anomalyturnseastwardsto NW-SE, parallelingto the Yusuf fault and reachingthe Algerian coast, where it becomes more irregular.According with the geodynamic history of the Alboran Sea, the emplacement of thesebasic igneous intrusions may be related to the rifting of the AlKaPeCa Domain during Oligocene-Early Miocene. This rifting process, which is due to a NW-SE extension associated with slab retreat,led to the spreading of the Algerian basin and the individualization of the Alboran Domain. Thus, the intrusions wouldrepresent the western tip of that rift,since they have the same trend that the rift axis and are also not related with the Miocene volcanic highs. Afterwards, these intrusions were affected by the STEPfault (Subduction Tear Edge Propagator fault)that accommodated the westward displacement of the Alboran Domainalong its southern limit. Since Late Miocene, the tectonic inversion of the Alboran basin curved the STEP fault and originated theYusuf fault, along which some new intrusions could take place. During Pliocene-Quaternary, tectonic indentation was develop as a result of the Eurasia-Africa convergence and the reduction of the Alboran Domain westwards displacement. In this setting, the intrusions act as a backstop that have favored the folding and uplift of the Alboran Ridgein the front of the indenter. Altogether shows that the d

In the Alboran Sea there are a few well exposed Neogene and Quaternary volcanic zones, often geographic highs, that are generally associated with magnetic anomalies. In this paper, we present a characterization of these magnetic anomalies based on a recent and accurate magnetic data compilation for the Abloran Sea area. The anomalies reveal the distribution of magmatism and shed light into the discussion about the origin and evolution of the westernmost Mediterranean. One of the most relevant magnetic anomalies is the Nador dipole, which extends from the Gourougou volcano to the Chafarinas Islands, and is related to an E-W crustal scale intrusion. However, the main NE-SW elongated continuous dipoles of the central Alboran Sea are not related to any surface structure, but they are parallel to the Alboran Ridge, which is the main volcanic high in the Alboran Sea, and are located to the north of it. These anomalies extend discontinuously eastward along the NW-SE dipoles located along the Yusuf fault zone. The results of our 2D magnetic forward modeling suggest that the causative bodies of these main magnetic dipoles are deep igneous bodies. According to the tectonic evolution of the region, and the high magnetic susceptibility values obtained, these igneous bodies probably are made of a basic igneous rocks. Their emplacement may represent the westward tip of the rift axis of the AlKaPeCa Domain, which is related to the Oligocene-Miocene NW-SE extension, and associated with the southern slab retreat stage and oceanic spreading of the Algerian basin. Afterwards, these bodies were displaced toward the west, together with the Alboran Domain, and affected by the STEP fault located at its southern limit. Since the Late Miocene, the north Alboran Ridge elongated intrusions acted as a backstop that conditioned the folding and uplift of the Alboran Ridge in a tectonic indentation setting. In this setting, the STEP fault is deformed and the eastern part of the bodies were segmen

Scotia Sea and the Drake Passage is key towards understanding the development of modern oceanic circulation patterns and their implications for ice sheet growth and decay. The sedimentary record of the southern Scotia Sea basins documents the regional tectonic, oceanographic and climatic evolution since the Eocene. However, a lack of accurate age estimations has prevented the calibration of the reconstructed history. The upper sedimentary record of the Scotia Sea was scientifically drilled for the first time in 2019 during International Ocean Discovery Program (IODP) Expedition 382, recovering sediments down to ∼643 and 676 m below sea floor in the Dove and Pirie basins respectively. Here, we report newly acquired high resolution physical properties data and the first accurate age constraints for the seismic sequences of the upper sedimentary record of the Scotia Sea to the late Miocene. The drilled record contains four basin-wide reflectors – Reflector-c, -b, -a and -a' previously estimated to be ∼12.6 Ma, ∼6.4 Ma, ∼3.8 Ma and ∼2.6 Ma, respectively. By extrapolating our new Scotia Sea age model to previous morpho-structural and seismic-stratigraphic analyses of the wider region we found, however, that the four discontinuities drilled are much younger than previously thought. Reflector-c actually formed before 8.4 Ma, Reflector-b at ∼4.5/3.7 Ma, Reflector-a at ∼1.7 Ma, and Reflector-a' at ∼0.4 Ma. Our updated age model of these discontinuities has major implications for their correlation with regional tectonic, oceanographic and cryospheric events. According to our results, the outflow of Antarctic Bottom Water to northern latitudes controlled the Antarctic Circumpolar Current flow from late Miocene. Subsequent variability of the Antarctic ice sheets has influenced the oceanic circulation pattern linked to major global climatic changes during early Pliocene, Mid-Pleistocene and the Marine Isotope Stage 11.

The Alboran Basin is a Neogene-Quaternary extensional basin located within the Betic-Rif alpine cordillera. The region where the current basin is located holds great oceanographic relevance, as it lies in the area of connection between the western (Atlantic Ocean basin) and eastern seas (ocean basins of the Ligurian Tethys and then Western Mediterranean Sea) of Iberia. The extensional collapse of the Eocene Alpine orogen led to the crustal thinning and formation of the Western Mediterranean basin and the splitting of lithospheric fragments, the Alboran Domain among them, along its margins. The N-S convergence of the African and Eurasian plates, together with the westward escape of the Alboran Domain and its extensional tectonics in the back-arc region linked to the retreat of a subduction zone northwestward has determined the basin’s formation and evolution since the upper Oligocene to Tortonian times. The stretching of the continental crust produced its configuration, creating several sub-basins and tectonic highs, and was accompanied by an important magmatic phase that peaked in the middle-late Miocene. The direction of African-Eurasian convergence evolved to NW-SE in the late Tortonian and is presently WNW-ESE, producing an inversion of the basin in its interior, with the uplift of main reliefs (e.g., the Alboran Ridge), and a progressive elevation of adjacent mountain ranges in southern Iberia (Betic) and northern Africa (Rif), substantially reducing the basin’s width. During this phase, convergence is resolved with an indentation tectonic model in the central Alboran Sea; and to accommodate this deformation, two conjugated sets of dextral WNW-ESE and sinistral NE-SW to NNE-SSW faults are generated. The sedimentary infill of the Alboran Basin consists of unconformable Miocene to Quaternary deposits controlled by the tectonic deformation and paleoceanography. Two important events marked the sedimentary evolution: Messinian desiccation and the opening of the Strai

Antarctic geothermal heat flow (GHF) affects the ice sheet temperature, determining how it slides and internally deforms, as well as the rheological behaviour of the lithosphere. However, GHF remains poorly constrained, with few borehole-derived estimates, and there are large discrepancies in currently available glaciological and geophysical estimates. This SCAR White Paper details current methods, discusses their challenges and limitations, and recommends key future directions in GHF research. We highlight the timely need for a more multidisciplinary and internationally-coordinated approach to tackle this complex problem.

The Juno mission is providing stunning new information about Jupiter and its environment. A new magnetic field model (JRM09) with much improved accuracy near the planet provides the basis for a better understanding of Io-related decametric radio emissions (DAM) and implications for auroral processes. Here, we selected Io-related DAM events observed by the Juno Waves instrument to shed light into the beaming angle, the resonant electron energy and radio source location by forward modeling. We use the JRM09 model to better constrain the location and observability of DAM, and characterize the loss cone-driven electron cyclotron maser instability. We obtained good agreement between synthetic and observed arcs with calculated beaming angles ranging from 33° to 85° and resonant electron energies up to 23 times higher than previously proposed. In addition, through a quantitative analysis, we provide an explanation regarding the higher likelihood of observing groups of arcs originating in the northern hemisphere relative to those originating in the southern hemisphere. This is primarily a consequence of the asymmetry of the magnetic field geometry, observer location, and pitch angles of the electrons at the equator.

Curie depths beneath Greenland are revealed by spectral analysis of data from the World Digital Magnetic Anomaly Map 2. A thermal model of the lithosphere then provides a corresponding geothermal heat flux map. This new map exhibits significantly higher frequency but lower amplitude variation than earlier heat flux maps, and provides an important boundary condition for numerical ice‐sheet models and interpretation of borehole temperature profiles. In addition, it reveals new geologically significant features. Notably, we identify a prominent quasi‐linear elevated geothermal heat flux anomaly running northwest‐southeast across Greenland. We interpret this feature to be the relic of the passage of the Iceland hotspot from 80 to 50 Ma. The expected partial melting of the lithosphere and magmatic underplating or intrusion into the lower crust is compatible with models of observed satellite gravity data and recent seismic observations. Our geological interpretation has potentially significant implications for the geodynamic evolution of Greenland.

Antarctica is the largest reservoir of ice on Earth. Understanding its ice sheet dynamics is crucial to unraveling past global climate change and making robust climatic and sea level predictions. Of the basic parameters that shape and control ice flow, the most poorly known is geothermal heat flux. Direct observations of heat flux are difficult to obtain in Antarctica, and until now continent-wide heat flux maps have only been derived from low-resolution satellite magnetic and seismological data. We present a high resolution heat flux map and associated uncertainty derived from spectral analysis of the most advanced continental compilation of airborne magnetic data. Small-scale spatial variability and features consistent with known geology are better reproduced than in previous models, between 36% and 50%. Our high-resolution heat-flux map and its uncertainty distribution provide an important new boundary condition to be used in studies on future subglacial hydrology, ice-sheet dynamics and sea-level change

The Alboran Sea basin is part of the Alboran Domain, and locates in the south-westernmost part of the Mediterranean, where the Eurasian and African plates interact. The geological evolution of this basin is consequence of the westward motion of the Alboran Domain since the Oligocene. It provides a good example of an extensional basin formed in a convergence regime, where the Eurasian and African plates experienced about 200 km of roughly N-S convergence between the mid-Oligocene and the late Miocene, followed by further 50 km of NW-SE oblique convergence in the late Miocene to recent times. Although seismic activity is widely distributed along the basin, its south central area (Al Hoceima area) constitutes the most active zone. In this study we use the most advance compilation of potential field marine data to get the most updated and complete picture of the Alboran Sea. Additionally we applied different image processing tools to identify the fault systems in the area, and analyzed their relationships with the most recent seismic activity. The results suggest a crustal thinning related to the southward end of the today active Al Idrissi and a new fault zone discovered in the Al-Hoceima area. Magnetic data also gives new insights in the geometry of the intermediate and basic rock bodies emplaced during the recent geodynamic evolution of the Alboran basin