Explore the vast range of titles available.

Venus provides a rich arena in which to stretch one's tectonic imagination with respect to non-plate tectonic processes of heat transfer on an Earth-like planet. Venus is similar to Earth in density, size, inferred composition and heat budget. However, Venus' lack of plate tectonics and terrestrial surficial processes results in the preservation of a unique surface geologic record of non-plate tectonomagmatic processes. In this paper, I explore three global tectonic domains that represent changes in global conditions and tectonic regimes through time, divided respectively into temporal eras. Impactors played a prominent role in the ancient era, characterized by thin global lithosphere. The Artemis superstructure era highlights sublithospheric flow processes related to a uniquely large super plume. The fracture zone complex era, marked by broad zones of tectonomagmatic activity, witnessed coupled spreading and underthrusting, since arrested. These three tectonic regimes provide possible analogue models for terrestrial Archaean craton formation, continent formation without plate tectonics, and mechanisms underlying the emergence of plate tectonics. A bolide impact model for craton formation addresses the apparent paradox of both undepleted mantle and growth of Archaean crust, and recycling of significant Archaean crust to the mantle. This article is part of a discussion meeting issue 'Earth dynamics and the development of plate tectonics'.

The paradigm of plate tectonics holds that ocean plates are rigid during drift and only experience tectonic deformation at subduction zones, but new findings from the Pacific challenge this idea. Geological and geophysical evidence from the Ontong Java, Shatsky, Hess, and Manihiki oceanic plateaux indicates that extensional deformation during plate drift is a widespread phenomenon across the Pacific plate. These anomalously thick oceanic plateaux are weaker regions of the ocean lithosphere and more prone to tectonic deformation. Numerical geodynamic models demonstrate that a slab pull force from distant subduction plate boundaries can be effectively transmitted to oceanic plateaux through strong ocean lithosphere and cause substantial extension during plate drift. Our findings reveal that a wide expanse of the Pacific has experienced syn‐drift plate tectonics linked to pull from the western Pacific subduction factory. Plain Language Summary New findings from the Pacific Ocean challenge the conventional understanding of plate tectonics. It was previously believed that oceanic plates remained rigid during plate drift and only experienced deformation at subduction zones. However, geological and geophysical evidence from the Ontong Java, Shatsky, Hess, and Manihiki oceanic plateaux suggests that extensional deformation is a common occurrence during plate drift. These plateaux, which are weaker regions of the ocean lithosphere, are more susceptible to tectonic deformation. Through numerical geodynamic models, we have demonstrated that the slab pull force exerted by distant subduction plate boundaries can effectively cause substantial extension in these oceanic plateaux. This study reveals a significant presence of intra ocean plate deformation associated with the Western Pacific subduction factory. Key Points Seismic and petrologic data indicate that oceanic plateaux on the Pacific Plate are undergoing extensional deformation during plate drift Numerical modeling finds a slab pull force may be causing the extension as the force is transmitted far away from the subduction zone Oceanic plates can experience substantial tectonic deformation during their drift to subduction

ContextWe describe how large landscape-scale conservation initiatives involving local communities, NGOs and resource managers have engaged with landscape scientists with the goal of achieving landscape sustainability. We focus on two landscapes where local people, practitioners and landscape ecologists have co-produced knowledge to design conservation interventions.ObjectiveWe seek to understand how landscape ecology can engage with practical landscape management to contribute to managing landscapes sustainably.MethodsWe focus on two large tropical landscapes: the Sangha Tri-National landscape (Cameroon, Republic of Congo and the Central African Republic) and the Batéké-Léfini Landscape (Gabon and Republic of Congo). We evaluate (1) a participatory method used in the Sangha Tri-National landscape that embeds interdisciplinary researchers and practitioners within a landscape to apply transdisciplinary learning to landscape conservation and (2) a participatory landscape zoning method where interdisciplinary teams of conservation practitioners analyse local land and resource use in the Batéké-Léfini landscape.ResultsWe find that landscape ecology’s tradition of understanding the historical context of resource use can inform landscape conservation practice and natural resource mapping. We also find that the Sangha Group provides an example for landscape ecology on how to integrate local people and their knowledge to better understand and influence landscape processes.ConclusionsPlace-based engagement as well as the uptake of co-produced knowledge by policy makers are key in enabling sustainable landscapes. Success occurs when researchers, local communities and resource managers engage directly with landscape processes.

We study the S = 1/2 Heisenberg antiferromagnet on the floret pentagonal lattice by numerical diagonalization method. This system shows various behaviours that are different from that of the Cairo-pentagonal-lattice antiferromagnet. The ground-state energy without magnetic field and the magnetization process of this system are reported. Magnetization plateaux appear at one-ninth height of the saturation magnetization, at one-third height, and at seven-ninth height. The magnetization plateaux at one-third and seven-ninth heights come from interactions linking the sixfold-coordinated spin sites. A magnetization jump appears from the plateau at one-ninth height to the plateau at one-third height. Another magnetization jump is observed between the heights corresponding to the one-third and seven-ninth plateaux; however the jump is away from the two plateaux, namely, the jump is not accompanied with any magnetization plateaux. The jump is a peculiar phenomenon that has not been reported.

The sediments of the pan-Arctic shelves contribute an important component to the Arctic Ocean ecosystem by providing a habitat for biota (benthos), a repository for organic and inorganic non-conservative substances entering or produced within the ocean, a reactor and source of transformed substances back to the water column, and a mechanism of burial. Sediments interact with ice, ocean, and the surrounding land over a wide range of space and time scales. We discuss the vulnerability of shelf sediment to changes in (i) organic carbon sources, (ii) pathways of sediment and organic carbon supply, and (iii) physical and biogeochemical alteration (diagenesis). Sedimentary environments of the shelves and basins are likely to exhibit a wide variance in their response to global change because of their wide variation in sediment sources, processes, and metabolic conditions. In particular, the Chukchi and Barents shelves are dominated by inflowing waters from oceans to the south, whereas the interior shelves are more closely tied to terrigenous sources due to river inflow and coastal erosion.

The urban areas in Algeria suffer from several imbalances in different regions, where the inequality of opportunities has led to an imbalance in the population density “from north to south”. And to the urban chaos, this matter made it face many challenges, which prompted us to search for this defect. Development plans in Algeria focus on the role of cities with high hills in restoring balance to the national sphere and reducing these disparities. The study aims to extract and evaluate the spatial differences of the three cities and reveal the spatial disparities, in order to establish a balanced regional development, while preparing the various development plans, based on several criteria by integrating the Delphi method with the analytical hierarchy process, and determining its spatial regions in the (GIS) environment. Through a comparative study of three cities, the study showed the progress of the city of Setif, achieving (11%) of the study area, achieving high quality, with an area (14.50 km²), Al-M’sila (03%) with an area (7.99 km²). Barika (01%) with an area of (3.98 km2). The results can be used during the preparation of development plans for this region.

Magnetic properties of the spin-1/2 XXZ Heisenberg cuboctahedron are examined using exact numerical diagonalization depending on a relative strength of the exchange anisotropy. While the Ising cuboctahedron exhibits in a low-temperature magnetization curve only one-third magnetization plateau, the XXZ Heisenberg cuboctahedron displays another four intermediate plateaux at zero, one-sixth, one-half and two-thirds of the saturation magnetization. The novel magnetization plateaux generally extend over a wider range of magnetic fields with increasing of a quantum ( xy ) part of the XXZ exchange interaction. It is shown that the XXZ Heisenberg cuboctahedron exhibits in the vicinity of all magnetization jumps anomalous thermodynamic behavior accompanied by an enhanced magnetocaloric effect.

Background and aims – Old-growth savannas in Africa are impacted by fire, have endemic and geoxylic suffrutices, and are understudied. This paper explores the Parc National des Plateaux Batéké (PNPB) in Gabon and the impact of fire on its flora to understand if it is an old-growth savanna. It presents 1) a vascular plant checklist, including endemic species and geoxylic suffrutices and 2) an analysis of the impact of fire on the savanna herbaceous flora, followed by recommendations for fire management to promote plant diversity. Material and methods – 1,914 botanical collections from 2001–2019 collected by the authors and others were extracted from two herbaria databases in 2021 to create the checklist. The impact of fire was explored through a three season plot-based inventory of plant species (notably forbs and geoxylic suffrutices) in five annually, dry-season burned study areas located at 600 m in elevation. A two-factor ANOVA was conducted across two burn treatments and three season treatments. Key results – The area has a vascular flora of 615 taxa. Seven species are endemic to the Plateaux Batéké forest-savanna mosaic. Seventeen species are fire-dependent geoxylic suffrutices, attesting to the ancient origins of these savannas. Burning promotes fire-dependent species. Conclusion – The PNPB aims to create a culturally-adapted fire management plan. The combination of customary fire and fire-adapted species in the savanna creates a unique ancient forest-savanna mosaic in Central Africa that merits protection while recognising the role that the Batéké-Alima people have in shaping and governing this landscape.

Lions (Panthera leo) are of particular conservation concern due to evidence of recent, widespread population declines in what has hitherto been seen as a common species, robust to anthropogenic disturbance. Here we use non-invasive methods to recover complete mitochondrial genomes from single hair samples collected in the field in order to explore the identity of the Gabonese Plateaux Batéké lion. Comparison of the mitogenomes against a comprehensive dataset of African lion sequences that includes relevant geographically proximate lion populations from both contemporary and ancient sources, enabled us to identify the Plateaux Batéké lion as a close maternal relative to now extirpated populations found in Gabon and nearby Congo during the twentieth century, and to extant populations of Southern Africa. Our study demonstrates the relevance of ancient DNA methods to field conservation work, and the ability of trace field samples to provide copious genetic information about free-ranging animals.

Lithic assemblages from five Aboriginal rock shelters in the Namadgi Ranges – including the first with cultural material dating to the early to mid-Holocene – provide new perspectives on our understanding of Holocene lithic technology for this region of the south-east Australian high country. They reveal a steady continuation of quartz predominance and bipolar knapping technique through time. Formal tools are rare, as is other evidence of retouch, but quantitative analyses reveal that raw material variation diversifies and artefact size decreases from the mid-Holocene towards the past millennium, with some associated evidence of a shift in reduction intensity. Re-analysis of the lithic assemblage from the nearby Birrigai rock shelter and information from other dated Namadgi sites provide further context for interpretation. This study finds a lack of evidence for Flood's proposed regional model of late Holocene technological transition from chert-dominated backed artefact to bipolar quartz industry. There is also no evidence for a cultural change associated with a backed artefact proliferation beginning around 4500 to 3500 years BP, as proposed by Hiscock and others for south-east Australia more generally. In fact, the technological shifts observed in the Namadgi high country – morphometric decline, raw material diversity and the appearance of backed artefacts – culminate in the past millennium. Des assemblages lithiques prévenants de cinq grottes situées dans la chaine montagneuse de Namadgi – y compris le premier dont le contenu culturel date du debut du holocène juque qu 'holocène moyen – fournissent de nouvelles perspectives pour la compréhension des technologies lithiques du holocène dans cette région des hauts plateaux de l'Australie du sud-est. Ills révélent une continuité forte de la predominance du quartz et de la technique de percussion bipolaire dans le temps. Les outils façonnés sont rares, comme le sont d'autres évidences de retouche, mais une analyse quantitative révéle que les materiaux de base se diversifient et que les dimensions des objets diminuent à partir du holocène moyen et ceci se poursuit j'usqu 'au dernier millénaire, avec l'évidence d'un changement dans l'intensité de la réduction qui peut lui être associé. Une nouvelle analyse d'un assemblage lithique de la grotte de Birrigai situé à proximité et des informations prévenants d'autres sites datés de Namadgi fournissent un contexte plus vaste pour l'interprétation. Cette étude ne trouve pas d'évidences qui supportent la proposition de Flood d'un modèle régionale de transition technologique de la fin du holocène allant d'un outiles taillé à pic principalement en chert vers une industrie du biface en quartz. Il n'y a également pas d'évidence d'un changement culturel associé à la prolifération d'outiles taillé à pic commençant vers 4500 à 3500 ans avant notre ère, comme le suggère Hiscock et d'autres pour l'Australie du sud-est en général. En fait, les changements technologiques observés dans les plateaux de Namadgi – morphometrique baisse, diversification des matériaux de base et l'apparition des outiles taillé à pic – culminent dans le dernier millénaire.