Tectonostratigraphic evolution and significance of the Afar Depression

Rime, Valentin; Foubert, Anneleen; Ruch, J.; Kidane, Tesfaye

doi:10.1016/j.earscirev.2023.104519

Cited by 11 publications

(17 citation statements)

References 488 publications

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“…Metagenome and MAG analyses allow to infer that these microbial communities rely on a wide variety of carbon sources and electron donors and acceptors. In particular, the WCLs likely constitute fully heterotrophy-based ecosystems depending on organics largely mobilized by upwelling hydrothermal fluids interacting with Proterozoic marine sediments below the Danakil desert salt crust 21,22,24 . Alkane and haloalkane degradation seem particularly important resources for these communities.…”

Section: Discussionmentioning

confidence: 99%

“…The Dallol area on the Northern Danakil Depression (Afar region, Ethiopia) is situated at the confluence of three major tectonic plates. The local combination of evaporitic and hydrothermal processes 21,22 produces up-welling thermal fluids enriched in diverse salts and minerals, generating polyextreme brines of contrasting hydrochemistry 23,24 . While some brines across the observed gradients of polyextreme conditions (pH from -1.5 to 6; salinity from ~30 to >70% w/v; temperature from ~30°C to 110°C) seem lifeless, others host microbial communities largely dominated by extremely halophilic archaea (up to 99% of community members) 19,25 .…”

Section: We Identified Previously Undescribed Halobacteria Families A...mentioning

confidence: 99%

“…In the Danakil hypersaline ponds, "famine" periods could correspond to dominant evaporative phases leading to full desiccation or trapping in halite brine inclusions 60 . "Feast" phases could be triggered by the geothermal activity linked to meteoric waters infiltrating from the high Ethiopian plateau towards the depression and the concomitant generation of upwelling fluids 21,22,24 , providing hydration and nutrients. The high variety of exploitable metabolic resources and abilities may partly explain the diversification of extremely halophilic archaea in these chaotropic Danakil ecosystems.…”

Section: Metabolic Flexibility and Feast-and-famine Strategiesmentioning

confidence: 99%

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Extremely acidic proteomes and metabolic flexibility in bacteria and highly diversified archaea thriving in geothermal chaotropic brines

Gutierrez-Preciado,

Dede,

Baker

et al. 2024

Preprint

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Few described archaeal, and fewer bacterial, lineages thrive at salt-saturating conditions, such as solar saltern crystallizers (salinity above 30%-w/v). They accumulate molar K+ cytoplasmic concentrations to maintain osmotic balance ("salt-in" strategy), and have proteins adaptively enriched in negatively charged, acidic amino acids. Here, we analyzed metagenomes and metagenome-assembled genomes (MAGs) from geothermally influenced hypersaline ecosystems with increasing chaotropicity in the Danakil Depression. Normalized abundances of universal single-copy genes confirmed that haloarchaea and Nanohaloarchaeota encompass 99% of microbial communities in the near life-limiting conditions of the Western-Canyon Lakes (WCLs). Danakil metagenome- and MAG-inferred proteomes, compared to those of freshwater, seawater and solar saltern ponds up to saturation (6-14-32% salinity), showed that WCL archaea encode the most acidic proteomes ever observed (median protein isoelectric points ≤4.4). We identified previously undescribed Halobacteria families as well as an Aenigmatarchaeota family and a bacterial phylum independently adapted to extreme halophily. Despite phylum-level diversity decreasing with increasing salinity-chaotropicity, and unlike in solar salterns, adapted archaea exceedingly diversified in Danakil ecosystems, challenging the notion of decreasing diversity under extreme conditions. Metabolic flexibility to utilize multiple energy and carbon resources generated by local hydrothermalism along feast-and-famine strategies seemingly shape microbial diversity in these ecosystems near life limits.

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Section: Discussionmentioning

confidence: 99%

Section: We Identified Previously Undescribed Halobacteria Families A...mentioning

confidence: 99%

Section: Metabolic Flexibility and Feast-and-famine Strategiesmentioning

confidence: 99%

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Extremely acidic proteomes and metabolic flexibility in bacteria and highly diversified archaea thriving in geothermal chaotropic brines

Gutierrez-Preciado,

Dede,

Baker

et al. 2024

Preprint

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“…9). In this context, the Afar Rift at the northernmost end of the Eastern Branch is a special case, as some authors characterise it as an embryonic (subaerial) mid-oceanic ridge (Rime et al, 2023). This highly volcanically active region is mostly a desert at present, with parts situated down to 160 m below sea level (Rime et al, 2023), but contains considerable populations that live with the risks of frequent volcanic eruptions.…”

Section: Hotspots Of Rift-related Volcanismmentioning

confidence: 99%

“…In this context, the Afar Rift at the northernmost end of the Eastern Branch is a special case, as some authors characterise it as an embryonic (subaerial) mid-oceanic ridge (Rime et al, 2023). This highly volcanically active region is mostly a desert at present, with parts situated down to 160 m below sea level (Rime et al, 2023), but contains considerable populations that live with the risks of frequent volcanic eruptions. For instance, although the 2008 Alu Dalafilla eruption did not cause any human or economic losses due to the remote location of the volcano (Pagli et al, 2012), the 2011 eruption of the Nabro volcano caused several fatalities (Goitom et al, 2015).…”

Section: Hotspots Of Rift-related Volcanismmentioning

confidence: 99%

(D)rifting in the 21^st century: Key processes, natural hazards and geo-resources

Zwaan,

Alves,

Cadenas

et al. 2023

Preprint

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Abstract. Rifting and continental break-up is a key research topic within geosciences, and a thorough understanding of the processes involved, as well as of the associated natural hazard and natural resources is of great importance to both science and society. As a result, a large body of knowledge is available in the literature, yet most of previous research focuses on tectonic and geodynamic processes and their links to the evolution of rift systems. However, we believe that the key challenge for researchers is to make our knowledge of rift systems available and applicable to face new societal challenges. In particular, we should embrace a system analysis approach, and aim to apply our knowledge to better understand the links between rift processes, natural hazards, and the geo-resources that are of critical importance to realize the energy transition and a sustainable future. The aim of this paper is therefore to provide a first-order framework for such an approach, by providing an up-to-date summary of rifting processes, hazards, and geo-resources, followed by an assessment of future challenges and opportunities for research. We address the varied terminology used to characterise rifting in the scientific literature, followed by a description of rifting processes with a focus on the impact of (1) rheology and stain rates, (2) inheritance in three dimensions, (3) magmatism, and (4) surface processes. Subsequently, we address the considerable natural hazards and risks that occur in rift settings, which are linked to (I) seismicity, (II) magmatism, and (III) mass wasting, and provide some insights in how the impacts of these hazards can be mitigated. Moreover, we classify and describe the geo-resources occurring in rift environments as (a) non-energy resources, (b) geo-energy resources, (c) water and soils, and (d) opportunities for geological storage. Finally, we discuss the key challenges for the future linked to the aforementioned themes, and identify numerous opportunities for follow-up research and knowledge application. In particular, we see great potential in systematic knowledge transfer and collaboration between researchers, industry partners and government bodies, which may be the key to future successes and advancements.

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From melt- to crystal-rich magmatic systems during rift localization: Insights from mineral chemistry in Central Afar (Ethiopia)

Tortelli,

Gioncada,

Pagli

et al. 2024

Contrib Mineral Petrol

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Magmatism plays a key role in accommodating and localizing extension during continental breakup. However, how the crustal magmatic systems evolve at the continental-ocean transition is poorly understood. We address these questions by studying the evolution of the magmatic system in the rift of Central Afar (Ethiopia), currently marking the transition from continental rifting to oceanic spreading. We focus on the voluminous and widespread Upper Stratoid Series (2.6–1.1 Ma) and the following Central Afar Gulf Series (1.1–0.6 Ma), the latter corresponding to localization of volcanism in narrow magmatic segments. We carried out the first systematic study of major and trace element mineral chemistry for these two Series and integrated it with geothermobarometry estimates and geochemical modeling, to reconstruct the evolution of the magmatic system architecture during rift localization. The Upper Stratoid magmas evolved by fractional crystallization in a melt-rich, moderately zoned, middle-lower crustal (10–18 km) magmatic system, from where they rose directly to the surface. Polybaric plagioclase convection and dissolution of a plagioclase-rich crystal mush is recorded in the phenocryst texture and chemistry. The Central Afar Gulf magmas evolved at similar depth in a more complex and dynamic storage system, with magma rising and mixing through multiple, relatively small, crystal-rich and interconnected reservoirs. Our study documents the transition during the continental breakup, from an overall stable and melt-rich magmatic system feeding the voluminous and homogeneous Upper Stratoid eruptions to a more dynamic, interconnected and crystal-rich situation feeding small-volume eruption while the rift localizes.

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Tectonostratigraphic evolution and significance of the Afar Depression

Cited by 11 publications

References 488 publications

Extremely acidic proteomes and metabolic flexibility in bacteria and highly diversified archaea thriving in geothermal chaotropic brines

Extremely acidic proteomes and metabolic flexibility in bacteria and highly diversified archaea thriving in geothermal chaotropic brines

(D)rifting in the 21^st century: Key processes, natural hazards and geo-resources

From melt- to crystal-rich magmatic systems during rift localization: Insights from mineral chemistry in Central Afar (Ethiopia)

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Tectonostratigraphic evolution and significance of the Afar Depression

Cited by 11 publications

References 488 publications

Extremely acidic proteomes and metabolic flexibility in bacteria and highly diversified archaea thriving in geothermal chaotropic brines

Extremely acidic proteomes and metabolic flexibility in bacteria and highly diversified archaea thriving in geothermal chaotropic brines

(D)rifting in the 21st century: Key processes, natural hazards and geo-resources

From melt- to crystal-rich magmatic systems during rift localization: Insights from mineral chemistry in Central Afar (Ethiopia)

Contact Info

Product

Resources

About

(D)rifting in the 21^st century: Key processes, natural hazards and geo-resources