Ancient Sea Research Articles

The Relationship of the Change in Hydrogeochemical Features and Lithium Values of Kızılırmak Basin (Nevsehir-Central Anatolia) Water with Tectonic Fields

In this study, in particular, the relationship between high lithium values and geological environments was examined. To determine this, the geology, structural geology, hydrogeology, and hydrogeochemistry of the area in the north of the Gülşehir-Yeşilöz sub-basin of the Kızılırmak Basin were investigated. For hydrogeological studies, 19 water samples were collected in May and September. Tectonically, this area has a horst-graben structure. The relationships between the water analysis values of the study area and the tectonic areas were investigated. In particular, the lithium content of the waters in the study area was investigated. Hydrogeochemical properties and seasonal changes in water resources were studied in detail, and their relationship with tectonic areas was evaluated. Water analyses were carried out during wet and dry periods to determine temporal hydrogeochemical changes. According to the analysis, the waters in the area are of Ca-HCO3 and Ca-Mg-HCO3 facies. In addition, there are water samples with high lithium content in the study area. IDW and Kernel diagrams of these were prepared. It was found that these high values were influenced by the rocks formed in the ancient sea and saline lake environments. The region with the highest lithium value is in the formations that represent the former salt lake environment. High lithium (Li) values are generally higher in the region within the Kızılırmak graben. Lithium values in this area were determined as 241.3 µg/L, 154.5 µg/L, 155.2 µg/L, 156.8 µg/L, and 155.6 µg/L.

Новые памятники археологии на северном побережье Кандалакшского залива Белого моря

The article is devoted to the results of the archaeological expedition of the Kola Scientific Center of the Russian Academy of Sciences on the northern shore of the Kandalaksha Bay of the White Sea near the city of Kandalaksha and on the Kolvitsa River in 2023. Three new archaeological monuments have been recorded: Niva XXIII — boulder pit, Kandalaksha XVI – charcoal pits and Kolvitsa – stone structures. The boulder pit is located on an ancient sea terrace, on the western slope of Mount Volosyanaya, 1 km from the Niva River. Three charcoal pits are located on the northern shore of Malaya Pitkulya Bay, near the southern slope of Mount Krestovaya, not far from the labyrinth. This is the first discovery of such objects in Russian Lapland and they date back to the late 15th–16th centuries. Seven formations of boulders are located on the northern bank of the Kolvitsa River near the rapids. Analogs are known to them in other places of Russian Lapland. There are also boulder pits on the Khlebnaya River and on the coast of the Barents Sea. The dating and ethnicity of the boulder structures are still speculative.

Deep-learning-enabled antibiotic discovery through molecular de-extinction.

Molecular de-extinction aims at resurrecting molecules to solve antibiotic resistance and other present-day biological and biomedical problems. Here we show that deep learning can be used to mine the proteomes of all available extinct organisms for the discovery of antibiotic peptides. We trained ensembles of deep-learning models consisting of a peptide-sequence encoder coupled with neural networks for the prediction of antimicrobial activity and used it to mine 10,311,899 peptides. The models predicted 37,176 sequences with broad-spectrum antimicrobial activity, 11,035 of which were not found in extant organisms. We synthesized 69 peptides and experimentally confirmed their activity against bacterial pathogens. Most peptides killed bacteria by depolarizing their cytoplasmic membrane, contrary to known antimicrobial peptides, which tend to target the outer membrane. Notably, lead compounds (including mammuthusin-2 from the woolly mammoth, elephasin-2 from the straight-tusked elephant, hydrodamin-1 from the ancient sea cow, mylodonin-2 from the giant sloth and megalocerin-1 from the extinct giant elk) showed anti-infective activity in mice with skin abscess or thigh infections. Molecular de-extinction aided by deep learning may accelerate the discovery of therapeutic molecules.

Contingency versus inevitability: a review and reinterpretation of Stephen Jay Gould’s book “Wonderful Life—The Burgess Shale and the Nature of History”

In 1989, Stephen Jay Gould published his Wonderful Life: “High in the Canadian Rockies is a small limestone quarry formed 530 million years ago called the Burgess Shale. It holds the remains of an ancient sea where dozens of strange creatures lived a forgotten corner of evolution preserved in awesome detail. In this book Stephen Jay Gould explores what the Burgess Shale tells us about evolution and the nature of history”. Gould, based upon a reinterpretation of the famous fossils from the Burgess Shale, proposed a conclusion that was revolutionary at the time, because it was centred on the notion of contingency in the course of biological evolution. The very last paragraph displayed in particular the following sentences: “This response does not cite a single law of nature; it embodies no statement about predictable evolutionary pathways, no calculation of probabilities based on general rules of anatomy or ecology. I do not think that any ‘higher’ answer can be given, and I cannot imagine that any resolution could be more fascinating.” In this essay, I intend to criticise Gould’s conclusions and to provide a new reinterpretation of the history of life, based not on contingency but on the inevitability of evolution.

Chemical and isotopic evidence to clarify the salinity of the bedrock groundwater at Finnish mining site

Study regionLithium mine in Ostrobothnia, Western Finland. Study focusClear anomalous electrical conductivity horizons and high salinity (Cl, Na, Ca) of groundwater were identified in several exploration boreholes. As these could not be explained thoroughly with geological variations, further studies on the origin of the anomalies were suggested. It was speculated that the abrupt rise in electrical conductivity shows a horizon of waters of different ages, the lower being either old brine, or having ancient marine origin. To understand the processes controlling the hydrochemistry and the evolution of the salinity of the groundwater, the hydrogeochemistry and isotopic composition (δ2H, δ18O, 87 Sr/86 Sr, 3 H, 14 C, δ13C) was analysed in 13 boreholes, two lakes, a test pit and a stream. New Hydrological insights for the regionThe isotope and geochemistry results indicate long residence times (up to 10,000 years BP), but no strong water-rock interaction and a typical Litorina SO4 layer is missing. The mismatching results could be explained by 1) the fact that even a small amount of ancient brine or ancient sea water mixing with fresh groundwater would affect water geochemistry, while the isotopic composition would stay immutable, or 2) the salinity originates from pre-Litorina SO4-poor brackish groundwater due to an earlier uplift from the Baltic Sea. Therefore, the groundwaters of the site are interpreted as a mixture of modern meteoric and fresh HCO3 water, brackish pre-Litorina subglacial groundwater, and glacial melt water.

Estimating the amount of uplift from the current elevation of strata at the Middle Miocene Climatic Optimum: A case study of Kibi Plateau in Southwest Japan

AbstractThe Middle Miocene Climatic Optimum (MMCO) formed shallow marine strata on continents and island arcs at ~15 Ma, and some of the MMCO strata later experienced uplift. The amount of uplift corresponded to sea level rise after the MMCO period, but ancient sea level could not be observed. This study uses a deductive approach to estimate the amount of uplift. The elevation of the youngest marine sedimentary layer of the MMCO strata approximates the sea level at the MMCO. The current elevation was reconstructed by adding the amount of denudation from the MMCO to the current elevation of the denuded MMCO strata at the outcrops, considering isostatic compensation. The amount of denudation since the MMCO period was estimated to be 180 m based on the global average denudation rate (Willenbring et al., 2013), and the estimated isostatic rebound was 153 m. By comparing the current, albeit virtual, elevation of the youngest marine sedimentary layer in the MMCO strata with sea level at the MMCO, the amount of uplift was estimated. For the MMCO sea level, a 66 m ice‐free line was adopted. This method was applied to the Kibi Plateau in Southwest Japan, where the MMCO strata are distributed. The reliability of the denudation amount of 180 m for the MMCO strata was confirmed by paleo‐water depths estimated using benthic foraminifera and mollusk fossils. The largest uplift of 504 ± 27 m occurred at the Jinseki‐Kogen since 15 Ma. A positive correlation was observed between the amount of uplift and the current altitude of the Kibi Plateau. The Kibi Plateau's topography most likely evolved after the MMCO. It is concluded that a new perspective on estimating the uplift was obtained by taking denudation into account.

Metals for microbes in the ancient sea

Metals for microbes in the ancient sea

Paleomagnetism and geochronology of the Gwalior Sills, Bundelkhand craton, Northern India Block: New constraints on Greater India assembly

We present an updated paleomagnetic pole from the Gwalior Sills in the Bundelkhand craton within the Northern India Block (NIB). Geochronological results from baddeleyite grains from one of the sills yielded an age of 1719 ± 7 Ma which together with a previously published age indicates the emplacement of sills between 1712 and 1756 Ma (∼1730 Ma). The paleomagnetic pole calculated from additional sites in this study, combined with previous studies, falls at 13.5°N, 173.7°E (A95 = 3.6°, K = 98) indicating near equatorial latitudes for northern India. Limestone sampled a few meters above the contact with the sill exhibits similar directions consistent with having been baked by the sill. The pole does not resemble any younger poles from Peninsular India and receives a reliability score of R = 5. Dykes in the Singhbhum craton are slightly older (1765 Ma) and indicate low paleolatitudes for the Southern Indian Block (SIB). Although the Gwalior and Singhbhum poles data indicate low latitudes for both the NIB and SIB, they are statistically different and indicate that a rotation of at least 65° is required to bring the poles into accord. We propose that the NIB and SIB were in proximity but were separated by an ocean basin. We propose the name Gotosindhu (‘Ancient Sea’) for the body of water separating the NIB and SIB. We also review previous models for the assembly of the Columbia supercontinent during this time and critically examine the position of the NIB/SIB in those reconstructions.

Rendzinas of the Russian Northwest: Diversity, Genesis, and Ecosystem Functions: A Review

Rendzinas in the taiga zone are intrazonal soils; moreover, all of their processes occur in ways that are different from podzolic soil formation, which is typical for the zonal taiga boreal ecosystem. At the same time, the habitats of carbonate soils are known as places in which there is a concentration of biodiversity in the more southern regions, as they are drier, are insolated, and have a higher trophic state than zonal podzols. The biotopes on carbonate soils are becoming more southern and are dominated by nemoralis species of flora, including abundant calciphilous plant species. Carbonate soils regulate biogeochemical processes within their distribution and in the geochemically subordinate landscapes of Northwest Russia. They are associated with the existence of a number of specially protected natural areas, as well as the implementation of a number of important ecosystem services. Carbonate soils of the southern taiga are endangered and require special protection. The belt of the carbonate soils in the northwestern Russian and Baltic regions extends to Poland and is the basis for the formation of a special landscape–ecological framework with specific biodiverse, biogeochemical, and geographical characteristics. The intensive extraction of limestone from quarries leads to the destruction of rendzinas, which makes them increasingly rare and extremely vulnerable. The rate of recovery of rendzina soils after technogenic impacts is much slower than the regeneration of zonal podzols; therefore, they are an almost non-renewable resource. Thus, rendzinas are an important component of the Northwest Russian soil cover, where all factors of soil formation “refract” and acquire specificity, leading to radical changes not only in the soil-forming potential of the environment but in all of the components of terrestrial ecosystems. In other words, the island of alkaline rocks inherited from the ancient seas is currently pedogeochemically actualized in the soil cover of vast taiga areas.

The first Late Permian fish fossils from Leszczyna quarry in South-West Poland

ABSTRACTPermian fishes and their isolated microremains are known from many localities in the Zechstein Basin. However, up to date the vertebrates have never been revealed in the southeasternmost part of this ancient sea. The new material consists of euselachian-type dermal denticles,?Listracanthus sp. dermal denticle,?Omanoselache sp. tooth, actinopterygian scales and actinopterygian teeth. Here, the detailed study of euselachian and actinopterygian remains, their stratigraphic distribution and geographical contexts is presented. Based on the qualitative analysis of teeth shapes several ecomorphotypes were described as well as the probable dietary preferences of fishes were reconstructed. These finds confirmed existence of small predators who fed on soft bodied prey as well as durophagous forms which were feeding on small shelly crustaceans or molluscs. The analysis of stratigraphic distribution of microremains, and their comparison with neighbouring sections revealed a spatially correlatable trend in increasing abundance of fishes in the more clayey parts of sections, interpreted to be positively associated with a sea level transgression event.

A Revised Estimate of Early Pliocene Global Mean Sea Level Using Geodynamic Models of the Patagonian Slab Window

AbstractPaleoshorelines serve as measures of ancient sea level and ice volume but are affected by solid Earth deformation including processes such as glacial isostatic adjustment (GIA) and mantle dynamic topography (DT). The early Pliocene Epoch is an important target for sea‐level reconstructions as it contains information about the stability of ice sheets during a climate warmer than today. Along the southeastern passive margin of Argentina, three paleoshorelines date to early Pliocene times (4.8–5.5 Ma), and their variable present‐day elevations (36–180 m) reflect a unique topographic deformation signature. We use a mantle convection model to back‐advect present‐day buoyancy variations, including those that correspond to the Patagonian slab window. Varying the viscosity and initial tomography‐derived mantle buoyancy structures allows us to compute a suite of predictions of DT change that, when compared to GIA‐corrected shoreline elevations, makes it possible to identify both the most likely convection parameters and the most likely DT change. Our simulations illuminate an interplay of upwelling asthenosphere through the Patagonian slab window and coincident downwelling of the subducted Nazca slab in the mantle transition zone. This flow leads to differential upwarping of the southern Patagonian foreland since early Pliocene times, in line with the observations. Using our most likely DT change leads to an estimate of global mean sea level of 17.5 ± 6.4 m (1σ) in the early Pliocene Epoch. This confirms that sea level was significantly higher than present and can be used to calibrate ice sheet models.

Thermodynamic and geochemical studies of formation water in Rag-e Sefid oil and gas field, Iran

<abstract> <p>Nowadays, the concentration of mineral cations and anions in the formation water of oil and gas fields is a challenging issue for oil industry technicians managing the formation of mineral deposits during water injection operations. For this reason, the analysis of formation water mineral ions during exploitation operations can be a valuable solution for the efficient management of oil production. Therefore, in this research, the thermodynamic and geochemical evaluation of formation water in the Reg-e Sefid oil and gas field is considered. Based on the results of this study, the formation of calcium sulfate and calcium carbonate can be expected due to the concentration of mineral ions dissolved in the formation water in the Reg-e Sefid oil and gas field according to the StimCad2 software. Also, based on the evaluation of ion ratios, the studied oil and gas field formation has ideal conditions for hydrocarbon production. Based on the results obtained from the comparison of the water and rock formation of the Rag-e Sefid oil and gas field, the source of ions (except calcium and magnesium ions) is related to ancient sea water.</p> </abstract>

Галечные орудия из террас горы Эчкидаг в Крыму: геоморфологический и археологический контекст

From the mid-1970s on, several findspots supplying archaic pebble tools were discovered in the southern coast of the Crimea. The main feature of all the sites is the absence of cultural layer. According to the dating of ancient sea terraces and the results of comparative typological method, the researchers have dated the said finds of pebble tools from the Oldowan and the Lower Acheulean Periods. The 2019 comprehensive archaeological and geomorphological researches in the southern slopes of Echkidag mountain uncovered that the upper part of the diluvial aprons of the terraces and their surface were younger, with some dating to the modernity, and therefore surface finds cannot be dated according to the positions on this or that level of Echkidag terraces. Moreover, the finds include cultural layers at the site Echkidag 6 containing pebble and flint tools, and hand-made ware. It has been discovered that the pebble tools date from the Neolithic and Bronze Age.

The Cup Whisperer

The Cup Whisperer

PRECAMBRIAN IRON FORMATIONS: PALEOECOLOGICAL AND PALEONTOLOGICAL ASPECTS

Ancient iron formations - chemogenic sedimentary rocks rich in iron and silica of Precambrian age contain information about environmental conditions in the Archean (4.0–2.5 Ga) and Proterozoic (2.5–0.539 Ga) eons. Despite disagreements about the mechanisms of their formation, iron formations are evidence of the influence of the Precambrian biosphere on the chemical composition of the ancient ocean. Since many iron ore formations are chemogenic deposits reflecting the composition of the waters from which they precipitated, they can also serve as detailed geochemical archives for studying the temperature of ancient seas, redox states and the cycle of chemical elements.

Lithofacies evaluation of the mamu formation, southeastern nigeria: implications for depositional setting and maastrichtian sea regression

Lithofacies analysis was carried out on the sediments and sedimentary rocks of the Mamu formation for the purpose of interpretation of the depositional setting and the Maastrichtian sea history. Both field and laboratory methods were employed in the study. Nine (9) lithofacies were identified and grouped into three lithofacies associations based on their stacking patterns. The three facies associations include the lagoonal/swamp, tidal flat (dominantly inter-tidal), and the shoreface. Vertical succession indicated deposition in a prograding deltaic system (marginal marine) influenced by both fluvial and marine (tide and wave) processes. The general coarsening upward pattern displayed by the lithofacies and facies association suggests sediment deposition during the regressive phase of the ancient sea.

A possibility of 18O-depleted oceans in the Precambrian inferred from triple oxygen isotope of shales and oceanic crust

Oxygen-18/16 ratio recorded in geological media has been utilized to reconstruct surface temperature and discuss associated climatological forcing through Earth’s history. The accuracy of the estimated paleo-temperature through the application of the δ18O record, however, is limited by our understanding of the oceanic 18O/16O ratio in the past. As a longstanding issue, sedimentary rocks in the Precambrian, which are generally depleted in 18O relative to the modern sediments, can be interpreted either to have reflected higher surface temperature when assuming relatively constant oceanic δ18O values, or more 18O-depleted oceans relative to the present day with limited global temperature (climate) deviations. Additional use of a third isotope, 17O, can help constrain the isotopic composition of the porewater during the formation of a rock record as it provides an additional fractionation equation within the same isotopic system. This study utilizes reactive-transport models of triple oxygen isotope (16O, 17O, 18O) for continental weathering and hydrothermal alteration of oceanic crust, built upon the δ18O modeling framework developed by Kanzaki (2020a, b). Comprehensive oxygen isotope exchanges in dynamically moving media, both rocks and porewaters, are realized in these models, reflecting spatially-variable and process-dependent alteration conditions (e.g., spreading rate of midocean ridges, uplift rate of continents, porewater advection rate, and isotope exchange kinetics). The models were confirmed to be able to reproduce the signatures of triple oxygen isotope in Phanerozoic shales and oceanic crust. The validated models were then applied to Precambrian shales, which suggests that the Precambrian oceans could have been depleted in 18O, e.g., as low as −12‰ at >2.5 Ga and − 4‰ around 0.5 Ga, relative to the present-day seawater. General absence of positive and near-zero Δ′17O signatures in oceanic crust also suggests that the buffering of oceanic 18O through hydrothermal alteration of the oceanic crust could have been weak. The 18O flux from continental weathering thus could have played a significant role in controlling the 18O/16O ratio of ancient sea and together with climatic forcing could have enabled a secular transition of oceanic δ18O during the Precambrian.

Channel, dune and sand sheet architectures of a strait-adjacent delta, Rifian Corridor, Morocco

Abstract Sea straits are elongated zones where geographical constriction can amplify marine currents. Sediment deposits that formed in sea straits are relatively well studied and robust models of tidal strait depositional systems have been developed. However, models of strait-adjacent systems remain uncommon. In this study, we present such a model which is based on detailed outcrop descriptions of Miocene deposits that formed adjacent to the Rifian Corridor, an ancient sea strait that existed in what is now northern Morocco. The kilometre-scale outcrops at the Ben Allou locality (30 km north of Fez, Morocco) contain a succession of claystones, siltstones and sandstones that formed under a sea strait-adjacent process regime characterized by marine current constriction, tidal amplification and reduced wave activity. Detailed descriptions of the sandstone's sedimentary architectures reflect a development from mud drape-bearing sand sheets in the proximal regions of the system to stacked cross-strata and channel forms nearer to the basin depocentre. In the deep, distal reaches of this system, sediment grain sizes are generally fine (silt and clay) and are sparsely interbedded with sandy turbidites. These results confirm existing models which show that proximal strait-adjacent deposits tend to be tide dominated, and wave and fluvial influence can be overprinted by tidal processes. Some insights into the formation of tidal dunes are discussed. For example, it is shown that compound tidal dunes may not be preserved differently than simple tidal dunes, which is relevant for predicting sedimentary architectures and fluid flow properties of ancient tide-dominated successions.

Sea Otters, Mercury, and Monitoring Climate Change

An increase in mobility of heavy metals, like mercury (Hg), has the potential to be one of the climate change related impacts on Arctic and sub-Arctic ecosystems. Sea level rise and flooding events in high latitude coastal ecosystems could increase the bioavailability of contaminants such as mercury. Mercury concentrations have been used as an indicator of past exposure to heavy metals in ancient Pacific cod and here we report on concentrations in archeologically recovered sea otter bones (Enhydra lutris). Methods utilizing stable isotope ratios can be used to reconstruct ancient food webs and help identify prey which may have bioaccumulated high concentrations of mercury. Modern sea otters have δ13C, δ15N, and mercury values corresponding largely to a benthic diet. Conversely, if higher δ15N and mercury levels were found in ancient sea otter bones located in a coastal ecosystem, these increases may be associated with rising sea level following the last glacial maximum. These data place present day and projected climate change related perturbations, like sea level rise, in a historical context.

The discovery of widespread agrichnia traces in Devonian black shales of North America: another chapter in the evolving understanding of a “not so anoxic” ancient sea

The discovery of widespread agrichnia traces in Devonian black shales of North America: another chapter in the evolving understanding of a “not so anoxic” ancient sea