نتایج جستجو برای: calcitic hypocoatings

تعداد نتایج: 223  

Journal: :Quaternary 2022

Recent findings of archaeological research in the Vathy gulf area, Astypalaia Island, indicate its continuous habitation since prehistoric times, most importantly transitional period from Final Neolithic to Early Bronze Age (late 4th/early 3rd millennium BC). The evaluation stone artefacts using non-invasive analytical methods (Near Infrared Spectroscopy—NIR), combination with mineral-petrograp...

Journal: :Frontiers in Earth Science 2022

Rhodolith limestones occur in the upper part of Miocene infill Ronda Basin southern Spain. This basin was an embayment at margin Atlantic-linked Guadalquivir Basin, foreland Betic Cordillera. Messinian rhodolith crop out mesa Roman settlement Acinipo. They mostly consist trough cross-bedded rudstones, which change basinward to large-scale planar turn pass laterally and flat-bedded bryozoan ruds...

Journal: :Frontiers in Earth Science 2021

Coccolithophores are one of the major contributors to pelagic production calcium carbonate and their fossilized remains a key component biogeochemical cycles (Ca), magnesium (Mg), other divalent cations present in intracellular precipitated calcitic structures (coccoliths). The geochemical signature coccoliths (e.g., Sr/Ca Mg/Ca ratios) is used as paleoproxy reconstruct past environmental condi...

Journal: :Radiocarbon 2022

ABSTRACT In many locations around the world, shell radiocarbon dates underpin archaeological research. The dating of brings chronological relationship between sample and target event (e.g., hunting food preparation) into congruence, while shells are valuable geochemical proxies for understanding past climate dynamics environments. However, this information can be lost as shell, composites biopo...

Journal: :Minerals 2021

Small Shelly Fossils (SSFs) from the Cambrian are widely distributed and well known across different paleocontinents of world. However, middle SSFs North China Platform have only rarely been documented until now. In this paper, we presented first report on bioclastic oolitic limestones Zhangxia Hsuzhuang formations Henan province, China. The carbonate-hosted fauna includes brachiopods (Micromit...

Journal: :Biogeosciences 2022

Abstract. Several foraminifera are deposit feeders that consume organic detritus (dead particulate material with entrained bacteria). However, the role of such in benthic food web remains understudied. Foraminifera feeding on methanotrophic bacteria, which 13C-depleted, may cause negative cytoplasmic and/or calcitic δ13C values. To test whether foraminiferal diet includes methanotrophs, we perf...

Journal: :Archaeological and Anthropological Sciences 2023

Abstract Limestones (CaCO 3 ) have been an important source for masonry and mortars throughout approx. 10,000 years of human history. They are often composed calcitic shells minute marine algae, known as calcareous nannofossils. The 0.25–30-µm large skeletons these primary producers well documented from various archaeological materials including building stones masonry. Surprisingly, tiny micro...

Journal: :Soil systems 2023

Combined paper mill biosolids (PB) and forest-derived liming by-products improve soil properties, but their residual effects following several years of application have hardly been investigated. A 13-year (2009–2021) field study was initiated at Yamachiche, QC, Canada, to assess the PB materials on properties a loamy soil. The applied during nine consecutive (2000–2008) 0, 30, 60, 90 Mg wet·ha−...

Journal: :Basin Research 2021

The Apennines are a retreating collisional belt where the foreland basin system, across large domains, is floored by subaerial forebulge unconformity developed due to uplift and erosion. This overlain diachronous sequence of three lithostratigraphic units made (a) shallow-water carbonates, (b) hemipelagic marls shales (c) siliciclastic turbidites. Typically, latter two have been interpreted reg...

Journal: :Paleobiology 2022

Abstract The end-Permian mass extinction occurred alongside a large swath of environmental changes that are often invoked as mechanisms, even when direct link is lacking. One way to elucidate the cause(s) investigate selectivity, it can reveal critical information on organismic traits key determinants and survival. Here we show machine learning algorithms, specifically gradient boosted decision...

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