PALYNOLOGICAL STUDIES OF BRONZE AGE ARCHAEOLOGICAL OBJECTS FROM THE ISHKINOVKA MINING SITE

В статье приводятся результаты палинологических исследований археологических объектов бронзового века в районе Ишкининского медного рудника: разреза на поселении Ишкиновка и погребенных почв, сохранившихся под отвалами карьеров. Палинологические исследования образцов с поселения Ишкиновка позволили получить информацию о характере формирования культурного слоя поселения, образование которого связано с руинированием саманных построек с органическими перекрытиями. Особенности строительных материалов предопределили сложный многокомпонентный состав палинологических комплексов. Результаты палинологических исследований на Ишкининском руднике и поселении Ишкиновка хорошо согласуются с реконструируемой моделью их функционирования, в соответствии с которой выделяется не менее трех этапов разработки Ишкининского месторождения на протяжении ПБВ. Каждому из выделенных хронологических этапов соответствует самобытный палинологический спектр, отражающий динамику природно-климатической ситуации в районе исследований. Эти данные надежно верифицируются результатами радиоуглеродного датирования погребенных почв, законсервированных под отвалами карьеров. The paper describes the results of palynological studies of Bronze Age archaeological assemblages discovered within the Ishkinovka copper mining center, i. e. the section at the Ishkinovka settlement, and the buried soils preserved under the dumps from the open-pit mines. Palynological studies of the samples from Ishkinovka helped obtain information on how the occupation layer at the settlement was formed. Its formation is linked to ruination of mudbrick constructions with organic roofing. Distinctive features of the construction materials predetermined a complex multi-component composition of palynological assemblages. The results of the palynological studies at the Ishkinovka mining site and the Ishkinovka settlement correlate well with the reconstructed model of their operation. At least three stages of the Ishkinovka deposit development during the Late Bronze Age have been singled out. Each identified chronological stage corresponds to a distinctive palynological spectrum reflecting changes over time in the natural and climatic situation in the studied region. These data are reliably verified by the radiocarbon dating of the buried soils preserved under the dumps of the open-pit mines.

Sedimentation, depositional environments, and hydrocarbon potential of the Maastrichtian-Paleocene Araromi Formation, eastern Dahomey (Benin) Basin, southwestern Nigeria

The Cretaceous sediments in southwestern Nigeria are host to one of the largest bitumen deposits in the world. In the current paper, an integrated study on sedimentology, palynology, and applied petroleum geochemistry of the Maastrichtian-Paleocene Araromi Formation was used to determine the depositional environments and hydrocarbon potentials of the formation on the eastern Dahomey Basin. Four sedimentary lithofacies were identified from core samples, namely, lower limestone (F1); medium to coarse-grained sandstone (F2); lower loosely consolidated sandstone (F3); and shale and siltstone (F4). Sedimentation in the eastern Dahomey Basin occurred mainly in fluvial and shallow-marine (shelf) environments. The palynological assemblages of the Araromi Formation reflect deposition in coastal through brackish water to shallow shelf environment with periods of localized wind-induced storms. The shale and siltstone samples of the Araromi Formation are characterized by total organic carbon (TOC) values of up to 2.50 wt % and S2 (hydrocarbon-generating potential) values ranging from 0.26 to 0.70 mgHC/g rock, indicating poor source rocks. Shales show poor quality and thermally immature organic matter at shallow depth and could neither have generated liquid hydrocarbon nor contributed to the heavy oil occurrence on the bitumen and tar-sand belt of eastern Dahomey (Benin) Basin.

A new Late Triassic palynological assemblage from western Gondwana (Carrizal Formation, Marayes Basin, Argentina)

The Carrizal Formation, exposed in the Marayes-El Carrizal Basin (western Argentina), has been the focus of palaeobotanical studies since the late 1800s. The recent finding of well-preserved palyno­logical assemblages provides the first detailed studies about its palynofloras. In this paper, the 63 taxa identified in the unit are illustrated and discussed, as well as their stratigraphic distribution in equivalent palynological assemblages of Argentina. Some spore species are revised: Uvaesporites hammenii (Herbst) Césari, comb. nov., Retusotriletes wielandii (Jain) Césari, comb. nov. and Lundbladispora stellae (Herbst) Césari, comb. nov. The recognition of Cadargasporites baculatus de Jersey & Paten emend. Reiser & Williams, Craterisporites rotundus de Jersey, Enzonalasporites vigens Leschik, ­Leptolepidites argenteaeformis (Bolkhovitina) Morbey, Protodiploxypinus americus Dunay & Fisher and Rugulatisporites permixtus Playford, among others, appears to be useful for local and intercontinental correlations. A Carnian age is proposed for the palynofloras.

Paleoclimatic and Redox Condition Changes during Early-Middle Jurassic in the Yili Basin, Northwest China

The Jurassic was mainly a “greenhouse” period characterized by global warming and by significant peat accumulations in some continental basins. However, studies of Jurassic climate and environments have mainly focused on marine records and only a few on terrestrial sediments. Yili Basin, a mid-latitude terrestrial basin in present Northwest China, included accumulation of the important recoverable coal seams. In this study, geological data, clay mineral analysis, and palynological assemblages were employed on fine-grained samples from the Su’asugou section in southern Yili Basin. The factors (paleoclimate, depositional conditions, and paleo-vegetation) impacting peat accumulation were investigated. The results suggest that the siliciclastics may have been derived from exposed Carboniferous rocks in a continental arc environment. A warm and humid paleoclimate in the Yili basin dominated during the early-Early Jurassic deposition of the Badaowan Formation and the Middle Jurassic deposition of the Xishanyao Formation. This climate contributed to high sedimentary rates and to a high productivity of peat-forming paleo-vegetation that was preserved under dysoxic conditions. In contrast, during the late-Early Jurassic between these two formations, the Sangonghe Formation was an interval of relatively aridity that included red beds preserved under more hypoxic sedimentary conditions, and with an interruption in peat formation and preservation.

Palynofacies, environments, and climate changes in the Magdalena River Basin

ABSTRACTFour environments (swamp, shallow lake, alluvial flood plain, and lagoon) from the Lower Magdalena River Basin were studied for palynofacies’ quantitative characterization. Each environment has been described based on four criteria: palynomorph assemblage, organic matter concentration, organic matter palynological composition, and organic particle morphology.Shallow lakes’ palynological assemblages are dominated by composite and grass pollen. The POM (particulate organic matter) morphology is characterized by a maximum at Φ 5 class (silt), and it has a sphericity histogram with bimodal distribution (peaks at 0.1 and 0.5/0.6). From a composition point of view, POM is mainly opaque amorphous materials. POM concentration is usually lower than 0.1%.Swamp environments palynological assemblages are dominated by grass pollen with a slightly smaller amount of composite pollen. The POM is dominated by finely dispersed amorphous and indeterminate “other” types (organo-mineral gel ?), depending on the oxidation degree. The swamp concentration of organic matter a few centimeters below the water-sediment interface varies between 0.1% and 0.3%. Below that, organic concentration is usually lower than 0.1%.Lagoon assemblages are rich in species and specimens, but assemblages are highly variable. Main components are either finely dispersed amorphous or plant cuticular/epidermal or amorphous homogeneous and heterogeneous or fungal remains. Peat lithology is rich in mangrove pollen, while clay assemblages are dominated by composites, grass, and water plants together with Botryococcus algal remains. Lagoon sediments are the richest in POM concentration, with values between 0.13% and 1% (excluding peats). Regarding particle size and shape, in this environment, they show a trend to decrease in grain size from Φ 1 to Φ 2 class (sand) dominated assemblages to Φ 5 to Φ 6 class (silt) dominated assemblages from base to top. Elongated shapes are abundant, with 30% to 50% of particles in the tabloid to elongated tabloid classes.Alluvial - fluvial flood basin samples are often barren in palynomorphs and organic matter. Occasionally present grass pollen and fungal remains. The POM, when present, is mainly of organo-mineral gel type and has a bimodal grain size distribution, with a minor peak at Φ 7 class (v.f.silt) and a major peak at Φ 4 to Φ 2 class (c. silt to f. sand).Significant changes in quantitative palynofacies occur within the top few meters of the cores, representing the last 1000 yr of sedimentation in the area. These changes are related to shifts in climate, from colder to warmer conditions or from dry to wet periods, most probably linked with E.N.S.O. A short dry and cold period related to the “Little Ice Age” was identified in the Ayapel and Cienaga de El Medio cores.

Multidisciplinary palaeoenvironmental characterisation of the late Permian Matinde Formation, Mozambique

<p>The Muarádzi Sub-basin is part of the Moatize-Minjova Basin (MMB), an important Karoo aged coalfield in Tete Province, Mozambique. It is a WNW-ESE trending, elongated sedimentary basin located in the eastern part of the MMB, whilst during the late Permian was situated in the southern-central part of Gondwana. In this study, we undertook a multidisciplinary approach involving the lithological, palynofacies, and palynological analysis of samples collected from 3 coal exploration boreholes (DW11, DW21, and DW141) collected from this sub-basin. A total of 99 core samples were collected and studied, allowing for the characterisation of depositional environments and existing palaeofloras for this sub-basin.</p><p>The palynological data indicates that all the successions have a Lopingian age, and a vast lowland fluvial setting existed in an area controlled by tectonic movements associated with a continental rifting phase. Correlation between the three sections enabled the recognition of an initial meandering fluvial system affected by repeated flooding events that changed to a braided river. The palynofacies corroborate the interpreted fluvial model and the palynological record obtained.</p><p>The existence of a humid and warm climate during the Lopingian led to the development of vast floodplains and diversified wetland types, typical of lowland settings recorded in the analysed samples. The palynofacies analysis also indicate that the thick coal beds’ development is associated with deposition in anoxic to dysoxic environments. Furthermore, the <em>Glossopteris </em>Province vegetation, responsible for the coal development in the Muarádzi Sub-basin, is documented in the palynological assemblages, allowing for the characterization of a flora dominated by glossopterids (<em>Protohaploxypinus </em>and <em>Striatopodocarpites</em>) and gymnosperm pollen (<em>Alisporites</em>). The palaeofloral analysis based on palynological data also shows that associated ferns (e.g., <em>Osmundidacites senectus</em>, <em>Thymospora pseudothiessenii</em>), sphenophytes (e.g., <em>Calamospora</em>) and lycophytes (e.g., <em>Lundbladispora</em>, <em>Kraeuselisporites</em>) were common in this area. Additionally, upland vegetation indicators in the palynological assemblages, as monosaccate pollen grains, are rare, indicating that upland regions were distant from the studied sections.</p><p> </p><p><strong>Acknowledgements</strong></p><p>This research was fully supported by the project PALEOCLIMOZ (PTDC/CTA-GEO/30082/2017), funded by Fundação para a Ciência e Tecnologia, Portugal. The authors would also like to acknowledge the financial support of the Portuguese Foundation of Science and Technology (FCT) to CIMA through UIDP/00350/2020.</p><p> </p>

A comparison of Holocene testate amoeba assemblages and paleohydrological records from pollen slides and wet-sieved peat

In this study, we compared new testate amoeba records produced by the conventional water-based wet-sieving method to testate amoeba data from previous palynological analyses of two Holocene peat profiles from British Columbia, Canada. We used 132 paired samples from the same peat cores to compare the composition of testate amoeba assemblages between the two methods and evaluate the potential of palynological testate amoeba records as quantitative paleohydrological proxies in peatlands. Our results suggest that the palynological treatments (acetolysis, 10% KOH and 150 µm sieving) substantially reduce test concentrations, diversity and richness in most pollen-slide samples. The smaller sieve size used in the palynological treatment (i.e. 150 µm) removed only a small fraction of the total tests, but could introduce a species-specific bias in assemblage composition. However, major shifts between wet and dry conditions, as shown by the water table depth (WTD) reconstructions using wet-sieved samples, were relatively well captured by the palynological datasets in most instances. The palynological assemblages with counts of >50 tests ( n = 30) provided WTD estimates similar to those inferred from the wet-sieved samples as the most dominant hydrophilous and xerophilous taxa were relatively well represented in the pollen-slide samples in the two studied peat cores. Testate amoeba data from pollen slides can provide useful paleohydrological information particularly when combined with other paleoenvironmental proxies. Nonetheless, if the goal is to generate quantitative paleohydrological reconstructions, we recommend that testate amoeba analyses be conducted using the wet-sieving method, as testate amoeba concentrations, diversity and richness are typically much lower in samples prepared with palynological treatments.