Accumulation History Research Articles

Depositional conditions of siliceous microfossil-rich shale during the Ordovician–Silurian transition of south China: Implication for organic matter enrichment

Knowledge of the paleoenvironment is crucial to understand organic matter enrichment and shale gas development. Like organic matter, siliceous microfossils such as radiolarians and sponge spicules are widely distributed in Late Ordovician to early Silurian shales. However, there are few characterizations of the depositional conditions of siliceous microfossil-enriched layers. Here siliceous microfossil-rich shales from the Ordovician–Silurian transition in South China were selected for this study. We used major/trace element geochemistry to determine the sedimentary environment of siliceous microfossil-rich shale and to strengthen the understanding of the effect of siliceous microorganisms on organic matter enrichment. Our results show that most siliceous microfossils were deposited in anoxic reducing conditions with the presence of free hydrogen sulfide and accompanied by a moderately to weakly restricted seawater circulation. In addition, the nutrient-rich water bodies could upwell from the deep sea into the Yangtze Sea, and siliceous microfossil-rich shale was deposited during a period of high primary productivity. The shale layers of siliceous microfossils generally correspond to high gas-producing intervals and high organic matter abundance. The accumulation and preservation of organic matter in siliceous microfossil-rich shales is attributed to anoxic benthic conditions, high levels of primary productivity and flourishing of siliceous microorganisms. This study addresses the knowledge gap of the depositional conditions in siliceous microfossil-rich shale, and can help better understand the history of organic matter accumulation.

Phylogenomic discovery of deleterious mutations facilitates hybrid potato breeding

Hybrid potato breeding will transform the crop from a clonally propagated tetraploid to a seed-reproducing diploid. Historical accumulation of deleterious mutations in potato genomes has hindered the development of elite inbred lines and hybrids. Utilizing a whole-genome phylogeny of 92 Solanaceae and its sister clade species, we employ an evolutionary strategy to identify deleterious mutations. The deep phylogeny reveals the genome-wide landscape of highly constrained sites, comprising ∼2.4% of the genome. Based on a diploid potato diversity panel, we infer 367,499 deleterious variants, of which 50% occur at non-coding and 15% at synonymous sites. Counterintuitively, diploid lines with relatively high homozygous deleterious burden can be better starting material for inbred-line development, despite showing less vigorous growth. Inclusion of inferred deleterious mutations increases genomic-prediction accuracy for yield by 24.7%. Our study generates insights into the genome-wide incidence and properties of deleterious mutations and their far-reaching consequences for breeding.

Sediment routing systems to the Atlantic rifted margin of the Guiana Shield

Abstract Sediment routing systems of cratonic domains have not been studied extensively because their relief and erosion rates are very low, although their vast dimensions allowed them to contribute to a significant proportion of the sediments exported to the global ocean. To gain further insights into the behavior of cratonic sediment routing systems at geological time scales, we investigated the Guiana Shield and its Atlantic rifted margin (i.e., the Guiana-Suriname and Foz do Amazonas Basins, northern South America) over the Meso-Cenozoic with an emphasis on paleoenvironment and accumulation histories of the offshore sediments. We show that the basins of the Guiana Shield rifted margin record (1) periods of very low siliciclastic supply concomitant with the development of carbonate platforms, alternating with (2) phases of higher siliciclastic supply associated with sand-dominated clastic deposits and turbidites. Low siliciclastic supplies reflect either very limited rift-related relief growth and erosion such as during the Central Atlantic rifting in the Late Jurassic or intense lateritic weathering of the cratonic source area during Paleogene–Miocene climate optima. Higher siliciclastic supplies correspond either to (1) periods of rapid rift-related relief growth and erosion such as during the Equatorial Atlantic rifting (Early Cretaceous), (2) periods of drainage reorganization over a steadily eroding cratonic domain (Late Cretaceous), or (3) periods of tapping of sediments stored in the Andean retro-foreland basins via the presentday Orinoco and Amazon Rivers (Plio-Pleistocene).

Effect of aluminum accumulation on bone and cardiovascular risk in the current era.

The prevalence of aluminum (Al) intoxication has declined over the past 3 decades. However, different groups still report on the diagnosis of Al in bone. Prolonged and low-intensity exposures to Al may not be captured by serum Al measurements, preventing its proper diagnosis. We hypothesize that bone Al accumulation may be related to bone and cardiovascular events in the current Era. To detect the diagnosis of bone Al accumulation; to explore bone and cardiovascular consequences of Al accumulation. This is a sub-analysis of The Brazilian Registry of Bone Biopsy, a prospective, multicentre cohort, with a mean follow-up of 3.4 years, including patients with CKD undergoing bone biopsy; bone fracture and major cardiovascular events (MACE) were adjudicated; Al accumulation was identified by solochrome-azurine staining; history of previous Al accumulation was registered based on information provided by the nephrologist who performed the bone biopsy; bone histomorphometry parameters, clinical data, and general biochemistry were registered. 275 individuals were considered; 96 (35%) patients have diagnosed with bone Al accumulation and were younger [50 (41-56) vs. 55 (43-61) years; p = 0.026], had lower body mass index [23.5 (21.6-25.5) vs. 24.3 (22.1-27.8) kg/m2; p = 0.017], higher dialysis vintage [108 (48-183) vs. 71 (28-132) months; p = 0.002], presented pruritus [23 (24%) vs. 20 (11%); p = 0.005], tendon rupture [7 (7%) vs. 3 (2%); p = 0.03) and bone pain [2 (0-3) vs. 0 (0-3) units; p = 0.02]. Logistic regression reveals that prior bone Al accumulation [OR: 4.517 (CI: 1.176-17.353); p = 0.03] and dialysis vintage [OR: 1.003 (CI: 1.000-1.007); p = 0.046] as independent determinants of bone Al accumulation; minor perturbations in dynamic bone parameters and no differences in bone fractures rate were noted; MACE was more prevalent in patients with bone Al accumulation [21 (34%) vs. 23 (18%) events; p = 0.016]. Cox regression shows the actual/prior diagnosis of bone Al accumulation and diabetes mellitus as independent predictors for MACE: [HR = 3.129 (CI: 1.439-6.804; p = 0.004) and HR = 2.785 (CI: 1.120-6.928; p = 0.028]. An elevated proportion of patients have bone Al accumulation, associated with a greater prevalence of bone pain, tendon rupture, and pruritus; bone Al accumulation was associated with minor perturbations in renal osteodystrophy; actual/prior diagnosis of bone Al accumulation and diabetes mellitus were independent predictors for MACE.

Bayesian age–depth modelling applied to varve and radiometric dating to optimize the transfer of an existing high-resolution chronology to a new composite sediment profile from Holzmaar (West Eifel Volcanic Field, Germany)

Abstract. This study gives an overview of different methods to integrate information from a varve chronology and radiometric measurements in the Bayesian tool Bacon. These techniques will become important for the future as technologies evolve with more sites being revisited for the application of new and high-resolution scanning methods. Thus, the transfer of existing chronologies will become necessary because the recounting of varves will be too time consuming and expensive to be funded. We introduce new sediment cores from Holzmaar (West Eifel Volcanic Field, Germany), a volcanic maar lake with a well-studied varve record. Four different age–depth models have been calculated for the new composite sediment profile (HZM19) using Bayesian modelling with Bacon. All models incorporate new Pb-210 and Cs-137 dates for the top of the record, the latest calibration curve (IntCal20) for radiocarbon ages as well as the new age estimation for the Laacher See Tephra. Model A is based on previously published radiocarbon measurements only, while Models B–D integrate the previously published varve chronology (VT-99) with different approaches. Model B rests upon radiocarbon data, while parameter settings are obtained from sedimentation rates derived from VT-99. Model C is based on radiocarbon dates and on VT-99 as several normal distributed tie points, while Model D is segmented into four sections: sections 1 and 3 are based on VT-99 only, whereas sections 2 and 4 rely on Bacon age–depth models including additional information from VT-99. In terms of accuracy, the parameter-based integration Model B shows little improvement over the non-integrated approach, whereas the tie-point-based integration Model C reflects the complex accumulation history of Holzmaar much better. Only the segmented and parameter-based age integration approach of Model D adapts and improves VT-99 by replacing sections of higher counting errors with Bayesian modelling of radiocarbon ages and thus efficiently makes available the best possible and most precise age–depth model for HZM19. This approach will value all ongoing high-resolution investigations for a better understanding of decadal-scale Holocene environmental and climatic variations.

Rates of regional tau accumulation in ageing and across the Alzheimer's disease continuum: an AIBL 18F-MK6240 PET study.

Tau positron emission tomography (PET) imaging enables longitudinal observation of tau accumulation in Alzheimer's disease (AD). 18F-MK6240 is a high affinity tracer for the paired helical filaments of tau in AD, widely used in clinical trials, despite sparse longitudinal natural history data. We aimed to evaluate the natural history of tau accumulation, and the impact of disease stage and reference region on the magnitude and effect size of regional change. One hundred and eighty-four participants: 89 cognitively unimpaired (CU) beta-amyloid negative (Aβ-), 44 CU Aβ+, 51 cognitively impaired Aβ+ (26 with mild cognitive impairment [MCI] and 25 with dementia) had follow-up 18F-MK6240 PET for one to four years (median 1.48). Regional standardised uptake value ratios (SUVR) were generated. Two reference regions were examined: cerebellar cortex and eroded subcortical white matter. CU Aβ- participants had very low rates of tau accumulation in the mesial temporal lobe (MTL). In CU Aβ+, significantly higher rate of accumulation was seen in the MTL (particularly the amygdala), extending into the inferior temporal lobes. In MCI Aβ+, the rate of accumulation was greatest in the lateral temporal, parietal and lateral occipital cortex, and plateaued in the MTL. Accumulation was global in AD Aβ+, except for a plateau in the MTL. The eroded subcortical white matter reference region showed no significant advantage over the cerebellar cortex and appeared prone to spill-over in AD participants. Data fitting suggested approximately 15-20 years to accumulate tau to typical AD levels. Tau accumulation occurs slowly. Rates vary according to brain region, disease stage and tend to plateau at high levels. Rates of tau accumulation are best measured in the MTL and inferior temporal cortex in preclinical AD and in large neocortical areas, in MCI and AD. NHMRC; Cerveau Technologies.

Materialist Girl

Abstract Beginning to reconcile the meaning of the contradiction at the heart of trans historiography requires two methodological insights. The first is a qualified recommitment to trans studies' partial global turn with a fervently anticolonial edge that recognizes the basic coloniality of trans as category. The second is a practice of historical political economy that can situate contemporary transness within longue durée colonial histories of class formation, social relation, and capital accumulation. Taken in tandem, these approaches demonstrate the need for scholarship that denaturalizes the category of trans and reinterrogates its economic and scholarly value if trans studies is to find a future that addresses its much-critiqued Eurocentrism and whiteness.

Soil antibiotic resistance genes accumulate at different rates over four decades of manure application.

Manure can be a source of antibiotic resistance genes (ARGs) that enter the soil. However, previous studies assessing ARG persistence in soil have generally lacked continuity over sampling times, consistency of location, and assessing the impact of discontinuing manure application. We evaluated both short- and long-term ARG accumulation dynamics in soil with a 40-year known history of manure use. Manure application caused a greater abundance of tetracycline, macrolide, and sulfonamide ARGs in the soil. There was an initial spike in ARG abundance resulting from manure bacteria harboring ARGs being introduced to soil, followed by resident soil bacteria out-competing them, which led to ARG dissipation within a year. However, over four decades, annual manure application caused linear or exponential ARG accumulation, and bacteria associated with ARGs differed compared to those in the short term. Eleven years after discontinuing manure application, most soil ARG levels declined but remained elevated. We systematically explored the historical accumulation of ARGs in manured soil, and provide insight into factors that affect their persistence.

Theories of Political Ecology: Monopoly Capital Against People and the Planet

This article engages with and critiques dominant theories of political ecology. It takes the theory of ecologically unequal exchange (EUE) as the framework of critique. It assesses the claims of “fossil capitalism,” eco-modernism, extractivism, and degrowth, as well as the theories of “post-development.” It finds that with the exception of degrowth, none of them take imperialism or the global history of accumulation sufficiently seriously, and either displace transformative obligations wholly onto the South or adopt a framework which centers merely the agency of the Northern working class or a class-blind movement of movements. Instead, it proposes modifications of EUE based on the polarized nature of accumulation and waste production and distribution, and neocolonialism. It uses that framework to identify the antisystemic role of nature-reliant peripheral semi-proletarian classes, and from there reopens the debate on appropriate-scale industrialization along with ecological transformations of agriculture as paths to development in the twenty-first century.

Utilitarian Qubit, Human Geography, and Pandemic Preparedness in the 21st Century

Human actions are ambivalent in nature and this in turn has an impact on all components of socio-ecological systems. Their ambivalence results from the fact that human actions have both positive and negative outcomes and properties, which occur and manifest concurrently in the ontological realm of human existence. In terms of space–time, both micro-geography and macro-geography of human existence are intertwined during the COVID-19 pandemic, thus affecting pre- and post-pandemic space–time continuum. The utilitarian qubit can be used to describe the nature of human existence, i.e., Homo sapiens has always been experiencing a state of existence where pain and pleasure are co-extensive. In this state, it is impossible to establish to what extent pain, and to what extent pleasure, will have a definitive impact on our status as individuals and humanity as a species. In this article, the authors explore how the record of an individual’s life before and after the COVID-19 pandemic has been impacted by the wellbeing and actions of other humans and prior to one’s existence. Drawing on the utilitarian qubit, the COVID-19 pandemic, and its impacts on the members of Homo sapiens, can be understood as a partial outcome of the cumulative actions of humanity on the biosphere and other elements of the global ecosystem (the Age of the Anthropocene). We argue that this paper is also useful to foster disaster preparedness and resilience in the pandemic and post-pandemic era, at micro- and macro-geographical interfaces of human existence in the 21st century. The existence of individual members of Homo sapiens and humanity as a species is unfolding at the boundary between two levels: fundamental reality and situational reality. The result is the historical accumulation and ontological interconnectedness of humanity’s activities with one’s own actions. Pain and pleasure resulting from the COVID-19 pandemic and the Age of Anthropocene, as well as the right and wrong consequences of humanity’s actions, are posited here to be symptoms of the Anthropocenic (phase of) epidemiological transition.

Violência, Lazer e Turismo na Baixada Fluminense - Verde

Baixada Fluminense region is located in the metropolitan area of the capital of Rio de Janeiro. Despite the geographical proximity, the territory, that contains 13 municipalities, is dipped in a context of social and historical accumulation of violence, murderers, poverty, underdevelopment and State negligence. The main objective of this investigation was born from this territorial complexity: before such violent territory, what is the perception of the population of Baixada Fluminense about violence, leisure and tourism? The chosen method is both bibliographic and statistical. Thus, the chosen approach was qualitative and quantitative and the research techniques were: bibliographic review and online survey with statistically relevant sampling applied to 385 valid respondents. Among the findings, it is possible to point: (1) the violence manifests in different ways in the territory over different historical times; (2) a considerable part of the interviewees practice leisure in the region and believe in the tourist potential.

The Development Path of the Integration of Folk Art and Rural Revitalization in the Areas along the Huaihe River in Anhui Province

Now, in the process of comprehensively implementing the rural revitalization strategy, strengthening the construction of confidence in rural culture can effectively reverse the imbalance between urban and rural relations. Realize the strategy of rural revitalization, encourage the development of folk art, and create a new era of artistic revitalization of the countryside. Excellent national folk art is the historical accumulation of national cultural relics, which has a positive impact on promoting rural construction. To explore the value and realization way of folk art in rural construction, learn from experience and give play to existing advantages, enrich its cultural connotation, promote theoretical research and practice, protect and inherit local folk art, and further revitalize the countryside through national policies and talent introduction.

Drivers of global carbon emission changes: A heterogeneity perspective of decomposition and attribution analysis

Due to the differences in economic development, resource endowment, and historical accumulation, different types of countries have significant technical heterogeneity in carbon emissions. Identifying the driving factors of carbon emission changes, under the premise of distinguishing national heterogeneity, can provide a basis for the formulation of the “Differentiated Responsibilities” emission reduction policies. Therefore, this study introduces the idea of Meta-frontier into the traditional production-theoretical decomposition analysis, and constructs a new influencing factor analysis framework. Based on the newly built method, the empirical study of 60 representative countries draws the following three meaningful conclusion: 1) Different types of countries have obvious heterogeneity in technology, efficiency and change trend of energy use. Specifically, countries with higher energy intensity values generally have a quicker decline rate than those with lower energy intensity values. There exists “catch-up” effects for the backward to the advanced countries. 2) Decomposition results show that potential energy intensity (PEI) is the dominant factor reducing carbon emissions, especially for those large economic output with large energy consumption (Group-L) countries (0.604). Economic activity effect (ECA) is the most significant driving force for countries with small economic output and small energy consumption (Group-S), reaching 1.806. Meanwhile, the attribution results showed different characteristics in different groups of countries. The impact of various factors that reflect the heterogeneity of production process on carbon emissions mainly comes from the contribution of Group-L. 3) We suggest that, in the process of carbon reduction, large energy consumption countries should pay more attention to the gap between the development and speed of the world’s cutting-edge technologies.

How Does Energy Consumption and Economic Development Affect Carbon Emissions? A Multi-Process Decomposition Framework

Against the background that climate warming has become a global challenge, exploring the factors that drive carbon emissions change is important to achieve emission reduction targets. Because of the differences in economic development, resource endowment, and historical accumulation, different countries generally have significant technological heterogeneity in the carbon generation process. Therefore, the heterogeneity-related factors should also be understood, which can help policy making and responsibility attribution more accurate. As such, this study developed a meta-frontier-based production–theoretical decomposition analysis method to track the progress of carbon emission change in 42 countries during 2012–2019 with production heterogeneity between the countries taken into account. The empirical study draws the following three meaningful conclusions: firstly, the carbon emission process of different countries has clear technological heterogeneity, mainly reflected in aspects of their energy-use efficiency and energy-use technology. Secondly, the decomposition analysis results showed that the potential energy intensity effect and the economic activity effect played the dominant role in driving and reducing carbon emissions, respectively. Additionally, this conclusion is right for all types of countries. Thirdly, the attribution analysis showed that different types of countries have significantly different contributions to the influencing factors of carbon emission changes, among which countries with large energy consumption and large economies need to take more responsibility for emission reduction.

Gendering strategic action fields in sports governance.

How do meso-level field relations shape the ways that sports organizations act on gender equality? In this paper, we approach international sports governance as comprised of meso-level fields of strategic action in which male dominance and relations of masculinity are centrally at stake. We focus on the Union Cycliste Internationale (UCI), showing how the organization's efforts to address gender inequality are shaped by its relations with adjacent actors in the field. These actors jockey to form strategic coalitions as they struggle over the influence and resources to define the field configuration of international cycling, with challenges to the gendered status quo requiring careful management. Based on semi-structured interviews with individuals who held an elected or staff position within the UCI between 2005 and 2020, we show how field relations shaped the work of the UCI Women's Committee during this period as well as the experiences of women who succeeded in accessing decision-making roles. The UCI emerges in our analysis as a central governance unit via which the historical accumulation of advantage to men is preserved. We suggest that studying meso-level fields of strategic action can advance sociological research more broadly on how sports organizations are shaped by their contingent, dynamic, and (gender) unequal context.

The History of Cenozoic Carbonate Flux in the Atlantic Ocean Constrained by Multiple Regional Carbonate Compensation Depth Reconstructions

AbstractThe Atlantic is the only ocean basin almost entirely surrounded by passive margins, and a major global long‐term sink of carbonate carbon that has evaded subduction. Quantifying the history of carbonate accumulation in the Atlantic has been limited by the absence of well‐defined regional carbonate compensation depth (CCD) models. We determine the CCD for the northern North Atlantic, central North Atlantic, and South Atlantic, and use these reconstructions to compute the carbonate carbon mass and carbonate carbon flux in a tectonic framework at 0.5 m.y. intervals since 66 Ma. We find that the total carbonate carbon mass of the Atlantic has grown 2.5‐fold from ∼1,500 Mt at 66 Ma to ∼3,800 Mt at present day. The overall Cenozoic increase in carbonate carbon flux toward the present day is punctuated by “carbonate crash” phases in the mid‐Eocene at ∼44–38 Ma and in the mid‐late Miocene at ∼19–8 Ma. During these times the flux decreases from ∼45 to ∼25 Mt C/yr, likely caused by carbonate dissolution and reductions in productivity. Reduced carbonate carbon flux in the mid‐Eocene also coincides with reduced calcification rates of small coccolithophores previously observed offshore Africa. After ∼8 Ma the carbonate carbon flux rises to a Cenozoic maximum of ∼75 Mt C/yr at ∼3 Ma, possibly driven by enhanced flux of nutrients into the ocean. Our CCD curves and the resulting carbonate accumulation history are useful for calibrating ocean chemistry models, and constraining global terrestrial weathering rates, climate perturbations, and carbon cycle models.

Chromosome-scale genome assembly of the brown anole (Anolis sagrei), an emerging model species

Rapid technological improvements are democratizing access to high quality, chromosome-scale genome assemblies. No longer the domain of only the most highly studied model organisms, now non-traditional and emerging model species can be genome-enabled using a combination of sequencing technologies and assembly software. Consequently, old ideas built on sparse sampling across the tree of life have recently been amended in the face of genomic data drawn from a growing number of high-quality reference genomes. Arguably the most valuable are those long-studied species for which much is already known about their biology; what many term emerging model species. Here, we report a highly complete chromosome-scale genome assembly for the brown anole, Anolis sagrei – a lizard species widely studied across a variety of disciplines and for which a high-quality reference genome was long overdue. This assembly exceeds the vast majority of existing reptile and snake genomes in contiguity (N50 = 253.6 Mb) and annotation completeness. Through the analysis of this genome and population resequence data, we examine the history of repetitive element accumulation, identify the X chromosome, and propose a hypothesis for the evolutionary history of fusions between autosomes and the X that led to the sex chromosomes of A. sagrei.

The Fucino 250–170 ka tephra record: New insights on peri-Tyrrhenian explosive volcanism, central mediterranean tephrochronology, and timing of the MIS 8-6 climate variability

The Fucino Basin, central Italy, with its long and continuous history of Quaternary sediment accumulation, is one of the richest Mediterranean Middle Pleistocene tephra records. Here, we present a new detailed investigation of tephra layers (tephras) of the 250–170 thousand years before present (ka) interval, corresponding to the entire Marine Isotope Stage (MIS) 7 and parts of the MIS 8 and MIS 6. The investigated tephras have been characterised in terms of major, minor and trace elements, Sr–Nd isotopic compositions and 40Ar/39Ar ages. For correlation purposes, glass compositions and several new 40Ar/39Ar ages of selected proximal pyroclastic units spanning the same temporal interval from Vulsini (Latera Volcanic Complex), Sabatini, and Vico volcanic systems, central Italy, were measured. The late MIS 8-early MIS 6 Fucino tephras were backtracked to their corresponding volcanic sources, which include the Vulsini, Vico, Sabatini, Roccamonfina, Ischia and Campi Flegrei volcanic systems. While some of these tephras have been correlated to specific eruption units, other layers are currently not documented or described in near-vent sections, thus highlighting previously unrecognised events generated by these volcanic systems. Furthermore, the new high precision 40Ar/39Ar ages provide improved temporal constraints for Fucino making it one of the most detailed and chronologically best constrained tephra records for central Mediterranean MIS 7 tephrochronology. The Fucino record thus provides new integrative information for reconstructing the explosive history of Italian volcanoes during the investigated time interval. Furthermore, the geochronological constraints provide the basis for future paleoclimatic investigations at local and regional scale.

Chronology of trace elements and radionuclides using sediment cores in Golden Horn Estuary, Sea of Marmara

Trace elements and radionuclides are substantial pollutants in marine environment since they are non-biodegradable and can be harmful even in minute concentrations. The Golden Horn estuary, where is an inlet of Bosphorus and two creeks, has been seriously polluted by untreated municipal and industrial dischargers for several decades. Since 1998, a large restoration and rehabilitation efforts have been undertaken in the estuary to mitigate the pollution. In the present study, four sediment cores were taken from the Golden Horn estuary to assess the historical accumulation of trace elements and radionuclides. Radiometric dating was implemented by 210Pb and 137Cs radionuclides and CRS model. Sedimentation rates were calculated in the range of 0.92–0.97 cm yr−1 in the estuary. The distribution of radionuclides (40K, 226Ra, and 228Ra) indicated some slight variations which ascribes to the geological characteristics of sediment along the cores. The concentrations of the anthropogenic elements were relatively higher in the intensive industrialization period. Their concentrations reduced in the latest 15–20 years thanks to the large-scale rehabilitation project in the estuary. The pollution indices, namely EF, Igeo, CF, and PLI showed that the concentrations of Cd, Cr, Cu, Pb, Sb, and Sn were above the world averages. Our results provide an insight on the long-term accumulation trends of trace element in the Golden Horn, which revealed that the estuary remains moderately polluted. We suggest that preventive countermeasures are much more important than post pollution remediation in the case of metallic pollution in the estuaries.

The Prisayan Formation (Lower and Middle Jurassic) of the Irkutsk Coal Basin: New Data on Litho- and Phytostratigraphy

Abstract —The demand for detailed bio- and lithostratigraphic research of the Prisayan Formation is significant because of the lack of its stratotype section. This leads to confusion about the meaning of the stratigraphic volume of the Prisayan Formation. On the basis of the results of a comprehensive research, a lectostratotype section that covers the whole section of the Prisayan Formation is proposed. The following three subformations are identified in the formation on the basis of lithological criteria: lower (Ust-Balei), middle (Idansk), and upper (Sukhov). Stratigraphic correlation of the Prisayan Formation with the coeval deposits of the West Siberian Plate is carried out. The common development trends of typical units of the flora of the Siberian paleofloral region are revealed in West Siberia and the Irkutsk Basin. The observed tendencies make it possible to compare the beds with Coniopteris murrayana, Sphenobaiera czekanowskiana from the lower subformation with the fossil plant assemblage of the Sharapovo Horizon; the beds with Coniopteris snigirevskiae from the middle subformation with the fossil plant assemblage of the Nadoyakh Horizon; and the beds with Raphaelia diamensis and Phoenicopsis irkutensis with the fossil plant assemblage of the Laidin Horizon of West Siberia. The Prisayan-1 palynoassemblage (PA) from the lower and middle subformations correlate with palynozones 5–7 of West Siberia. The Prisayan-2 PA corresponds to palynozone 8 of West Siberia. The paleobotanical and palynological data suggest that the stratigraphic volume of the Prisayan Formation is the upper Pliensbachian–Aalenian of the Lower–Middle Jurassic. This paper touches upon the history of accumulation of the Prisayan Formation, as well as the evolution of the paleorelief and vegetation.