Middle Interval Research Articles

Allocyclic and autocyclic controls on facies distribution in interdistributary bayfill deposits of the Campanian Neslen Formation, Eastern Book Cliffs, Utah, U.S.A.

ABSTRACT The Campanian Neslen Formation, in the eastern part of the Book Cliffs, is divided into three stratigraphic intervals. The middle Neslen interval consists of paralic bayfill deposits that average 23 m in thickness. This article describes the lateral and vertical variability within the bayfills deposited in this middle Neslen interval. Comprehensive mapping along 27 km of outcrops, including high-resolution description of 62 sedimentary logs and incorporation of wireline log data from 86 wells, has led to a detailed understanding of the processes related to infilling of interdistributary bays. Six vertically stacked heterolithic to sand-prone bayfill units are identified. A distinction is made between bayfill units and bayfill successions, based on their bounding autocyclic or allocyclic flooding surfaces. Units are bounded by high-frequency flooding surfaces, and show large lateral variations in thickness, facies associations, and lithology. These bayfill units are laterally subdivided into a varying number of bayfill successions, separated by interdistributary channel systems or associated bayhead-delta facies associations. Lateral variation in facies architecture, salinity, and depositional energy levels are mapped in each bayfill succession. This variation is attributed to several controlling factors, including proximity to sediment entry points, water depth, the sequence stratigraphic position of the bayfill succession, and the compaction of underlying sandbodies. The detailed facies patterns and multitude of tributary causes described and discussed here are applicable to an overall understanding of facies architecture in paralic environments.

Enrichment Mechanism of Polymetallic Elements at the Base of the Niutitang Formation in Southeast Chongqing

Polymetallic enrichment layers are commonly found at the base of the Lower Cambrian and extensively distributed across the Upper Yangtze Platform, yet their genetic models remain controversial. This study systematically collected samples from a typical section in the southeastern Chongqing region for mineral, organic, and inorganic analyses. It investigates the relationship between the abundance of various trace metal elements and organic matter at the base of the Niutitang Formation, as well as the vertical distribution characteristics of organic carbon isotopes and organic matter features. The results indicate that the Niutitang Formation shale exhibits a distinct three-part structure from bottom to top. Various metal elements are enriched in the lower interval, showing a close correlation between the abundance of polymetallic elements and the carbon isotopes of shale organic matter. The middle interval contains the highest TOC value and the lowest Ti/Al ratio, while the upper interval shows a significant decrease in organic matter abundance, with a clear positive correlation between the excess silicon content and Ti/Al ratio. Additionally, the mixing effect of deep-sea upwelling is the primary control on the formation of polymetallic enrichment layers in the lower interval, followed by the adsorption of organic matter under anoxic conditions. The sedimentary environment of the upper interval of the Niutitang Formation trends toward oxidation, with paleoclimate shifting toward colder and drier conditions, exhibiting aeolian sedimentary features that are unfavorable for the enrichment of trace metal elements. Consequently, upwelling is a key factor in the enrichment and mineralization of trace metal elements at the base of the Lower Cambrian in the Upper Yangtze region.

Role of Doppler Trasonography in Predicting Recovery From Early Allograft Dysfunction in Liver Postoperative Patients

ObjectiveThe aim of this study was to observe the recovery of liver function in patients with early allograft dysfunction (EAD) at one month postoperatively and explore whether early postoperative ultrasonic hemodynamic parameters can predict this outcome. MethodsPatients with EAD postoperatively, who underwent orthotopic liver transplantation (OLT) in our hospital from December 2012 to June 2021, were retrospectively collected. Based on the recovery of liver function within one month, patients were divided into two groups: the recovery group (FR-1M) and the non-recovery group (Non-FR-1M). Ultrasonic hemodynamic parameters within the first seven days postoperatively were compared between the two groups. ResultsAmong the 254 EAD patients included in this study, 158 (62%) patients recovered their liver function within one month. Of the 96 (38%) patients who did not recover, The RI of the non-FR-1M group was significantly lower than that of the FR-1M group on postoperative day 6 (POD6) and POD7. In the high resistance interval (RI all > 0.7), Group FR-1M represents a significant proportion (29/3, ratio 12/1), while in the low resistance interval (RI < 0.5 at least once), Group non-FR-1M accounts for a relatively high proportion (12/27, ratio 5/11). In the middle resistance interval (more than 1 time ≤ 0.7 and all ≥ 0.5), the proportions of the two groups are balanced (85/88, ratio 1/1). ConclusionLiver function typically recovers within 1 month in most patients with EAD. The high resistance state of the hepatic artery in the early postoperative period is illustrative an important role in its recovery. Low-resistance state is most unfavorable for the recovery of liver function.

MOSCOVIAN FUSULINIDS (FORAMINIFERA) FROM SE TUNISIA: THE CASE OF KR-1 KIRCHAOU BOREHOLE (TATAOUINE AREA)

Moscovian (Middle Pennsylvanian) deposits with mixed oolitic and fossil-rich carbonates have long been known from the Kirchaou KR-1 borehole in SE Tunisia. However, its biostratigraphy has never been investigated in detail. This study is mainly dedicated to reviewing the late Bashkirian and Moscovian successions, and characterizing the late Moscovian-early Kasimovian boundary interval. The important fusulinoid faunas of the Middle Pennsylvanian interval within the 315.5-meter-thick KR-1 borehole mainly include staffellines, eostaffellines, millerellines, pseudostaffellines, and Fusulinoidea, which are first illustrated here. The distribution of the main index taxa allows us to distinguish four foraminiferal biozones: (1) the Tikhonovichiella tikhonovichi - Profusulinella Zone of the Melekessian-Vereian (latest Bashkirian-earliest Moscovian), (2) the Beedeina – Citronites Zone of the Kashirian (late early Moscovian), (3) the Taitzehoella prolibrovichi – Fusulina of the Podolskian (early late Moscovian), (4) the Protriticites - Quasifusulinoides Zone of the Myachkovian - Krevyakinian (late late Moscovian – early Kasimovian). The Moscovian - Kasimovian transition is mainly characterized by Protriticites, Quasifusulinoides, Montiparus, Topilinia, Beedeina, Fusiella, Profusulinella, and Fusulinella taxa. The study of fusulinoid assemblages allows reliable correlations with coeval associations from the Russian Platform, Southern Urals, Western Europe, Spain, and Donbas (Ukraine)

Characterization of seismic-scale petrofacies variability in the Arbuckle Group using supervised machine learning: Wellington Field, Kansas

The Arbuckle Group in southern Kansas has been investigated for carbon geosequestration-related studies. In this study, we evaluated the seismic-scale petrophysically defined facies variability of the Arbuckle Group at the Wellington Field, Kansas, using quantitative seismic interpretation and a supervised Random Forest classification approach. We first defined three petrophysics-based rock types (petrofacies) from core-derived porosity and permeability measurements using the flow-zone indicator approach. Then, using the artificial neural network, we classified these petrofacies in noncored intervals. We observed that petrofacies 1 corresponds to medium and coarse-grained dolomitic packstone, wackestone, and dolomitic breccia with up to 8% porosity and D-scale permeability values. Whereas petrofacies 2 and 3 correspond to argillaceous and fine-grained micritic dolomites and dolomitic mudstones with lower permeability values for a given porosity, with respect to petrofacies 1. Using the common reflection-point gathers, we performed prestack seismic inversion and calculated various amplitude-variation-with-offset (AVO) attribute volumes. We used these elastic properties and AVO attribute volumes as input for estimating supervised seismic-scale 3D petrofacies and petrofacies probability volumes using the Random Forest algorithm. Results reveal the complex distribution of the petrofacies in the candidate injection and baffle zones in the study area, where petrofacies 1 is mainly prevalent within the lower and upper portions of the Arbuckle group, whereas petrofacies 2 and 3 are mainly present in the middle Arbuckle interval. The workflow we present through this study provides the spatial variability of facies distribution that is reflective of the actual lithology and petrophysical properties of the Arbuckle group in the study area with limited well control.

Lenition of fricative sibilants in casual conversations in Basque

This paper analyses lenition of lamino-alveolar and apico-alveolar fricative sibilants in Basque in casual conversations between speakers of the variety of Beasain (Central Basque dialect). To describe the phonetic realisation of sibilants, the following measures were used: the proportion of voiced frames, the centre of gravity and relative intensity. Results show that 13% of sibilants can be classified as ‘voiced’ (i.e. they show uninterrupted voicing during the middle 50% of the duration) and another 25% has at least one voiced frame in the middle interval. Several factors were identified as important predictors of voicing: context, speech rate and the presence of the word boundary. It is also shown that voicing lowers the sibilants’ centre of gravity and relative intensity. Finally, the paper discusses potential lexical effects in lenition phenomena.

Chronostratigraphy and tectono‐sedimentary history of the Eastern South Pyrenean foreland basin (Ripoll Syncline, North‐East Spain)

AbstractThis paper contributes to an understanding of the tectono‐sedimentary evolution of the South Pyrenean foreland system by reviewing the chronostratigraphic framework of the basin infill in its eastern sector. Six sections are analysed and cross‐correlated to build a 6.5 km thick composite magnetostratigraphy that represents the complete record of the Cadí Nappe in the Ripoll Syncline. New and previous magnetostratigraphic sections are integrated with available biostratigraphy to provide a new age calibration of the sedimentary succession of the Cadí Nappe, encompassing from Palaeocene to Middle Lutetian age. The proposed correlation with the Geomagnetic Polarity Time Scale aims at best reconcile magnetostratigraphic data with the regional biochronology built on the marine Shallow Benthic Zonation (SBZ biozones), the continental mammalian biochronology (MP levels) and the newly collected charophyte data. A subsidence analysis was performed on the calibrated composite succession, resulting in two well‐defined intervals bounded by a hiatus. A Palaeocene to Early Eocene interval with low (11–21 cm/kyr) total subsidence rates, and an Early to Middle Eocene interval, characterised by high (70–75 cm/kyr) total subsidence rates. The detailed trends in both subsidence and sedimentation mark the development and evolution of the foreland depozones, from distal foreland depozones to foredeep and wedge‐top depozones, relative to the emplacement of the Pedraforca Nappe and Cadí Thrust Nappe. The most pronounced sedimentary shift in the Cadí Nappe occurred at 49 Ma, with the rapid drowning of the carbonate platforms and its transition into talus and deep basinal environments. Carbonate platforms collapsed and resedimented on the talus of the elongated trough, newly formed parallel to the orogenic front. This marked the onset of tectonic subsidence triggered by the submarine emplacement of the Lower Pedraforca Nappe. The emersion of the orogenic wedge drove the entry of siliciclastics, lagged by 1 Myr, into the Ripoll Trough. The foredeep filled rapidly (5.5 km thickness in less than 7 Myr) compared to other South Pyrenean regions, favoured by its semi‐enclosed palaeogeography. The emplacement of the Vallfogona Thrust as early as the Middle Lutetian (43 Ma) brought the Cadi Nappe into a wedge‐top setting. However, the Ripoll growth syncline continued acting as a temporary sink for alluvial sedimentation while a foredeep developed further south in the autochthonous Ebro Basin. The flexural response of the Iberian plate to the tectonic thickening of the Axial Zone counterbalanced for a period the local uplift of the Cadi Nappe, providing accommodation space for the top sediments filling the Ripoll Syncline.

Palaeoenvironmental Conditions of the Upper Middle Pleistocene Warm Intervals in the Upper Volga Region, Northwestern Russia, Based on Palynological, Paleocarpological and Quantitative Geochronological Data

The climatostratigraphic scale of the Upper Middle Pleistocene in the northwest of the East European Plain contains a number of controversial issues, one of which is the position of the Likhvin (Holstein) Interglacial and lesser warm (interstadial) climatic events. To approach this problem, we have studied two sections of Quaternary deposits, Bolshaya Kosha (a well-known and long-studied natural exposure) and Nazarovo (a new, previously unknown section studied in a borehole), in which warm intervals of the Middle Pleistocene are recognized. In both sections, we performed lithological and paleobiological (carpological, spore-pollen) analyses and luminescence dating. In the Bolshaya Kosha section, seeds of the extinct species Caulinia goretskyi were revealed, which allowed us to attribute the obtained IRSL (ca 250–260 ka) dates to the post-Likhvin Bolshaya Kosha interstadial. The sum of data let us propose that both our IRSL and recently published 230Th/U dates (ca 240–290 ka) underestimate the age by 10–15%, and the post-Likhvin Kosha interstadial deposits were formed in the late MIS 9. In the Nazarovo section, palynological study showed the conditions of a relatively warm interstadial, with a change in the composition of vegetation from northern to middle taiga forests. According to IRSL dating, the section was formed in the MIS 10 late glacial between 330–370 ka. The two studied interstadials bracket the Likhvin (Holstein) Interglacial and sedimentary units in the Bolshaya Kosha section are proposed to have formed in MIS 9e.

Middle Eocene Climatic Optimum (MECO) and its imprint in the continental Escanilla Formation, Spain

Abstract. The Middle Eocene Climatic Optimum (MECO) is a global warming event mainly recognized in the marine domain and described less in the terrestrial environment. Here we present a comprehensive geochemical record of the MECO from the Escanilla Formation, a fluvial sedimentary succession in the southern Pyrenees, Spain, based on a suite of sampled paleosols, fluvial stromatolites, and pedogenic nodules. Our multiproxy approach involves using carbon and oxygen stable isotope compositions to identify the regional preservation of the MECO, calculate chemical weathering intensity and mean annual precipitation, perform clumped isotopes on carbonates, and identify clay mineralogy assemblages of paleosols. Results indicate that the Middle Eocene interval in the southern Pyrenees was characterized by low weathering rates under warm and arid climatic conditions. This is further supported by the presence of smectite, palygorskite, illite, and chlorite, which suggest seasonal rainfall but under generally dry conditions resulting in weak chemical weathering. Importantly, a negative organic carbon isotopic excursion indicates the regional, terrestrial impact of the MECO, highlighting that fluvial sedimentary successions even in active foreland basins can represent particularly interesting terrestrial archives of past changes in global climate.

The Ruler Sequence Revisited: A Dynamic Perspective

The Ruler function or the Gros sequence is a classical infinite integer sequence that underlies some interesting mathematical problems. In this paper, we provide four new problems containing this type of sequence: (i) demographic discrete dynamical automaton, (ii) the middle interval Cantor set, (iii) construction by duplication of polygons and (iv) the horizontal visibility sequence at the accumulation point of the Feigenbaum cascade. In all of them, the infinite sequence is obtained through a recursive procedure of duplication. The properties of the ruler sequence, in particular, those relating to recursiveness and self-containing, are used to achieve a deeper understanding of these four problems. These new representations of the ruler sequence could inspire new studies in the field of discrete mathematics.

First dinosaur tracks found in the Mulichinco Formation (Lower Cretaceous), Neuquén Basin, Argentina: Paleoenvironmental implications

This study focuses on the analysis of the first dinosaur tracks discovered in the Mulichinco Formation, Neuquén Basin, Argentina. The deposition of this unit occurred during the early Valanginian, Early Cretaceous, making it the oldest known record of dinosaur tracks for that period in the basin. The aim of this study is to provide a paleoenvironmental interpretation of the area and potential trackmakers based on the morphology of the tracks and the facies analysis of the depositional system. The depositional system evolved from a moderately sinuous fluvial system in the lower interval to a braid distal plain system with the development of bodies of water without marine influence, culminating in an estuary with marine influence in the upper interval. The paleoenvironmental conditions during the deposition of the unit were favourable for the presence and interaction of diversity large continental vertebrates. The track-bearing surfaces in the lower interval suggest that the organisms exploited the temporary gaps created between channel migration and floodplain formation as areas for transit or water sources. In the middle interval, the abundant presence of traces fossils of invertebrates and symmetrical ripples suggest a more stable depositional system where fluctuations in the water column were common. The co-occurrence of various track-makers and remains of large vertebrates described in the Mulichinco Formation is unusual among track sites at the basin. Overall, this study provides new insights into the Early Cretaceous paleoenvironmental conditions of the Neuquén Basin and the diversity of large vertebrates that inhabited the region during this time.

Enhanced Denudation of the Emeishan Large Igneous Province and Precipitation Forcing in the Late Permian

AbstractHydroclimate is an important factor controlling landscape evolution. But establishing the impact of hydroclimate is complicated by the influences of other processes and is especially hard to prove for those in deep time from geological record. During the late Permian, voluminous basaltic sediments were derived from the erosion of the Emeishan large igneous province in western South China. They provide a unique record critical in understanding the responses of tropical basaltic erosion to hydroclimate change without impacts of orogenic uplift, lithologic variation, vegetational difference and glacial‐interglacial change. Sampled successions define a negative carbon isotope excursion capable of making regional and global stratigraphic correlations in the middle Wuchiapingian interval corresponding to the final phase of the late Paleozoic ice age. This interval is associated with a petrofacies shift and a decreasing source weathering intensity, a downward shift of erosion loci, and a reduced coastal water paleosalinity. Applying present‐day temperature dependence pattern of basaltic weathering and using land surface temperatures approximated from nearby paleo‐seawaters, denudation rates were calculated for the Emeishan basaltic province and shows an increase from ∼71 to ∼107 m/Ma. This erosional acceleration is temporally correlated with a decrease in paleosalinity and likely linked to enhanced freshwater discharge in the middle Wuchiapingian. Scaling and landscape erosion modeling suggest ∼80%–130% increase in catchment precipitation could have driven this acceleration in denudation. Our work provides a positive test for the hydroclimate forcing on landscape erosion in deep time and underlines the mechanistic linkage of sediments with erosion and climate change.

A neural oscillatory signature of sustained anxiety.

Anxiety is a sustained response to uncertain threats; yet few studies have explored sustained neurobiological activities underlying anxious states, particularly spontaneous neural oscillations. To address this gap, we reanalysed magnetoencephalographic (MEG) data recorded during induced anxiety to identify differences in sustained oscillatory activity between high- and low-anxiety states. We combined data from three previous MEG studies in which healthy adults (total N = 51) were exposed to alternating periods of threat of unpredictable shock and safety while performing a range of cognitive tasks (passive oddball, mixed-saccade or stop-signal tasks). Spontaneous, band-limited, oscillatory activity was extracted from middle and late intervals of the threat and safe periods, and regional power distributions were reconstructed with adaptive beamforming. Conjunction analyses were used to identify regions showing overlapping spectral power differences between threat and safe periods across the three task paradigms. MEG source analyses revealed a robust and widespread reduction in beta (14-30 Hz) power during threat periods in bilateral sensorimotor cortices extending into right prefrontal regions. Alpha (8-13 Hz) power reductions during threat were more circumscribed, with notable peaks in left intraparietal sulcus and thalamus. Threat-induced anxiety is underpinned by a sustained reduction in spontaneous beta- and alpha-band activity in sensorimotor and parietal cortical regions. This general oscillatory pattern likely reflects a state of heightened action readiness and vigilance to cope with uncertain threats. Our findings provide a critical reference for which to identify abnormalities in cortical oscillatory activities in clinically anxious patients as well as evaluating the efficacy of anxiolytic treatments.

Cambrian through Ordovician reef transitions in North and South China: Changes in reef construction and background geobiological environments

The Cambrian–Ordovician interval was an intriguing period of geologic time, when reef transitions occurred along with important biodiversification events. This study examines the secular reef transitions in North and South China during the Cambrian and Ordovician in terms of changes in reef construction and related geobiological changes. Microbial reefs in the Terreneuvian have not been well documented in South China. The Cambrian Series 2 interval saw the almost simultaneous appearance of reef-building skeletal archaeocyaths and calcimicrobes. The widely developed archaeocyath–calcimicrobe reefs had totally disappeared by the middle of Series 2 in South China and were followed by purely calcimicrobial reefs. During the Miaolingian and Furongian, skeletal-reef builders were commonly thought to have been inhibited owing to elevated sea-water temperature, which caused lowered oxygen. However, microbial reefs containing lithistid sponges and keratosan sponges were more common in this interval in North China than previously thought. The first skeletal-dominated reefs were established during the Early Ordovician, coincident with a decline in stromatolite reefs in the central Yangtze Platform. During the Middle and Late Ordovician interval, a variety of skeletal reef-builders with diversified calcimicrobes contributed markedly to reef construction in limited areas of both North and South China. The appearance and increase of skeletal-dominated reefs are considered to have been related to lowering global sea-water temperature. Recently reported Late Ordovician cement-rich reefs in both North and South China may contain further evidence of global cooling; however, from an ecological perspective, the novel niches and biological interactions created by early skeletal-dominated reefs may have promoted the further development of reef-building organisms. Cambrian and Ordovician reef successions in North and South China are distributed discontinuously; however, integrating information from both North and South China could yield improved understanding of reef evolution and background environments through these intervals.

Upper Carnian to Rhaetian (Upper Triassic) conodont and carbon-isotope stratigraphy of the Csővár borehole succession, Hungary

A total of 125 samples from core from the Csővár borehole (north-central Hungary) were investigated for conodont bio- and carbon-isotope chemostratigraphy. This 620 m thick continuous pelagic carbonate succession comprises strata from the upper Carnian to upper Rhaetian, including both, the Carnian-Norian and the Norian-Rhaetian stage boundaries. The mass occurrence of the Metapolygnathus communisti conodont group followed by the occurrence of Primatella gulloae mark the base of the Norian in the lowermost part of the section, which allows good correlation with the Pizzo Mondello section (Sicily, Italy). The lower Norian conodonts of the core belong predominantly to the genus Ancyrogondolella. Subdivision of the middle Norian interval is hampered by the lack of fully adult specimens. The upper Norian shows a greater diversity than the rest of the Norian, and the rich assemblages give an insight into the evolutionary transition from Misikella hernsteini to Mi. posthernsteini (sensu stricto). The first occurrence of Mi. ultima in the core changes the previous views of the thickness of the upper Rhaetian in the Csővár area and emphasizes the necessity of re-calibration of the isotope stratigraphic results of previous studies. The carbon-isotope results show distinct fluctuations and trends. Some of them are similar to literature data, others are different. It can be stated from the new data that a ∼ 2 ‰ long-term δ13C background decline throughout the Norian is most probably global in extent. Negative carbon-isotope excursions occur in Norian substages: (upper) Alaunian, lower Sevatian, middle Sevatian and upper Sevatian. Distinct positive δ13C excursions are present across the Alaunian-Sevatian boundary and the Norian-Rhaetian boundary, and the climax of the latter is located in the lower part of the posthernsteini Zone. This last isotope event is particularly important because at the Global Stratotype Section and Point (GSSP) candidate for the base of the Rhaetian stage at Pignola (Southern Apennines, Italy) a distinct negative δ13C excursion has been reported for this stratigraphic level.

U-Pb zircon dates from North American and British Avalonia bracket the Lower–Middle Cambrian boundary interval, with evaluation of the Miaolingian Series as a global unit

AbstractHigh-precision U-Pb zircon ages on SE Newfoundland tuffs now bracket the Avalonian Lower–Middle Cambrian boundary. Upper Lower Cambrian Brigus Formation tuffs yield depositional ages of 507.91 ± 0.07 Ma (Callavia broeggeriZone) and 507.67 ± 0.08 Ma and 507.21 ± 0.13 Ma (Morocconus-Condylopyge eliAssemblage interval). Lower Middle Cambrian Chamberlain’s Brook Formation tuffs have depositional ages of 506.34 ± 0.21 Ma (Kiskinella cristataZone) and 506.25 ± 0.07 Ma (Eccaparadoxides bennettiZone). The composite unconformity separating the Brigus and Chamberlain’s Brook formations is constrained between these ages. An Avalonian Lower–Middle Cambrian boundary between 507.2 ± 0.1 and 506.3 ± 0.2 Ma is consistent with maximum depositional age constraints from southwest Laurentia, which indicate an age for the base of the Miaolingian Series, as locally interpreted, of ≤ 506.6 ± 0.3 Ma. The Miaolingian Series’ base is interpreted as correlative within ≤ 0.3 ± 0.3 Ma between Cambrian palaeocontinents, although its exact synchrony is questionable due to taxonomic problems with a possibleOryctocephalus indicus-plexus, invariable dysoxic lithofacies control ofO. indicusand diachronous occurrence ofO. indicusin temporally distinct δ13C chemozones in South China and SW Laurentia. The lowest occurrence ofO. indicusassemblages is linked to onlap (epeirogenic or eustatic) of dysoxic facies. A united Avalonia is shown by late Early Cambrian volcanics in SW New Brunswick; Cape Breton Island; SE Newfoundland; and the Wrekin area, England. The new U-Pb ages revise Avalonian geological evolution as they show rapid epeirogenic changes through depositional sequences 4a–6.

Terminal Ediacaran–Late Ordovician evolution of the NE Laurentia palaeocontinent: rift–drift–onset of Taconic Orogeny, sea-level change and ‘Hawke Bay’ onlap (not offlap)

Abstract Rodinia break-up with late Ediacaran rifting defined a NE Laurentia triple junction (New York Promontory–Ottawa–Bonnechere aulacogen (OBA)–Quebec Reentrant). Rifting persisted to c. 510 Ma. The oldest passive-margin shelf units (Forestdale Marble and Moosalamoo Phyllite) underlie a sandstone (Cheshire) commonly regarded as the oldest passive unit. Late Dyeran–Middle Cambrian rifting led to the oldest OBa sedimentation and formed the Franklin Basin (NW Vermont). Cambrian–Darriwillian shelf–slope facies are linked eustatically – not Taconic Orogeny onset. Onlap and shelf carbonates are coeval with black slope mud; and lowstand shelf unconformities with green, oxic slope mud. Early–middle Dyeran eustatic change defined slope units: (1) Browns Pond Formation dysoxic–anoxic (d–a) interval with debrite cap (Holcombville Member, new); (2) Middle Granville Formation Oxic Interval (new); and (3) lower Hatch Hill Formation d–a interval. Our analysis leads to two controversial conclusions: (i) the existence of the Dashwoods and other micro-continental blocks due to hyperextension is not supported by cover sequences linking Laurentia to proposed Dashwoods areas (i.e. Green Mountains) and an arc origin of the type Dashwoods; and (ii) ‘Hawke Bay Event(s)’, widely interpreted as Cambrian global regressive event(s), is a local highstand systems tract facies with shelf sand bypass onto the Hatch Hill Formation slope in its NE Laurentia type region.

Рulmonary sarcoidosis in HIV-infected patients

OBJECTIVE. To determine the clinical, X-ray examination features in the newly detected sarcoidosis in HIV-infected patients.&#x0D; MATERIALS AND METHODS. HIV-infected patients (6 women, 10 men, middle age – 43.5, range – 25-62 years) with the newly detected sarcoidosis had been observed during 2006-2022 years. The level of CD4+ cells, signs or symptoms of disease, dependence of development of sarcoidosis on the terms of setting of antiretroviral therapy were considered. The following criteria were evaluated during X-ray examination and computer tomography (CТ): lymphadenopathy, pulmonary knots, focal consolidations, reticular or grainy changes, symptom of ground glass, cysts or fibrosis.&#x0D; RESULTS AND DISCUSSION. A middle interval between two diagnoses was 1 year. A level of CD4+ cells was 424/µl (range – 34-680 cells/µl). All patients had pulmonary signs or symptoms at diagnosis giving of sarcoidosis. X-ray examination showed a lymphadenopathy, pulmonary knots, focal consolidations, reticular changes, symptom of ground glass, cysts. CТ showed a lymphadenopathy, knots, bulge of intersegments partitions, focal consolidations, reticular dimnesses, symptom of ground glass and cysts. All patients received a course of treatment based on corticosteroids. The result of the treatment was assessed as positive. No relapses of the disease were found.&#x0D; CONCLUSIONS. The X-ray and clinical features in the newly detected pulmonary sarcoidosis in HIV-infected patients are analogical to those in patients without HIV-infection. A level of CD4+ cells in most patients was &gt;200/µl. Development of sarcoidosis depends from conservation or updating of level of CD4+ of lymph cells, and mostly it exceeds 200 cells/µl. A treatment with corticosteroids promotes recovery.

Spatiotemporal connectivity maps abnormal communication pathways in major depressive disorder underlying gamma oscillations.

Auditory steady-state response underlying gamma oscillations (gamma-ASSR) have been explored in patients with major depressive disorder (MDD), while ignoring the spatiotemporal dynamic characteristics. This study aims to construct dynamic directed brain networks to explore the disruption of spatiotemporal dynamics underlying gamma-ASSR in MDD. This study recruited 29 MDD patients and 30 healthy controls for a 40Hz auditory steady-state evoked experiment. The propagation of gamma-ASSR was divided into early, middle, and late time interval. Partial directed coherence was applied to construct dynamic directed brain networks based on graph theory. The results showed that MDD patients had lower global efficiency and out-strength in temporal, parietal, and occipital regions over three time intervals. Additionally, distinct disrupted connectivity patterns occurred in different time intervals with abnormalities in the early and middle gamma-ASSR in left parietal regions cascading forward to produce dysfunction of frontal brain regions necessary to support gamma oscillations. Furthermore, the early and middle local efficiency of frontal regions were negatively correlated with symptom severity. These findings highlight patterns of hypofunction in the generation and maintenance of gamma-band oscillations across parietal-to-frontal regions in MDD patients, which provides novel insights into the neuropathological mechanism underlying gamma oscillations associated with aberrant brain network dynamics of MDD.

Depositional history of peatland pines (Pinus sylvestris L.) in NW Enontekiö, Finnish Lapland: implications for Middle Holocene drought and temperature fluctuations

High altitude and latitude findings of subfossil peatland pine trees were unearthed from the region of NW Finnish Lapland and dated by 14C and tree‐ring methods. The depositional history of the trees illustrated two distinct peatland pine phases dated to Middle Holocene intervals 4900–4400 and 4100–3400 cal. a BC. It seems evident that both thermal and hydroclimatic fluctuations have played roles of varying importance in the establishment of this pine population and its demise. The presence of these pines, from a site ~60 km north of the coniferous timberline and conditions ~1 °C and 100 degree‐days colder than those at the present‐day timberline, concurs with previous studies demonstrating the association between the high‐latitude summer‐temperature cooling and circumpolar timberline retreat since the Middle Holocene due to Milankovitch forcing. On the other hand, the peatland pine recruitment was made possible by drier than present surface conditions during the previously reconstructed Middle Holocene drought anomaly (Hyvärinen‐Alhonen event). Our data suggest this event was not continuous but reached its two‐phase climax during the peatland pine phases, with an interruption of several centuries with moister surface conditions between 4400 and 4100 cal. a BC. The findings highlight the sensitivity of well‐dated peatland tree assemblages in terms of recording past climatic evolution and events and the need for new collections from north and south Fennoscandia and the Baltic region, for more detailed analyses over extended time intervals and regions.