Multiple Palaeoproterozoic carbon burial episodes and excursions

Organic-rich rocks (averaging 2–5% total organic carbon) and positive carbonate-carbon isotope excursions (View the MathML source and locally much higher, i.e. the Lomagundi-Jatuli Event) are hallmark features of Palaeoproterozoic successions and are assumed to archive a global event of unique environmental conditions following the c. 2.3 Ga Great Oxidation Event. Here we combine new and published geochronology that shows that the main Palaeoproterozoic carbon burial episodes (CBEs) preserved in Russia, Gabon and Australia were temporally discrete depositional events between c. 2.10 and 1.85 Ga. In northwest Russia we can also show that timing of the termination of the Lomagundi-Jatuli Event may have differed by up to 50 Ma between localities, and that Ni mineralisation occurred at c. 1920 Ma. Further, CBEs have traits in common with Mesozoic Oceanic Anoxic Events (OAEs); both are exceptionally organic-rich relative to encasing strata, associated with contemporaneous igneous activity and marked by organic carbon isotope profiles that exhibit a stepped decrease followed by a stabilisation period and recovery. Although CBE strata are thicker and of greater duration than OAEs (100 s of metres versus metres, ∼106 years versus ∼105 years), their shared characteristics hint at a commonality of cause(s) and feedbacks. This suggests that CBEs represent processes that can be either basin-specific or global in nature and a combination of circumstances that are not unique to the Palaeoproterozoic. Our findings urge circumspection and re-consideration of models that assume CBEs are a Deep Time singularity

ЭТИОЛОГИЧЕСКАЯ СТРУКТУРА И ДИФФЕРЕНЦИАЛЬНАЯ ДИАГНОСТИКА САЛЬМОНЕЛЛЕЗА ПТИЦ

The article presents the results of a study of the etiological structure and differential diag-nostic signs of avian salmonellosis. When identifying bacteria isolated from 128 blood samples of chickens with the use of rapid test "Salmonella latex kit" established the dominance of cultures of the microorganisms Salmonella spp. — of 10.94% (14 samples); 10 strains (71,43%) were attributed to Salmonella gallinarum, 4 (of 28.57%) to Salmonella pullorum. The overall level of resistance of Salmonella to ampicillin — 57,58%; tetracycline — 60,61%; streptomycin — 66,67%; had to 57,58%; 60,61% and 66,67% are sensitivity to norfloxacin amounted to 69,70%, to ceftazidime — 78,79%, enrofloxacin — 57,58%, ciprofloxacin — 69,70% of the tested strains. At postmortem examination the most frequently detected signs of pericarditis, hemorrhagic pneumonia, aeroscout, catarrhal-hemorrhagic enteritis, perihepatitis, hyperplasia of the spleen. The most frequently detected signs of pericarditis, aeroscout, catarrhal-hemorrhagic gastroenterocolitis, perihepatitis, inflam-mation of the ovaries, hyperplasia of the spleen. Revealed signs of congestive hyperemia, macrophage reaction, hyperplasia and plasmocytomas of lymphocyte transformation, increase the permeability of microcirculatory vessels, lymphoid-cellular infil-tration of loose fibrous connective tissue, perivascular oedema, disseminated thrombosis, proliferation of lymphocytes from lymph nodes, spleen, liver, and pancreas. In violation of the porosity of the blood vessels of serous membranes of organs were observed extensive serous oedema, the output of the formed elements of blood and the loss of fibrinogen.В статье представлены результаты изучения этиологической структуры и дифференциально-диагностических признаков сальмонеллеза птиц. При идентификации бактерий, выделенных из 128 проб крови цыплят, с применением экспресстеста «Salmonella latex kit» установлено доми-нирование культур микроорганизмов Salmonella spp. - 10,94% (14 проб); 10 штаммов (71,43%) были отнесены к Salmonella gallinarum, 4 (28,57%) - к Salmonella pullorum. Общий уровень резистентности сальмонелл к ампициллину - 57,58%, тетрациклину - 60,61%; стрептомицину - 66,67%; чувствительность к норфлоксацину - 69,70%; цефтазидиму - 78,79%; энрофлоксацину - 57,58%; ципрофлоксацину - 69,70% испытанных штаммов. При патологоанатомическом исследовании наиболее часто выявлялись признаки перикардита, геморрагической пневмонии, аэросаккулита, катарально-геморрагического энтерита, перигепатита, гиперплазия селезенки. Наиболее часто выявлялись признаки перикардита, аэросаккулита, катарально-геморрагического гастроэнтероколита, перигепатита, воспаление яичников, гиперплазия селезенки. Выявляли признаки застойной гиперемии, макрофагальной реакции, гиперплазии и плазмоцитарной трансформации лимфоцитов, повышения проницаемости сосудов микроциркуляторного русла, лимфоидно-клеточной инфильтрации рыхлой волокнистой соединительной ткани, периваскулярного отека тканей, диссеминированного тромбоза, пролиферации лимфоцитов лимфатических узлов, селезенки, печени, поджелудочной железы. При нарушении порозности кровеносных сосудов серозных оболочек органов наблюдались обширные серозные отеки, выход форменных элементов крови и выпадение фибриногена

The grandest of them all : the Lomagundi-Jatuli Event and Earth's oxygenation

Funding: K.K., A.L. and T.K. received funding from Estonian Science Agency Project PRG447 and Yu.D., A.R., D.R. and P.M. were supported by the state assignment of the Institute of Geology, Karelian Research Centre of the Russian Academy of Sciences.The Paleoproterozoic Lomagundi–Jatuli Event (LJE) is generally considered the largest, in both amplitude and duration, positive carbonate C-isotope (δ13Ccarb) excursion in Earth history. Conventional thinking is that it represents a global perturbation of the carbon cycle between 2.3–2.1 Ga linked directly with, and in part causing, the postulated rise in atmospheric oxygen during the Great Oxidation Event. In addition to new high-resolution δ13Ccarb measurements from LJE-bearing successions of NW Russia, we compiled 14 943 δ13Ccarb values obtained from marine carbonate rocks 3.0–1.0 Ga in age and from selected Phanerozoic time intervals as a comparator of the LJE. Those data integrated with sedimentology show that, contra to consensus, the δ13Ccarb trend of the LJE is facies (i.e. palaeoenvironment) dependent. Throughout the LJE interval, the C-isotope composition of open and deeper marine settings maintained a mean δ13Ccarb value of +1.5 ± 2.4‰, comparable to those settings for most of Earth history. In contrast, the 13C-rich values that are the hallmark of the LJE are limited largely to nearshore-marine and coastal-evaporitic settings with mean δ13Ccarb values of +6.2 ± 2.0‰ and +8.1 ± 3.8‰, respectively. Our findings confirm that changes in δ13Ccarb are linked directly to facies changes and archive contemporaneous dissolved inorganic carbon pools having variable C-isotopic compositions in laterally adjacent depositional settings. The implications are that the LJE cannot be construed a priori as representative of the global carbon cycle or a planetary-scale disturbance to that cycle, nor as direct evidence for oxygenation of the ocean–atmosphere system. This requires rethinking models relying on those concepts and framing new ideas in the search for understanding the genesis of the grandest of all positive C-isotope excursions, its timing and its hypothesized linkage to oxygenation of the atmosphere.Publisher PDFPeer reviewe

To the knowledge of the genus Acrocrypta Baly, 1862 (Chrysomelidae: Galerucinae: Alticini) from Borneo

Checklist of Bornean species of the genus Acrocrypta Baly, 1862 and a key to them are given. Eight new species: Acrocrypta bifasciata sp.  n., Acrocrypta bruneica  sp.  n., Acrocrypta geiseri  sp.  n., Acrocrypta pseudoaureipennis sp. n., Acrocrypta kinabaluensis sp. n., Acrocrypta sarawakensis  sp.  n., Acrocrypta sexstigmatica sp.  n. and Acrocrypta trusmadiensis sp.  n. are described from Borneo. A following new synonymy is proposed: Acrocrypta sabahensis Medvedev et Romantsov, 2014 = Acrocrypta cruciata Medvedev et Romantsov, 2014, syn. n

New and poorly known Chrysomelidae (Coleoptera) from South-East Asia

Nine species: Cleoporus udovichenkoi sp. n. (Vietnam), Bangprella nigristernum sp. n., Platyxantha thailandica sp. n., Taumacera antennalis sp. n., Levnma thailandica sp. n., Lipromorpha thaiensis sp. n., Gonophora thailandica (Thailand) sp. n., Hyphaenia patrikeevi sp. n. (China), Levnma malayana sp. n. (Malaysia) are described as new for science. New localities are indicated for 9 species

Palaeoproterozoic magnesite-stromatolite-dolostone-'red bed' association, Russian Karelia: palaeoenvironmental constraints on the 2.0 Ga-positive carbon isotope shift

The ca. 2000 Ma. Tulomozerskaya Formation, Russian Karelia, is composed of an 800 m-thick magnesite-stromatolite-dolostone- 'red bed' succession with the most C-13-rich dolostones (up to +18 parts per thousand V-PDB) that have ever been reported. Terrigenous 'red beds' are developed throughout the sequence and represent three main depositional settings: (1) a braided fluvial system over a lower energy, river-dominated coastal plain, (2) a low-energy, barred lagoon or bight, and (3) a non- marine, playa lake. A significant component of the sequence consists of biostromal and biohermal columnar stromatolites accreted in shallow-water, low-energy, intertidal zones, barred evaporitic lagoons and peritidal evaporitic environments. Only a small portion of stromatolites might have been accreted in relatively 'open' marine environments. The red, flat-laminated, dolomitic and magnesite stromatolites formed in evaporative ephemeral ponds, coastal sabkhas and playa lakes. Tepees, mudcracks, pseudomorphs after calcium sulphate, halite casts, and abundant 'red beds' in the sequence suggest that (1) terrestrial environments dominated over aqueous, and (2) partial or total decoupling took place between the stromatolite-dominated depositional systems and the bordering sea. The greatest enrichment in C-13 occurs in the playa magnesite (up to +17.2 parts per thousand) and in the laminated dolomitic stromatolites accreted in ephemeral ponds (up to +16.8 parts per thousand), whereas the dolostones from more open environments are less rich in C-13 (+5.6 to +10.7 parts per thousand). The isotopic shift (ca. 5 parts per thousand) induced by global factors (i.e. accelerated accumulation of organic material in an external basin) was augmented by that driven by a series of local factors (restriction, evaporation, biological photosynthesis). The latter enhanced a global delta(13)C value due to an isotopic disequilibrium between atmospheric CO2 and dissolved inorganic carbon in the local aquatic reservoirs precipitating the carbonate minerals. The interplay between global and local factors should be taken into account when interpreting the Palaeoproterozoic carbon isotope excursion and its implications