climatic transition
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Zootaxa ◽  
2021 ◽  
Vol 5025 (1) ◽  
pp. 1-75
Author(s):  
MATHIAS HARZHAUSER ◽  
BERNARD M. LANDAU

We document 37 Columbellidae species, placed in 15 genera, from the middle Miocene of the Paratethys Sea, adding about 20% of new species to the previously known Columbellidae fauna of the Paratethys. This distinct increase is based on a careful revision of museum material that was collected during the 19th century. A detailed revision revealed numerous misidentifications of published material, which greatly distorted the understanding of many species in the literature. The revised fauna reveals only minimal affinities with coeval faunas from the Proto-Mediterranean Sea and suggests a palaeogeographic subdivision within the Central Paratethys between northern and southern basins. A major drop in columbellid diversity occurred at the Langhian/Serravallian boundary, coinciding with the Miocene Climatic Transition. This event led to a severe diversity decline from a high Langhian level of 32 species, which was comparable in the number of columbellid species to that of the modern Red Sea and tropical West Africa (~23 species), down to a diversity level of nine species, equalling that of the modern Mediterranean Sea.                 Auingeria nov. gen., Bellacolumbella nov. gen., Martaia nov. gen. and Defensina nov. gen. are introduced as new genera. Mitrella dacica nov. sp., Mitrella demaintenonae nov. sp., Mitrella elongatissima nov. sp., Mitrella viennensis nov. sp. and Zafrona sphaerocorrugata nov. sp. are described as new species. Costoanachis venzoi is proposed as replacement name for Anachis (Costoanachis) subcorrugata Venzo & Pelosio, 1963 non Columbella (Anachis) subcorrugata Boettger, 1906.                 Lectotypes are designated for Columbella (Anachis) guembeli Hoernes & Auinger, 1880, Columbella januskiewiczi Friedberg, 1938, Columbella (Mitrella) fallax Hoernes & Auinger, 1880, Atilia (Macrurella) hilberi Cossmann, 1901, Columbella petersi Hilber, 1879, Columbella (Mitrella) complanata Sacco, 1890, Columbella (Mitrella) bittneri Hoernes & Auinger, 1880, Columbella (Orthurella) elongata var. convexula Sacco, 1890, Columbella (Anachis) moravica Hoernes & Auinger, 1880, Columbella (Mitrella) bucciniformis Hoernes & Auinger, 1880, Columbella (Anachis) haueri Hoernes & Auinger, 1880, Columbella (Anachis) austriaca Hoernes & Auinger, 1880, Pyrene (Anachis) bellardii grussbachensis Csepreghy-Meznerics, 1969, Columbella (Anachis) dujardini Hoernes & Auinger, 1880, Columbella (Anachis) zitteli Hoernes & Auinger, 1880, Columbella (Nitidella) karreri Hoernes & Auinger, 1880, and Columbella (Nitidella) katharinae Hoernes & Auinger, 1880.                 Scabrellana is introduced as replacement name for the trilobite genus Scabrella Wenndorf (1990) non Scabrella Sacco, 1890.


2021 ◽  
Vol 7 (1) ◽  
pp. 87-95
Author(s):  
Shuldan L ◽  

The global climate system shows signs of rapid changes called a Climatic Transition in specialized literature. The article has studied climate trends in territorial (global, macro-climatic, meso-climatic, and micro-climatic) and time limits (historical overview; current state; long-term, medium-term, and short-term prospects). The most probable medium-term forecasts until 2050 have been taken as a basis. The climate data analysis for the previous 60 years has been carried out and continued by our research with linear averaging of data for 2009-2020, the dynamics of main parameters changes on the territory of Ukraine and for Lviv city have been determined. The main requirements for architectural solutions in various climatic conditions have been formulated. Correlation analysis of energy efficiency improvements in architecture and current external micro-climatic conditions has been performed. It has been proposed to make appropriate changes to the regulatory documents.


Author(s):  
Alper Gürbüz ◽  
Nizamettin Kazancı ◽  
H. Yavuz Hakyemez ◽  
Suzanne A. G. Leroy ◽  
Neil Roberts ◽  
...  

2021 ◽  
Author(s):  
Pierre-Henri Blard ◽  
Stéphane Molliex ◽  
Apolline Mariotti ◽  
Julien Charreau ◽  
Gwenaël Jouet ◽  
...  

<p>It is important to better understand how climatic fluctuations modified denudation, in particular during the large amplitude glacial cycles of the Quaternary, not only because denudation is thought to be a long-term climate pacer, but also because available denudation records are contradictory and sometimes underconstrained. To make progress on this question, we present here a compilation of <sup>10</sup>Be-derived denudation rates from 6 boreholes and cores drilled in offshore sediments from two alpine massifs of the Mediterranean Sea: Southern Alps (Var River) and Corsica (Golo River). This original dataset of 60 <sup>10</sup>Be samples from well-dated sedimentary archives documents at high resolution (1 kyr in some sections) the denudation variability over the last 3 million years of the alpine reliefs, with a special focus on the last five 100 kyr glacial cycles. Our new record brings two main results:</p><p>1) At the million years timescale, the appearance of the Quaternary glaciations at the Plio-Pleistocene transition (2.6 Ma) had a negligible impact on the mean <sup>10</sup>Be-derived denudation rates of Mediterranean Alpine reliefs. This observation is in good agreement with other <sup>10</sup>Be-denudation rates records from Asia (Tianshan and Himalaya) that report a limited impact of the Pleistocene climatic transition (Puchol et al., 2017; Charreau et al., 2020; Lenard et al., 2020), but at odds with other regions of the American Cordilleras, where tectonic may have played a role (Stock et al., 2004; Granger and Schaller, 2014).</p><p>2) At the glacial-interglacial cycles timescale, our high resolution <sup>10</sup>Be data over the last 500 kys reveal that glacial maxima enhanced denudation compared to interglacial periods. However, this impact is variable in space and time, different denudation responses being observed between Southern Alps and Corsica. This contrasted behavior appears to be controlled by the velocity of paleoglaciers. Glacier flow being determined by the combined impact of paleoclimate and basin reliefs, this mechanism is responsible for a non-linear response of denudation to glacier fluctuations. This may explain why glaciations had regionally variable impacts on denudation (Mariotti et al., 2021).</p><p><strong>References</strong></p><p>Charreau, J. et al. (2020) Basin Research. doi: 10.1111/bre.12511; Granger, D. E. and Schaller, M. (2014) Elements, doi: 10.2113/gselements.10.5.369; Lenard, S. J. P. et al. (2020) Nature Geoscience, doi: 10.1038/s41561-020-0585-2; Mariotti, A. et al. (2021) Nature Geoscience, doi: 10.1038/s41561-020-00672-2; Puchol, N. et al. (2017) Bulletin of the Geological Society of America, doi: 10.1130/B31475.1; Stock, G. M., et al. (2004) Geology, doi: 10.1130/G20197.1.</p>


2021 ◽  
Author(s):  
Mathilde Banjan ◽  
Christian Crouzet ◽  
Pierre Sabatier ◽  
Hervé Jomard ◽  
François Demory ◽  
...  

<p>Seismic hazard calculations are based on the assumption that seismicity rates are stable over time. In a given area, the seismicity recorded through historical archives and seismometers is considered a reliable indicator to model the occurrence of future high magnitude seismic events. But, to discuss this hypothesis regionally, it is essential to reconstruct long term seismicity.</p><p>The junction between the Jura mountains and the Alps is seismically active, as shown by the occurrence of numerous seismic events and the presence of several active faults (De La Taille, 2015). Since the 15<sup>th </sup>century, more than twenty earthquakes of epicentral intensity greater than VII have been identified in this area. In addition, sedimentary sequences from Lake Annecy and Lake du Bourget have highlighted the capacity of these "natural archives" to record recurrent seismic activity (Beck 2009), with a potential major seismic event identified around 9900 cal. BP (Arnaud et al., 2012). Such lacustrine archives are key to better understand 1) the occurrence of major seismic events and 2) the evolution of seismicity rates through time, prior to historical and instrumental records.</p><p>Here, we present two sedimentary sequences of 11 and 16 metres long respectively, sampled in the shallowest and deepest basins of Lake Aiguebelette (altitude: 374 m). We performed sedimentological, geochemical and paleomagnetic analyses combined with seismic profile analyses and radiocarbon dating to study processes of event layer deposition in this lake. Multi-proxy analyses allow a quantitative identification of event layers, contrasting with varved-sedimentation. In the deepest basin sequence, 33 homogenites are identified through variations of the laboratory induced isothermal remanent magnetization of sediments measured with a high-resolution fluxgate scanner (Demory et al., 2019) and high foliation (>2%) of the Anisotropy of Magnetic Susceptibility. These parameters are usually associated with seiche effect induced by seismic activity (Campos et al., 2013). Among these event layers, archived in the deep basin sequence, three of them occured synchronously in the shallow basin (at 3000 ± 100, 6900 ± 100 and 11400 ± 300 cal. BP, respectively).</p><p>The oldest and thickest event layer recorded in Lake Aiguebelette was deposited at the transition between the Late Glacial and Holocene stages. In the deepest basin, this 1.15-meter-thick deposit is composed of an upward-graded base and a 0.84 meter-thick homogenite, which was also identified as a transparent facies on seismic profiles. In Lake Le Bourget, Lake Annecy, and central Swiss perialpine lakes, several seismic profiles analyses show transparent seismic facies interpreted as mass movement deposits occurring at the same period of time: the Late glacial-Holocene transition.</p><p>Did this climatic transition influence the seismic activity in the Alps? If so, the impact of such climatic forcing on seismic hazard assessment should be evaluated.</p><p> </p><p>Arnaud et al (2012). Lake Bourget regional erosion patterns... QSR., 51, 81-92.</p><p>Beck (2009). Late Quaternary lacustrine paleo-seismic... EarthSciRev., 96(4), 327-344.</p><p>Campos et al (2013). Deciphering hemipelagites from homogenites... SedGeol., 292, 1-14.</p><p>De La Taille et al (2015). Impact of active faulting... Tectonophysics, 664, 31-49.</p><p>Demory et al (2019). A new high‐resolution magnetic scanner... Geochem,Geophy,Geosys., 20(7), 3186-3200.</p><p> </p><p><strong>Keywords: </strong>Lake sediment, homogenites, paleo-earthquakes, seismic hazard, French Alps</p><p> </p><p> </p>


2021 ◽  
Author(s):  
Daniela Constantin ◽  
Joseph Mason ◽  
Ulrich Hambach ◽  
Daniel Veres ◽  
Cristian Panaiotu ◽  
...  

<p>Here we investigate the timing of Pleistocene-Holocene climatic transition as reflected in nine luminescence dated loess-palaeosol sequences across the northern hemisphere, from the Chinese Loess Plateau, the southeastern European loess belt and the central Great Plains, Nebraska, USA.<br>First, logs of high-resolution magnetic susceptibility and its frequency dependence were used as palaeoclimatic proxies to define the environmental transition from the last glacial loess to the current interglacial soil. Second, the onset of increase in their values above typical loess values was used to assess the onset of, and developments during, the Pleistocene-Holocene climatic transition. The variability seen in the magnetic susceptibility records are interpreted based on high-resolution luminescence dating applied on multiple grain-sizes (4-11 µm, 63-90 µm, 90-125 µm) of quartz extracts from the same sample. In order to increase the overall precision of the luminescence based chronology we rely on weighted average ages. Based on these, Bayesian modeling allowed the determination of age-depth models and mean sedimentation rates for each investigated site.<br>The magnetic susceptibility signal shows a smooth and gradual increase for the majority of the sites from the typical low loess values to the interglacial ones. At all but one site, this increase, associated to the onset of the Pleistocene-Holocene boundary (ie., 11.7 ka) was dated to 14 ka or even earlier. Our results highlight the need of combining palaeoclimatic proxies (magnetic susceptibility) with absolute dating when placing the Pleistocene-Holocene climatic transition as reflected by the evolution of this proxy in order to avoid misinterpretations in loess-paleosol records caused by simple pattern correlation. These results indicate diverse environmental dynamics recorded in the different North Hemisphere loess regions during the major global climatic shift from the last glacial to the Holocene.<br>The detailed luminescence chronology coupled with magnetic susceptibility records indicate the formation of accretional Holocene soils in the sites investigated. Modeled accumulation rates for the Holocene soil are similar for European, Chinese and American loess sites investigated and vary from 0.02 m/ka to 0.09 m/ka.</p>


2021 ◽  
Author(s):  
Roland Neofitu ◽  
Chris Mark ◽  
Suzanne O'Connell ◽  
Samuel Kelley ◽  
Delia Rösel ◽  
...  

<p>Antarctic ice-sheet instability is recorded by ice-rafted debris (IRD) in mid- to high-latitude marine sediment, especially throughout climate transitions. The middle Miocene climatic transition (MMCT), 14.2 to 13.8 Ma, which marks the end of a significant warm period during the mid-Miocene, saw a rapid cooling of ca. 6-7 °C in the high-latitude Southern Ocean. This climatic shift was also accompanied by a global δ<sup>18</sup>O excursion of ca. 1‰, indicating a time of global cooling and significant Antarctic ice expansion (Shevenell et al., 2004). The MMCT is recorded by numerous IRD-rich sediment horizons in deep-sea sediment cores around the Antarctic margin, reflecting iceberg calving during times of ice-sheet instability. Resolving the locations of iceberg calving sites by detrital provenance analysis during the MMCT will be an important tool for forecasting effects of anthropogenic climate change.</p><p>Here we present results of a multi-proxy provenance study by using K- and plagioclase feldspar, selected due to their relative abundance in clastic sediment, and tendency to incorporate Rb (Kfs only), Pb, and Sr at analytically useful concentrations, thus enabling source-terrane fingerprinting. While Pb-isotope fingerprinting is an established method for provenance analysis of glaciogenic sediment (Flowerdew et al., 2012), combining in-situ Sr-isotope fingerprinting with <sup>87</sup>Rb/<sup>87</sup>Sr dating is a novel approach. These techniques are applied to deep-sea core ODP113-694, which was recovered from the Weddell Sea; as this is located ca. 750 km from the continental rise, in 4671.3 m of water. This location is ideal, as it acts as a major iceberg graveyard making it a key IRD depocenter (Barker, Kennett et al., 1988). Within the core, several IRD layers were identified and analysed with preliminary depositional ages of 14 to 14.4 Ma.</p><p>We discuss the implications of our results in terms of location of active iceberg calving sites and further consider the viability of our multi-proxy provenance approach to the Antarctic offshore.</p><p>Barker, P.F., Kennett, J.P., et al., 1988, Proc. Init. Repts. (Pt. A): ODP, 113, College Station, TX (Ocean Drilling Program).</p><p>Flowerdew, M.J., et al., 2012, Chemical Geology, v. 292–293, p. 88–102, doi: 10.1016/j.chemgeo.2011.11.006.</p><p>Shevenell, A.E., et al., 2004, Science, v. 305, p. 1766-1770, doi: 10.1126/science.1100061.</p>


eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Joaquín Calatayud ◽  
Magnus Neuman ◽  
Alexis Rojas ◽  
Anton Eriksson ◽  
Martin Rosvall

Climate regions form the basis of many ecological, evolutionary, and conservation studies. However, our understanding of climate regions is limited to how they shape vegetation: they do not account for the distribution of animals. Here, we develop a network-based framework to identify important climates worldwide based on regularities in realized niches of about 26,000 tetrapods. We show that high-energy climates, including deserts, tropical savannas, and steppes, are consistent across animal- and plant-derived classifications, indicating similar underlying climatic determinants. Conversely, temperate climates differ across all groups, suggesting that these climates allow for idiosyncratic adaptations. Finally, we show how the integration of niche classifications with geographical information enables the detection of climatic transition zones and the signal of geographic and historical processes. Our results identify the climates shaping the distribution of tetrapods and call for caution when using general climate classifications to study the ecology, evolution, or conservation of specific taxa.


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