2,182 research outputs found
Synura korshikovii Kapustin & Gusev
No full text<i>Synura korshikovii</i> Kapustin & Gusev (Fig. 4E) <p>DISTRIBUTION. — In the present study this species has been recorded for the second time since its description (Kapustin & Gusev 2015); this species restricted to Polissia so far.</p> REMARKS <p>This recently-described species has scales which are covered with a hexagonal reticulum and spine with a flat apex terminating in a few rows of papillae-like teeth.</p>Published as part of <i>Kapustin, Dmitry A., Gusev, Evgeniy S., Lilitskaya, Galina G. & Kulikovskiy, Maxim S., 2020, Silica-scaled chrysophytes from the Ukrainian Polissia, pp. 121-135 in Cryptogamie, Algologie 20 (12)</i> on page 132, DOI: 10.5252/cryptogamie-algologie2020v41a12, <a href="http://zenodo.org/record/7819057">http://zenodo.org/record/7819057</a>
Geissleria baicalosimilis Kulikovskiy, Gusev, Andreeva & Annenkova 2014, sp. nov.
No full textGeissleria baicalosimilis Kulikovskiy, Gusev, Andreeva & Annenkova sp. nov. Figs 2–19 LM, live cells (12–14): One large chloroplast with two lobes. LM (Figs 2–11): Valves elliptic, ends protracted and capitate. Length 14.0–15.6 µm, breadth 5–6 µm. Raphe filiform, axial area narrow, central area small and irregularly bordered. One isolated pore near the middle of central nodule, on primary part of valve. Striae weakly radiate, 16–17 in 10 µm. SEM, external view (Figs 15, 16, 18): The raphe slit is straight without visible sternum. One isolated pore near central nodule. Central raphe ends straight. Terminal raphe ends deflected towards the secondary side of valve and continue onto mantle. Striae uniseriate throughout. Areolae present as short slits, 65–70 in 10 µm of stria. Annulus presents as two rows of larger then in stria areolae, apically elongated. In every row from 3 to 4 apically elongated areolae are present. SEM, internal view (Figs 17, 19): Raphe slit lying in internal sternum.Central raphe endings straight, terminal ends terminate in small helictoglossae. Elongated subpolar areolae (annulus) with warty outgrowths. Internally no hymens or occlusions are observed on the areolae. Type:— RUSSIA: Lake Baikal, pool near Bay, fouling on tree submerged in water, at 8 km from Enkhaluk village, N 52027.042 E 106053.215, 14.07.2011, leg. M. Kulikovskiy (IBIW slide no. 18589/B088, holotype designated here (= Fig. 3)), COLO slide 18589/B088p is isotype. Etymology: —Epithet refers to the similarity with Geissleria similis (Krasske) Lange-Bertalot & Metzeltin (1996: 68) and the type locality. Observations: This species is very similar to G. similis. However it is easy distinguish this species by both quantitative and qualitative features. G. baicalosimilis sp. nov. has finer striae in 10 µm (16–17, not 15) and more finer areolae in 10 µm of stria (65–70, not 60) than in G. similis. Striae in the central area of G. similis are long and almost reach central nodule. Additionally, only two elongate pores (one in each stria) at the end of valve present in G. similis. G. baicalosimilis sp. nov. possesses six or more elongated pores.Published as part of Kulikovskiy, Maxim, Gusev, Evgeniy, Andreeva, Svetlana & Annenkova, Natalia, 2014, Phylogenetic position of the diatom genus Geissleria Lange-Bertalot & Metzeltin and description of two new species from Siberian mountain lakes, pp. 249-260 in Phytotaxa 177 (5) on page 252, DOI: 10.11646/phytotaxa.177.5.1, http://zenodo.org/record/514488
Non-uniqueness and prescribed energy for the continuity equation
No full textIn this note, we provide new non-uniqueness examples for the continuity equation by constructing infinitely many weak solutions with prescribed energy
3D Structure of the Gusev Crater region
No full textGusev Crater lies within the Aeolis Quadrangle of Mars at the boundary between the northern lowlands and southern highlands. The ancient valley Ma'adim Vallis dissects the highlands south of Gusev Crater and is thought to have fed the crater with sediments.High Resolution Stereo Camera data and Digital Elevation Models were used to construct a geologic-geomorphic map (173.5-178.5° E, 10-18° S) and cross-sections, complemented by data from Mars Orbiter Camera, Mars Orbiter Laser Altimeter and Thermal Emission Imaging System.Three geologic domains are recognised: the highlands in the south, Gusev Crater and lowlands in the north. Twelve units are mapped, with thicknesses ranging from hundred meters to several kilometres. Thicknesses of units, and their bedding attitude, are estimated combining the geologic map and topographic information. Relative ages are determined from crater counts, ranging from Early Noachian for highland units to Middle Amazonian for units in Gusev Crater and in lowlands. Episodes of intense geologic activity (deposition, volcanism, deformation) occur at around 4.0. Ga, 3.7. Ga, and 3.5. Ga. Comparing the geometry of the Gusev Crater with similar sized, filled and un-filled, Martian craters, suggests that the Columbia Hills are relics of the original central peak of Gusev Crater. © 2010 Elsevier B.V
Mallomonas pseudocorymbosa Gusev, Martynenko & Shkurina 2023, sp. nov.
No full text<i>Mallomonas pseudocorymbosa</i> Gusev, Martynenko & Shkurina <i>sp. nov.</i> (Figure 2). <p> <b>Diagnosis:</b> Scales are oval, tripartite, 4.8–5.9 × 3.3–4.3 µm in size, with or without a dome. The dome is large, rounded, oval or asymmetrical. The V-rib is acute, slightly hooded and its arms continuous with the anterior submarginal ribs. Anterior submarginal ribs are well developed. The anterior flange is wide, especially on the domeless scales, with a row of base plate pores at each side. The posterior flange is wide, with numerous base plate pores distributed on the surface. The shield and posterior flange have a secondary siliceous layer forming circular or elongated oval meshes unevenly distributed on the surface often with areas without development of the secondary layer. Numerous pores are placed on the basal plate. The posterior upturned rim is narrow, with inner struts visible only on TEM images, encircles less than a half of the scale perimeter. Bristles are 13–25 μm long, curved and serrated at the distal half. Shorter bristles have a bifurcated tip with a long terminal spine, and longer bristles have a prolonged thread-like terminal part. Cysts unknown.</p> <p> <i>Holotype (here designated):</i> Portion of a single gathering of cells on SEM stub No. CD8 deposited at the Herbarium, Papanin Institute for Biology of Inland Waters RAS, Borok (IBIW). Material from Ahn Hai Lake, Côn SƠn Island, Bà Rịa-Vũng Tàu Province, Vietnam. Figure 2C illustrates a representative scale from the holotype specimen.</p> <p> <i>Type Locality:</i> Ahn Hai Lake, Côn SƠn Island, Bà Rịa-Vũng Tàu Province, Vietnam. Latitude / Longitude: 8° 40.645’ N 106° 35.867’ E. At the time of collection, the pH was 6.5, temperature 30 °C, and specific conductance 201 µS cm-1. Material was collected by E.S. Gusev and Nguyen-Ngoc Lam on 3 May 2015.</p> <p> <i>Etymology:</i> The species name is derived from the fact that its scales resemble, and could be confused with, those of <i>Mallomonas corymbosa</i>.</p> <p> <i>Distribution:</i> This species has been observed in 17 localities in 13 provinces of Vietnam (Table 1). Scales of this species were also observed in Bangladesh (Takahashi & Hayakawa 1979), China (Wei &Yuan 2001, 2013; Wei <i>et al</i>. 2014), Brazil (Franceschini & Couté 1991)and South Africa (Janse van Vuuren <i>et al</i>. 2022). <i>Mallomonas pseudocorymbosa</i> was found at wide ranges of environmental parameters: pH from 6.1 to 8.6, specific conductance from 62 to 2370 µS cm-1, chlorophyll <i>a</i> values from 5 to 76 µg l –1, and temperature 17–39 ºC (Table 1).</p>Published as part of <i>Gusev, Evgeniy, Martynenko, Nikita, Shkurina, Nataliya & Dien, Tran Duc, 2023, Description of a new species of the genus Mallomonas from section Mallomonas (Synurales, Chrysophyceae) in the tropics, pp. 59-68 in Phytotaxa 618 (1)</i> on page 62, DOI: 10.11646/phytotaxa.618.1.5, <a href="http://zenodo.org/record/8389917">http://zenodo.org/record/8389917</a>
Geissleria frolikhiensis Kulikovskiy, Gusev, Andreeva & Annenkova 2014, sp. nov.
No full text<i>Geissleria frolikhiensis</i> Kulikovskiy, Gusev, Andreeva & Annenkova <i>sp. nov.</i> Figs 20–42 <p>LM, live cells (Figs 36–39): The single, large chloroplast is divided into two plates lying one against each valve, connected by a broad column.</p> <p>LM (Figs 20–35): Valves elliptical to linear-elliptical with ends obtusely rounded. Length 8.0–9.5 µm, breadth 5 µm. Raphe filiform.Axial area very narrow, linear. Central area small. Isolated pore lacking. Striae radiate throughout, 18–20 in 10 µm.</p> <p>SEM, external view (Fig. 40): The raphe slit is straight with visible sternum. Isolated pore absent. Central raphe ends straight. Terminal raphe ends deflected towards the secondary side of the valve and continue onto mantle. Striae uniseriate or irregularly biseriate near axial area. Annulus structure is not recognizable with striae similar to ones of striae. Areolae present as short slits, 70 in 10 µm of stria length.</p> <p>SEM, internal view (Figs 41, 42): Raphe slit lying in internal sternum. Central raphe endings straight, terminal ends terminate in evident helictoglossae. Elongated subpolar areolae (about 4, two of which are striae) with warty outgrowths. Internally no hymens or occlusions are observed on the areolae.</p> <p> <b>Type:</b> — RUSSIA: Lake Frolikha, N 55027.005 E 109058.649, 26.07.2012, leg. M. Kulikovskiy (IBIW slide no. 80/ B369, holotype designated here (= Fig. 20)), COLO slide 80/B369p is isotype.</p> <p> <b>Etymology:</b> —Epithet refers to the type locality.</p> <p> <b>Observations:</b> This species is similar to <i>Geissleria acceptata</i> (Hustedt) Lange-Bertalot & Metzeltin (1996: 64) but differs by rather large valves and more elliptical valves (not linear-elliptical). <i>G. acceptata</i> possesses an isolated pore, a structure that is absent in <i>G. frolikhiensis</i> sp. nov. (Novais <i>et al.</i> 2013). Other similar species are absent from Europe or elsewhere (see Lange-Bertalot 2001, Novais <i>et al.</i> 2013). <i>G. irregularis</i> Kulikovskiy, Lange-Bertalot & Metzeltin (2012: 117) from Lake Baikal differs by asymmetrical valves to the apical axis, central area. No similar species are known from Lake Baikal.</p>Published as part of <i>Kulikovskiy, Maxim, Gusev, Evgeniy, Andreeva, Svetlana & Annenkova, Natalia, 2014, Phylogenetic position of the diatom genus Geissleria Lange-Bertalot & Metzeltin and description of two new species from Siberian mountain lakes, pp. 249-260 in Phytotaxa 177 (5)</i> on page 252, DOI: 10.11646/phytotaxa.177.5.1, <a href="http://zenodo.org/record/5144887">http://zenodo.org/record/5144887</a>
Phase equilibrium investigations of the Adirondack class basalts from the Gusev plains, Gusev crater, Mars
No full textPhase equilibrium experiments have been performed on a synthetic analog of the Gusev plains basalt composition from the Spirit landing site on Mars. Near-liquidus phase relations were determined over the pressure range of 0.1 to 1.5 GPa and at temperatures from 1125 to 1390 C in a piston cylinder apparatus and 1 atm gas mixing furnace. The composition is multiply saturated with olivine, orthopyroxene, and spinel near its liquidus at 1320 C and 1.0 GPa, or 85 km depth on Mars, placing an upper limit constraint on the thickness of the Martian lithosphere at the time of eruption. Our experimental work suggests that the Gusev basalts are anhydrous batch melts of a primitive Martian mantle similar to the composition estimated by Dreibus and Wnke (1984). The temperature of multiple saturation indicates the persistence of high mantle potential temperatures on Mars, similar to those on the modern Earth, until at least the very latest Noachian (3.7 Ga). These high mantle temperatures would be responsible for persistent basaltic volcanism throughout the southern highlands during the first billion years of Mars's history. The source for Gusev basalts differs strongly from the source for shergottite meteorites, reinforcing the idea of the absence of global mantle convection and mixing on Mars. The existence of a relatively primitive mantle reservoir requires that at least part of the mantle underwent little modification during early planetary differentiation
Characterization and petrologic interpretation of olivine-rich basalts at Gusev Crater, Mars
No full textRocks on the floor of Gusev crater are basalts of uniform composition and mineralogy. Olivine, the only mineral to have been identified or inferred from data by all instruments on the Spirit rover, is especially abundant in these rocks. These picritic basalts are similar in many respects to certain Martian meteorites (olivine-phyric shergottites). The olivine megacrysts in both have intermediate compositions, with modal abundances ranging up to 20–30%. Associated minerals in both include low-calcium and highcalcium pyroxenes, plagioclase of intermediate composition, iron-titanium-chromium oxides, and phosphate. These rocks also share minor element trends, reflected in their nickel-magnesium and chromium-magnesium ratios. Gusev basalts and shergottites appear to have formed from primitive magmas produced by melting an undepleted mantle at depth and erupted without significant fractionation. However, apparent differences between Gusev rocks and shergottites in their ages, plagioclase abundances, and volatile contents preclude direct correlation. Orbital determinations of global olivine distribution and compositions by thermal emission spectroscopy suggest that olivine-rich rocks may be widespread. Because weathering under acidic conditions preferentially attacks olivine and disguises such rocks beneath alteration rinds, picritic basalts formed from primitive magmas may even be a common component of the Martian crust formed during ancient and recent times.Additional co-authors: PR Christensen, BC Clark, JA Crisp, DJ DesMarais, T Economou, JD Farmer, W Farrand, A Ghosh, M Golombek, S Gorevan, R Greeley, VE Hamilton, JR Johnson, BL Joliff, G Klingelhöfer, AT Knudson, S McLennan, D Ming, JE Moersch, R Rieder, SW Ruff, PA de Souza Jr, SW Squyres, H Wnke, A Wang, A Yen, J Zipfe
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Phase equilibrium investigations of the Adirondack class basalts from the Gusev plains, Gusev crater, Mars
No full textPhase equilibrium experiments have been performed on a synthetic analog of the Gusev plains basalt composition from the Spirit landing site on Mars. Near-liquidus phase relations were determined over the pressure range of 0.1 to 1.5 GPa and at temperatures from 1125 to 1390 degrees C in a piston cylinder apparatus and 1 atm gas mixing furnace. The composition is multiply saturated with olivine, orthopyroxene, and spinel near its liquidus at 1320 degrees C and 1.0 GPa, or 85 km depth on Mars, placing an upper limit constraint on the thickness of the Martian lithosphere at the time of eruption. Our experimental work suggests that the Gusev basalts are anhydrous batch melts of a primitive Martian mantle similar to the composition estimated by Dreibus and Wänke (1984). The temperature of multiple saturation indicates the persistence of high mantle potential temperatures on Mars, similar to those on the modern Earth, until at least the very latest Noachian (3.7 Ga). These high mantle temperatures would be responsible for persistent basaltic volcanism throughout the southern highlands during the first billion years of Mars's history. The source for Gusev basalts differs strongly from the source for shergottite meteorites, reinforcing the idea of the absence of global mantle convection and mixing on Mars. The existence of a relatively primitive mantle reservoir requires that at least part of the mantle underwent little modification during early planetary differentiation.The Meteoritics & Planetary Science archives are made available by the Meteoritical Society and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform February 202
Water alteration of rocks and soils on Mars at the Spirit rover site in Gusev crater
No full textGusev crater was selected as the landing site for the Spirit rover because of the possibility that it once held a lake. Thus one of the rover’s tasks was to search for evidence of lake sediments. However, the plains at the landing site were found to be covered by a regolith composed of olivine-rich basaltic rock and windblown ‘global’ dust. The analyses of three rock interiors exposed by the rock abrasion tool showed that they are similar to one another, consistent with having originated from a common lava flow.Here we report the investigation of soils, rock coatings and rock interiors by the Spirit rover from sol (martian day) 1 to sol 156, from its landing site to the base of the Columbia hills. The physical and chemical characteristics of the materials analysed provide evidence for limited but unequivocal interaction between water and the volcanic rocks of the Gusev plains. This evidence includes the softness of rock interiors that contain anomalously high concentrations of sulphur, chlorine and bromine relative to terrestrial basalts and martian meteorites; sulphur, chlorine and ferric iron enrichments in multilayer coatings on the light-toned rockMazatzal; high bromine concentration in filled vugs and veins within the plains basalts; positive correlations between magnesium, sulphur and other salt components in trench soils; and decoupling of sulphur, chlorine and bromine concentrations in trench soils compared to Gusev surface soils, indicating chemical mobility and separation.Additional co-authors: Paulo A de Souza, Jr, Douglas W Ming, Ralf Gellert, Jutta Zipfel, Johannes Brückner, James F Bell, III, Kenneth Herkenhoff, Phil R Christensen, Steve Ruff, Diana Blaney, Steven Gorevan, Nathalie A Cabrol, Larry Crumpler, John Grant, Lawrence Soderblo
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