Foraminiferal Analysis of the Late Miocene- Early Pleistocene Mangaopari Mudstone, South Wairarapa, New Zealand

<p>The foraminiferal content of thirty-two samples from the late Miocene-early Pleistocene Mangaopari Mudstone within the southern Wairarapa region have been examined with the aim of determining the age and depositional environment of the unit. In particular the study addressed whether or not there were glacioeustatic cycles present in the unit. Integrating foraminiferal faunal distributions and sedimentological analysis provided geological, paleoclimactic, and paleoceanographic evidence to aid in the reconstruction of the paleoenvironment. The data was then compared with conclusions from previous studies. The section was divided into two different parts (upper and lower) based on changes in foraminiferal assemblages and grainsize distributions. The age and depositional environment of the Mudstone is suggested by the presence of several genera and species of foraminifera which is supported by grainsize analysis. The presence of Martinottiella communis and Karreriella cylindrica between 0-157.1m stratigraphically suggest that accumulation began in bathyal conditions at depths greater than 400m between. This is supported by grainsize analysis which indicates a medium silt with a high percent mud content ranging from 91.5-100%. This demonstrates deposition beginning in the late Miocene-early Pliocene at bathyal depths greater than 400m. The upper part of the mudstone (157.6-216.3) illustrates a regressive sequence with a distinctive shift to a much shallower depositional environment at outermost shelfal depths likely of 150-200m. This is represented with the presence of Truncorotalia sp. and Zygochlamys delicatula. Grainsize also support this discovery with a shift to very fine sandy silts with a percent mud content ranging from 83-93%. Previous findings conclude that this distinctive shift was caused by glacioeustatic cycles yet our data do not correlate with our glacioeustatic findings. Therefore, this shift is believed to be triggered by a tectonic event.</p>

Foraminiferal Analysis of the Late Miocene- Early Pleistocene Mangaopari Mudstone, South Wairarapa, New Zealand

<p>The foraminiferal content of thirty-two samples from the late Miocene-early Pleistocene Mangaopari Mudstone within the southern Wairarapa region have been examined with the aim of determining the age and depositional environment of the unit. In particular the study addressed whether or not there were glacioeustatic cycles present in the unit. Integrating foraminiferal faunal distributions and sedimentological analysis provided geological, paleoclimactic, and paleoceanographic evidence to aid in the reconstruction of the paleoenvironment. The data was then compared with conclusions from previous studies. The section was divided into two different parts (upper and lower) based on changes in foraminiferal assemblages and grainsize distributions. The age and depositional environment of the Mudstone is suggested by the presence of several genera and species of foraminifera which is supported by grainsize analysis. The presence of Martinottiella communis and Karreriella cylindrica between 0-157.1m stratigraphically suggest that accumulation began in bathyal conditions at depths greater than 400m between. This is supported by grainsize analysis which indicates a medium silt with a high percent mud content ranging from 91.5-100%. This demonstrates deposition beginning in the late Miocene-early Pliocene at bathyal depths greater than 400m. The upper part of the mudstone (157.6-216.3) illustrates a regressive sequence with a distinctive shift to a much shallower depositional environment at outermost shelfal depths likely of 150-200m. This is represented with the presence of Truncorotalia sp. and Zygochlamys delicatula. Grainsize also support this discovery with a shift to very fine sandy silts with a percent mud content ranging from 83-93%. Previous findings conclude that this distinctive shift was caused by glacioeustatic cycles yet our data do not correlate with our glacioeustatic findings. Therefore, this shift is believed to be triggered by a tectonic event.</p>

Microplastics in Lake Onego sediments: occurrence and accumulation patterns.

&lt;p&gt;Lake Onego is the second largest lake in Europe. Sediment samples (23) were collected in different regions of the lake. Microplastics (MPs) were extracted from sediments with heavy liquid, oxidized and its abundance was determined using a microscope with a magnification of 40x. The extraction efficiency and the level of external contamination were evaluated, the results were blank-corrected. The anthropogenic origin of randomly selected MPs items was confirmed by Raman spectroscopy. MPs were detected in all samples. Maximum MPs abundances in sediments were observed in areas associated with the mouth of the second largest tributary of the lake &amp;#8211; river Shuya and Petrozavodsk Bay (2244 &amp;#177; 1901 pcs/kg DW; n= 6, p = 0.95), the open part of the lake (2356 &amp;#177; 1689; n = 5, p = 0.95) and in Kizhi National Park (3413 &amp;#177; 2005; n = 4, p = 0.95). In mean MPs abundance in Lake Onego was 2141&amp;#177;1144; n=22; p = 0.95). &amp;#160;&amp;#160;Fibers dominated in most of the samples (64&amp;#177;14%; n=22; p = 0.95). It was established, that fibers accumulate in sediments together with medium silt fraction (0.01-0.05 mm). MPs abundance was extremely high in Kondopoga bay (217 000 pcs/kg DW) and was mainly represented by microcapsules, possibly due to impact of the wastewaters of the Pulp and Paper mill plant at this site. In mean, MPs abundance in Lake Onego sediments was at least two times higher, than was previously established in Baltic Sea with similar methodology. Further comprehensive assessment of MPs contamination rates and forecasting consequences of this contamination to ecosystem is an urgent need in current research.&lt;/p&gt;&lt;p&gt;The study was supported by the Russian Science Foundation grant number 19-17-00035.&lt;/p&gt;

THE MICROMORPHOLOGY AND MINERALOGY OF GRAY FOREST SOILS IN VLADIMIR OPOLYE

The investigations were conducted on the gray forest heavy clay loamy soils, formed on the loess-like loams, which are widely spread on the territory of Vladimir Opolye. The eluvial-illuvial profile differentiation, its different intensity and the specificity of illuvial coatings (fine dispersed clayey and humus-clayey coatings with sparse skeletal content of soil) is confirmed. The presence of the coarse wooden plant residues, thick humus-clayey illuvial coatings within the illuvial horizons speak about the forest origin of the grey forest soils in Vladimir Opolye. The micromorphology of humus horizon reflects the direction of the soil forming process and the ecological status of soils. The illimerization is the main process of the matter migration and soil profile differentiation. The mixed-layer formations prevail in the clayey fraction. Mica, quartz, and K-feldspars are the prevailing compounds of the fine and medium silt within the gray forest soils. In the silt fraction of the second humus horizon prevail quartz and feld-spar. The most of the nutrients is concentrated in the clayey and fine-silt frac-tion. The micromorphological investigations confirmed the theory, which speaks about the presence of forest (the presence of illuvial coatings) as well as steppe soils (mull humus type in the SHH, the presence of primary and newly formed carbonates) specificities in the modern soil forming process within the gray forest soil of Vladimir Opolye.

SEDIMENTOLOGICAL OBSERVATIONS IN THE LAGOON OF KAIAFA (W PELOPONNESE)

The Kaifa lagoon is located along a coast in the western Péloponnèse. It is relatively shallow with an average depth 3.29 m. The lagoonal bottom sediment is dominantly sandy mud while few places are covered with muddy sad. They have an average Md 5.48 Φ (2.20Φ-7.80Φ) while in the greater part of the lagoon the Mz varies between 5.00Φ and 6.00Φ which points to the medium silt grade. The bottom sediments as a whole are very poorly sorted because of the significant absence of a wave or current action. Phi skewness varies between very negative and very positive values. These suggest the presence both the winnowing action and the process of the addition of a suspension material. The kurtosis values mostly are under 1.00. These probably suggest that the velocity of the depositional agent changes wide. The average amount of CaC03 is 45.28% (22.18%- 67.21%). CaC03 can be supplied by eolian action which operates on the barrier island. This mostly consists of carbonate clastic grains. The amount of organic carbon averages 3.58% (1.7%-6.10%) and the higher values (5%-6%) occur in the eastern lagoonal margin near a marsh zone.

THE GROUP COMPOSITION OF HUMUS AND FRACTIONS OF FINE-DISPERSED PHASE IN THE SODDY-PODZOLIC MEDIUM-LOAMY SOIL IN A LONG-TERM EXPERIMENT

The group composition of humus in microaggregates (colloidal, pre-colloidal, fine, medium and coarse silt) of the soddy-podzolic medium-loamy soil has been first studied in three five-course grain-tilled crop rotations in the long-term experiment of V.V. Dokuchaev Soil Science Institute. It is shown that in the trial with a higher dose of fertilizers (N150P150K180 kg/ha/year + 120 t/ha of manure) the humus content increases in soil after the first rotation as compared to that with average fertilizer doses (N60P60K60). This is explained by the content of carbon bond to microaggregates of medium and coarse silt. At the same time both experimental variants reveal deterioration of the microstructure including the decrease in the content of medium silt, accumulation of pre-colloidal and fine-dispersed fractions. It becomes evident that the best microstructure is observed in the variant enriched with fertilizer: it contains a great amount of silty fractions and humus components in the form of humates and nonhydrolyzed residues. Moreover, both experimental variants show a tendency towards decreasing the content of humates bond to silty fractions. The intensive system of fertilization in three rotations allowed maintaining the stable content of humus in the fraction of medium silt, the latter being disturbed to a lesser extent than that in the variant without manure application.

Locomotion and feeding traces in Champlain Sea subaqueous outwash deposits near Ottawa, Canada

Locomotion and feeding traces (repichnia and fodichnia) observed on bedding planes of rhythmically bedded subaqueous outwash deposits in the Brazeau sand pit, Nepean, Ontario, Canada, are the first bedding-plane traces described in detail from the western Champlain Sea. The Planolites–Palaeophycus-like and Taenidium-like traces are cylindrical with circular cross section, smooth sided, unlined, sinuous, sometimes branching, and sometimes meniscate. Organisms producing the traces are tentatively identified as errant polychaetes or nemerteans. The enclosing sediments are rhythmic couplets of alternating fine sand and silt layers overlain by silty clay and fine–medium silt layers. The occurrence of traces within the uppermost portion of the coarse unit, and within the coarser, upper portion of the overlying fine unit, and the rhythmic alternation of coarse and fine layers suggest these deposits may be varves. The traces formed during the more biologically suitable summer months but were preserved only during the latter portion of the summer. Traces are distributed on bedding planes in close association with bedforms and show a high correlation with the substrate and possibly the hydrodynamic regime. This is interpreted as indicating a strong preference in feeding behaviour. The presence of traces in the subaqueous outwash environment necessitates rethinking of the depositional environment to include the presence of errant polychaetes, nemerteans or similar organisms, and the lower life-forms such as epontic algae and bacteria on which they live.