scholarly journals MAIN STAGES OF DEVELOPMENT OF THE LATE CARBONIFEROUS FLORA AND VEGETATION IN THE DONETS BASIN AS THE BASIS OF JUSTIFICATION OF REGIONAL STRATIGRAPHIC UNITS AT THE PALAEOECOSYSTEM LEVEL

2021 ◽  
Vol 14 (1) ◽  
pp. 117-128
Author(s):  
Nataliya I. Boyarina
Keyword(s):  
Lower Boundary ◽  
Late Carboniferous ◽  
Donets Basin ◽  
Stages Of Development ◽  
Time Intervals ◽  
Vegetation Development ◽  
Seasonally Dry ◽  
River Valleys ◽  
Plant Migrations ◽  
Coastal Lowlands

Four stages of development of the late Carboniferous vegetation cover have been established that correspond to the time intervals of four regional subdivisions of the Donets Basin − the Toretsian and Kalynovian Regional Stages, the Luganskian and Vyskrivskian Horizons of the Myronivskian Regional Stage. The analysis of phytostratigraphic and paleophytocenological data showed that the stages of vegetation development are characterized by the dominant plant communities in rank of orders of widespread landscapes. Сhanges from one stage to another are considered as the paleophytocenotic events, which are expressed by the changes of dominant communities of certain landscape types. The levels of paleophytocenotic events coincid with the bases of regional subdivisions The bases of the Toretsian and Kalynovian correspond to the levels of paleophytocenotic events, which were manifested by the formation of new communities types as a result of the evolutionary renewal of composition of wetland calamitean-fern and fern-pteridosperm forests of coastal lowlands as well as lycopsid and calamitean-fern forests of deltaic plains. The base of the Myronivskian (Luganskian Horizon) corresponds to the level of the paleophytocenotic event that was expressed by, firstly, the appearance of new communities types of seasonally dry pteridosperm woodlands of river valleys as a result of the evolutionary renewal of their composition, secondly, the appearance of new communities types of wetland calamitean-fern woodlands of coastal lowlands and calamitean-fern and pteridosperm woodlands of deltaic plains, the formation of which were due to the reduction of species compositions and the changes of dominants. The lower boundary of the Vyskrivskian Horizon corresponds to the level of the paleophytocenotic event that was expressed by the appearance of new communities types of wetland calamitean-fern and fern-pteridosperm woodlands of coastal lowlands and seasonally dry fern-pteridosperm woodlands of lacustrine-lagoon plains, the formation of which were associated with plant migrations and the appearance of new dominants. The considered paleophytocenotic events are manifestations of phytocoenogenetic processes, which led to paleophytocenotic changes, and mark main palaeoecosystem transformations in view of vegetation development stages.

scholarly journals ON THE POSITION OF THE BOUNDARY BETWEEN THE MOSCOVIAN AND KASIMOVIAN GLOBAL STAGES OF THE CARBONIFEROUS IN THE DONETS BASIN

2021 ◽  
Vol 14 (1) ◽  
pp. 63-71
Author(s):  
Tamara I. Nemyrovska
Keyword(s):  
Lower Boundary ◽  
Donets Basin ◽  
Present Position ◽  
Precise Position ◽  
Index Species ◽  
Potential Index ◽  
Type Area ◽  
Extinction Event ◽  
Moscow Basin ◽  
Definition Of

Detailed new data on paleontology and stratigraphy were obtained in the process of fulfilling the tasks of the International Carboniferous Subcommission on definition of the scopes of the Moscovian and Kasimovian global stages and the precise position of the boundary between them. The analysis of these data has shown that the position of this boundary in the type  area and in the other regions needs the revision. Recently the investigation of the conodonts from the Moscovian–Kasimovian boundary deposits in the Donets Basin revealed that the boundary between the Moscovian and Kasimovian stages in the official Ukrainian Carboniferous Stratigraphic Scheme does not correspond to this boundary in the type area of these stages in the  Moscow Basin. To correct this situation the lower boundary of the Kasimovian in the Ukrainian Scheme must be downgraded by two conodont zones — Swadelina subexcelsa and Sw. makhlinae. To update this boundary in the type area to fulfill the task of the Carboniferous Subcommission four conodont species were proposed as potential index-species for the definition of the boundary between the Moscovian and Kasimovian global stages. These conodont species are as follows Sw. subexcelsa,  Idiognathodus sagittalis, I. turbatus and I. heckeli. One of these species, which is selected, will be used as a marker of the  studied boundary. None of these species is officially selected as a marker. If Sw. subexcelsa will be selected, the position of  the Moscovian–Kasimovian boundary will remain at the present position. In this case this boundary in the Donets Basin has to be downgraded by two conodont zones. If one of three Idiognathodus will be selected, this boundary in the type area will be   upgraded by one and a half regional substage. In the Donets Basin it will be upgraded by less than a cycle. Keywords: Carboniferous, stratigraphy, conodonts, extinction event, index-­species. 

scholarly journals Conodont association of the Bashkirian-Moscovian boundary interval of the Donets Basin, Ukraine

2018 ◽  
Vol 33 (1) ◽  
pp. 105 ◽  
Author(s):  
Tamara I. NEMYROVSKA ◽  
Keyi HU
Keyword(s):  
Lower Boundary ◽  
The Other ◽  
Donets Basin ◽  
Conodont Evolution ◽  
Biotic Events ◽  
Definition Of ◽  
Moscovian Stage ◽  
Stage D

Ten sections spanning the Bashkirian-Moscovian boundary interval were studied in the Donets Basin. Six of them contain most representative conodont and foraminifer associations. In this paper we focused on three the most complete sections that include stratigraphically important conodont species, which belong to the Declinognathodus, Idiognathoides, Idiognathodus, Neognathodus, “Streptognathodus”, Mesogondolella and Diplognathodus genera. The majority of those species are widely distributed, which makes the correlation to other areas reliable. Two biotic events in conodont evolution were discovered in these sections. Two conodont lineages established here are considered as potential markers for the definition of the lower boundary of the Global Moscovian Stage: D. marginodosus – D. donetzianus and Id. sulcatus sulcatus – Id. postsulcatus. The conodonts D. donetzianus and Id. postsulcatus, both proposed before as potential markers for the de? nition of the GSSP at the Bashkirian-Moscovian boundary, are described and compared to those from the other areas. The entry of D. donetzianus is updated and con? rmed to the top of the limestone K1 in both sections, the Zolota Valley and the Malo-Mykolaivka sections. The other proposals for the de???? nition of the lower Moscovian boundary by conodonts are discussed. Three conodont zones characterize the Bashkirian-Moscovian boundary interval. These are, in ascending order: the Id. tuberculatus – Id. fossatus Zone and D. marginodosus Zone from the upper Bashkirian, and D. donetzianus Zone from the lower Moscovian. They were recently described and shortly given in this paper.

Editorial Introduction

2009 ◽  
Author(s):  
Jamie Woodward
Keyword(s):  
Spatial Scales ◽  
Soft Rock ◽  
Human Action ◽  
Ecosystem Change ◽  
Climate Data ◽  
Theoretical Frameworks ◽  
Sediment Yields ◽  
Seasonally Dry ◽  
The Mediterranean ◽  
River Valleys

The nine chapters in Part II build on the physical, biological, and theoretical frameworks set out in Part I, but with a focus on process regimes and change in specific environments. With its emphasis on much larger spatial scales, Part I showed how the Mediterranean basin is a product of long-term interactions between all components of the Earth system. It showed how these interactions drive landscape and ecosystem processes and environmental change. The chapters in Part II examine Mediterranean-wide patterns too, but explore process interactions in sharper resolution and across scales ranging from individual soil profiles, hillslopes, and habitats to larger landscape elements including lake basins, river valleys, dune systems, and coastal plains. Much of the region is dominated by mountains and many process interactions are especially vivid in the Mediterranean because of the erosive energy available in steep and active tectonic settings, and the presence of soft rocks vulnerable to mass movements and water erosion. Abrupt transitions from uplands to lowlands— and the differential response to tectonic uplift of hard and soft rock terrains—are notable features. The seasonally dry climate can leave bare slopes exposed to high intensity rains, and river sediment yields are typically much higher than in adjacent regions. It can be argued that the Quaternary records of these interactions are more varied and better preserved than in any other part of the world. Recent major advances include the development of high resolution proxy climate data from speleothems and robust dating frameworks for fluvial, glacial, and palaeoecological records. These records have provided important new insights into the tempo of climate, landscape, and ecosystem change in the Mediterranean region and beyond. A variety of sedimentary archives also provide insights into the changing nature and intensity of human action in the Mediterranean landscape during the course of the Pleistocene and Holocene and this is a core theme of Part II. The region is unique because of the very early and widespread impact of humans in landscape and ecosystem change—and the richness of the archaeological and geological archives in which it is chronicled.

PALEOGEOGRAPHY OF THE SARTAN GLACIATION OF THE PATOMSKY AND NORTH-BAIKAL HIGHLANDS

2020 ◽  
Vol 26 (8) ◽  
pp. 16-30
Author(s):  
F. Enikeev ◽  
Keyword(s):  
Lower Boundary ◽  
Gold Deposits ◽  
Valley Bottom ◽  
Mountain Valley ◽  
The North ◽  
Ice Surface ◽  
Time Period ◽  
Direction Of Movement ◽  
The Difference ◽  
River Valleys

The article presents the results of the reconstruction of the spatial boundaries and parameters of glaciers for the isolated mountain structures of the Patomsky and North Baikal uplands in the era of the Last Glaciation (MIS 2) with the construction of a paleogeographic map. The object of this study is the dynamics of exogenous processes during the development of the permafrost zone in Eastern Siberia. The subject of research is the glacial relief forms of the Late Neopleistocene of the Patomsky and North Baikal uplands. The comparative, descriptive, cartographic research methods, methods of observation and actualism have been used. Based on the interpretation of aerial and satellite images, the identification of typomorphic glaciers with the maximum number of preserved destructive and accumulative glaciogenic forms, a depression of the snow boundary was established, which at that time was at the level of 2000…2100 m. The features of the lower boundary deformations of the chionosphere were revealed. Its deepest minimum is noted on the northwestern edge of the considered territory. The greatest decrease in relation to the paleoclimatic snow boundary, which extended to an altitude of 1600…1700 m, was 600…700 m. The positive extremum was confined to the central part of the Patom upland and exceeded the paleoclimatic snow line by 50…100 m. Anomalous extremes at that time period are due to global climatic, regional orographic and local (slope exposure) causes. It has been determined that in terms of morphology, glaciation of the territories under consideration is mountain-valley and reticulate with several sections of mountain-cover, confined to the flattened surfaces of the summit belt of mountain structures. According to the difference between the ice surface isolines and the valley bottom in the cross section, the thickness of the glacier was specified, and could reach 400…600 m. When searching for alluvial occurrences and gold deposits, as well as when sampling placer flows and secondary geochemical halos, it is recommended to orient prospecting in the direction of movement of ice masses. The new paleogeographic data obtained will increase the possibilities of more efficient mapping of Quaternary sediments within the North Baikal and Patom uplands and the identification of specific sections of river valleys in this area, favourable for placer formation

scholarly journals Late Carboniferous – Early Permian (Ghzelian – Artinskian) Palynomorphs

1985 ◽  
Vol 4 (1) ◽  
pp. 93-105 ◽  
Author(s):  
W. A. Brugman ◽  
J. W. Eggink ◽  
S. Loboziak ◽  
H. Visscher
Keyword(s):  
Pollen Grains ◽  
Early Carboniferous ◽  
Point Of View ◽  
Late Carboniferous ◽  
Donets Basin ◽  
Early Permian ◽  
Low Frequencies ◽  
Transition Sequence ◽  
As Species ◽  
The Status

Abstract. The preliminary results of the palynological investigations in the Late Carboniferous – Early Permian of Northeast Libya indicate that at least two successive intervals can be readily recognised:Ghzelian – Asselian interval. This lower interval is characterised by assemblages showing a dominance of saccate pollen; miospores usually occur in very low frequencies. Throughout the interval one may recognise (a) monosaccate pollen, attributable to genera such as Potonieisporites, Plicatipollenites, Cannanoropollis and Barakarites; (b) taeniate (striate) bisaccate pollen, identified as species of Illinites, Protohaploxypinus, Strotersporites, Striatoabieites and Distriatites; and (c) non-taeniate bisaccate pollen, represented by alete genera and Limitisporites.Although some of the monosaccate elements may already occur in the Early Carboniferous of Libya, the observed diversification points to a Late Carboniferous – Early Permian age of the assemblages. Taeniate pollen grains are known to make their first appearance in the Moscovian (e.g., in the Donets Basin; compare Inosova et al., 1976) but the observed diverse assemblages appear more characteristic for the latest Carboniferous and/or Early Permain, of both the Euramerican and Gondwana provinces (compare, e.g., Inosova et al., 1976; Kemp et al., 1977). Consequently, the authors consider the interval to represent a Carboniferous – Permian transition sequence, broadly comprising the Ghzelian and Asselian Stages. It should be noted, however, that the status of the Asselian Stage is still under discussion; some authors prefer the inclusion of this unit (or part of it) in the Carboniferous. From a palynological point of view the incoming of Distriatites could well mark a datum level corresponding to the Carboniferous . . .

Determination of the Bashkirian–Moscovian boundary in the Volga region via conodont species Declinognathodus donetzianus Nemirovskaya

2014 ◽  
Vol 151 (2) ◽  
pp. 299-310 ◽  
Author(s):  
GUZEL SUNGATULLINA
Keyword(s):  
Detailed Analysis ◽  
Lower Boundary ◽  
Appalachian Basin ◽  
Volga Region ◽  
Donets Basin ◽  
Moscow Syneclise ◽  
Selection Of

AbstractThe selection of the global biomarker of the lower boundary of the Moscovian stages is one of the pressing issues of Carboniferous stratigraphy. Several solutions are suggested for this problem: Diplognathodus ellesmerensis Bender, Streptognathodus expansus (Igo & Koike) and Idiognathoides postsulcatus Nemirovskaya. The conodont species Declinognathodus donetzianus Nemirovskaya is one of the most prospective. It was detected in the rock sections of west Europe, the Donets Basin, the Moscow Syneclise, south Ural and the Appalachian Basin. The Volga region is also one of the places where Declinognathodus donetzianus Nemirovskaya is often met and this article is dedicated to detailed analysis of this species.

EFFECT OF ROOT ZONE TEMPERATURES ON CORN LEAF MORPHOLOGY

1966 ◽  
Vol 46 (6) ◽  
pp. 593-601 ◽  
Author(s):  
Eric G. Beauchamp ◽  
D. J. Lathwell
Keyword(s):  
Root Zone ◽  
Morphological Characteristics ◽  
Cell Types ◽  
Shoot Meristem ◽  
Sand Culture ◽  
Stages Of Development ◽  
Time Intervals ◽  
Root Zone Temperature ◽  
Corn Plants ◽  
Zone Temperature

Corn plants were grown at constant root zone temperatures of 15°, 20°, and 25 °C using sand culture in the greenhouse. Stages of development were defined, using as a basis the appearance of leaf tips from the whorl, so that morphologically similar plants grown at different root zone temperatures could be compared.The time intervals required by the corn plants to reach specific stages of development increased substantially with decreasing temperatures. The total dry weights of the plants at specified stages of development decreased significantly with increasing temperatures. Plants grown at 25° produced on the average 1.7 leaves more than those grown at 15 °C prior to tassel formation. Lamina lengths and dry weights decreased with increasing temperatures. Lamina widths and areas were greatest at 20 °C. The narrowest laminae were produced by plants grown at 15° and smallest lamina areas at 25 °C. While the diameters of one cell type in the laminae were not affected by temperature, the lengths of two other cell types decreased significantly with increasing temperatures.The variations in morphological characteristics of leaf laminae were interpreted on the premise of a direct influence of root zone temperature on the shoot meristem.

scholarly journals An $$L^2$$ approach to viscous flow in the half space with free elastic surface

2021 ◽  
Author(s):  
Reinhard Farwig ◽  
Andreas Schmidt
Keyword(s):  
Half Space ◽  
Lower Boundary ◽  
Strong Solutions ◽  
Plate Equation ◽  
Damping Term ◽  
Time Intervals ◽  
Elastic Surface ◽  
Inhomogeneous Boundary Data ◽  
Nonlinear Free Surface ◽  
Interaction Problem

AbstractWe consider a linearized fluid-structure interaction problem, namely the flow of an incompressible viscous fluid in the half space $${\mathbb {R}}^n_+$$ R + n such that on the lower boundary a function h satisfying an undamped Kirchhoff-type plate equation is coupled to the flow field. Originally, h describes the height of an underlying nonlinear free surface problem. Since the plate equation contains no damping term, this article uses $$L^2$$ L 2 -theory yielding the existence of strong solutions on finite time intervals in the framework of homogeneous Bessel potential spaces. The proof is based on $$L^2$$ L 2 -Fourier analysis and also deals with inhomogeneous boundary data of the velocity field on the “free boundary” $$x_n=0$$ x n = 0 .

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