scholarly journals Lithological and isotopic (δ 13C and δ 18O) features of the Upper Silurian back-reef lagoon deposits of the Ilych River Basin, the Northern Urals

2021 ◽  
Vol 11 ◽  
pp. 43-54
Author(s):  
E. S. Ponomarenko ◽  
Keyword(s):  
River Basin ◽  
Isotopic Fractionation ◽  
Wide Distribution ◽  
Back Reef ◽  
Clastic Material ◽  
Reef Lagoon ◽  
Northern Urals ◽  
Rock Types ◽  
Δ 13C ◽  
Upper Silurian

The Upper Silurian is widely developed in the Northern Urals, where it is represented by various facies. The continental slope facies and the reef shoal facies are well documented in the geological literature, while as back-reef lagoon facies have not yet been characterized in detail. The studied objects included two sections of the back-reef deposits in the Ilych River basin. In this work, we characterize rock types the make up the sections, and their isotopic characteristics. The Late Silurian back-reef lagoon was characterized by a mosaic sediments distribution, which included the island areas between which there were areas with a quiet hydrodynamic regime. In the latter, mainly muddy carbonates were accumulated, represented by clotted fenestral limestones. The area of small islands was characterized by a wide distribution of lime sands, which clastic material was derived from probable paleosoil carbonates. They are characterized by slightly increased δ 13C values, which, probably, reflects isotopic fractionation at the evaporative geochemical barrier. Dolomitization and karstification are described among secondary alterations in the studied sections. Cementstones is interpreted as karst cavities precipitates.

Seasonal distribution and movement of juvenile Atlantic sturgeon (Acipenser oxyrinchus oxyrinchus) in the lower Saint John River Basin, New Brunswick, Canada

2018 ◽  
Vol 75 (12) ◽  
pp. 2354-2363 ◽  
Author(s):  
Margaret M. Whitmore ◽  
Matthew K. Litvak
Keyword(s):  
River Basin ◽  
Movement Patterns ◽  
Principal Component ◽  
Wide Distribution ◽  
Atlantic Sturgeon ◽  
Coarse Scale ◽  
Brackish Waters ◽  
Single Location ◽  
Saint John ◽  
Acipenser Oxyrinchus

Juvenile Atlantic sturgeon (Acipenser oxyrinchus oxyrinchus) movement and distribution varies seasonally within the lower Saint John River Basin. We use acoustic telemetry to track coarse-scale movement and a network-based approach to develop metrics describing distribution and movement patterns of juvenile Atlantic sturgeon tagged in two rivers, the Saint John and Kennebecasis rivers. We use principal component analysis to develop indices of movement and residency and test for differences among seasons and between fish from each river. Juvenile Atlantic sturgeon exhibit higher residency during summer months compared with winter and spring. Juveniles are primarily concentrated in the brackish waters of the lower river reaches but make movements as far upriver as rkm 88. There was high variation in distribution and movement patterns exhibited by fish tagged in the Kennebecasis River, ranging from single-location occupancy to wide distribution. Three fish left the system during the study, indicating juveniles embark on brief marine excursions. Identifying spatiotemporal distributions of juvenile Atlantic sturgeon in their natal river systems is a crucial step towards identifying critical habitat and informing management decisions for this species.

Distribution and Conservation Status of the Black-Footed Rock-Wallaby, Petrogale lateralis (MacDonnell Ranges race), in the Northern Territory.

1999 ◽  
Vol 21 (2) ◽  
pp. 213
Author(s):  
D.F. Gibson
Keyword(s):  
National Parks ◽  
Conservation Status ◽  
South Australia ◽  
Wide Distribution ◽  
Northern Territory ◽  
Capra Hircus ◽  
Conservation Areas ◽  
Rock Outcrops ◽  
Term Survival ◽  
Rock Types

The distribution and conservation status of the Black-footed Rock-wallaby Petrogale lateralis (MacDonnell Ranges race), in the Northern Territory were investigated to complement previous surveys in adjoining areas of Western Australia and South Australia. Historical data were collated and compared with recent biological survey results obtained between 1870 and 1999. From a total of 469 records, 400 were collated for the period 1975-1999. The species occurs over ten biogeographic regions, principally within the MacDonnell Ranges bioregion, but with many populations in the Burt Plain and Great Sandy Desert bioregions. It is widely distributed through pastoral, Aboriginal, conservation and urban land and, at present, retains much the same distribution as concluded from early records. Thirteen conservation areas and 30 pastoral leases currently support populations of the species. An unknown number of animals live in and about Alice Springs. Only two National Parks, the West MacDonnells and Finke Gorge, are considered large and diverse enough to ensure the long-term survival of P. lateralis. Measures of abundance are not available but numbers of animals in conservation areas are perceived to have remained stable or to have increased over the past 20 years. Surveys undertaken during the period 1975-1999 indicate that P. lateralis have disappeared from 21 of 400 sites. Petrogale lateralis were present on all major rock types, including many granite outcrops. They were most widespread and apparently abundant on major quartzite ranges such as the MacDonnells where steep cliff faces, gorges, scree slopes and fire shadow areas are common. The wide distribution of P. lateralis in the Northern Territory in comparison to other states may be due to a variety of factors: widespread, relatively contiguous and variable habitat, occupation of country north of the core distribution of Oryctolagus cuniculus and of Vulpes vulpes, the inability of Capra hircus to persist and thus to compete in rocky range habitat, and a government 1080 poisoning programme for Canis lupus dingo on pastoral land. There is however, concern for the survival of some populations on many small ranges and rock outcrops on the fringes of its known distribution where recent observations indicate that numbers of animals are low.

Growth rates and ecology of coralline rhodoliths from the Ras Ghamila back reef lagoon, Red Sea

2016 ◽  
Vol 37 (4) ◽  
pp. 713-726 ◽  
Author(s):  
Annalisa Caragnano ◽  
Daniela Basso ◽  
Graziella Rodondi
Keyword(s):  
Red Sea ◽  
Growth Rates ◽  
Back Reef ◽  
Reef Lagoon

Drivers of carbon isotopic fractionation in a coral reef lagoon: Predominance of demand over supply

2015 ◽  
Vol 153 ◽  
pp. 105-115 ◽  
Author(s):  
Matheus C. Carvalho ◽  
Isaac R. Santos ◽  
Damien T. Maher ◽  
Tyler Cyronak ◽  
Ashly McMahon ◽  
...  
Keyword(s):  
Coral Reef ◽  
Isotopic Fractionation ◽  
Reef Lagoon ◽  
Carbon Isotopic ◽  
Coral Reef Lagoon ◽  
Carbon Isotopic Fractionation

scholarly journals Alkaline rocks of the Ukrainian Shield: Some mineralogical, petrological and geochemical features

Mineralogia ◽  
2013 ◽  
Vol 44 (3-4) ◽  
pp. 115-124 ◽  
Author(s):  
Aleksandr N. Ponomarenko ◽  
Stepan G. Kryvdik ◽  
Aleksandr V. Grinchenko
Keyword(s):  
Wide Distribution ◽  
Ukrainian Shield ◽  
Alkaline Magmatism ◽  
Alkaline Rocks ◽  
Precambrian Rocks ◽  
Western Province ◽  
Rock Types ◽  
Alkaline Feldspar ◽  
Granite Complex ◽  
Proterozoic Age

AbstractThe Ukrainian Shield (USh) is a typical province of Proterozoic alkaline magmatism where about 50 massifs and occurrences of alkaline rocks and carbonatites have been found. In spite of the wide distribution of Devonian basaltic- and alkaline magmatic rocks in the Dnieper-Donetsk depression adjacent to the USh, and in a marginal zone of the USh adjacent to folded Donbass, only alkaline rocks of Proterozoic age (1.8-2.1 Ga) that have been identified in the central interior of the USh. Some discrete bodies of 2.8 Ga subalkaline rocks also occur in Bogdanivka massif (Azov area). Occurrences of both Proterozoic (prevailing) and Phanerozoic (Devonian) alkaline rocks and kimberlites are only found in the eastern part of the USh (Azov area). Kimberlites in the central part of the Ukrainian Shield (Kirovograd region) are also of Proterozoic age (ca 1.8 Ga). It is this predominance of Precambrian rocks that makes the USh so different from other alkaline provinces where Phanerozoic alkaline rocks and kimberlites commonly prevail over Precambrian rocks. The lack of Phanerozoic alkaline magmatism on USh is poorly understood. Two main complexes of alkaline rocks - alkaline-ultrabasic (carbonatitic) and gabbro- syenitic - are distinguished in the USh. There are also rare occurrences of rock types such as alkaline- and alkaline-feldspar granites that may represent one separate alkaline-granite complex. Alkaline rocks present in the Eastern (Azov) province and in the Western province display essentially different geochemical character. Those of the Eastern province show characteristics typical of alkaline-ultrabasic rocks (e.g. high contents of incompatible rare elementssuch as Nb, REE, Zr, Y, Sr, whereas those in the Western province are characterized by low contents of Nb and Zr, and REE in some cases. This fact is interpreted as reflecting different geodynamic conditions of their origin. The Eastern rocks were formed in rift settings, the Western rocks in crustal compressional settings (collision, subduction). Various mineral deposits of phosphorus (apatite), niobium, REE, yttrium and zirconium, including unusually rich ores of REE, Y and Zr (Azov and Yastrybetsky) are associated with the alkaline rocks and carbonatites of the USh.

Selective Elimination of Rooted Plants from a Tropical Seagrass Bed in a Back-Reef Lagoon: A Hypothesis Tested by Hurricane Wilma (2005)

2008 ◽  
Vol 241 ◽  
pp. 278-281 ◽  
Author(s):  
Brigitta I. van Tussenbroek ◽  
M. Guadalupe Barba Santos ◽  
Jent Kornelis van Dijk ◽  
S. N. Marisela Sanabria Alcaraz ◽  
M. Lourdes Téllez Calderón
Keyword(s):  
Back Reef ◽  
Seagrass Bed ◽  
Hurricane Wilma ◽  
Reef Lagoon ◽  
Selective Elimination

scholarly journals A Billion Years of History within the Grevena-Deskati Watershed

2019 ◽  
Vol 54 (1) ◽  
pp. 20 ◽  
Author(s):  
Dina Ghikas ◽  
Anne Ewing Rassios
Keyword(s):  
River Basin ◽  
River System ◽  
Climatic Conditions ◽  
Geologic History ◽  
River Systems ◽  
High Quality ◽  
River Flows ◽  
Rock Types ◽  
Tectonic Events ◽  
Selection Of

The river system of West Macedonia comprises the headwaters and western extent of the Aliakmon watershed.  This region has a unique and highly complex geologic history (Rassios, 2008; Rassios, 2011), many aspects of which can be inferred by examining conglomerate (river-cobble) formations in the region.  These formations contain all rock types found within the modern-day river basin, as well as some which are not found within today's basin.  River-deposited sediments and cobbles found along today’s Aliakmon and Venetikos River systems trace the courses of ancient river flows, and thus provide information about past climatic conditions and tectonic events.  The sediments making up conglomerate formations in the region are mature, containing cobbles which have been transported, consolidated, eroded and redeposited up to five times (Rassios and Grivas, 1998).  This recycling of cobbles leaves only the most durable rocks while softer rocks are destroyed via abrasion.  Prehistoric peoples availed themselves of this concentrated and convenient selection of high-quality stones for the purpose of fashioning tools and weapons.

scholarly journals Microbial structure in the Visean deposits of the Ilych river (Northern Urals)

2020 ◽  
Author(s):  
Keyword(s):  
River Basin ◽  
Microbial Structure ◽  
Northern Urals ◽  
First Time

The paper presents data on the distribution of microbial formations in the Visean rocks of the Ilych River basin (Northern Urals). They were found to be present in significant numbers only in the Venevian level. Stromatolites were found in the Visean on the Ilych River for the first time.

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