The response of a basin-scale Miocene barrier reef system to long-term, strong subsidence on a passive continental margin, Barcoo Sub-basin, Australian North West Shelf

2015 ◽  
Vol 28 (1) ◽  
pp. 103-123 ◽  
Author(s):  
Beke Rosleff-Soerensen ◽  
Lars Reuning ◽  
Stefan Back ◽  
Peter A. Kukla
Keyword(s):  
Continental Margin ◽  
Passive Continental Margin ◽  
Barrier Reef ◽  
North West ◽  
Reef System ◽  
Basin Scale

scholarly journals Bajocian to Tithonian age of radiolarian cherts in the Tolmin basin (NW Slovenia)

2012 ◽  
Vol 183 (4) ◽  
pp. 369-382 ◽  
Author(s):  
Špela Goričan ◽  
Jernej Pavšič ◽  
Boštjan Rošič
Keyword(s):  
Continental Margin ◽  
Proximal Part ◽  
Plate Boundaries ◽  
Distributional Pattern ◽  
Western Tethys ◽  
Long Term Effect ◽  
Basin Scale ◽  
Two Factors ◽  
Vertical Variations

Abstract The Tolmin basin is a typical example of a deep-water Mesozoic basin that developed on the rifted south Tethyan continental margin. Remnants of this basin are preserved at the intersection of the Dinarides and the southern Alps in northwestern Slovenia. The Jurassic successions consist of carbonate gravity-flow deposits, radiolarian cherts and shales, and are overlain by pelagic Biancone limestone. A distinctive chert-dominated interval (the upper member of the Tolmin Formation) was dated with radiolarians. The base of this interval was assigned to the late Bajocian in the distal part of the basin and to the middle Callovian-early Oxfordian in the more proximal part of the basin. The topmost radiolarian cherts are early Tithonian in age. The mid-Tithonian transition from chert to the Biancone limestone was also determined with nannoplankton. The beginning of highly siliceous sedimentation in the Bajocian correlates well over the entire western Tethys and was linked to two factors: an increase in water depth due to regional subsidence and an increase in plankton productivity. The pronounced silica enrichment coincided with the opening of the Alpine Tethys and with the intraoceanic subduction that occurred in the Meliata-Maliac-Vardar Ocean. Reorganization of the plate boundaries may have induced substantial changes in the circulation of water masses that, in turn, had a long-term effect on surface productivity. On the basin scale, radiolarian dating revealed considerable lateral and vertical variations in the thickness of chert successions. This distributional pattern implies that, in narrow continental-margin basins, sedimentation rates were primarily determined by the redeposition of pelagic sediments. Important stratigraphic gaps occur even in the distal basinal setting.

scholarly journals Hydrogeological dissimilarity of geodynamically different terranes

2021 ◽  
Vol 44 (2) ◽  
pp. 134-140
Author(s):  
V. E. Glotov
Keyword(s):  
Continental Margin ◽  
Sandy Loam ◽  
Active Continental Margin ◽  
Passive Continental Margin ◽  
Coarse Grained ◽  
Active Margin ◽  
Water Abundance ◽  
Fine Grained ◽  
Weathering Processes

The article presents and analyzes the data on ground waters of active (suprapermafrost) and hindered (subpermafrost) water exchange of geodynamically different terrains in order to prove the hydrogeological importance of their historical and tectonic characteristics. On the example of Trans-Polar Chukotka it is shown that, under suprapermafrost conditions, the ubiquitous eluvial-deluvial nappes are the most water-abundant on the terrane – a fragment of the passive continental margin, whereas they are the least water-abundant on the terrains of the active margin. Hydrogeological situation changes under subpermafrost conditions: more permeable and water-retaining rocks compose the terranes of the active margin. These differences are associated with the level of rock tectonic decompaction and, accordingly, with different intensity of weathering processes in the terrane rocks of different geodynamic origin in suprapermafrost and subpermafrost conditions. The hypergenesis zone on the terranes of the passive continental margin features coarse-grained rock weathering products accumulated in relatively calm geological and historical environments, the aggregate is sandy. The terranes of the active margin, which underwent long-term subvertical and subhorizontal displacements contain more fine-grained weathering products; the aggregate includes sandy loam and clay sand. Since the permafrost strata in both Trans-Polar Chukotka and Eastern Siberia is greater than the depth of hypergene transformations, the terranes of the active continental margin, the rocks of which were impacted by tectonic decompaction processes, mainly of a strike-slip and thrust nature, feature greater water abundance in subpermafrost conditions.

Effects of wind and tide on upper-layer currents at Davies Reef, Great Barrier Reef, during MECOR (July-August 1984)

1986 ◽  
Vol 37 (5) ◽  
pp. 545 ◽  
Author(s):  
GL Pickard
Keyword(s):  
Great Barrier Reef ◽  
Reef Flat ◽  
Clear Correlation ◽  
Barrier Reef ◽  
The South ◽  
North West ◽  
The North ◽  
Transit Times ◽  
Strong Winds

At Davies Reef, flow over the east reef flat was unidirectional downwind at 10-20 cm s-1 with strong winds and smaller tides but was semi-diurnal tidal reversing at 5-15 cm s-1 with lighter winds and higher tides. The flood direction was to the south-east out of the lagoon and the ebb into the lagoon. Wave overtopping was estimated to contribute at least 40% of the flow over the reef flat-the first estimate of this component of flow over reef flats. Transit times over the reef flat were 30-170 min and flushing times for the east lagoon were estimated as ½ -1 day for strong winds to the north-west but 2-4 days for lighter winds. In the east lagoon, the upper-layer currents were semi-diurnal tidal reversing all the time at speeds up to 20 cm s-1, with longer-term net flow downwind at about 2 cm s-1 with strong winds but upwind at 0.2 cm s-1 with light winds. In the east passage, the strongly tidal currents (up to 60 cm s-1.) had a long-term net flow to the south at about 2 cm s-1 without any clear correlation with the wind.

The southern Moroccan passive continental margin: An example of differentiated long-term landscape evolution in Gondwana

2018 ◽  
Vol 53 ◽  
pp. 129-144 ◽  
Author(s):  
Manuel Sehrt ◽  
Ulrich A. Glasmacher ◽  
Daniel F. Stockli ◽  
Haddou Jabour ◽  
Oliver Kluth
Keyword(s):  
Continental Margin ◽  
Landscape Evolution ◽  
Passive Continental Margin

CURRENT STATE AND DEVELOPMENT PERSPECTIVES OF THE CASPIAN SPRAT FISHERIES

2018 ◽  
pp. 69-75
Author(s):  
Tatiana Vasilievna Pomogaeva ◽  
Aliya Ahmetovna Aseinova ◽  
Yuriy Aleksandrovich Paritskiy ◽  
Vjacheslav Petrovich Razinkov
Keyword(s):  
Food Item ◽  
Growth Potential ◽  
North West ◽  
Marine Fishery ◽  
The North ◽  
Current State ◽  
West Part ◽  
Eggs And Larvae ◽  
Intensive Growth

The article presents annual statistical data of the Caspian Research Institute of Fishery. There has been kept track of the long term dynamics of the stocks of three species of Caspian sprat (anchovy, big-eyed kilka, sprat) and investigated a process of substituting a food item of sprats Eurytemora grimmi to a small-celled copepod species Acartia tonsa Dana. According to the research results, there has been determined growth potential of stocks of each species. Ctenophoran-Mnemiopsis has an adverse effect on sprat population by eating fish eggs and larvae. Ctenophoram - Mnemiopsis is a nutritional competitor to the full-grown fishes. The article gives recommendations on reclamation of stocks of the most perspective species - common sprat, whose biological characteristics helped not to suffer during Ctenophoram outburst and to increase its population during change of the main food item. Hydroacoustic survey data prove the intensive growth of common sprat biomass in the north-west part of the Middle Caspian. According to the results of the research it may be concluded that to realize the volumes of recommended sprat catch it is necessary to organize the marine fishery of common sprat at the Russian Middle Caspian shelf.

Management of Water Quality in the Great Barrier Reef Marine Park

1989 ◽  
Vol 21 (2) ◽  
pp. 31-38 ◽  
Author(s):  
Simon Woodley
Keyword(s):  
Water Quality ◽  
Coral Reef ◽  
Great Barrier Reef ◽  
Barrier Reef ◽  
Management Issue ◽  
Reef System ◽  
Marine Park ◽  
World Heritage List ◽  
The World ◽  
Coral Reef System

The Great Barrier Reef is the largest coral reef system in the world. It is recognised and appreciated worldwide as a unique environment and for this reason has been inscribed on the World Heritage List. The Reef is economically-important to Queensland and Australia, supporting substantial tourism and fishing industries. Management of the Great Barrier Reef to ensure conservation of its natural qualities in perpetuity is achieved through the establishment of the Great Barrier Reef Marine Park. The maintenance of water quality to protect the reef and the industries which depend on it is becoming an increasingly important management issue requiring better knowledge and possibly new standards of treatment and discharge.

Long-term vegetation restoration promotes the stability of the soil micro-food web in the Loess Plateau in North-west China

CATENA ◽  
2021 ◽  
Vol 202 ◽  
pp. 105293
Author(s):  
Yang Wu ◽  
WenJing Chen ◽  
Wulan Entemake ◽  
Jie Wang ◽  
HongFei Liu ◽  
...  
Keyword(s):  
Food Web ◽  
Loess Plateau ◽  
Vegetation Restoration ◽  
The Loess Plateau ◽  
West China ◽  
North West ◽  
The Stability
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