A new formation model of the Atlantic-Arctic heterochronous rifting system: A concept and basic provisions

2021 ◽  
pp. 18-27
Author(s):  
Alexander KREMENETSKIY
Keyword(s):  
Arctic Ocean ◽  
Rift System ◽  
Formation Model ◽  
Outer Continental Shelf ◽  
Tectonic Zone ◽  
Gakkel Ridge ◽  
System A ◽  
History Of ◽  
Eurasian Basin ◽  
New Formation

A new formation model of the global Atlantic-Arctic heterochronous rifting system is substantiated, according to which the Central and North Atlantics, Labrador-Baffin seas, and Arctic Ocean represent morpho-tectonic elements of different orders of the united recent Atlantic-Arctic Ocean. Evolution of the global rift system of this ocean includes three stages: the first stage (D–J1) was expressed by establishment of a tectonic zone in the lithosphere of Pangea with formation of the ophiolite ultrabasite-gabbro association; the second stage (J1–₽1) represented stretching of the continental crust to form depressions and uplifts with areal manifestation of trap magmatism of Cretaceous and other ages; and the third one (₽2–present) is neotectonic-magmatic reactivation with formation of a middle ridge, that is being accompanied by outpouring of glassy basalts and by hydrothermal manifestations. Within the framework of this model, the history of formation is reconstructed of the Eurasian Basin and the Gakkel Ridge, that were included in the Russia's updated application for expansion of the outer continental shelf border.

Seismic history of Minnesota and its geological significance

1981 ◽  
Vol 71 (1) ◽  
pp. 199-210 ◽  
Author(s):  
Harold M. Mooney ◽  
G. B. Morey
Keyword(s):  
Maximum Intensity ◽  
Rift System ◽  
Tectonic Zone ◽  
Midcontinent Rift ◽  
Western Margin ◽  
The North ◽  
Midcontinent Rift System ◽  
History Of ◽  
Tectonic Features ◽  
Felt Area

abstract Twelve earthquakes have been documented in Minnesota in the last 120 yr. The first nine were felt, whereas the last three (all in 1979) were detected instrumentally by a six-element seismic array which has recently been put into operation. Estimated magnitudes range from 0.1 (instrumental only) to 4.8, with four of magnitude 4.3 or greater. The highest intensity values were VI to VII. Depths where obtainable are estimated at 5 to 20 km. The best documented event occurred on 9 July 1975 near Morris, Minnesota, with a magnitude of 4.6, a maximum intensity of VI, and a felt area of 82,000 km2 covering parts of four states. The event was recorded to epicentral distances of at least 38°. The epicenters show a clear relationship to tectonic features of the state. Four epicenters lie along the newly defined Great Lakes Tectonic Zone, an east-northeast-trending belt extending across several states and into Canada. The zone separates 3,000 to 3,600 m.y. rocks of a gneissic terrane to the south from 2,700 m.y. rocks of a greenstone-granite terrane to the north. Four other events lie on known major northwest-trending faults in the greenstone-granite terrane. Two and possibly three events are associated with the western margin of the Midcontinent Rift System.

MINERAL DEPOSITS OF THE MIDCONTINENT RIFT SYSTEM - A NEW TIME/SPACE CLASSIFICATION

2018 ◽  
Author(s):  
Laurel G. Woodruff ◽  
◽  
Suzanne W. Nicholson ◽  
Connie L. Dicken ◽  
Klaus J. Schulz
Keyword(s):  
Mineral Deposits ◽  
Rift System ◽  
Midcontinent Rift ◽  
System A ◽  
Time Space ◽  
Midcontinent Rift System ◽  
New Time

scholarly journals Neotectonic evolution and sediment budget of the Meuse catchment in the Ardennes and the Roer Valley Rift System

2002 ◽  
Vol 81 (2) ◽  
pp. 211-215 ◽  
Author(s):  
R.T. Van Balen ◽  
R.F. Houtgast ◽  
F.M. Van der Wateren ◽  
J. Vandenberghe
Keyword(s):  
Digital Terrain Model ◽  
River System ◽  
Sediment Budget ◽  
Middle Pleistocene ◽  
Rift System ◽  
Terrain Model ◽  
Fluvial Terraces ◽  
Digital Terrain ◽  
History Of ◽  
Planation Surfaces

AbstractUsing marine planation surfaces, fluvial terraces and a digital terrain model, the amount of eroded rock volume versus time for the Meuse catchment has been computed. A comparison of the amount of eroded volume with the volume of sediment preserved in the Roer Valley Rift System shows that 12% of the eroded volume is trapped in this rift. The neotectonic uplift evolution of the Ardennes is inferred from the incision history of the Meuse River system and compared to the subsidence characteristics of the Roer Valley Rift System. Both areas are characterized by an early Middle Pleistocene uplift event.

scholarly journals Combined high-resolution seismostratigraphic and morphobathymetric analysis reveals glacial history of the northwestern Chukchi margin, Arctic Ocean

2020 ◽  
Author(s):  
Sookwan Kim ◽  
Leonid Polyak ◽  
Young Jin Joe ◽  
Frank Niessen ◽  
Hyoung Jun Kim ◽  
...  
Keyword(s):  
High Resolution ◽  
Arctic Ocean ◽  
Glacial History ◽  
History Of

scholarly journals Association of family risk and lifestyle/comorbidities in ovarian cancer patients

2015 ◽  
Vol 61 (3) ◽  
pp. 234-239 ◽  
Author(s):  
Natália Teixeira ◽  
Maria Aparecida Azevedo Koike Folgueira ◽  
Simone Maistro ◽  
Giselly Encinas ◽  
Geertruida Hendrika de Bock ◽  
...  
Keyword(s):  
Ovarian Cancer ◽  
Mutation Detection ◽  
Regression Analyses ◽  
Family Risk ◽  
Familial Predisposition ◽  
Factors Associated ◽  
System A ◽  
History Of ◽  
Psychiatric Conditions ◽  
The Impact

Summary Objectives: to analyze factors that might indicate familial predisposition for ovarian cancer in patients diagnosed with this disease. Methods: in a prospective single center cohort study at the Institute of Cancer of the State of São Paulo (ICESP), 51 women diagnosed with ovarian cancer were included. Familial predisposition for ovarian cancer was defined as having a higher than 10% chance of having a BRCA1/2 mutation according to the Manchester scoring system, a validated method to assess the likelihood of mutation detection. Each patient was interviewed with a standardized questionnaire on established risk factors for ovarian cancer and other factors that might influence the risk to develop ovarian cancer. Logistic regression analyses were performed to estimate the impact of the evaluated factors on the likelihood of mutation detection, by calculating odds ratios and 95% confidence intervals. Results: seventeen out of 51 patients had a family history of breast and/or ovarian cancer, four patients had a history of breast or endometrial cancer, 11 were diagnosed before the age of 50, and 12 presented a risk of familial predisposition to ovarian cancer higher than 10%. Patients with comorbidities, such as hypertension, diabetes, hormonal disorders, dyslipidemia and psychiatric conditions, presented a lower chance of having a familial predisposition for ovarian cancer (OR: 0.22; 95% CI: 0.06-0.88; p=0.03). Conclusion: in this study, having comorbidities was associated with a lower risk of having a familial predisposition for ovarian cancer. Other factors associated with the risk of ovarian cancer did not have an impact on this predisposition.

scholarly journals Recent Sea Ice Decline Did Not Significantly Increase the Total Liquid Freshwater Content of the Arctic Ocean

2018 ◽  
Vol 32 (1) ◽  
pp. 15-32 ◽  
Author(s):  
Qiang Wang ◽  
Claudia Wekerle ◽  
Sergey Danilov ◽  
Dmitry Sidorenko ◽  
Nikolay Koldunov ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Sea Ice ◽  
Arctic Ocean ◽  
Ocean Circulation ◽  
General Circulation ◽  
The Arctic ◽  
Sea Ice Decline ◽  
The Arctic Ocean ◽  
Eurasian Basin ◽  
The Impact

Abstract The freshwater stored in the Arctic Ocean is an important component of the global climate system. Currently the Arctic liquid freshwater content (FWC) has reached a record high since the beginning of the last century. In this study we use numerical simulations to investigate the impact of sea ice decline on the Arctic liquid FWC and its spatial distribution. The global unstructured-mesh ocean general circulation model Finite Element Sea Ice–Ocean Model (FESOM) with 4.5-km horizontal resolution in the Arctic region is applied. The simulations show that sea ice decline increases the FWC by freshening the ocean through sea ice meltwater and modifies upper ocean circulation at the same time. The two effects together significantly increase the freshwater stored in the Amerasian basin and reduce its amount in the Eurasian basin. The salinification of the upper Eurasian basin is mainly caused by the reduction in the proportion of Pacific Water and the increase in that of Atlantic Water (AW). Consequently, the sea ice decline did not significantly contribute to the observed rapid increase in the Arctic total liquid FWC. However, the changes in the Arctic freshwater spatial distribution indicate that the influence of sea ice decline on the ocean environment is remarkable. Sea ice decline increases the amount of Barents Sea branch AW in the upper Arctic Ocean, thus reducing its supply to the deeper Arctic layers. This study suggests that all the dynamical processes sensitive to sea ice decline should be taken into account when understanding and predicting Arctic changes.

scholarly journals Eastern Arctic Ocean Diapycnal Heat Fluxes through Large Double-Diffusive Steps

2019 ◽  
Vol 49 (1) ◽  
pp. 227-246 ◽  
Author(s):  
Igor V. Polyakov ◽  
Laurie Padman ◽  
Y.-D. Lenn ◽  
Andrey Pnyushkov ◽  
Robert Rember ◽  
...  
Keyword(s):  
Arctic Ocean ◽  
Dissipation Rate ◽  
Critical Role ◽  
Density Ratio ◽  
Atlantic Water ◽  
Heat Fluxes ◽  
The Arctic ◽  
Eurasian Basin ◽  
Average Flux ◽  
Double Diffusive

AbstractThe diffusive layering (DL) form of double-diffusive convection cools the Atlantic Water (AW) as it circulates around the Arctic Ocean. Large DL steps, with heights of homogeneous layers often greater than 10 m, have been found above the AW core in the Eurasian Basin (EB) of the eastern Arctic. Within these DL staircases, heat and salt fluxes are determined by the mechanisms for vertical transport through the high-gradient regions (HGRs) between the homogeneous layers. These HGRs can be thick (up to 5 m and more) and are frequently complex, being composed of multiple small steps or continuous stratification. Microstructure data collected in the EB in 2007 and 2008 are used to estimate heat fluxes through large steps in three ways: using the measured dissipation rate in the large homogeneous layers; utilizing empirical flux laws based on the density ratio and temperature step across HGRs after scaling to account for the presence of multiple small DL interfaces within each HGR; and averaging estimates of heat fluxes computed separately for individual small interfaces (as laminar conductive fluxes), small convective layers (via dissipation rates within small DL layers), and turbulent patches (using dissipation rate and buoyancy) within each HGR. Diapycnal heat fluxes through HGRs evaluated by each method agree with each other and range from ~2 to ~8 W m−2, with an average flux of ~3–4 W m−2. These large fluxes confirm a critical role for the DL instability in cooling and thickening the AW layer as it circulates around the eastern Arctic Ocean.

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