Caledonian nappe geometry in north-central Sweden and basin evolution on the Baltoscandian margin

1989 ◽  
Vol 126 (5) ◽  
pp. 499-513 ◽  
Author(s):  
Rodney A. Gayer ◽  
Reinhard O. Greiling
Keyword(s):  
Cross Sections ◽  
Foreland Basin ◽  
Sedimentary Basins ◽  
The South ◽  
Apparent Lack ◽  
North Central ◽  
The North ◽  
Basin Development ◽  
Basement High ◽  
Sedimentary Fill

AbstractStructural analysis of the Lower Allochthon in the north-central Scandinavian Caledonides has allowed the construction of restorable cross-sections consistent with the development of a foreland-propagating linked thrust system. The internal geometry of an antiformal stack, the Njakafjäll duplex, within the Lower Allochthon demonstrates tectonic shortening of c. 50% and suggests an overall predeformational width for the Lower Allochthon in this area of at least c. 130 km, and possibly considerably greater if the buried trailing edge of the Lower Allochthon lies in a comparable position to that farther south in Tröndelag. These results, combined with a stratigraphic analysis of the imbricates within the Lower Allochthon and of the adjoining Autochthon and Middle Allochthon, indicate the development, from Proterozoic through Cambrian times, of two sedimentary basins on the c. 200 km wide continental margin of Baltica bordering the Iapetus Ocean. The basins were separated by a region of basement relief, the Børgefjell domain, above which a reduced sequence of Vendian to Cambrian rocks accumulated. This Børgefjell basement high, and the similar Njakafjäll basement high to the east, subsequently became the sites of antiformal stack development. It is argued that the frequent incorporation of basement into the thrust sheets, together with the thin sedimentary fill of these basins, compared with the much greater fill in basins to the south in Jämtland and to the north of Finnmark, implies major palaeogeographic changes along the Baltoscandian margin, possibly related to early rift geometries. The apparent lack of subsequent foreland basin development in north-central Scandinavia compared with areas to the south may indicate a deeper level of thrust detachment beneath the Middle Allochthon to the north, such that any foreland basin sediments have been removed in the hangingwall and subsequently eroded. An alternative possibility is a primary absence of foreland basin development that may relate to a differing response to thrust loading by continental lithosphere which had been variably thinned during the earlier rift regime.

scholarly journals Chronology of thrust propagation from an updated tectono-sedimentary framework of the Miocene molasse (western Alps)

Solid Earth ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 2735-2771
Author(s):  
Amir Kalifi ◽  
Philippe Hervé Leloup ◽  
Philippe Sorrel ◽  
Albert Galy ◽  
François Demory ◽  
...  
Keyword(s):  
Cross Sections ◽  
Foreland Basin ◽  
Sedimentary Basins ◽  
Western Alps ◽  
Strong Interactions ◽  
Seismic Profiles ◽  
The North ◽  
Deformation Kinematics ◽  
Westward Migration ◽  
And Migration

Abstract. After more than a century of research, the chronology of the deformation of the external part of the western Alpine belt (France) is still controversial for the Miocene epoch. In particular, the poor dating of the foreland basin sedimentary succession hampers a comprehensive understanding of the deformation kinematics. Here we focus on the Miocene molasse deposits of the northern subalpine massifs, southern Jura, Royans, Bas-Dauphiné, Crest, and La Bresse sedimentary basins through a multidisciplinary approach to build a basin-wide tectono-stratigraphic framework. Based on sequence stratigraphy constrained by biostratigraphical, chemostratigraphical (Sr isotopes), and magnetostratigraphical data between the late Aquitanian (∼ 21 Ma) and the Tortonian (∼ 8.2 Ma), the Miocene molasse chronostratigraphy is revised with a precision of ∼ 0.5 Ma. The Miocene molasse sediments encompass four different paleogeographical domains: (i) the oriental domain outlined by depositional sequences S1a to S3 (∼ 21 to ∼ 15 Ma), (ii) the median domain characterized by sequences S2 to S5 (∼ 17.8 to ∼ 12 Ma), (iii) the occidental domain in which sequences S2a to S8 (∼ 17.8 to ∼ 8.2 Ma) were deposited, and (iv) the Bressan domain where sedimentation is restricted to sequences S6 to S8 (∼ 12 to ∼ 8.2 Ma). A structural and tectono-sedimentary study is conducted based on new field observations and the reappraisal of regional seismic profiles, thereby allowing the identification of five major faults zones (FZs). The oriental, median, and occidental paleogeographical domains are clearly separated by FZ1, FZ2, and FZ3, suggesting strong interactions between tectonics and sedimentation during the Miocene. The evolution in time and space of the paleo-geographical domains within a well-constrained structural framework reveals syntectonic deposits and a westward migration of the depocenters, allowing for proposing the succession of three deformation phases at the western Alpine front. (i) The first is a compressive phase (P1) corresponding to thrusting above the Chartreuse oriental thrust (FZ1), which was likely initiated during the Oligocene and rooted east of Belledonne. This tectonic phase generated reliefs that limited the Miocene transgression to the east. (ii) The second is a ∼ WNW–ESE-directed compressive phase (P2) lasting between 18.05 ± 0.25 Ma and ∼ 12 Ma, with thrusts rooted in the Belledonne basal thrust. Thrusts were activated from east to west: the Salève (SAL) and Gros Foug (GF) thrusts and then successively FZ2, FZ3, FZ4, and FZ5. Along two WNW–ESE balanced cross sections the amount of horizontal shortening is of ∼ 6.3 to 6.7 km, corresponding to average shortening rates of ∼ 1.2 km Myr−1 and migration of the deformation toward the west at a rate of ∼ 2.9 km Myr−1. During ∼ 6 Myr, the Miocene Sea was forced to regress rapidly westwards in response to westward migration of the active thrusts and exhumation of piggyback basins atop the fault zones. Phase P2 thus deeply shaped the Miocene paleogeo-graphical evolution of the area and appears as a prominent compressive phase at the scale of the western Alps from the Swiss molasse basin to the Rhodano–Provencal one. (iii) The third is a ∼ 300 m phase of uplift in the Bas-Dauphiné (P3) of probable Tortonian age (∼ 10 Ma), which would have induced southward sea retreat and been coeval with the folding of the Jura in the north and possibly with back-thrusting east of the Chartreuse massif.

Timing of magmatism, foreland basin development, metamorphism and inversion in the Anglo-Brabant fold belt

1997 ◽  
Vol 134 (5) ◽  
pp. 607-616 ◽  
Author(s):  
G. VAN GROOTEL ◽  
J. VERNIERS ◽  
B. GEERKENS ◽  
D. LADURON ◽  
M. VERHAEREN ◽  
...  
Keyword(s):  
Subduction Zones ◽  
Foreland Basin ◽  
Fold Belt ◽  
East Anglia ◽  
Basin Inversion ◽  
Tectonic Model ◽  
The North ◽  
Basin Development ◽  
The North Sea ◽  
And Inversion

New data implying crustal activation of Eastern Avalonia along the Anglo-Brabant fold belt are presented. Late Ordovician subduction-related magmatism in East Anglia and the Brabant Massif, coupled with accelerated subsidence in the Anglia Basin and in the Brabant Massif during Silurian time, indicate a foreland basin development. Final collision resulted in folding, cleavage development and thrusting during the mid-Lochkovian to mid-Eifelian. In the southeast of the Anglo-Brabant fold belt, Acadian deformation produced basin inversion and the regional antiformal structure of the Brabant Massif. The uplift, inferred from the sedimentology, petrography and reworked palynomorphs in the Lower Devonian of the Dinant Synclinorium is confirmed by illite crystallinity studies. The tectonic model discussed implies the presence of two subduction zones in the eastern part of Eastern Avalonia, one along the Anglo-Brabant fold belt and another under the North Sea in the prolongation of the North German–Polish Caledonides.

Climatology and Trends of Climate Extremes of Temperature and Precipitation in Belo Monte Hydropower Plant – Eastern Amazon, Brazil

2021 ◽  
Author(s):  
Wanderson Luiz-Silva ◽  
Pedro Regoto ◽  
Camila Ferreira de Vasconcellos ◽  
Felipe Bevilaqua Foldes Guimarães ◽  
Katia Cristina Garcia
Keyword(s):  
Climate Change ◽  
Climate Extremes ◽  
Annual Rainfall ◽  
The South ◽  
North Central ◽  
Adaptation Capacity ◽  
The North ◽  
South Central ◽  
Daily Data ◽  
Belo Monte

<p>This research aims to support studies related to the adaptation capacity of the Amazon region to climate change. The Belo Monte Hydroelectric Power Plant (HPP) is in the Xingu River basin, in eastern Amazonia. Deforestation coupled with changes in water bodies that occurred in the drainage area of Belo Monte HPP over the past few decades can significantly influence the hydroclimatic features and, consequently, ecosystems and energy generation in the region. In this context, we analyze the climatology and trends of climate extremes in this area. The climate information comes from daily data in grid points of 0.25° x 0.25° for the period 1980-2013, available in http://careyking.com/data-downloads/. A set of 17 climate extremes indices based on daily data of maximum temperature (TX), minimum temperature (TN), and precipitation (PRCP) was calculated through the RClimDex software, recommended by the Expert Team on Climate Change Detection and Indices (ETCCDI). The Mann-Kendall and the Sen’s Curvature tests are used to assess the statistical significance and the magnitude of the trends, respectively. The drainage area of the Belo Monte HPP is dominated by two climatic types: an equatorial climate in the north-central portion of the basin, with high temperatures and little variation throughout the year (22°C to 32°C), in addition to more frequent precipitation; and a tropical climate in the south-central sector, which experiences slightly more pronounced temperature variations throughout the year (20°C to 33°C) and presents a more defined wet and dry periods. The south-central portion of the basin exhibits the highest temperature extremes, with the highest TX and the lowest TN of the year occurring in this area, both due to the predominant days of clear skies in the austral winter, as to the advance of intense masses of polar air at this period. The diurnal temperature range is lower in the north-central sector when compared to that in the south-central region since the first has greater cloud cover and a higher frequency of precipitation. The largest annual rainfall volumes are concentrated at the north and west sides (more than 1,800 mm) and the precipitation extremes are heterogeneous across the basin. The maximum number of consecutive dry days increases from the north (10 to 20 days) to the south (90 to 100 days). The annual frequency of warm days and nights is increasing significantly in a large part of the basin with a magnitude ranging predominantly from +7 to +19 days/decade. The annual rainfall shows a predominant elevation sign of up to +200 mm/decade only in the northern part of the basin, while the remainder shows a reduction of up to -100 mm/decade. The duration of drought periods increases in the south-central sector of the basin, reaching up to +13 days/decade in some areas. The results of this study will be used in the future as an important input, together with exposure, sensibility, and local adaptation capacity, to design adaptation strategies that are more consistent with local reality and to the needs of local communities.</p>

scholarly journals A Study of the Surface Air Temperature Variations in Nigeria

2017 ◽  
Vol 11 (1) ◽  
pp. 54-70 ◽  
Author(s):  
Najib Yusuf ◽  
Daniel Okoh ◽  
Ibrahim Musa ◽  
Samson Adedoja ◽  
Rabia Said
Keyword(s):  
Air Temperature ◽  
Cloud Cover ◽  
Coastal Region ◽  
Surface Air Temperature ◽  
The South ◽  
Climate Type ◽  
Temperature Variations ◽  
North Central ◽  
North East ◽  
The North

Background: Simultaneous measurements of air temperature were carried out using automatic weather stations at 14 tropical locations in Nigeria. Diurnal variations were derived from the 5-minute update cycle initial data for the years ranging between 2007 and 2013. The temperature trends in Nigeria revealed a continuous variability that is seasonally dependent within any particular year considered. Method: The analysis was carried out using available data from the network and the results are presented with a focus to characterize the temperature variations at different locations in the country using the mean, maximum and minimum temperatures from the north which is arid in nature to the south, which is a tropical monsoon climate type and a coastal region. Result: In overall, temperature variations in Nigeria were observed to have higher values in the far north, attributed to the influence of Sahara Desert, which has less cloud cover and therefore is more transparent to solar irradiance and lowers values in the south, where there are more cloud cover and abundant vegetation. Conclusion: Measured maximum and minimum temperatures in Nigeria are respectively 43.1°C at Yola (north-east part of Nigeria) and 10.2°C for Jos (north-central part of Nigeria). The least temperature variations were recorded for stations in the southern part of the country, while the largest variations were recorded in the north-central region of the country.

scholarly journals Performance of Landscape Roses Grown with Minimal Input in the North-central, Central, and South-central United States

2017 ◽  
Vol 27 (5) ◽  
pp. 718-730 ◽  
Author(s):  
David C. Zlesak ◽  
Randy Nelson ◽  
Derald Harp ◽  
Barbara Villarreal ◽  
Nick Howell ◽  
...  
Keyword(s):  
United States ◽  
National Level ◽  
The United States ◽  
The South ◽  
Flower Number ◽  
North Central ◽  
The North ◽  
South Central ◽  
Central United States ◽  
Plant Hardiness

Landscape roses (Rosa sp.) are popular flowering shrubs. Consumers are less willing or able to maintain landscape beds than in years past and require plants that are not only attractive, but well-adapted to regional climatic conditions, soil types, and disease and pest pressures. Marketing and distribution of rose cultivars occurs on a national level; therefore, it is difficult for U.S. consumers in the U.S. Department of Agriculture (USDA) Plant Hardiness Zones 3 to 5 to identify well-adapted, cold-hardy cultivars. Identifying suitable cultivars that have strong genetic resistance to pests and disease and that will tolerate temperature extremes without winter protection in the USDA Plant Hardiness Zones 3 to 5 is of tremendous value to consumers and retailers in northern states. Twenty landscape rose cultivars, primarily developed in north-central North America, were evaluated at five locations in the United States (three in the north-central United States, one in the central United States, and one in the south-central United States) using the low-input, multiyear Earth-Kind® methodology. Six roses had ≥75% plant survival at the end of the study and were in the top 50% of performers for overall mean horticultural rating at each of the three north-central U.S. sites: ‘Lena’, ‘Frontenac’, ‘Ole’, ‘Polar Joy’, ‘Sunrise Sunset’, and ‘Sven’. Five of these six roses met the same criteria at the central United States (exception ‘Lena’) and the south-central United States (exception ‘Polar Joy’) sites. Cultivar, rating time, and their interaction were highly significant, and block effects were not significant for horticultural rating for all single-site analyses of variance. Significant positive correlations were found between sites for flower number, flower diameter, and overall horticultural rating. Significant negative correlations were found between flower number and diameter within each site and also between black spot (Diplocarpon rosae) lesion size from a previous study and overall horticultural rating for three of the five sites. Cane survival ratings were not significantly correlated with overall horticultural rating, suggesting some cultivars can experience severe winter cane dieback, yet recover and perform well. Data from this study benefit multiple stakeholders, including nurseries, landscapers, and consumers, with evidence-based regional cultivar recommendations and breeders desiring to identify regionally adapted parents.

Patterns of Variation in Eucalyptus sideroxylon A. Cunn. Ex. Woolls. I. Variation in Adult Morphology

1984 ◽  
Vol 32 (3) ◽  
pp. 263 ◽  
Author(s):  
HW Bramwells ◽  
T Whiffin
Keyword(s):  
General Pattern ◽  
The South ◽  
North Central ◽  
Adult Morphology ◽  
The North ◽  
Adult Leaf ◽  
Morphological Differences ◽  
Fruit Characters ◽  
Eucalyptus Sideroxylon

Eucalyptus sideroxylon, a woodland tree occumng in an arc from central and southern Victoria to south-eastem Queensland, is currently divided into subsp. slderoxylon to the north, and subsp. tricarpa to the south. Thirty populations were sampled throughout the range of the species and studied for adult leaf and fruit characters. There were found to be very marked and highly significant morphological differences between the two subspecies, more especially in the fruit characters. Within subsp. sideroxylon there was a general distinction between the inland populations and the more coastal populations, while within subsp. trlcarpa there was similarly a general differentiation of the coastal populations from the northern and north-central Victorian populations. The extent and general pattern of these various differences are documented as a prelude to further studies.

Tectonic controls on Cenozoic foreland basin development in the north-eastern Andes, Colombia

2010 ◽  
Author(s):  
Mauricio Parra ◽  
Andrés Mora ◽  
Carlos Jaramillo ◽  
Vladimir Torres ◽  
Gerold Zeilinger ◽  
...  
Keyword(s):  
Foreland Basin ◽  
The North ◽  
Basin Development ◽  
North Eastern

scholarly journals Geological structure and petroleum potential of the Kara Sea shelf

2019 ◽  
Vol 489 (3) ◽  
pp. 272-276
Author(s):  
V. A. Kontorovich ◽  
A. E. Kontorovich
Keyword(s):  
Oil And Gas ◽  
Sedimentary Basins ◽  
Geological Structure ◽  
Water Area ◽  
Kara Sea ◽  
Gas Content ◽  
Liquid Hydrocarbons ◽  
The South ◽  
Petroleum Potential ◽  
The North

On the Kara Sea shelf, there are two sedimentary basins separated by the North-Siberian sill. Tectonically the southern part of the Kara Sea covers the South Kara regional depression, which is the northern end of the West Siberian geosyncline. This part of the water area is identified as part of the South Kara oil and gas region, within which the Aptian-Albian-Senomanian sedimentary complex is of greatest interest in terms of gas content, in terms of liquid hydrocarbons - Neocomian and Jurassic deposits. The northern part of the Kara Sea is an independent North Kara province, for the most part of which the prospects of petroleum potential are associated with Paleozoic sedimentary complexes. Oil and gas perspective objects of this basin may be associated with anticlinal, non-structural traps and reef structures.

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