Continental displacement and expansion of the earth during the Mesozoic and Cenozoic

1976 ◽  
Vol 281 (1303) ◽  
pp. 223-291 ◽  
Keyword(s):  
Upper Jurassic ◽  
Mean Value ◽  
Ocean Floor ◽  
The Arctic ◽  
Late Triassic ◽  
Geological Evidence ◽  
Global Expansion ◽  
Field Evidence ◽  
Constant Dimension ◽  
Ocean Floor Spreading

Most reconstructions of Pangaea, the early Mesozoic supercontinent, assume an Earth of modern dimensions. Such reconstructions produce major geometric and Earth of modern dimensions. Such reconstructions produce major geometric and geological fit inconsistencies particularly in areas such as the Arctic, Caribbean, Mediterranean, and southeast Asia and Indonesia. The ocean floor spreading history of these regions and the adjacent oceans indicates that they have grown by areal expansion since their initiation. In contrast, the various reconstructions of Mesozoic and Cenozoic stages which assume an Earth of constant dimensions, require that these regions, either initially or during their development, should contract in area. The geological evidence from the continental margins and from the Earth’s oceans does not support the amount of subduction, either in whole or in part, required by the constant dimension hypothesis. It is shown that an exact fit of the various continental fragments together to reform Pangaea, which agrees with the geometric and geological matches, is obtained when the value of the Earth’s surface curvature is increased to the point at which the diameter of the globe is 80 % of its current mean value. This corresponds in time to the late Triassic-early Jurassic. It is asserted that the early Upper Jurassic to Recent ocean floor spreading data now available, displayed here in maps, also demonstrate progressive global expansion commensurate with an increase in diameter of 20 % of the Earth’s current mean value. Series of maps employing a zenithal equidistant projection are used to illustrate stages in the inferred development of certain regions during the Mesozoic and Cenozoic according to the ocean floor spreading data. The global expansion deduced from the geometric requirements of the spreading data in these maps permits a much more straightforward reading of the development of ocean basins and associated displacement of continents; one which accords with the field evidence. The inconsistencies seen in constant dimensions reconstructions do not arise. The results are summarized in outline hemisphere maps for which a new cartographic projection has been developed.

COMPROMISE AND ORIGINAL ACQUISITION: EXPLAINING RIGHTS TO THE ARCTIC

2015 ◽  
Vol 32 (1) ◽  
pp. 149-170 ◽  
Author(s):  
Cara Nine
Keyword(s):  
Political Philosophy ◽  
Natural Resources ◽  
Deep Sea ◽  
Large Degree ◽  
Geographic Area ◽  
Ocean Floor ◽  
The Arctic ◽  
Human Settlement ◽  
The Commons ◽  
Original Acquisition

Abstract:Up until now, political philosophy has explained the acquisition of natural resources, in one way or another, through the terms of human settlement. An agent acquires natural resources by moving into the geographic area that contains these resources. Even how we make claims to the ocean floor depends on settlement — claimants must be adjacent to settled land. This essay extends original acquisition theories so that they can respond to cases that do not presuppose any conditions of human settlement. I suggest that resource rights in the deep sea may be created, alternatively, through acts of compromise. Compromise can alleviate conflict, allowing for claimants to move beyond stalemate to acquire goods. It also allows for a large degree of flexibility in the specification of rights, and thereby can explain nontraditional rights over areas of migration. The tricky part of a theory that grants rights through agreement is explaining why external parties, those not part of the agreement, have a duty to respect those rights. A compromise under certain conditions, I argue, places all persons under a duty to respect the rights created by the compromise. Thus, when two parties compromise, they may acquire goods from the commons — creating a duty for all others to respect the parties’ rights over these goods. Importantly, rights created through compromise are constrained by a set of concerns for those excluded.

scholarly journals Jurassic ammonite biochronology of Greenland and the Arctic

1994 ◽  
Vol 41 ◽  
pp. 128-137
Author(s):  
John H. Callomon
Keyword(s):  
Fossil Record ◽  
Upper Jurassic ◽  
Time Correlation ◽  
Resolving Power ◽  
The Arctic ◽  
Time Intervals ◽  
Single Section ◽  
Compositional Changes ◽  
Primary Standards ◽  
Conjugate Time

􀀬e standard biochronological chronostratigraphy of the Phanerozoic and of its conjugate time-scale has been refined over a century and a half by a process of top-down subdivision in a hierarchy of successively smaller units. The finest units currently accepted, at the seventh level of the hierarchy, are the Subzones widely used in the Jurassic, thanks to that System's exceptional guide-fossils, its ammonites. But the time-resolution even at this level is not yet at the limits attainable through biostratigraphy. The ultimate observable is a characteristic fauna! horizon, defined as a fossiliferous stratum or succession of strata within whose specified fossil assemblages no further evolutionary - as opposed to compositional - changes can be dis­tinguished. Such a horizon represents effectively a biochronological instant. The fossil record is resolved into a succession of such instants, recognizable perhaps in as little as a single section and separated by time-gaps of unknown duration. The time-intervals between the ages t of successive horizons represent the limits of temporal resolution, bt, discernible by means of fossils. They depend strongly on the fossils employed and may be expressed in terms of their secular resolving-power, R = tlbt. Some estimates selected from the Mesozoic and Palaeozoic are compared in a Table. The geographical limits of time-correlation by means of fossils are often set by bioprovincial endemisms of the organisms of which the fossils are the remains. The biochronology, and any standard chronostratigraphical scale based upon it, has therefore to be worked out in each Province separately, and such provincial scales correlated in regions of provincial overlap, if known. An excellent example is found in the Middle and Upper Jurassic of East Greenland. Its ammonite biochronology is today represented by some 100 fauna! horizons. But the ammonites are largely confined to a sharply segregated Arctic, Boreal Province, for which they now provide a standard zonation. Detailed correlations with the primary standards of Europe continue to range from the problematical to the impossible.

Global carbon isotope signal in the Middle Triassic on Svalbard

2021 ◽  
Author(s):  
Victoria S. Engelschiøn ◽  
Øyvind Hammer ◽  
Fredrik Wesenlund ◽  
Jørn H. Hurum ◽  
Atle Mørk
Keyword(s):  
Carbon Isotope ◽  
Depositional Environment ◽  
Middle Triassic ◽  
Barents Sea ◽  
Water Productivity ◽  
Sedimentary Environment ◽  
The Arctic ◽  
Late Triassic ◽  
Triassic Boundary ◽  
Thin Sections

<p>Several carbon isotope curves were recently published for the Early and Middle Triassic in Tethys. Recent work has also been done on the Early Triassic of Svalbard, but not yet for the Middle Triassic. This work is the first to measure δ<sup>13</sup>C for different Middle Triassic localities on Svalbard, which was then part of the Boreal Ocean on northern Pangea. Our aim is to understand the controls on the Svalbard carbon isotope curve and to place them in a global setting.</p><p>Correlating Triassic rocks around the world is interesting for several reasons. The Triassic Period was a tumultuous time for life, and the Arctic archipelago of Svalbard has shown to be an important locality to understand the early radiation of marine vertebrates in the Triassic. Much effort is also made to understand the development of the Barents Sea through Svalbard’s geology.</p><p>Carbon isotope curves are controlled by depositional environment and global fluctuations. Global factors such as the carbon cycle control the long-term carbon isotopic compositions, while short-term fluctuations may reflect the origin of organic materials in the sediment (e.g. algal or terrestrial matter), stratification of the water column, and/or surface water productivity. Carbon isotopes can therefore be useful to understand the depositional environment and to correlate time-equivalent rocks globally.</p><p>The dataset was collected through three seasons of fieldwork in Svalbard with localities from the islands Spitsbergen, Edgeøya and Bjørnøya. Detailed stratigraphic sampling has resulted in high-resolution δ<sup>13</sup>C curves. These show three strong transitions; 1) on the boundary between the Early and Middle Triassic, 2) in the middle of the formation and 3) at the Middle and Late Triassic boundary. Several Tethyan localities show a possibly similar Early-Middle Triassic signal. Current work in progress is sedimentological analysis by thin sections and X-ray fluorescence spectroscopy (XRF) to further understand the sedimentary environment.</p>

The systematic position of the Late Jurassic alleged dinosaur Macelognathus (Crocodylomorpha: Sphenosuchia)

2005 ◽  
Vol 42 (3) ◽  
pp. 307-321 ◽  
Author(s):  
Ursula B Göhlich ◽  
Luis M Chiappe ◽  
James M Clark ◽  
Hans-Dieter Sues
Keyword(s):  
Late Jurassic ◽  
Upper Jurassic ◽  
Systematic Position ◽  
Lower Jurassic ◽  
Late Triassic ◽  
Morrison Formation ◽  
Postcranial Skeleton ◽  
Western Colorado ◽  
New Material ◽  
Limb Posture

Macelognathus vagans was described by O.C. Marsh in 1884, based on a mandibular symphysis from the Upper Jurassic Morrison Formation of Wyoming. Often considered a dinosaur but later tentatively referred to the Crocodylia, its phylogenetic identity has until now been enigmatic. New material of this species from the Morrison Formation of western Colorado demonstrates its affinities with basal crocodylomorphs commonly grouped together as the Sphenosuchia, which are characterized by a gracile postcranial skeleton with erect limb posture. Macelognathus shares features with Kayentasuchus from the Lower Jurassic Kayenta Formation of Arizona and Hallopus, which may be from the Morrison Formation of eastern Colorado. The new material constitutes the youngest definitive occurrence of a sphenosuchian, previously known from the Late Triassic to the Middle or Late? Jurassic.

GEOLOGY OF BARROW ISLAND OIL FIELD

1973 ◽  
Vol 13 (1) ◽  
pp. 49 ◽  
Author(s):  
Keith Crank
Keyword(s):  
Oil And Gas ◽  
Water Injection ◽  
Water Source ◽  
Upper Jurassic ◽  
Oil Field ◽  
Late Triassic ◽  
Low Permeability ◽  
High Porosity ◽  
The South ◽  
The North

The Barrow Island oil field, which was discovered by the drilling of Barrow 1 in 1964, was declared commercial in 1966. Since then 520 wells have been drilled in the development of this field which has resulted in 309 Windalia Sand oil producers (from about 2200 feet), eight Muderong Greensand oil wells (2800 feet), five Neocomian/Upper Jurassic gas and oil producers (6200 to 6700 feet), eight Barrow Group water source wells and 157 water injection wells.Production averages 41,200 barrels of oil per day, and 98% of this comes from the shallow Windalia Sand Member of Cretaceous (Aptian to Albian) age. These reserves are contained in a broad north-plunging nose truncated to the south by a major down-to-the-south fault. The anticline is thought to have been formed initially from a basement uplift during Late Triassic to Early Jurassic time. Subsequent periods of deposition, uplift and erosion have continued into the Tertiary and modified the structure to its present form. The known sedimentary section on Barrow Island ranges from Late Jurassic to Miocene.The Neocomian/Jurassic accumulations are small and irregular and are not thought to be commercial in themselves. The Muderong Greensand pool is also a limited, low permeability reservoir. Migration of hydrocarbons is thought to have occurred mainly in the Tertiary as major arching did not take place until very late in the Cretaceous or early in the Palaeocene.The Windalia Sand reservoir is a high porosity, low permeability sand which is found only on Barrow Island. One of the most unusual features of this reservoir is the presence of a perched gas cap. Apparently the entire sand was originally saturated with oil, and gas subsequently moved upstructure from the north, displacing it. This movement was probably obstructed by randomly-located permeability barriers.

scholarly journals Chemical equilibrium of groundwater with minerals of the host rocks in Upper Jurassic sediments (Arctic regions of Western Siberia)

2019 ◽  
Vol 98 ◽  
pp. 01037 ◽  
Author(s):  
Dmitry A. Novikov
Keyword(s):  
Chemical Composition ◽  
Chemical Equilibrium ◽  
Western Siberia ◽  
Upper Jurassic ◽  
The Arctic ◽  
Geochemical Environment ◽  
Rock System ◽  
Arctic Regions ◽  
Host Rocks ◽  
Mineral Changes

The results of thermodynamic calculations for a water-rock system in the Upper Jurassic deposits of the Arctic regions of Western Siberia are presented. In the area under investigation the groundwaters have been identified with mineralization up to 63.3 g/L and various chemical composition and genesis. Despite the long interaction with the rock (150-160 ma) equilibrium with endogenous minerals (albite, microcline and anorthite) is practically not observed. At the same time, groundwaters are in equilibrium with clay minerals and micas, such as: Caand Na-montmorillonites, kaolinite, paragonite, margarite, illite, muscovite and Mg-chlorite. The establishment of a balance of groundwater with primary aluminosilicate minerals is also affected by interactions with carbonate minerals. The differences in composition of groundwater in equilibrium with certain aluminosilicates and carbonates indicate that the mineral changes are formed from a solution of a strictly defined chemical composition in an appropriate geochemical environment.

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