Facies distribution resulting from sedimentation under polar interglacial climatic conditions within a high-latitude marginal basin, McMurdo Sound, Antarctica

1991 ◽  
pp. 27-50 ◽  
Author(s):  
Louis R. Bartek ◽  
John B. Anderson
Keyword(s):  
High Latitude ◽  
Climatic Conditions ◽  
Mcmurdo Sound ◽  
Facies Distribution ◽  
Marginal Basin

scholarly journals Paleocene-Eocene volcanic segmentation of the Norwegian-Greenland seaway reorganized high-latitude ocean circulation

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Jussi Hovikoski ◽  
Michael B. W. Fyhn ◽  
Henrik Nøhr-Hansen ◽  
John R. Hopper ◽  
Steven Andrews ◽  
...  
Keyword(s):  
Ocean Circulation ◽  
High Latitude ◽  
Seismic Reflection ◽  
Arctic Region ◽  
Climatic Conditions ◽  
The Arctic ◽  
Early Eocene ◽  
Subaerial Exposure ◽  
Thermal Maximum ◽  
Volcanic Facies

AbstractThe paleoenvironmental and paleogeographic development of the Norwegian–Greenland seaway remains poorly understood, despite its importance for the oceanographic and climatic conditions of the Paleocene–Eocene greenhouse world. Here we present analyses of the sedimentological and paleontological characteristics of Paleocene–Eocene deposits (between 63 and 47 million years old) in northeast Greenland, and investigate key unconformities and volcanic facies observed through seismic reflection imaging in offshore basins. We identify Paleocene–Eocene uplift that culminated in widespread regression, volcanism, and subaerial exposure during the Ypresian. We reconstruct the paleogeography of the northeast Atlantic–Arctic region and propose that this uplift led to fragmentation of the Norwegian–Greenland seaway during this period. We suggest that the seaway became severely restricted between about 56 and 53 million years ago, effectively isolating the Arctic from the Atlantic ocean during the Paleocene–Eocene thermal maximum and the early Eocene.

scholarly journals An archaic crested plesiosaur in opal from the Lower Cretaceous high-latitude deposits of Australia

2006 ◽  
Vol 2 (4) ◽  
pp. 615-619 ◽  
Author(s):  
Benjamin P Kear ◽  
Natalie I Schroeder ◽  
Michael S.Y Lee
Keyword(s):  
High Latitude ◽  
Lower Cretaceous ◽  
Convergent Evolution ◽  
Cold Water ◽  
Extreme Environment ◽  
Climatic Conditions ◽  
Short Neck ◽  
Diverse Range ◽  
Marine Reptiles ◽  
Large Head

Umoonasaurus demoscyllus gen. et sp. nov. is a new small-bodied (approx. 2.5 m) pliosauroid plesiosaur from the Lower Cretaceous (Aptian–Albian) of southern Australia. It is represented by several partial skeletons (one with a near complete skull is the most complete opalized vertebrate fossil yet known), and is unique in having large crests on the skull midline and above the orbits. Umoonasaurus is surprisingly archaic despite its relatively late age (approx. 115 Myr ago)—being simultaneously the most basal (primitive) and last surviving rhomaleosaurid. Notably, it lacks the ‘pliosauromorph’ features (large head, short neck, gigantism) typically characterizing many more derived Jurassic rhomaleosaurids; thus, reinforcing the suspected convergent evolution of the ‘pliosauromorph’ hypercarnivore body plan. Umoonasaurus inhabited an Early Cretaceous high-latitude (approx. 70° S) inland seaway subject to seasonally near-freezing climatic conditions. This extreme environment supported a diverse range of plesiosaur taxa, suggesting that these marine reptiles might have possessed adaptations (e.g. heightened metabolic levels) to cope with cold-water temperatures. Indeed, survival of ancient endemic lineages such as Umoonasaurus is a common phenomenon in Australian Cretaceous vertebrate assemblages and might have been facilitated by isolation in low-temperature high-latitude regions.

scholarly journals The Upper Jurassic Garedu Red Bed Formation of the northern Tabas Block: elucidating Late Cimmerian tectonics in east-Central Iran

2021 ◽  
Author(s):  
Markus Wilmsen ◽  
Franz Theodor Fürsich ◽  
Kazem Seyed-Emami ◽  
Mahmoud Reza Majidifard
Keyword(s):  
Vertical Axis ◽  
Upper Jurassic ◽  
Climatic Conditions ◽  
Tectonic Event ◽  
Facies Distribution ◽  
Nw Iran ◽  
Eastern Margin ◽  
Regional Tectonic ◽  
Semi Arid ◽  
Red Bed

AbstractThe Garedu Red Bed Formation (GRBF) of the northern Tabas Block (Central-East Iranian Microcontinent, CEIM) is a lithologically variable, up to 500-m-thick, predominantly continental unit. It rests gradually or unconformably on marine limestones of the Esfandiar Subgroup (Callovian–Oxfordian) and is assigned to the Kimmeridgian–Tithonian. In the lower part, it consists of pebble- to boulder-sized conglomerates/breccias composed of limestone clasts intercalated with calcareous sandstones, litho-/bioclastic rudstones and lacustrine carbonates. Up-section, sharp-based pebbly sandstones and red silt-/fine-grained sandstones of braided river origin predominate. Palaeocurrent data suggest a principal sediment transport from west to east and a lateral interfingering of the GRBF with marine greenish marls of the Korond Formation at the eastern margin of the Tabas Block. Westwards, the GRBF grades into the playa deposits of the Magu Gypsum Formation. Red colours and common calcretes suggest arid to semi-arid climatic conditions. The onset of Garedu Red Bed deposition indicates a major geodynamic change with the onset of compressive tectonics of the Late Cimmerian Tectonic Event (LCTE), being strongest at the eastern margin of the northern Tabas Block. When traced southwards, the same tectonic event is expressed by extension, indicating a shift in tectonic style along the boundary fault between the Tabas and Lut blocks. The complex Upper Jurassic facies distribution as well as the spatio-temporal changes in tectonic regime along the block-bounding faults are explained by the onset of counterclockwise vertical-axis rotation of the CEIM in the Kimmeridgian. The block boundaries accommodated the rotation by right-lateral strike slip, transpressional in today’s northern and transtensional in today’s southern segments of the block-bounding faults. Rotation occurred within bracketing transcurrent faults and continued into the Early Cretaceous, finally resulting in the opening of narrow oceanic basins encircling the CEIM. Palaeogeographically, the GRBF is part of a suite of red bed formations not only present on the CEIM, but also along the Sanandaj-Sirjan Zone (NW Iran), in northeastern Iran and beyond, indicating inter-regional tectonic instability, uplift and erosion under (semi-)arid climatic conditions across the Jurassic–Cretaceous boundary. Thus, even if our geodynamic model successfully explains Late Jurassic tectonic rotations, fault motions and facies distribution for the CEIM, the basic cause of the LCTE still remains enigmatic.

Space Observations to Determine the Location of Locally Vertical Geomagnetic Field

2017 ◽  
Vol 13 (S335) ◽  
pp. 135-138
Author(s):  
Stefania Lepidi ◽  
Domenico Di Mauro ◽  
Roberta Tozzi ◽  
Lili Cafarella ◽  
Paola De Michelis ◽  
...  
Keyword(s):  
High Latitude ◽  
Geomagnetic Field ◽  
Climatic Conditions ◽  
Magnetic Survey ◽  
Spatial Shift ◽  
Different Seasons ◽  
Magnetospheric Dynamics ◽  
Rotation Of The Earth ◽  
Using Data ◽  
Short Time

AbstractThe points where the horizontal component of the geomagnetic field vanishes are located in polar areas, far away from the geomagnetic (analytic) poles and the poles of rotation of the Earth and, differently from the geomagnetic poles, can be found experimentally with a magnetic survey to determine where the field is vertical. The experimental determination of the area where the total field is perfectly vertical, commonly known as dip pole, is not simple, due to the remoteness and harsh climatic conditions; another difficulty is related to the short term geomagnetic field variations, due to the interaction with the external solar wind, which causes the magnetospheric dynamics, particularly evident at high latitude, and as a consequence a displacement of the dip pole. Actually, the study of the dip pole displacements over short time scales can be an important tool for monitoring the magnetospheric dynamics at high latitude. In this study we present the updated location of the the dip poles, using data from the Swarm ESA’s constellation of satellites along their almost polar orbits. We also analyse the spatial shift of these areas during different seasons and interplanetary magnetic field orientations.

Effect of climatic conditions and soil type on antioxidant compounds in organic and conventional blueberries (Vaccinium corymbosum L.)

Planta Medica ◽  
2016 ◽  
Vol 81 (S 01) ◽  
pp. S1-S381
Author(s):  
MD López ◽  
P Jara ◽  
S Fischer ◽  
R Wilckens ◽  
H Serri ◽  
...  
Keyword(s):  
Soil Type ◽  
Vaccinium Corymbosum ◽  
Climatic Conditions ◽  
Antioxidant Compounds
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