Miocene start of modern carbonate platforms

Geology ◽  
2019 ◽  
Vol 47 (8) ◽  
pp. 771-775 ◽  
Author(s):  
Christian Betzler ◽  
Gregor P. Eberli
Keyword(s):  
Ocean Circulation ◽  
Deep Sea ◽  
Middle Miocene ◽  
Carbonate Platforms ◽  
Deep Time ◽  
Particle Sorting ◽  
Circulation Patterns ◽  
The World ◽  
Stacking Patterns ◽  
Extract Information

Abstract The middle Miocene onset of modern ocean circulation patterns changed the growth style of isolated tropical carbonate platforms because surface and contour currents began shaping the flanks of these edifices. Since then, ocean currents have redistributed the off-bank–transported sediment, reduced sedimentation by particle sorting or winnowing, and even eroded slopes. As a result, the flanks of isolated carbonate platforms around the world after 13–10 Ma have not only been constructed by mass gravity deposits, but equally by contourites with distinct drift and moat geometries. These produce specific stacking patterns of platform flank deposits. This flank architecture, produced by combined current and gravity processes, is typical of tropical carbonate platforms growing in the Neogene icehouse world. Comparison of this architecture with geometries in older platforms also has the potential to extract information about the rigor of ocean circulation in deep time where the deep-sea record is missing.

scholarly journals Deep Floats Reveal Complex Ocean Circulation Patterns

Eos ◽  
2018 ◽  
Vol 99 ◽  
Author(s):  
Andr�e Ramsey ◽  
Heather Furey ◽  
Amy Bower
Keyword(s):  
Ocean Circulation ◽  
Deep Sea ◽  
Central Repository ◽  
Circulation Patterns ◽  
Sea Currents

Acoustically tracked floats drift far below the ocean’s surface, providing fresh discoveries about deep-sea currents. A new archive gathers decades’ worth of float data into a central repository.

scholarly journals Eustatic, Climatic, and Oceanographic Influences on Geomorphology and Architecture of Isolated Carbonate Platforms: Miocene, Northwest Shelf, Australia

Lithosphere ◽  
2020 ◽  
Vol 2020 (1) ◽  
Author(s):  
Eugene C. Rankey
Keyword(s):  
Seismic Data ◽  
Middle Miocene ◽  
Seismic Facies ◽  
Global Changes ◽  
Carbonate Platforms ◽  
Stratigraphic Subdivision ◽  
Complex Architecture ◽  
Stacking Patterns ◽  
3D Seismic Data

Abstract The Miocene represents an interval of marked global change, and this evolution is reflected in carbonate platforms from this epoch. Seismic stratigraphic characterization of high-resolution (ca 60 Hz) 3D seismic data from the Browse Basin, offshore Australia, reveals a middle to upper Miocene three-part seismic stratigraphic subdivision. Each unit consists of several seismic sequence sets and their component sequences. Seismic stratal geometries and seismic facies define a prograding shelf (Langhian and older), a barrier-reef complex with scattered platforms (upper Langhian–early Tortonian), and aggrading and prograding isolated platforms (early Tortonian–Messinian). The data permit description and interpretation of high-fidelity stratigraphic details of the initiation, expansion, termination, and geomorphology of over 100 platforms in this interval. The results reveal that the isolated platforms initiated following the Middle Miocene Climatic Optimum. The succession includes major seismic stratigraphic boundaries and overall patterns of platform growth and demise that correspond roughly with periods of pronounced eustatic change associated with initiation of eastern Antarctic ice sheets. Although invoking a eustatic control for coarse trends may be tempting, mismatch between the numbers and ages of sequences, as well as the variable stacking patterns among contemporaneous platforms regionally, precludes such an interpretation; conversely, some globally recognized eustatic changes do not have a pronounced manifestation in this area. Thus, it appears that the eustatic signal combined with dynamic physical regional processes such as waves, currents, and variable subsidence creates the complex architecture and geomorphology of platforms. These results illustrate how global changes can interact with local controls to create diverse patterns of birth, growth, and demise of carbonate platforms and drive local stratal heterogeneity.

ON EVALUATION OF THE ROLE OF THERMAL AND WIND FACTORS FOR A PHYSICAL MODEL OF THE WORLD OCEAN GENERAL CIRCULATION SYSTEM

2019 ◽  
Vol 47 (3) ◽  
pp. 80-91
Author(s):  
V. G. Neiman
Keyword(s):  
Physical Model ◽  
Ocean Circulation ◽  
General Circulation ◽  
World Ocean ◽  
Circulation System ◽  
The Public ◽  
The World ◽  
Almost All ◽  
Conceptual Foundations

The main content of the work consists of certain systematization and addition of longexisting, but eventually deformed and partly lost qualitative ideas about the role of thermal and wind factors that determine the physical mechanism of the World Ocean’s General Circulation System (OGCS). It is noted that the conceptual foundations of the theory of the OGCS in one form or another are contained in the works of many well-known hydrophysicists of the last century, but the aggregate, logically coherent description of the key factors determining the physical model of the OGCS in the public literature is not so easy to find. An attempt is made to clarify and concretize some general ideas about the two key blocks that form the basis of an adequate physical model of the system of oceanic water masses motion in a climatic scale. Attention is drawn to the fact that when analyzing the OGCS it is necessary to take into account not only immediate but also indirect effects of thermal and wind factors on the ocean surface. In conclusion, it is noted that, in the end, by the uneven flow of heat to the surface of the ocean can be explained the nature of both external and almost all internal factors, in one way or another contributing to the excitation of the general, or climatic, ocean circulation.

Loss of sleep or loss of dark?

2018 ◽  
Author(s):  
Richard G. Stevens
Keyword(s):  
Mood Disorders ◽  
Deep Sea ◽  
Short Distance ◽  
Water Surface ◽  
Ocean Floor ◽  
Physiological Adaptation ◽  
Poor Sleep ◽  
Short Period ◽  
The World ◽  
Night And Day

Before electricity, night was something akin to the deep sea: just as we could not descend much below the water surface, we also could not investigate the night for more than a short distance, and for a short period of time. Things changed with two inventions: the Bathysphere to plumb the ocean floor, and electricity to light the night for sustained exploration. Exploration led to dominance, and night has become indistinguishable from day in many parts of the world. The benefits of electric light are myriad, but so too are the possible detriments of loss of dark at night, including poor sleep, obesity, diabetes, cancer, and mood disorders. Our primordial physiological adaptation to the night and day cycle is being flummoxed by the maladaptive signals coming from electric lighting around the clock. The topic of sleep and health has finally attained scientific respect, but dark and health is not yet fully appreciated.

scholarly journals Glacial – interglacial atmospheric CO<sub>2</sub> change: a simple "hypsometric effect" on deep-ocean carbon sequestration?

2006 ◽  
Vol 2 (5) ◽  
pp. 711-743 ◽  
Author(s):  
L. C. Skinner
Keyword(s):  
Carbon Sequestration ◽  
Carbon Storage ◽  
Ocean Circulation ◽  
Deep Water ◽  
Deep Sea ◽  
Storage Capacity ◽  
Deep Ocean ◽  
Contributing Factors ◽  
Carbon Reservoir ◽  
Ocean Carbon

Abstract. Given the magnitude and dynamism of the deep marine carbon reservoir, it is almost certain that past glacial – interglacial fluctuations in atmospheric CO2 have relied at least in part on changes in the carbon storage capacity of the deep sea. To date, physical ocean circulation mechanisms that have been proposed as viable explanations for glacial – interglacial CO2 change have focussed almost exclusively on dynamical or kinetic processes. Here, a simple mechanism is proposed for increasing the carbon storage capacity of the deep sea that operates via changes in the volume of southern-sourced deep-water filling the ocean basins, as dictated by the hypsometry of the ocean floor. It is proposed that a water-mass that occupies more than the bottom 3 km of the ocean will essentially determine the carbon content of the marine reservoir. Hence by filling this interval with southern-sourced deep-water (enriched in dissolved CO2 due to its particular mode of formation) the amount of carbon sequestered in the deep sea may be greatly increased. A simple box-model is used to test this hypothesis, and to investigate its implications. It is suggested that up to 70% of the observed glacial – interglacial CO2 change might be explained by the replacement of northern-sourced deep-water below 2.5 km water depth by its southern counterpart. Most importantly, it is found that an increase in the volume of southern-sourced deep-water allows glacial CO2 levels to be simulated easily with only modest changes in Southern Ocean biological export or overturning. If incorporated into the list of contributing factors to marine carbon sequestration, this mechanism may help to significantly reduce the "deficit" of explained glacial – interglacial CO2 change.

Deep-sea panoramas: Progress and remaining challenges in late Miocene stratigraphy and climate

2021 ◽  
Author(s):  
Anna Joy Drury ◽  
Thomas Westerhold ◽  
David A. Hodell ◽  
Mitchell Lyle ◽  
Cédric M. John ◽  
...  
Keyword(s):  
High Resolution ◽  
Ocean Circulation ◽  
Late Miocene ◽  
Deep Sea ◽  
Deep Ocean ◽  
High Resolution Data ◽  
Ongoing Work ◽  
Climate Evolution ◽  
Deep Ocean Circulation ◽  
Geological Timescale

&lt;p&gt;During the late Miocene, meridional sea surface temperature gradients, deep ocean circulation patterns, and continental configurations evolved to a state similar to modern day. Deep-sea benthic foraminiferal stable oxygen (&amp;#948;&lt;sup&gt;18&lt;/sup&gt;O) and carbon (&amp;#948;&lt;sup&gt;13&lt;/sup&gt;C) isotope stratigraphy remains a fundamental tool for providing accurate chronologies and global correlations, both of which can be used to assess late Miocene climate dynamics. Until recently, late Miocene benthic &amp;#948;&lt;sup&gt;18&lt;/sup&gt;O and &amp;#948;&lt;sup&gt;13&lt;/sup&gt;C stratigraphies remained poorly constrained, due to relatively poor global high-resolution data coverage.&lt;/p&gt;&lt;p&gt;Here, I present ongoing work that uses high-resolution deep-sea foraminiferal stable isotope records to improve late Miocene (chrono)stratigraphy. Although challenges remain, the coverage of late Miocene benthic &amp;#948;&lt;sup&gt;18&lt;/sup&gt;O and &amp;#948;&lt;sup&gt;13&lt;/sup&gt;C stratigraphies has drastically improved in recent years, with high-resolution records now available across the Atlantic and Pacific Oceans. The recovery of these deep-sea records, including the first astronomically tuned, deep-sea integrated magneto-chemostratigraphy, has also helped to improve the late Miocene geological timescale. Finally, I will briefly touch upon how our understanding of late Miocene climate evolution has improved, based on the high-resolution deep-sea archives that are now available.&lt;/p&gt;

Old Norse Mythology as Sacred Narrative

2021 ◽  
pp. 65-102
Author(s):  
John Lindow
Keyword(s):  
Thirteenth Century ◽  
Deep Sea ◽  
Old Norse ◽  
Viking Age ◽  
Chronological Order ◽  
Simple Fact ◽  
The Earth ◽  
The World ◽  
Norse Mythology

This chapter presents a case study of one myth that we have from pictorial sources in the Viking Age, from poems almost certainly composed in the Viking Age, and from thirteenth-century sources, namely the encounter between the god Þórr (Thor) and his cosmic enemy, the World serpent, a beast that encircles the earth, in the deep sea. In this myth, Þórr fishes up the serpent, and depending on the variant, Þórr may or may not kill the serpent. I present and analyze the texts in more or less chronological order, from the older skalds through the Eddic poem Hymiskviða, through Snorri Sturluson in Edda, and compare the texts to the rock carvings that portray the myth. I argue that the issue of the death or survival of the serpent is less important than the simple fact that Þórr had the serpent on his hook.

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