scholarly journals Особенности спектров ЯМР -=SUP=-63,65-=/SUP=-Cu в локальном поле образцов полупроводникового минерала CuFeS-=SUB=-2-=/SUB=- из сульфидных месторождений океана

2018 ◽  
Vol 52 (8) ◽  
pp. 836
Author(s):  
В.Л. Матухин ◽  
А.И. Погорельцев ◽  
А.Н. Гавриленко ◽  
С.О. Гарькавый ◽  
Е.В. Шмидт ◽  
...  
Keyword(s):  
Room Temperature ◽  
Global Ocean ◽  
Island Arcs ◽  
Nmr Spectrum ◽  
Nmr Method ◽  
The Pacific ◽  
Different Types ◽  
Asymmetric Shape ◽  
The Pacific Ocean ◽  
Polymetallic Sulfides

AbstractThe results of studying natural samples of CuFeS_2 chalcopyrite mineral from hydrothermal ore manifestations of island arcs of the Pacific Ocean by ^63Cu nuclear magnetic resonance (^63Cu NMR) in a local field at room temperature are presented. The asymmetric shape of the detected resonance lines in the ^63Cu NMR spectrum indicates the presence of at least two overlapping lines. The presence of two overlapping central components can be a consequence of the occurrence of regions with different types of structural distortion near the resonant nuclei. These results show that the pulsed ^63Cu NMR method can be an effective method for studying the physical properties of deep-sea polymetallic sulfides of the global ocean.

Different Types of Island-Arcs in the Pacific

1945 ◽  
Vol 106 (5/6) ◽  
pp. 198 ◽  
Author(s):  
J. H. F. Umbgrove
Keyword(s):  
Island Arcs ◽  
The Pacific ◽  
Different Types

scholarly journals Differences in Epicentral Location of Mexican Earthquakes between Local and Global Catalogs: An update

2016 ◽  
Vol 55 (1) ◽  
Author(s):  
Vala Hjörleifsdóttir ◽  
Shri Krishna Singh ◽  
Allen Husker
Keyword(s):  
Subduction Zone ◽  
Velocity Structure ◽  
The United States ◽  
The State ◽  
The Pacific ◽  
Different Types ◽  
The Pacific Ocean ◽  
Epicentral Location ◽  
Large Earthquakes ◽  
Mexican Subduction Zone

Differences in epicentral locations between local and global catalogs for earthquakes in the Mexican subduction zone were first observed to be biased in the 1980s, based on a few well studied events. In this study we compare locations between two local catalogs; (1) a recent high precision catalog of events in the state of Guerrero and (2) the catalog of the Servicio Sismológico Nacional (SSN), to the global catalog of the United States Geological Service (USGS). We find that on average epicentral locations in the global catalog of earthquakes larger than M 5 in the Mexican subduction zone are 26 km towards N54°E of those in the local catalogs. We investigate how the errors vary for different types of earthquakes in Guerrero, and how they vary along the trench, from the state of Jalisco to the state of Chiapas. The average differences are largest for thrust events occurring close to the trench, and for events in Michoacán. The differences are greater on average for large earthquakes than for small. There is a trade-off between the distance from the trench and timing, suggesting a poor resolution of these parameters, due to the lack of stations the Pacific Ocean. We attribute the differences in locations to systematic patterns in the velocity structure of the mantle, with consistently fast paths to the northeast and relatively slow paths towards the southwest.

The Variable Southern Ocean Carbon Sink

2019 ◽  
Vol 11 (1) ◽  
pp. 159-186 ◽  
Author(s):  
Nicolas Gruber ◽  
Peter Landschützer ◽  
Nicole S. Lovenduski
Keyword(s):  
Southern Ocean ◽  
Carbon Sink ◽  
Global Ocean ◽  
The Pacific ◽  
Southward Shift ◽  
Storage Rate ◽  
The Pacific Ocean ◽  
Ocean Models ◽  
Ocean Carbon ◽  
Decadal Predictions

The CO2uptake by the Southern Ocean (<35°S) varies substantially on all timescales and is a major determinant of the variations of the global ocean carbon sink. Particularly strong are the decadal changes characterized by a weakening period of the Southern Ocean carbon sink in the 1990s and a rebound after 2000. The weakening in the 1990s resulted primarily from a southward shift of the westerlies that enhanced the upwelling and outgassing of respired (i.e., natural) CO2. The concurrent reduction in the storage rate of anthropogenic CO2in the mode and intermediate waters south of 35°S suggests that this shift also decreased the uptake of anthropogenic CO2. The rebound and the subsequent strong, decade-long reinvigoration of the carbon sink appear to have been driven by cooling in the Pacific Ocean, enhanced stratification in the Atlantic and Indian Ocean sectors, and a reduced overturning. Current-generation ocean models generally do not reproduce these variations and are poorly skilled at making decadal predictions in this region.

Plate Tectonics

2021 ◽  
pp. 114-136
Author(s):  
Elisabeth Ervin-Blankenheim
Keyword(s):  
Plate Tectonics ◽  
Plastic Material ◽  
Convergent Margins ◽  
Island Arcs ◽  
Mountain Ranges ◽  
Ocean Ridges ◽  
Rock Types ◽  
The Pacific ◽  
The Pacific Ocean ◽  
The Many

Plate tectonics, the grand unifying theory of geology, and its relation to the Earth is explained in this chapter. The planet transforms through time by means of the movement of rigid plates carrying the continents riding on the plastic material in the Earth’s upper mantle. Three major plate boundaries are divergent margins, where new ocean floor is being created along mid-ocean ridges and plates separate from one another; convergent margins, where the material is subducted and consumed as different types of plates collide, creating trenches, island arcs or mountain ranges, and transform boundaries; and where plates slide past one another. Besides the three predominant boundaries, hot spots caused by mantle plumes and diffuse boundaries make up additional dynamic forces in tectonics. Beyond these categories, geologists still are learning about tectonics; some boundaries are unknown or speculative. Plate tectonics explains why many of the Earth’s hazards are found where there are. Earthquakes trace many plate margins, as do volcanoes. The area around the Pacific Ocean is called the “Ring of Fire” because of the many volcanoes related to subducting plates. Tectonics accounts for why certain rocks are located where they are; for example, all rock types are found at convergent margins. The theory also predicts where valuable mineral and economic deposits are located.

Going Big in the Pacific

2020 ◽  
Vol 5 (1) ◽  
pp. 186-204 ◽  
Author(s):  
Quentin Hanich ◽  
Clive Schofield ◽  
Chris Smyth
Keyword(s):  
Pacific Ocean ◽  
Protected Areas ◽  
Marine Protected Areas ◽  
Large Scale ◽  
Marine Conservation ◽  
Global Ocean ◽  
Conservation Targets ◽  
The Pacific ◽  
The Pacific Ocean ◽  
Definition Of

The definition of large-scale marine protected areas in the Pacific Ocean is fundamental to the achievement of global marine conservation targets. The threatened nature of the global ocean is emphasised, the evolution of global spatial targets for marine conservation outlined and the implementation of large-scale marine protected areas in Australia and the Pacific Ocean more broadly is reviewed. The article concludes with some reflections on the efficacy of such mechanisms in the Pacific.

scholarly journals Delineating ecologically significant taxonomic units from global patterns of marine picocyanobacteria

2016 ◽  
Vol 113 (24) ◽  
pp. E3365-E3374 ◽  
Author(s):  
Gregory K. Farrant ◽  
Hugo Doré ◽  
Francisco M. Cornejo-Castillo ◽  
Frédéric Partensky ◽  
Morgane Ratin ◽  
...  
Keyword(s):  
Global Ocean ◽  
Ecological Niches ◽  
Reference Database ◽  
Marquesas Islands ◽  
Physico Chemical ◽  
The Pacific ◽  
The Pacific Ocean ◽  
Community Shifts ◽  
Taxonomic Marker ◽  
Tight Correlation

ProchlorococcusandSynechococcusare the two most abundant and widespread phytoplankton in the global ocean. To better understand the factors controlling their biogeography, a reference database of the high-resolution taxonomic markerpetB, encoding cytochromeb6, was used to recruit reads out of 109 metagenomes from theTaraOceans expedition. An unsuspected novel genetic diversity was unveiled within both genera, even for the most abundant and well-characterized clades, and 136 divergentpetBsequences were successfully assembled from metagenomic reads, significantly enriching the reference database. We then defined Ecologically Significant Taxonomic Units (ESTUs)—that is, organisms belonging to the same clade and occupying a common oceanic niche. Three major ESTU assemblages were identified along the cruise transect forProchlorococcusand eight forSynechococcus. AlthoughProchlorococcusHLIIIA and HLIVA ESTUs codominated in iron-depleted areas of the Pacific Ocean, CRD1 and the yet-to-be cultured EnvB were the prevalentSynechococcusclades in this area, with three different CRD1 and EnvB ESTUs occupying distinct ecological niches with regard to iron availability and temperature. Sharp community shifts were also observed over short geographic distances—for example, around the Marquesas Islands or between southern Indian and Atlantic Oceans—pointing to a tight correlation between ESTU assemblages and specific physico-chemical parameters. Together, this study demonstrates that there is a previously overlooked, ecologically meaningful, fine-scale diversity within some currently defined picocyanobacterial ecotypes, bringing novel insights into the ecology, diversity, and biology of the two most abundant phototrophs on Earth.

scholarly journals Persistence of deeply sourced iron in the Pacific Ocean

2015 ◽  
Vol 112 (5) ◽  
pp. 1292-1297 ◽  
Author(s):  
Tristan J. Horner ◽  
Helen M. Williams ◽  
James R. Hein ◽  
Mak A. Saito ◽  
Kevin W. Burton ◽  
...  
Keyword(s):  
Pacific Ocean ◽  
Carbon Fixation ◽  
Global Ocean ◽  
Oceanic Circulation ◽  
Multiple Sources ◽  
Central Pacific ◽  
Central Pacific Ocean ◽  
The Past ◽  
The Pacific ◽  
The Pacific Ocean

Biological carbon fixation is limited by the supply of Fe in vast regions of the global ocean. Dissolved Fe in seawater is primarily sourced from continental mineral dust, submarine hydrothermalism, and sediment dissolution along continental margins. However, the relative contributions of these three sources to the Fe budget of the open ocean remains contentious. By exploiting the Fe stable isotopic fingerprints of these sources, it is possible to trace distinct Fe pools through marine environments, and through time using sedimentary records. We present a reconstruction of deep-sea Fe isotopic compositions from a Pacific Fe−Mn crust spanning the past 76 My. We find that there have been large and systematic changes in the Fe isotopic composition of seawater over the Cenozoic that reflect the influence of several, distinct Fe sources to the central Pacific Ocean. Given that deeply sourced Fe from hydrothermalism and marginal sediment dissolution exhibit the largest Fe isotopic variations in modern oceanic settings, the record requires that these deep Fe sources have exerted a major control over the Fe inventory of the Pacific for the past 76 My. The persistence of deeply sourced Fe in the Pacific Ocean illustrates that multiple sources contribute to the total Fe budget of the ocean and highlights the importance of oceanic circulation in determining if deeply sourced Fe is ever ventilated at the surface.

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