scholarly journals Oceanic Core Complex or not? When partial spreading asymmetry triggers seafloor diversity

2021 ◽  
Author(s):  
Florent Szitkar ◽  
Laurent Gernigon ◽  
Anna Lim ◽  
Marco Brönner
Keyword(s):  
Magnetic Data ◽  
Core Complex ◽  
Oceanic Core Complex ◽  
New Class ◽  
Mid Ocean Ridge ◽  
Slow Spreading ◽  
Loki’S Castle ◽  
Definition Of ◽  
Ocean Ridge ◽  
Oceanic Structure

Abstract We use high-resolution and regional geophysical data to study a bathymetric high near the Mohns/Knipovich ridges junction, in the Norwegian-Greenland Sea. Near-seafloor magnetic data over hydrothermal site Loki’s Castle first support the basaltic nature of the seafloor. We then combine this result with regional magnetic and bathymetric considerations to investigate the crustal architecture in the vicinity of the junction. We show that the spreading asymmetry is insufficient to allow the development of Oceanic Core Complexes. Instead, this atypical off-axis hill is dominantly basaltic and should be interpreted as the first inside corner hogback structure identified along an active mid-ocean ridge system. Our conclusion tempers the definition of Oceanic Core Complex and underlines that bathymetric highs located off axis from slow-spreading centers cannot always be interpreted as such. This intermediate type of spreading paves the way to the introduction of a new class of oceanic structure referred to as Proto-Core Complexes.

Fluid composition of the sediment-influenced Loki’s Castle vent field at the ultra-slow spreading Arctic Mid-Ocean Ridge

2016 ◽  
Vol 187 ◽  
pp. 156-178 ◽  
Author(s):  
Tamara Baumberger ◽  
Gretchen L. Früh-Green ◽  
Ingunn H. Thorseth ◽  
Marvin D. Lilley ◽  
Cédric Hamelin ◽  
...  
Keyword(s):  
Fluid Composition ◽  
Mid Ocean Ridge ◽  
Slow Spreading ◽  
Loki’S Castle ◽  
Ocean Ridge

scholarly journals Assessing the impact of sedimentation on fault spacing at the Andaman Sea spreading center

Geology ◽  
2020 ◽  
Author(s):  
Clément de Sagazan ◽  
Jean-Arthur Olive
Keyword(s):  
Active Faults ◽  
Spreading Rate ◽  
Andaman Sea ◽  
Spreading Center ◽  
Normal Faults ◽  
Mid Ocean Ridge ◽  
Plate Separation ◽  
Slow Spreading ◽  
Ocean Ridge ◽  
The Impact

The stabilizing effect of surface processes on strain localization, albeit predicted by several decades of geodynamic modeling, remains difficult to document in real tectonic settings. Here we assess whether intense sedimentation can explain the longevity of the normal faults bounding the Andaman Sea spreading center (ASSC). The structure of the ASSC is analogous to a slow-spreading mid-ocean ridge (MOR), with symmetric, evenly spaced axis-facing faults. The average spacing of faults with throws ≥100 m (8.8 km) is however large compared to unsedimented MORs of commensurate spreading rate, suggesting that sedimentation helps focus tectonic strain onto a smaller number of longer-lived faults. We test this idea by simulating a MOR with a specified fraction of magmatic plate separation (M), subjected to a sedimentation rate (s) ranging from 0 to 1 mm/yr. We find that for a given M ≥ 0.7, increasing s increases fault lifespan by ~50%, and the effect plateaus for s > 0.5 mm/yr. Sedimentation prolongs slip on active faults by leveling seafloor relief and raising the threshold for breaking new faults. The effect is more pronounced for faults with a slower throw rate, which is favored by a greater M. These results suggest that sedimentation-enhanced fault lifespan is a viable explanation for the large spacing of ASSC faults if magmatic input is sufficiently robust. By contrast, longer-lived faults that form under low M are not strongly influenced by sedimentation.

scholarly journals Simultaneous Leaching of Seafloor Massive Sulfides and Polymetallic Nodules

Minerals ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 482 ◽  
Author(s):  
Przemyslaw Kowalczuk ◽  
Hassan Bouzahzah ◽  
Rolf Kleiv ◽  
Kurt Aasly
Keyword(s):  
Industrial Applications ◽  
The Arctic ◽  
Central Pacific ◽  
Massive Sulfides ◽  
Central Pacific Ocean ◽  
Polymetallic Nodules ◽  
Mid Ocean Ridge ◽  
Different Types ◽  
Loki’S Castle ◽  
Ocean Ridge

Simultaneous leaching of seafloor massive sulfides (SMS) from Loki’s Castle on the Arctic Mid-Ocean Ridge (AMOR) and polymetallic nodules (PN) from Clarion Clipperton Zone (CCZ) of the Central Pacific Ocean was studied. Leaching tests were conducted using sulfuric acid and sodium chloride, at a temperature of 80 °C for 48 h under reflux. The effect of PN-to-SMS ratio was examined. It was shown that simultaneous leaching of two different types of marine resources was possible resulting in high dissolution rates of metals. The proposed process has many advantages as it does not require pyrometallurgical pretreatment, and yields solid products (i.e., silica, barite, elemental sulfur, albite, microcline, muscovite), which might be utilized for various industrial applications.

Jump event of mid-ocean ridge during the eastern subbasin evolution of the South China Sea

2016 ◽  
Vol 4 (3) ◽  
pp. SP67-SP77 ◽  
Author(s):  
Yan Qiu ◽  
Yingmin Wang ◽  
Wenkai Huang ◽  
Weiguo Li ◽  
Haiteng Zhuo ◽  
...  
Keyword(s):  
South China Sea ◽  
South China ◽  
Seafloor Spreading ◽  
The South China Sea ◽  
Magnetic Data ◽  
The South ◽  
Tectonic Event ◽  
China Sea ◽  
Mid Ocean Ridge ◽  
Ocean Ridge

The South China Sea is one of the largest marginal seas in the Western Pacific region, and it has been widely accepted that the evolution of the basin and the development of its oceanic crusts is closely linked to seafloor spreading. A great controversy, however, is around whether or not there was a jump of mid-ocean ridges during seafloor spreading, particularly in the eastern South China Sea subbasin. A tectonostratigraphic interpretation using high-resolution seismic data demonstrated that: (1) a southward jump event of the mid-ocean ridge took place in the eastern subbasin during the seafloor spreading; (2) the orientation of the mid-ocean ridge had dramatically changed after the event resulting in that the abandoned mid-ocean ridge is along an east–west direction, whereas the younger one is generally east–northeast/west–southwest oriented; (3) the corresponding surface caused by the jump tectonic event and the pre-event sequence can be traced throughout the earlier formed oceanic crust; and (4) paleo-magnetic data showed that the event occurred at approximately 25–23.8 Ma. The results of this study could be used to better understand the evolution and filling of the South China Sea and other associated marginal basins.

scholarly journals Microbial diversity of Loki's Castle black smokers at the Arctic Mid-Ocean Ridge

Geobiology ◽  
2012 ◽  
Vol 10 (6) ◽  
pp. 548-561 ◽  
Author(s):  
A. Jaeschke ◽  
S. L. Jørgensen ◽  
S. M. Bernasconi ◽  
R. B. Pedersen ◽  
I. H. Thorseth ◽  
...  
Keyword(s):  
Microbial Diversity ◽  
The Arctic ◽  
Mid Ocean Ridge ◽  
Black Smokers ◽  
Loki’S Castle ◽  
Ocean Ridge

Longest continuously erupting large igneous province driven by plume-ridge interaction

Geology ◽  
2020 ◽  
Author(s):  
Qiang Jiang ◽  
Fred Jourdan ◽  
Hugo K.H. Olierook ◽  
Renaud E. Merle ◽  
Joanne M. Whittaker
Keyword(s):  
Short Pulse ◽  
Large Igneous Province ◽  
Igneous Provinces ◽  
Mid Ocean Ridge ◽  
Slow Spreading ◽  
Magma Flux ◽  
And Migration ◽  
Main Construct ◽  
Ocean Ridge

Large igneous provinces (LIPs) typically form in one short pulse of ~1–5 Ma or several punctuated ~1–5 Ma pulses. Here, our 25 new 40Ar/39Ar plateau ages for the main construct of the Kerguelen LIP—the Cretaceous Southern and Central Kerguelen Plateau, Elan Bank, and Broken Ridge—show continuous volcanic activity from ca. 122 to 90 Ma, a long lifespan of >32 Ma. This suggests that the Kerguelen LIP records the longest, continuous high-magma-flux emplacement interval of any LIP. Distinct from both short-lived and multiple-pulsed LIPs, we propose that Kerguelen is a different type of LIP that formed through long-term interactions between a mantle plume and mid-ocean ridge, which is enabled by multiple ridge jumps, slow spreading, and migration of the ridge. Such processes allow the transport of magma products away from the eruption center and result in long-lived, continuous magmatic activity.

scholarly journals Dynamic Accretion Beneath a Slow‐Spreading Ridge Segment: IODP Hole 1473A and the Atlantis Bank Oceanic Core Complex

2019 ◽  
Vol 124 (12) ◽  
pp. 12631-12659 ◽  
Author(s):  
H. J. B. Dick ◽  
C. J. MacLeod ◽  
P. Blum ◽  
N. Abe ◽  
D. K. Blackman ◽  
...  
Keyword(s):  
Spreading Ridge ◽  
Core Complex ◽  
Oceanic Core Complex ◽  
Atlantis Bank ◽  
Slow Spreading
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