scholarly journals Seafloor geomagnetic vector anomaly of the intersection of the Mid-Atlantic Ridge and the Kane Transform Fault: Implications for magnetization of the oceanic crust

1998 ◽  
Vol 103 (B12) ◽  
pp. 30335-30349 ◽  
Author(s):  
Toshiya Fujiwara ◽  
Hiromi Fujimoto
Keyword(s):  
Oceanic Crust ◽  
Transform Fault ◽  
Mid Atlantic Ridge ◽  
Kane Transform

PRELIMINARY FORESHOCK ANALYSIS OF SUBMARINE TRANSFORM FAULT EARTHQUAKES ALONG THE EQUATORIAL MID-ATLANTIC RIDGE

2016 ◽  
Author(s):  
Ross P. Meyer ◽  
◽  
Joe H. Haxel ◽  
Robert P. Dziak ◽  
Deborah K. Smith
Keyword(s):  
Transform Fault ◽  
Mid Atlantic Ridge

Deep-tow studies of the Vema Fracture Zone: 1. Tectonics of a major slow slipping transform fault and its intersection with the Mid-Atlantic Ridge

1986 ◽  
Vol 91 (B3) ◽  
pp. 3334-3354 ◽  
Author(s):  
Ken. C. Macdonald ◽  
David A. Castillo ◽  
Stephen P. Miller ◽  
Paul J. Fox ◽  
Kim A. Kastens ◽  
...  
Keyword(s):  
Fracture Zone ◽  
Transform Fault ◽  
Mid Atlantic Ridge

Petrology of a transform fault zone and adjacent ridge segments

1971 ◽  
Vol 268 (1192) ◽  
pp. 423-441 ◽  
Keyword(s):  
Oceanic Crust ◽  
Fault Zone ◽  
Fracture Zone ◽  
Volcanic Eruptions ◽  
Spreading Ridge ◽  
Transform Fault ◽  
Transform Faults ◽  
Near Surface ◽  
The North ◽  
Transform Fault Zone

The Verna Fracture Zone in the North Atlantic (9 to 11° N), which has been identified as a transform fault zone, contains exposures of serpentinized peridotites, while its adjacent ridge segments are floored mainly by typical abyssal ocean ridge basalts. This petrologic contrast correlates with the greater frequency of volcanic eruptions along the actively spreading ridge segments compared to the transform fault zone. Where rifting components occur across transform faults, exposures of the deeper zone of oceanic crust may result. The bathymetry of the Verna Fracture Zone suggests that some uplift parallel to the fracture zone as well as rifting led to exposures of deeper rocks. The basalts from the adjacent ridge axes contain ‘xenocrysts’ of plagioclase and olivine and more rarely of chromite. These appear to have a cognate origin, perhaps related to cooling and convection in near surface magma chambers. The basalts from the ridge axes, offset and on opposite sides of the transform fault, have similar features and compositions. The plagioclase peridotites have mineralogical features which indicate equilibration in the plagioclase pyrolite facies, suggesting maximum equilibration depths of around 30 km for a temperature of around 1200 °C. The chemical characteristics of the Vema F.Z. peridotites suggest that they may be undifferentiated mantle, emplaced as a subsolidus hot plastic intrusion or as a crystal mush. The abundance of peridotites and serpentinized peridotites is believed to reflect their abundance in seismic layer three of the oceanic crust.

Thermohaline multi-phase simulations of vent fluid salinity evolution following a diking event at East Pacific Rise

2020 ◽  
Author(s):  
Falko Vehling ◽  
Jörg Hasenclever ◽  
Lars Rüpke
Keyword(s):  
Phase Separation ◽  
Numerical Model ◽  
Oceanic Crust ◽  
Vapor Phase ◽  
Numerical Models ◽  
East Pacific Rise ◽  
Hydrothermal Systems ◽  
Low Salinity ◽  
East Pacific ◽  
Mid Atlantic Ridge

<p>Submarine hydrothermal systems sustain unique ecosystems, affect global-scale biogeochemical ocean cycles, and mobilize metals from the oceanic crust to form volcanogenic massive sulfide deposits. Quantifying these processes requires linking seafloor observations to physico-chemical processes at depth and this is where numerical models of hydrothermal circulation can be particularly useful. One region where sufficient data is available to establish such a link is the East Pacific Rise (EPR) at 9°N, where vent fluid salinity and temperature have been repeatedly measured over a long time period. Here, large salinity and temperature changes of vents at the axial graben have been correlated with diking events and extrusive lava flows. Salinity changes imply the phase separation of seawater into a high-salinity brine and a low-salinity vapor phase. The intrusion of a new dike is likely to result in a characteristic salinity signal over several years: first the low salinity vapor phase rises and later the brine phase appears along with a decreasing vent temperature. These short-term salinity variations are super-imposed on the background salinity signal, which is modulated by phase separation phenomena on top of the axial magma lens. </p><p>From these variations, numerical models can help to infer sub-surface properties and processes such as permeability, background flow rates, and brine retention as well as mobilization – if the employed model can resolve the complexity of phase separation. We here present a novel numerical model for saltwater hydrothermal systems, which uses the Finite Volume Method on unstructured meshes and the Newton-Raphson Method for solving the coupled equations. We use this new 2-D model to investigate a setup that mimics hydrothermal convection on top of the axial magma lens, which is then perturbed by a dike intrusion. In a comprehensive suite of model runs, we have identified the key controls on the time evolution of vent fluid salinity following the diking event. Based on these insights, we can reproduce time-series data from the EPR at 9°N and infer likely ranges of rock properties for the oceanic crust layer 2B. </p><p>Our work shows how useful data integration into numerical hydrothermal models is. Unfortunately, data collection like mapping of magmatic events, continuous measurements of hydrothermal vent fluids or crustal drilling are very expensive and technically challenging. Here global and transdisciplinary collaboration would be very useful for achieving data with maximal benefit for all disciplines. Compared to the EPR the Mid-Atlantic Ridge shows a higher geological complexity, due to its lower spreading rate, and a higher diversity of vent fluid chemistry, but less continuous data is available, which hampers research using numerical models here for now. Therefore, numerical case studies at EPR serve as important validity checks for our numerical model and indicate where it has to be enhanced for quantifying processes related to hydrothermal systems at Mid-Atlantic Ridge.     </p>

Microearthquake evidence for extension across the Kane Transform Fault

1990 ◽  
Vol 95 (B10) ◽  
pp. 15439 ◽  
Author(s):  
William S. D. Wilcock ◽  
G. M. Purdy ◽  
Sean C. Solomon
Keyword(s):  
Transform Fault ◽  
Kane Transform
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