Isostatic compensation of tectonic features of the Mid-Atlantic Ridge: 25–27°30′S

1991 ◽  
Vol 96 (B7) ◽  
pp. 11741 ◽  
Author(s):  
Donna K. Blackman ◽  
Donald W. Forsyth
Keyword(s):  
Isostatic Compensation ◽  
Mid Atlantic Ridge ◽  
Tectonic Features

scholarly journals Extensive decentralized hydrogen export from the Atlantis Massif

Geology ◽  
2021 ◽  
Author(s):  
Susan Q. Lang ◽  
Marvin D. Lilley ◽  
Tamara Baumberger ◽  
Gretchen L. Früh-Green ◽  
Sharon L. Walker ◽  
...  
Keyword(s):  
Geographical Area ◽  
Circulation System ◽  
Depth Range ◽  
Mass Wasting ◽  
Lost City ◽  
Atlantis Massif ◽  
Mid Atlantic Ridge ◽  
Flow Pathways ◽  
Tectonic Features ◽  
Lost City Hydrothermal Field

Hydrogen is an important energy source for subsurface microbial communities, but its availability beyond the flow focused through hydrothermal chimneys is largely unknown. We report the widespread export of H2 across the Atlantis Massif oceanic core complex (30°N, Mid-Atlantic Ridge; up to 44 nM), which is distinct from the circulation system feeding the Lost City Hydrothermal Field (LCHF) on the massif’s southern wall. Methane (CH4) abundances are generally low to undetectable (<3 nM) in fluids that are not derived from the LCHF. Reducing fluids exit the seafloor over a wide geographical area and depth range, including the summit of the massif and along steep areas of mass wasting east of the field. The depth of the fluids in the water column and their H2/CH4 ratios indicate that some are sourced separately from the LCHF. We argue that extensive H2 export is the natural consequence of fluid flow pathways strongly influenced by tectonic features and the volume and density changes that occur when ultramafic rocks react to form serpentinites, producing H2 as a by-product. Furthermore, the circulation of H2-rich fluids through uplifted mantle rocks at moderate temperatures provides geographically expansive and stable environmental conditions for the early evolution of biochemical pathways. These results provide insight into the spatial extent of H2- and CH4-bearing fluids associated with serpentinization, independent of the focused flow emanating from the LCHF.

Acoustic Reverberation at Selected Sites in the Mid-Atlantic Ridge Region,

1993 ◽  
Author(s):  
Jerald W. Caruthers ◽  
J. R. Fricke ◽  
Ralph A. Stephen
Keyword(s):  
Mid Atlantic Ridge ◽  
Acoustic Reverberation

The age of magmatic and metamorphic events in the Mid-Atlantic Ridge: interpretation of K-Ar isotope dating data

2001 ◽  
Vol 2 (3) ◽  
pp. 269-278
Author(s):  
S. A. Silantiev ◽  
L. K. Levskiy ◽  
M. M. Arakelyants ◽  
V. A. Lebedev ◽  
A. Bugo ◽  
...  
Keyword(s):  
Mid Atlantic Ridge ◽  
Isotope Dating

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

scholarly journals Fissure Ridges: A Reappraisal of Faulting and Travertine Deposition (Travitonics)

Geosciences ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 278
Author(s):  
Andrea Brogi ◽  
Enrico Capezzuoli ◽  
Volkan Karabacak ◽  
Mehmet Cihat Alcicek ◽  
Lianchao Luo
Keyword(s):  
State Of The Art ◽  
Tectonic Setting ◽  
Original Data ◽  
Apical Part ◽  
Thermal Waters ◽  
Growth Mechanisms ◽  
Depositional Facies ◽  
Geothermal Fluids ◽  
Tectonic Features ◽  
Travertine Deposition

The mechanical discontinuities in the upper crust (i.e., faults and related fractures) lead to the uprising of geothermal fluids to the Earth’s surface. If fluids are enriched in Ca2+ and HCO3-, masses of CaCO3 (i.e., travertine deposits) can form mainly due to the CO2 leakage from the thermal waters. Among other things, fissure-ridge-type deposits are peculiar travertine bodies made of bedded carbonate that gently to steeply dip away from the apical part where a central fissure is located, corresponding to the fracture trace intersecting the substratum; these morpho-tectonic features are the most useful deposits for tectonic and paleoseismological investigation, as their development is contemporaneous with the activity of faults leading to the enhancement of permeability that serves to guarantee the circulation of fluids and their emergence. Therefore, the fissure ridge architecture sheds light on the interplay among fault activity, travertine deposition, and ridge evolution, providing key geo-chronologic constraints due to the fact that travertine can be dated by different radiometric methods. In recent years, studies dealing with travertine fissure ridges have been considerably improved to provide a large amount of information. In this paper, we report the state of the art of knowledge on this topic refining the literature data as well as adding original data, mainly focusing on the fissure ridge morphology, internal architecture, depositional facies, growth mechanisms, tectonic setting in which the fissure ridges develop, and advantages of using the fissure ridges for neotectonic and seismotectonic studies.

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