scholarly journals Thermal segmentation of mid-ocean ridge-transform faults

2017 ◽  
Vol 18 (9) ◽  
pp. 3405-3418 ◽  
Author(s):  
Monica Wolfson-Schwehr ◽  
Margaret S. Boettcher ◽  
Mark D. Behn
Keyword(s):  
Transform Faults ◽  
Mid Ocean Ridge ◽  
Ocean Ridge

Investigation into the influence of the Réunion plume on the Central Indian Ridge

2020 ◽  
Author(s):  
Clément Vincent ◽  
Jung-Woo Park ◽  
Sang-Mook Lee ◽  
Jonguk Kim ◽  
Sang-Joon Pak
Keyword(s):  
High Resolution ◽  
Leading Edge ◽  
Middle Part ◽  
Geochemical Data ◽  
Long Distance ◽  
Transform Faults ◽  
Central Indian Ridge ◽  
Mid Ocean Ridge ◽  
Indian Ridge ◽  
Ocean Ridge

<p>Plume-ridge interaction is an important thermal and geological process, which results in various physical and chemical anomalies along a significant length of the global mid-ocean ridge system. Despite numerous studies, some remaining questions to be solved are the origin and mechanisms of geochemical variations and their possible correlation with the morphology of mid-ocean ridges.</p><p>The Central Indian Ridge, with a slow to intermediate spreading rate, provides an ideal opportunity to explore the long-distance plume-ridge interactions. Presently, the ridge is moving away from the Réunion hotspot which is located 1000 km away from the Central Indian Ridge at Réunion Island. Paleogeographic reconstruction suggests that the hotspot crossed the middle part of the Central Indian Ridge (MCIR) between 8°S and 17°S at ~34 Ma. Previous studies argue that the plume material currently flows into the Central Indian Ridge at around 19°S, south of Marie Celeste Fracture Zone (MCFZ) and geochemical enrichments of the mid-ocean ridge basalts (MORB) from the MCIR 14°S and 19°S segments can be attributed to a fossil Réunion plume component. However, a recent geophysical study has suggested that the geochemical anomalies along the Rodrigues segment (18-21°S) can be ascribed to the asthenospheric flow from the Réunion plume, reopening the debate about the origin of the enriched anomalies along the MCIR (14-19°S).</p><p>In this study, we revisited the MCIR from 14°S to 17°S with new geochemical data obtained based on high-resolution sampling and ship-board high-resolution bathymetry data to constrain the influence of the Réunion plume on geochemistry and bathymetry of the MCIR. The results show that trace element ratios and isotopic compositions of on-axis MORB vary in association with ridge discontinuities such as transform faults and non-transform fault discontinuities. The MORB from the northern parts of segments display substantially enriched geochemical features and the enrichments correspond to a shallower axial bathymetry. We attribute the chemical and morphological anomalies along the ridge to the influence of a Réunion plume component focussed by a hotspot leading edge effect. The hotspot leading segments are offset in the direction of the plume and are more efficiently affected by the enriched plume materials. These findings suggest that lithospheric discontinuities such as transform faults and fracture zones may control the flow of mantle plume material into the ridge and the geometry of the ridge coupled to its hotspot proximity may play an important role, particularly in the long-distance plume-ridge interaction.</p>

MORGEN – The Mid Ocean Ridge GENerating algorithm

2021 ◽  
Author(s):  
Thomas van der Linden ◽  
Douwe van Hinsbergen
Keyword(s):  
Conceptual Knowledge ◽  
Smooth Curve ◽  
Weddell Sea ◽  
Plate Boundaries ◽  
Plate Tectonic ◽  
Transform Faults ◽  
Ocean Ridges ◽  
Euler Pole ◽  
Mid Ocean Ridge ◽  
Ocean Ridge

<p>Paleo-digital elevation models (paleoDEM) based on plate tectonic and paleogeographic reconstructions use age grids of ocean floor to determine ocean bathymetry. In recent years, such age grids have also been developed for now-subducted oceans from the far geological past, as far back as the Neoproterozoic, using geology and paleomagnetism-based estimates of ocean opening. In such reconstructions, mid ocean ridges are drawn based on estimated Euler poles and rotations, and conceptual knowledge on the geometry consisting of spreading ridges and transform faults.</p><p>Current procedures to draw mid ocean ridges in plate tectonic reconstructions are laborious, as new ridges are drawn every time the Euler pole location changes. Fortunately this is also a task that can be automated. We have written an algorithm using pyGPlates that takes as input a smooth curve at the approximate position of the reconstructed mid ocean ridge at the moment of its formation, and then calculates spreading and transform segments according to their typical geometries in modern oceans, assuming symmetric spreading. The algorithm allows gradual readjustment of ridge orientations upon Euler pole changes comparable to documented cases in the modern oceans (e.g., in the Weddell Sea). The algorithm also contains modules that can convert the calculated mid ocean ridges with other plate boundaries to boundary topologies – which can be used as input for the recently published TracerTectonics algorithm, produce isochrons which can be converted to age grids, check for subduction of isochrons and subsequently create bathymetry grids. We illustrate the use of the MORGEN algorithm with recently published reconstructions of subducted, as well as future oceans.</p>

Geology of the Charlie Gibbs transform system (52-53ºN, Mid Atlantic Ridge): preliminary results from Akademik Nikolaj Strakhov Expedition S50

2021 ◽  
Author(s):  
Alessio Sanfilippo ◽  
Sergey Skolotnev ◽  
Alexander Peyve ◽  
Keyword(s):  
North Atlantic ◽  
Large Scale ◽  
Single Channel ◽  
Continental Margins ◽  
Transform Faults ◽  
The North ◽  
Mid Ocean Ridge ◽  
Mid Atlantic Ridge ◽  
Ocean Ridge ◽  
Resolution Single

<p>The Charlie Gibbs offsetting by ~340 km the Mid Atlantic Ridge (MAR) axis between 52°-53° N is one of the main transform systems of the North Atlantic. Located between long mid-ocean ridge segments influenced to the south by the Azores and to the north by the Iceland mantle plume, this transform system has been active since the early phases of North Atlantic rifting. Object of several surveys in the ‘70 and ‘80, Charlie Gibbs received great attention for its unique structure characterized by two long-lived right-lateral transform faults linked by a short ~40 km-long intra-transform spreading centre (ITR) with parallel fracture zone valleys extending continuously towards the continental margins. In October 2020 expedition S50 of the R/V A.N. Strakhov surveyed an area of 54552 km<sup>2</sup> covering the entire Charlie Gibbs transform system and the adjacent MAR spreading segments. We collected new bathymetric, magnetic and high-resolution single channel seismic data, along with basaltic, gabbroic and mantle rocks from 21 dredges. In this contribution we present preliminary data from cruise S50 and discusses the large-scale architecture of this unique, long-lived transform system.</p>

Marie Tharp: Seafloor mapping and ocean plate tectonics

2020 ◽  
Author(s):  
Mathilde Cannat ◽  
Deborah Smith ◽  
Daniel Fornari ◽  
Vicki Ferrini ◽  
Javier Escartin
Keyword(s):  
Plate Tectonics ◽  
Essential Element ◽  
Central Valley ◽  
Fracture Zones ◽  
Transform Faults ◽  
Seafloor Mapping ◽  
Mid Ocean Ridge ◽  
The 1960S ◽  
Ocean Ridge ◽  
Central Atlantic

<p><span>The pioneering seafloor mapping by Marie Tharp played a key role in the acceptance of the plate tectonic theory. Her physiographic maps,  published with Bruce Heezen,  covered the Earth’s oceans and revealed with astonishing accuracy the submarine landscape. She exposed the full extent of the global mid-ocean ridge system, documented features such as seamounts and volcanic chains, trenches, and transform faults. Marie Tharp co-authored the first papers describing the major fracture zones in the Central Atlantic (Chain, Romanche, Vema). In 1952, she also discovered that the Atlantic ridge has a central valley (the axial valley), and convinced her colleague Bruce Heezen that it, which corresponds to sustained seismicity (highlighted by other researchers at the same time thanks to the worldwide networking of seismological stations), is a rift that separates the eastern and western provinces of the Atlantic Ocean. Tharp and Heezen were not yet talking about plate tectonics at this time. But when, at the beginning of the 1960s, the first magnetic anomaly maps showed that the oceans were "young", and that the age of the seabed increased with the distance from the ridges, their physiographic map became an essential element in understanding the role that these ridges play, as well as the distribution of the main current terrestrial plates. In this poster, we present original maps and sketches that document this key contribution to the understanding of the Earth's tectonics.</span></p>

PETROGENESIS OF GABBRO FROM ARCTIC GAKKEL MID-OCEAN RIDGE

2019 ◽  
Author(s):  
Yung Ping Lee ◽  
◽  
Jonathan E. Snow ◽  
Yongjun Gao
Keyword(s):  
Mid Ocean Ridge ◽  
Ocean Ridge
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