Interplay between magmatic accretion, spreading asymmetry and detachment faulting at a segment end: Crustal structure south of the Ascension Fracture Zone

Bialas, J.; Dannowski, Anke; Reston, T. J.

doi:10.1016/j.epsl.2015.09.027

Cited by 3 publications

(1 citation statement)

References 43 publications

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“…Given the right balance between magmatism and tectonic extension [20][21][22] , oceanic core complexes can form when long-lived low-angle normal faults, so-called detachment faults, accommodate large amounts of strain 20,23 , and exhume lower crustal and mantle rocks. This asymmetric accretion mode is now thought to play a key role in the accretion of Atlantic-type slow-spread crust [23][24][25] . Where tectonic processes dominate and faulting shapes the ridge segment structure, vent sites can be located far off-axis pointing to strong links between tectonic faulting and hydrothermal circulation [26][27][28] .…”

Section: Introductionmentioning

confidence: 99%

Detachment-parallel recharge explains high discharge fluxes at the TAG hydrothermal field

Rüpke

Guo

Petersen

et al. 2021

Preprint

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Submarine massive sulfide deposits on slow-spreading ridges are larger and longer-lived than deposits at fast-spreading ridges1,2, likely due to more pronounced tectonic faulting creating stable preferential fluid pathways3,4. The TAG hydrothermal mound at 26°N on the Mid-Atlantic Ridge (MAR) is a typical example located on the hanging wall of a detachment fault5-7. It has formed through distinct phases of high-temperature fluid discharge lasting 10s to 100s of years throughout at least the last 50,000 years8 and is one of the largest sulfide accumulations on the MAR. Yet, the mechanisms that control the episodic behavior, keep the fluid pathways intact, and sustain the observed high heat fluxes of up to 1800 MW9 remain poorly understood. Previous concepts involved long-distance channelized high-temperature fluid upflow along the detachment5,10 but that circulation mode is thermodynamically unfavorable11 and incompatible with TAG's high discharge fluxes. Here, based on the joint interpretation of hydrothermal flow observations and 3-D flow modeling, we show that the TAG system can be explained by episodic magmatic intrusions into the footwall of a highly permeable detachment surface. These intrusions drive episodes of hydrothermal activity with sub-vertical discharge and recharge along the detachment. This revised flow regime reconciles problematic aspects of previously inferred circulation patterns and can be used as guidance to one critical combination of parameters that can generate substantive mineral systems.

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Section: Introductionmentioning

confidence: 99%

Detachment-parallel recharge explains high discharge fluxes at the TAG hydrothermal field

Rüpke

Guo

Petersen

et al. 2021

Preprint

Self Cite

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Detachment-parallel recharge can explain high discharge fluxes at the TAG hydrothermal field

Guo

Rüpke

Petersen

et al. 2023

Earth and Planetary Science Letters

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Distinctive Seafloor Fabric Produced Near Western Versus Eastern Ridge‐Transform Intersections of the Northern Mid‐Atlantic Ridge: Possible Influence of Ridge Migration

Cormier

Sloan

2019

Geochem Geophys Geosyst

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Multibeam bathymetry compiled along fracture zones of the northern Atlantic reveals a striking morphological asymmetry. Seafloor fabric produced at western ridge‐transform intersections (RTIs) tends to consist of linear ridges, small in amplitude, and regularly spaced, and oceanic core complexes (OCCs) occur infrequently. In contrast, seafloor fabric produced at eastern RTIs is more irregular and blocky and displays characteristics usually associated with melt‐poor accretion: These include more than double the occurrence of OCCs as well as greater seafloor depths, even where seafloor is younger than that on the opposite side of the fracture zone. We propose that this asymmetry is a consequence of the westward migration of the Mid‐Atlantic Ridge. Such migration is expected to result in an enhanced melt supply at leading (western) RTIs compared to trailing (eastern) RTIs. The morphological asymmetry is observed for ridge offsets of ~40 to ~200 km, a range that may be related to the width of melting regimes that supply ridge segments. At slow spreading ridges, contrasting melt supplies across fracture zones may therefore be best expressed in the distinct seafloor fabrics preserved beyond the dynamically maintained relief of the axial rift valley and walls rather than in the contrasting axial depths documented for faster spreading ridges. Although OCCs appear to form preferentially at spreading rates lower than 30 mm/year, their common occurrence along the northern Mid‐Atlantic Ridge may also reflect the significantly higher rates at which it is migrating compared to the southern Mid‐Atlantic Ridge.

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Interplay between magmatic accretion, spreading asymmetry and detachment faulting at a segment end: Crustal structure south of the Ascension Fracture Zone

Cited by 3 publications

References 43 publications

Detachment-parallel recharge explains high discharge fluxes at the TAG hydrothermal field

Detachment-parallel recharge explains high discharge fluxes at the TAG hydrothermal field

Detachment-parallel recharge can explain high discharge fluxes at the TAG hydrothermal field

Distinctive Seafloor Fabric Produced Near Western Versus Eastern Ridge‐Transform Intersections of the Northern Mid‐Atlantic Ridge: Possible Influence of Ridge Migration

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