Mapping absolute migration of global mid-ocean ridges since 80 Ma to Present

Masalu, Desiderius C. P.

doi:10.1186/bf03352047

Cited by 9 publications

(9 citation statements)

References 37 publications

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“…That the three northern ridge segments appear to have migrated towards the northeast while the southern segment migrated towards the northwest between Chron 34 and 6 suggests clockwise rotation of the Pacific plate. This is consistent with Masalu (2007), which suggests that the clockwise rotation is superimposed on its north-westerly migration. Furthermore, the amount of northeast migration is progressively less southwards, which is also consistent with clockwise rotation of the Pacific plate.…”

Section: Resultssupporting

confidence: 87%

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Absolute migration of Pacific basin mid-ocean ridges since 85 Ma and tectonics in the circum-Pacific region

Masalu

2011

New Zealand Journal of Geology and Geophysics

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We have investigated the absolute migration of mid-ocean ridges in the Pacific basin since 85 Ma and their tectonic implications. Our results indicate that ridges in the northern and central Pacific basin and those in the southern Pacific basin underwent different tectonic histories. The northern and central Pacific basin ridges do not show any change in absolute migration direction at the time of the HawaiiÁEmperor chain bend, while the southern Pacific basin ridges changed their absolute migration direction at Chron 21 (the time of the bend). These results imply that tectonic events in southern Pacific basin may be more localised. The migration of the southern Pacific basin ridges may record the reorganisation of the southern Pacific triple junction or an episode of Cenozoic EastÁWest separation of Antarctica and the initiation of seafloor spreading in the Adare basin, or a combination of the two events. Furthermore, the clockwise rotation of the Pacific plate since Chron 34 ended at Chron 6, after which the Pacific plate has migrated in a north-westerly direction without rotating.

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Section: Resultssupporting

confidence: 87%

“…This implies that the whole northÁsouth ridge system in the eastern Pacific basin (including the Juan de Fuca, the EPR and the PacificÁAntarctic ridge) is now migrating in same direction, i.e. northwest, indicating that the clockwise rotation of the Pacific basin ridge system and the Pacific plate (Masalu 2007) ended at Chron 6.…”

Section: Discussionmentioning

confidence: 99%

Absolute migration of Pacific basin mid-ocean ridges since 85 Ma and tectonics in the circum-Pacific region

Masalu

2011

New Zealand Journal of Geology and Geophysics

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“…All these previous studies considered a steady‐state upper mantle flow. Although this assumption has been proved correct in intra‐oceanic settings, where the flow has been rather constant over the last 43 Ma [ Becker et al ., ], it might not be valid in proximity of, for example, migrating subduction zone trenches, or mid‐ocean ridges which are frequently observed on Earth [ Heuret and Lallemand , ; Masalu , ].…”

Section: Introductionmentioning

confidence: 99%

“…All these previous studies considered a steady-state upper mantle flow. Although this assumption has been proved correct in intra-oceanic settings, where the flow has been rather constant over the last 43 Ma [Becker et al, 2003], it might not be valid in proximity of, for example, migrating subduction zone trenches, or mid-ocean ridges which are frequently observed on Earth [Heuret and Lallemand, 2005;Masalu, 2007]. [7] In this paper, we quantify the seismic anisotropy due to crystal LPO in 3-D numerical subduction models and estimate synthetic SKS splitting with a methodology recently introduced by Faccenda and Capitanio [2012].…”

Section: Introductionmentioning

confidence: 99%

Seismic anisotropy around subduction zones: Insights from three‐dimensional modeling of upper mantle deformation and SKS splitting calculations

Faccenda

Capitanio

2013

Geochem Geophys Geosyst

123

119

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[1] Inferring the circulation of the mantle around subducting plates from surface measurements of shear wave splitting patterns remains to date elusive. To assist the interpretation of the seismic signal and its relation with the mantle circulation pattern, we present a new methodology to compute the seismic anisotropy directly from the flow in the upper mantle of 3-D numerical models of Earth-like subduction. This computational strategy accounts for the non-steady-state evolution of subduction zones yielding mantle fabrics that are more consistent with the deformation history than previously considered. In the subduction models, a strong mantle fabric develops throughout the upper mantle with a magnitude of the anisotropy that is proportional to the amount of subduction and is independent of the subduction rate. The sub-slab upper mantle is characterized by two domains with different fabrics: at shallow depth, the mantle entrained with the subducting slab develops trench-perpendicular directed anisotropy due to simple shear deformation, while in the deeper mantle, slab rollback induces pure shear deformation causing trench-parallel extension and fast seismic directions. Subducting plate advance favors the development of the fabric in the entrained mantle domain, while slab retreat increases the trench-parallel anisotropy in the deeper upper mantle. In the deeper domain, the strength of the fabric is proportional to the horizontal divergence of the flow and weakens from the slab edges toward the center. As such, strong trench-parallel anisotropy forms below retreating and relatively narrow slabs or at the margins of wider plates. The synthetic SKS splitting patterns calculated in the fore arc are controlled by the magnitude of the anisotropy in the upper domain, with trench-perpendicular fast azimuths in the center of large plates and trench parallel toward the plate edges. Instead, above relatively narrow, retreating slabs (≤600 km and low subduction partitioning ratio [SPR]), azimuths are trench parallel due to the strong anisotropy in the lower sub-slab domain. In all models, the anisotropy in the back arc and on the sides of the subducting plate is, respectively, trench perpendicular and sub-parallel to the return flow at depth. Results from our regional scale models may help to infer the flow and composition of the upper mantle by comparison with the wide range of subduction zones seismic data observed globally.

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“…This information would assist in the detail understanding and/or quantification of the various studies on mid-ocean ridges such as mid-ocean ridge basalt chemical systematics [e.g. 13,14], correlation with kinematic parameters [e.g., 15], mid-ocean ridge tectonics [e.g., [16][17][18] and other geophysical and geochemical studies.…”

Section: Introductionmentioning

confidence: 99%

Global Mid-Ocean Ridges Mantle Tomography Profiles

Masalu¹

2015

EARTH

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Abstract:We have studied mantle tomography profiles of global mid-ocean ridges to investigate their depth of origin and other characteristics. The Mid-Atlantic and the South West Indian Ridges are deep rooted ridges that extend as far down in the mantle to 250-300 km. The Central Indian Ridge, South East Indian Ridge, Antarctica Nazca, Pacific Antarctica, Pacific Nazca and Juan de Fuca are shallow rooted ridges that extend down in the mantle only to 100 km. The deep rooted ridges appear to be characterized by a weak low velocity ridge anomaly while the shallow rooted ridges are characterized by strong low velocity ridge anomaly. This may be due to the variations of the geochemistry of the ridges due to the fractionation process during magma ascent. Furthermore, despite the three ridges that make the Indian Rodriguez Triple Junction having different characteristics, all the three sections of the ridges that make the Triple Junction are characterized by strong low velocity ridge anomaly and extended down to only 100 km. This is particularly typical for the length of nine to ten degrees from the Triple Junction which makes it appear as an independent system.

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Mapping absolute migration of global mid-ocean ridges since 80 Ma to Present

Cited by 9 publications

References 37 publications

Absolute migration of Pacific basin mid-ocean ridges since 85 Ma and tectonics in the circum-Pacific region

Absolute migration of Pacific basin mid-ocean ridges since 85 Ma and tectonics in the circum-Pacific region

Seismic anisotropy around subduction zones: Insights from three‐dimensional modeling of upper mantle deformation and SKS splitting calculations

Global Mid-Ocean Ridges Mantle Tomography Profiles

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