Evidence of episodic long-lived eruptions in the Yuma, Ginsburg, Jesús Baraza and Tasyo mud volcanoes, Gulf of Cádiz

Abstract

High-resolution single channel and multichannel seismic reflection profiles and multibeam bathymetric and backscatter data collected during several cruises over the period 1999 to 2007 have enabled characterising not only the seabed morphology but also the subsurface structural elements of the Yuma, Ginsburg, Jesús Baraza and Tasyo mud volcanoes (MVs) in the Gulf of Cádiz at 1,050-1,250 m water depth. These MVs vary strongly in morphology and size. The data reveal elongated cone-shaped edifices, rimmed depressions, and scarps interpreted as flank failures developed by collapse, faulting, compaction and gravitational processes. MV architecture is characterised by both extrusive and intrusive complexes, comprising stacked edifices (including seabed cones and up to four buried bicones) underlain by chaotic vertical zones and downward-tapering cones suggesting feeder systems. These intrusive structures represent the upper layer of the feeder system linking the fluid mud sources with the constructional edifices. The overall architecture is interpreted to be the result of successive events of mud extrusion and outbuilding alternating with periods of dormancy. Each mud extrusion phase is connected with the development of an edifice, represented by a seabed cone or a buried bicone. In all four MVs, the stacked edifices and the intrusive complexes penetrate Late Miocene-Quaternary units and are rooted in the Gulf of Cádiz wedge emplaced during the late Tortonian. Major phases of mud extrusion and outbuilding took place since the Late Pliocene, even though in the Yuma and Jesús Baraza MVs mud volcanism started in the Late Miocene shortly after the emplacement of the Gulf of Cádiz wedge. This study shows that fluid venting in the eastern sector of the Gulf of Cádiz promoted the outbuilding of large long-lived mud volcanoes active since the Late Miocene, and which have been reactivated repeatedly until recent times.

The role of mud volcanism and deep‐seated dewatering processes in the Nankai Trough accretionary prism and Kumano Basin, Japan

“…Figures a and b specifically show how the seismic reflectors in MV#2 are bend toward the interior part of the edifice, typical of collapsing, inactive MVs [ Yusifov and Rabinowitz , ]. There is no hemipelagic cover on top of the cone, to be taken as a sign of a “relatively young age,” and an articulate “Christmas Tree” structure develops all around the feeder channel, which is arguably a sedimentary testimony of an episodic behavior [ Kopf , ; Toyos et al ., ]. The subbottom profile coupled with the flow rate and the geometry of the edifice give us the scientific grounds to confirm that points (I), (II) and (IV) we hypothesized in the previous paragraph are indeed well founded.…”

Rheology and Biostratigraphy of the Mariana Serpentine Muds Unravel Mud Volcano Evolution

“…Through analytical solutions and necessary simplifications, we were able to estimate a range of flow velocity and a possible depth for the sediments source. Finally, the calculations are emphasizing what was already hypothesized by several authors for other subduction zones (Deville & Guerlais, ; Kutterolf et al, ; Menapace et al, ; Toyos et al, ) but never proven before, through a real quantification: SMVs are formed by short episodes of high activity alternated by long periods of quiescence.…”

“…Generally, MVs structures are composed of a variable amount of edifices stacked in vertical piles and buried underneath drapes of seafloor sediments, with the most recent cone emerging from the seafloor (Deville et al, ; Toyos et al, ). In 2002, various multichannel seismic lines were acquired on different SMVs of the Mariana forearc, including Fantangisña, showing that the edifices were mostly growing on top of the forearc sediments instead (Asafuah & Calvert, ; Oakley et al, ).…”

Submarine Active Faults and Morpho-Tectonics Around the Iberian Margins: Seismic and Tsunamis Hazards

“…A main unconformity marking a pronounced basin at the southern edge of the Larache fault allows to determine the beginning of the fault activity. We correlate this discontinuity with the base of Quaternary Discontinuity (BQD, ∼2.6 My) reported by Toyos et al (2016) and associated with the development of the Ginsburg MV. An overlying major unconformity is interpreted as the Mid-Pleistocene Discontinuity (MPD, ∼0.9 My).…”