GMPV5.3 | Fluid Flow in the upper crust: geysers, hydrothermal vents, mud volcanoes and cold seeps and their role for life.

Fluid flow in the Earth’s crust is driven by pressure gradients and temperature changes induced by internal heat. The expression of crustal fluid flow is associated with a range of structural and geochemical processes taking place in the basement and in sedimentary basins. Groundwater, hydrothermal brines and gases circulating in the subsurface interact with local structures across different tectonic and geological settings. Under near-lithostatic conditions fluids and rocks are expelled vertically to the near-surface featuring a variety of surficial geological phenomena ranging from hydrothermal systems to sedimentary and hybrid volcanism and cold seeps both onshore and offshore. These vertical fluid flow expressions and piercement structures are characterized by complex sedimentary deformation and geochemical reactions where life can adapt to thrive in extremely harsh environments making them ideal windows to the deep biosphere. Several studies have shown that CO2- and CH4-dominated (or hybrid) vents played a key role in the evolution of our planet and the cycles of life during several geological eras. Similar structures on other planets are promising sites for exploration where habitable niches could have been present. Furthermore, the elevated pore pressures often encountered in reservoirs at depth make piercements ideal natural laboratories to capture precursors of seismic events and dynamically triggered geological processes. Yet, the geochemical and geophysical processes associated with the evolution of these vertical fluid flow features and piercements remain poorly understood.
This session welcomes contributions from the community working on magmatic and sedimentary environments and the domains where they interact on Earth and in the Universe using geophysical, geochemical, microbial, geological, remote sensing, numerical and laboratory studies to promote a better understanding of modern and paleo fluid-driven systems in the upper crust. In particular we call for contributions from: 1) investigations of tectonic discontinuities pre-existing geological structures; 2) the geochemical reactions occurring at depth and at the surface including microbiological studies; 3) geophysical imaging and monitoring of fluid flow systems associated with vertical fluid expulsion at the upper crust; 4) experimental and numerical studies about fluid flow evolution; 5) studies of piercement dynamics related to climatic and environmental implications.

Co-organized by BG7/SSP1
Convener: Adriano Mazzini | Co-conveners: Matteo Lupi, Andreia Plaza-FaverolaECSECS
Orals
| Tue, 25 Apr, 14:00–15:35 (CEST)
 
Room -2.33
Posters on site
| Attendance Tue, 25 Apr, 10:45–12:30 (CEST)
 
Hall X2
Posters virtual
| Attendance Tue, 25 Apr, 10:45–12:30 (CEST)
 
vHall GMPV/G/GD/SM
Orals |
Tue, 14:00
Tue, 10:45
Tue, 10:45

Orals: Tue, 25 Apr | Room -2.33

14:00–14:05
14:05–14:25
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EGU23-12778
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GMPV5.3
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solicited
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On-site presentation
Sverre Planke, Ben Manton, Christian Berndt, Stefan Bünz, Cornelia M Binde, Henrik H Svensen, and Reidun Myklebust

Intrusion of magma into sedimentary basins leads to devolatilization of the host rock in contact metamorphic aureoles. Hydrothermal vent complexes are formed by fracturing the overburden sediments if sufficient overpressure is developed in the aureoles, releasing hot fluids and gases into the hydrosphere and atmosphere. We have mapped the structure and distribution of hydrothermal vent complexes using extensive 3D seismic reflection surveys (c. 40,000 km2) in the Møre and Vøring basins offshore mid-Norway by a combination of seismic horizon and attribute mapping. The seismic horizons have been tied to exploration wells to constrain the timing of their formation. A shallowly buried vent complex, the Modgunn Vent, was subsequently imaged by high-resolution P-Cable 3D seismic data collected using the R/V Helmer Hansen. The upper part of this vent complex was recently drilled by five holes during IODP Expedition 396. In total, more than a thousand hydrothermal vent complexes have been identified in the two basins. A typical vent complex has a diameter of between a few hundred meters and five kilometers and extends from the tip of a sill intrusion to the paleosurface. The upper part of the vent complexes are commonly eye-shaped, where the lower surface represents the base of a crater and the upper dome-shaped surface represents the top of the crater infill. Overlying reflections are sub-parallel to the upper vent surface, locally associated with discontinuous high-amplitude reflections and minor faulting. The chimney-shaped lower part of the vent complexes are characterized by disrupted reflections, sometimes including bulbous-shaped transparent bodies with high-amplitude reflections at the top and base. Surrounding reflections are often dipping towards the center of the chimneys. The structure of the vent complexes suggest they were dominantly formed by erupting fluids and sediments during the Paleocene-Eocene Thermal Maximum (PETM), about 56 million years ago. The craters were subsequently rapidly infilled by sediments, and later inverted forming domes above the craters. High-amplitude discontinuous reflections above some vent complexes are interpreted as evidence of long-term fluid flow, sometimes lasting until recent times.

How to cite: Planke, S., Manton, B., Berndt, C., Bünz, S., Binde, C. M., Svensen, H. H., and Myklebust, R.: The structure and origin of hydrothermal vent complexes in volcanic basins, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-12778, https://doi.org/10.5194/egusphere-egu23-12778, 2023.

14:25–14:35
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EGU23-8193
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GMPV5.3
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ECS
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On-site presentation
Nicolò Carfagna, Albachiara Brindisi, Enrico Paolucci, Antonello Piombo, and Dario Albarello

Mud volcanoes are diapirical structures expression of cold overpressured fluidized fine sediments rising from depths of hundreds of meters. When depositional process was fast enough to hamper dehydratation of buried sediments, isolated geological reservoirs are generated marked by elevated fluids pressure also due to gas produced by decompositional processes affecting trapped animals.  Due to the density difference with respect to surrounding rocks and because of the high fluid pressure, those sediments move upwards by following faults or other mechanical discontinuities. In the last decades such Sedimentary Diapirism has increasingly interested scientific community as possible markers of hydrocarbon reservoirs, as responsible for explosive events and their close connection with regional seismotectonic activity. Many studies, in the last years, tried also to find a solid relationship between mud volcanoes and gases emissions, in particular CO2 and CH4, two of the most important greenhouse gases.

Among the Italian mud volcanoes, those of Nirano (north Italy), represent a typical example of mud volcanic field, with small and uneventful surface structures. This natural reserve is marked by three main lined up surface structures along the NE-SW direction, close to small pools with less thick clay materials, called “salse”.

The structure beneath Nirano mud volcanic field has been investigated by several methodologies, such as geoelectrical, gravimetrical and seismic surveys. In the present work, the study of dynamic behaviour of these structures is focused on aiming at monitoring gas outflow and locating eventual ducts and secondary reservoirs at shallow depth. Specifically, seismic signals possibly associated to gas outflow are investigated by deploying seismic arrays and three directional velocimetric stations.

Outcomes of these measurements show that subsonic seismic emissions of these structures present analogies with to those of active volcanoes, possibly due to similar dynamic mechanisms, probably associated to gas bubbling phenomena. Three kinds of seismic activity have been identified: background ambient vibrations, short periodic energy bursts (drumbeats) and high energy paroxysmic phases. All these observed events, compared to that of active volcanoes, present higher frequencies range.

The analysis of these signals, in particular of the drumbeats phases, allow the location of the sources. The final locations appear to be local (limited to a few tens of meters away from instruments) and shallow (around 5-10 m from the surface). If these emissions were actually associated to gas bubbling, this kind of outcomes could represent an effective tool for measuring gas outflow and monitoring outgoing mud volcanoes activity.

How to cite: Carfagna, N., Brindisi, A., Paolucci, E., Piombo, A., and Albarello, D.: Seismic observation at Nirano mud volcanoes, north Italy, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-8193, https://doi.org/10.5194/egusphere-egu23-8193, 2023.

14:35–14:45
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EGU23-13707
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GMPV5.3
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ECS
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Virtual presentation
Massimo Nespoli, Marco Antonellini, Dario Albarello, Matteo Lupi, Nicola Cenni, Eleonora Rivalta, and Antonello Piombo

Mud volcanoes are distributed throughout the globe, both on- and offshore. Mud volcanism has been widely investigated from the geological, geophysical, and geochemical points of view. The study of mud volcanoes has important implications in energy resource exploration, geohazard identification, and greenhouse gas emissions assessment (mainly CH4 and CO2). Mud volcano eruptions are mainly driven by a gravitative instabilities and fluid overpressure, due to the overall low density of clay/water/gas mixtures with respect to surrounding units. The geohazard of mud volcanoes is to date underrated despite the violent eruptive examples occurred in the past. For instance, the eruption of the Piparo mud volcano (1997, island of Trinidad) damaged electrical and water infrastructures and killed animals and livestock. In 2014, the eruption of the Macalube di Aragona (Italy) mud volcano killed two children. The understanding of the mechanisms regulating mud volcanoes is, therefore, important also in terms of hazard evaluation. To date, a physical conceptual model of the Nirano Salse, Italy, ascribes the eruptions to the presence of over-pressurized fluids that are expelled from a main deep reservoir. The latter is put into communication with the surface due to the episodically reactivation of pre-existing faults or pipes. The debate about this conceptual model is still open. To improve our current understanding, a new high-resolution dataset of gravimetric data was acquired. Our goal is to provide an insight about the subsurface structure of the investigated domain. The gravimetric inversion aims to identify the structural setting of Nirano and the presence of gas traps and faults. The gravity inversion results indicate the existence of a low-density zone (1200-1500 m long, 100-200 m wide, 800 m deep) with an almost planar shape aligned along a NW-SE structural trend, typical of the Northern Apennines chain. This zone likely represents the intrusion of mud/gas in the damage zone of a sub-vertical fault, which feeds shallow fluid reservoirs.

How to cite: Nespoli, M., Antonellini, M., Albarello, D., Lupi, M., Cenni, N., Rivalta, E., and Piombo, A.: The ”Salse di Nirano” mud volcanoes: hints from gravity data, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-13707, https://doi.org/10.5194/egusphere-egu23-13707, 2023.

14:45–14:55
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EGU23-182
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GMPV5.3
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ECS
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On-site presentation
Satoko Owari, Marcelo Ketzer, Nagisa Suzuki, Elia d'Acremont, Sara Lafuerza, Sylvie Leroy, Daniel Praeg, and Alana Oliveira de Sa

Fluid migration in sedimentary basins has profound effects on a range of geological processes, including the methane cycle, tectonic and sedimentary geohazards, and microbial communities in the oceans. The Alboran Sea is a tectonically active basin characterized by contourite drifts that host migrating fluids, expressed in places by pockmarks and mud volcanoes, the latter associated with seafloor methane seepage. In this study, we examine the composition and origin of near-seafloor fluids in the Alboran Sea using sediment cores (up to 20 m long) from a pockmark field (site CL06), a nearby background area (site CL04) and a fault zone (site CL55).

We use halogens (Cl, Br, and I) dissolved in interstitial water to understand the origin of fluids in the Alboran Sea. Chlorine is considered a conservative ion in interstitial water geochemistry, its concentration changing with pore water salinity. Iodine has a strong biophilic character and is incorporated in organic matter deposited with sediments, which during burial decomposes in response to geothermal heat or microbial activity to produce methane. Iodine and methane concentrations are strongly correlated and highly concentrated compared to seawater, so that iodine has been used as a methane tracer. Bromide also has a weak biophilic character and behaves similarly to iodine.

Interstitial water was extracted aboard ship using Rhizon samplers. Chloride concentration was determined by ion chromatography (ICS-1600, DIONEX) at the Tokyo University of Marine Science and Technology; iodine and bromine concentrations were determined by Inductively coupled plasma mass spectrometry (ICP-MS Agilent 7500) at Micro Analysis Laboratory, Tandem accelerator (MALT), University of Tokyo.

The results reveal halogen profiles that differ between the pockmark and fault sites, providing evidence of different modes of fluid migration within the contourite drifts of the Alboran Sea:

(1)Pockmark and background sites: surprisingly, halogen profiles are similar at these two sites. Cl concentration decreases with depth from 610 to 590 mM over the 15 m length of the cores, a trend indicating fresher water is present in deeper sediments. I and Br concentrations increase with depth (I: 0 to 70 µM, Br: 760 to 820 µM). I and Br are strongly enriched (up to 8% and 60%, respectively) by a deep fluid source, which may relate to high TOC or evaporated seawater in deeper sediment.

(2)Fault zone site: in contrast to the other two sites, Cl concentration increases with depth from 600 to 610 mM over the 16 m length of the core 55, a trend indicating saline water is dominant in deeper sediments. I and Br concentrations increase with depth (I: 35 to 70 µM, Br: 800 to 830 µM). I and Br concentrations in near-seafloor sediments are usually less strongly affected by organic decomposition, with concentrations as low as seawater; however, at site 55, I and Br are strongly enriched in near-seafloor sediments. This observation suggests vertical fluid migration is active and reaches the seafloor to maintain high I and Br concentrations.

How to cite: Owari, S., Ketzer, M., Suzuki, N., d'Acremont, E., Lafuerza, S., Leroy, S., Praeg, D., and Oliveira de Sa, A.: Halogens dissolved in interstitial water reveal the origin of migrating fluids in sediments of the Alboran Sea (western Mediterranean), EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-182, https://doi.org/10.5194/egusphere-egu23-182, 2023.

14:55–15:05
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EGU23-9938
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GMPV5.3
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ECS
|
On-site presentation
Luke Kearney, Christopher MacMinn, Richard Katz, and Joe Cartwright

Mud volcanoes erupt sediment sourced from subsurface, consolidated mudstones via a conductive flow pathway (conduit). A 3-D seismic survey of mud volcanoes in the Eastern Mediterranean shows localised thinning of the source unit in zones at the base of each conduit, interpreted to result from mud depletion [1]. These depletion zones are typically bowl-shaped, suggesting that they grow radially outward from the base of the conduit. Fluidisation, whereby consolidated sediments can be mobilised by migrating pore fluids of a sufficient velocity, has previously been proposed as a mechanism to explain mud volcano formation [2,3]. However, the dynamics of fluidisation during eruptions are poorly understood due to limited subsurface observations. We hypothesise that the sudden opening of the conduit initiates rapid fluid expulsion, inducing porous flow through and fluidisation of the source rock. This is in contrast to previous modelling work, which attributes the flow of mud to plastic failure [4]. We present a novel theoretical model of flow-driven fluidisation, capturing the dynamic interface between the solid and fluidised regions. The solid region is modelled as a poroelastic material and the fluidised region is modelled as a viscous fluid. Our results indicate that fluidisation initiates at the conduit and spreads radially. We demonstrate that fluidisation amplifies the rate of fluid flow and vice versa, leading to nonlinear growth of the fluidised region. We explore the mechanisms that regulate this growth to produce a depletion zone with a characteristic size.

[1] Kirkham, Chris, et al. "The spatial, temporal and volumetric analysis of a large mud volcano province within the Eastern Mediterranean." Marine and Petroleum Geology, https://doi.org/10.1016/j.marpetgeo.2016.12.026

[2] Brown, Kevin M. "The nature and hydrogeologic significance of mud diapirs and diatremes for accretionary systems." Journal of Geophysical Research: Solid Earth, https://doi.org/10.1029/JB095iB06p08969

[3] Nermoen, Anders, et al. "Experimental and analytic modeling of piercement structures." Journal of Geophysical Research: Solid Earth, https://doi.org/10.1029/2010JB007583

[4] Mazzini, Adriano, et al. "Strike-slip faulting as a trigger mechanism for overpressure release through piercement structures. Implications for the Lusi mud volcano, Indonesia." Marine and Petroleum Geology, https://doi.org/10.1016/j.marpetgeo.2009.03.001

How to cite: Kearney, L., MacMinn, C., Katz, R., and Cartwright, J.: The dynamics of fluidisation during mud volcano eruptions, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9938, https://doi.org/10.5194/egusphere-egu23-9938, 2023.

15:05–15:15
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EGU23-3182
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GMPV5.3
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ECS
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On-site presentation
Ondřej Krýza, Petr Brož, Mark Fox-Powell, Věra Pěnkavová, Adriano Mazzini, Susan Conway, Ernst Hauber, Mattew Sylvest, and Manish Patel

The behavior and the rheology of mud during the emplacement of terrestrial sedimentary volcanism has been extensively investigated (e.g., [1,2]). In contrast, this is not the case for Mars and other planetary bodies within the Solar System for which sedimentary volcanism has been proposed [e.g., 3]. The propagation behavior of low viscosity mud in a low-pressure chamber, that partly simulated the environment of Mars, was firstly experimentally studied by [4,5]. Their work revealed that bentonite-based mud could flow in a completely different manner in such conditions. On Mars, mud flowing over cold surfaces would rapidly freeze due to evaporative cooling [6] forming an icy-crust leading to the behavior of some of the mud flows in a similar manner to pahoehoe lava on Earth [4]. However, we lack the knowledge how variations of salt types and their content would affect the flow style and finite pattern of such mudflows as a presence of various salts can be natural on Mars as well (e.g., [7,8]). Therefore increased content of salts can strongly affect the P-T-t dependent cooling and at the same time the rheology of mud which can lead to significantly different propagation potential and finite geometry. 

In a set of experiments, performed in the Mars Simulation Chamber (Open University, UK), we tested several selected salts relevant for the Mars environment (namely NaCl, MgSO4, Na2SO4 and CaSO4) and various salinities of these salts (0.5-15 wt%). These experiments were performed in metallic trays infilled with dry and precooled sand to -25 °C (to simulate the martian surface) and which were inclined to 5°. A container filled with 500 ml mud was positioned above the tray. Then we decreased the pressure to 4.5-6 mbar and released mud. Experiments were documented by a system of video cameras situated around the model box. At the same time, referential cooling experiments of binary solutions (water-salt) were performed. 

Results revealed contrasting scenarios of mud propagation which result in a wide range of shapes. We also found several transitional regimes in behavior between current concentrations and various salts. It was confirmed that the high content of salt in a mud or mud composed by different salts can undergo slightly to significantly different cooling according to thermodynamic equilibria which shifts both freezing and boiling point. Thus, the resultant style of flow process and finite morphology of such mudflows can be highly variable. For example, high content of MgSO4 (typically 5-10 wt%) leads to development of long and narrow streams and with increasing content also develops a “ropy pattern” structure, whereas the same behavior occurs for 2.5 wt% of the NaCl.  

References: [1] O’Brien and Julien (1988), Journal of Hydraulic Engineering 114 [2] Laigle and Coussot (1997), J. Hydraul. Eng., 123 [3] Ruesch et al. (2019) Nature Geoscience 12 [4] Brož et al. (2020), Nature Geoscience [5] Brož et al. (2020), EPSL 545 [6] Bargery et al. (2010), Icarus 210(1), Chevrier et al. (2020), The planetary science journal, 1(3) [8] Nuding, et al. (2014), Icarus, 243.

How to cite: Krýza, O., Brož, P., Fox-Powell, M., Pěnkavová, V., Mazzini, A., Conway, S., Hauber, E., Sylvest, M., and Patel, M.: The presence of salts changes the architecture of potential mudflows on Mars - insights from laboratory simulations, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-3182, https://doi.org/10.5194/egusphere-egu23-3182, 2023.

15:15–15:25
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EGU23-1791
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GMPV5.3
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On-site presentation
Gary Wilson, Livio Ruggiero, Alessandra Sciarra, Adriano Mazzini, Fabio Florindo, Maria Tartarello, Claudio Mazzoli, Jacob Anderson, Valentina Romano, and Giancarlo Ciotoli

Contemporary studies conducted in northern polar regions reveal that permafrost stability plays an important role in the modern carbon cycle as it potentially stores considerable quantities of greenhouse gases. Rapid and recent warming of the Arctic permafrost is resulting in significant greenhouse gas emission, both from physical and microbiological processes. The potential impact of greenhouse gas release from Antarctica is now also being investigated. In Antarctica, the McMurdo Dry Valleys comprise 10% of the ice-free soil surface areas in Antarctica and like the northern polar regions are also warming albeit from lower mean temperatures.

The work presented herein examines a comprehensive sample suite of soil gases (e.g., CO2, CH4 and He) concentrations and CO2 flux measurements conducted in the Taylor Valley during the Austral summer 2019/2020. Analytical results reveal the presence of significant concentrations of CH4, CO2 and He (up to 18,447 ppmv, 34,400 ppmv and 6.49 ppmv, respectively) at the base of the active layer. When compared with the few previously obtained measurements, we observe increasing CO2 flux rates (estimated CO2 emission in the study area of 21.6 km2 ≈ 15 tons day-1). The distribution of the gas anomaly, when compared with geophysical investigations, implies an origin from deep brines migrating from inland (potentially from beneath the Antarctic Ice Sheet) towards the coast beneath the permafrost layer. These newly obtained data provide a baseline for future investigations aimed at monitoring the changing rate of greenhouse gas emission from Antarctic permafrost, and the potential origin of gases, as the southern polar region warms.

How to cite: Wilson, G., Ruggiero, L., Sciarra, A., Mazzini, A., Florindo, F., Tartarello, M., Mazzoli, C., Anderson, J., Romano, V., and Ciotoli, G.: Permafrost degassing in Taylor Valley, Antarctica, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-1791, https://doi.org/10.5194/egusphere-egu23-1791, 2023.

15:25–15:35
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EGU23-3908
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GMPV5.3
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ECS
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On-site presentation
Filippo Zummo, Dario Buttitta, Antonio Caracausi, and Michele Paternoster

The southern Apennines are affected by great crustal deformation and tectonic activity, where fluids from different reservoirs mix and rise to the surface through fault structures. Tramutola well (TRW) is an old borehole built by ENI, with the occurrence of bubbling gases located in the High Agri Valley (HAV), Southern Italy. The HAV is an inter-montane basin of the southern Apennine chain characterized by complex geological setting and high seismicity, this area hosts also the largest onshore Western European oil field. TRW is about 400 m deep it crosses clays, silicic clays and silicic limestone and is characterized by the continuous emission of thermal water (28°C) and bubbling gas. The water belong to Na-HCO3 hydrofacies.  TRW gases are CH4-dominated (82,6 %), and low amounts of N2 (12,9%), CO2 (1,7%), C2H6 (0,3%). The noble gases are used to discriminate the fluids origin (atmospheric, crustal and mantle). The 4He/20Ne ratio values are in three orders of magnitude higher that air-one (0,318) and 40Ar/36Ar ratio it is about 320 (Air=295.5; Hilton and Porcelli, 2003), this confirm the atmospheric contribution is present. Value Helium isotope (3He/4He, expressed as R/Ra) is between 1,13 and 1,26 Ra, and indicate a radiogenic component with a contribution of a mantle-derived helium (~20%). Methane isotope composition indicates a likely microbial isotopic signature (δ13C-CH4 =-63‰, δD-CH4= −217‰), probably due to either (1) biodegradation processes of thermogenic hydrocarbons or (2) ongoing microbial methanogenesis in the shallow organic‐rich clays hosting the gas. The δ13C-CO2 value between of -3.5‰ and -6‰ VPDB, consistent with a mantle origin. The gases have low CO2/3He ratios compared to mantle carbon end-member, probably due to secondary processes such as calcite precipitation. In conclusion, at Tramutola well have three gas sources and their possible mixing processes: (1) Shallow source, highlighted by atmospheric gas and rainwater entering the system through water infliltration; (2) crustal sources, CH4-dominant gas sources in correspondence of the hydrocarbon reservoir; (3) SCLM mantle source, mantle-derived fluids uprising through lithospheric normal faults.

How to cite: Zummo, F., Buttitta, D., Caracausi, A., and Paternoster, M.: Geochemical and isotopic study of Tramutola thermal water (High Agri Valley, Southern Italy): Interaction between crustal and mantle fluids, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-3908, https://doi.org/10.5194/egusphere-egu23-3908, 2023.

Posters on site: Tue, 25 Apr, 10:45–12:30 | Hall X2

X2.152
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EGU23-9633
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GMPV5.3
Adriano Mazzini, Clara Jodry, Petr Broz, Grigorii Akhmanov, Jan Blahůt, Matteo Lupi, Nigar Karimova, Damian Braize, Adriano Nobile, Ayten Khasayeva-Huseynova, and Ibrahim Guliyev

Mud volcanism is a natural phenomenon manifesting at the surface of the body with spectacular eruptions and a large variety of morphologies resulting both from explosive and effusive activity. In this study, we targeted two large (MVs) in Azerbaijan (Lokbatan and Goturdagh) characterized by different behaviors in eruptive activity. We investigated them using a multidisciplinary approach including field observation combined with drone photogrammetry, InSAR imaging, subsurface multisource survey, geotechnical analyses of mud breccia flows and numerical stability modeling in order to reveal the way the mud flows.

Lokbatan most recently erupted in August 2022. Field observations in September 2022, before significant modification by rain, reveal that this most recent eruption, albeit small in terms of extruded mud breccia, triggered the disruption of huge segmented portions of the older mud flows that extend for more than 1 km. This was identified by the formation of series of fractures recording the detachment and subsequent downhill movement of the old flow. No evident ground deformations have been observed before the eruption and, repetitive field campaigns in subsequent months do not reveal any network of fresh fractures and dislocations. On the other hand, Goturdagh MV features a constant slow extrusion of compacted mud breccia from the subsurface forming an extended >1.2 km long mud flow that continuously moves. This movement is clearly visible at the top of the MV where repetitive field observations reveal an extrusion of wet and dark colored mud breccia. Along the slope, the movement creates well-developed shear zones and compressional structures typical of slope deformations. At the bottom however, the movement seem to be discontinuous and might be triggered occasionally when the force of the new material becomes critical.

The field observations show that kilometer scale mass transport can extend at MVs for more than 1 km along the flank of these structures. The additional approaches will help us identify possible eruptive precursors and understand if external elements (tectonics, rainfall, …) can influence this mass movement. The same phenomenon is likely happening at many other large-scale features worldwide.

How to cite: Mazzini, A., Jodry, C., Broz, P., Akhmanov, G., Blahůt, J., Lupi, M., Karimova, N., Braize, D., Nobile, A., Khasayeva-Huseynova, A., and Guliyev, I.: Mud volcanism and creeping mud flows, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9633, https://doi.org/10.5194/egusphere-egu23-9633, 2023.

X2.153
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EGU23-2520
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GMPV5.3
Masatoshi Miyazawa, Adriano Mazzini, and Matteo Lupi

The Lusi eruption started on Java Island on the 29th of May 2006, almost two days after a M6.5 earthquake struck Yogyakarta. More than 16 years later, Lusi is still erupting clasts, mud, oil, and surges of thermogenic methane and mantle-derived CO2. Lusi features a geysering behaviour, and its flow rate currently averages 50.000 m3/day with peaking up to 180.000 m3/day during the early phases of the eruption. Previous investigations revealed that at 4.5 km depth, Lusi is connected with the neighbouring volcanic complex that is fueling the eruption site. Observations also show that since 2006, Lusi’s behaviour has been periodically perturbed by seismic events and possibly by neighbouring volcanic eruptions. However, it remains unclear if/how other factors may influence Lusi’s eruptive behaviour. We use a statistical approach comparing flow rate records against a multiparametric database accounting for peak ground velocities and accelerations, tidal phases, Pressure and Temperature atmospheric variations, Geodetic monitoring (subsidence and inflation of the edifice), and faulting. A preliminary investigation of the relationship between daily flow rate and peak ground motion imposed by regional and teleseismic earthquakes shows that large amplitude seismic waves are often associated with increasing the flow rate at Lusi. Results can be fit by a power law. Geodetic monitoring shows a sudden increase in subsidence following major ground accelerations imposed by nearby seismic events and eruptions of neighbouring volcanic systems. Similarly, these events are also consistent with fresh extended fractures around Lusi and/or major breaching and deformations of the tall embankment walls surrounding the eruption site. When considering daily variations and using a higher resolution catalogue accounting for the fluid temperature of Lusi, we find that external factors such as local P/T and tidal events can alter the local temperature of the fluids emitted at the Lusi site.

Our results reveal that multiparameter monitoring represents a valuable approach to understanding the dynamics controlling the activity and the evolution of active eruption sites. Results could be useful in identifying potential precursors.

How to cite: Miyazawa, M., Mazzini, A., and Lupi, M.: On endogenous and exogenous factors controlling the behaviour of the Lusi eruption (Java, Indonesia), EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-2520, https://doi.org/10.5194/egusphere-egu23-2520, 2023.

X2.154
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EGU23-9935
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GMPV5.3
Matteo Lupi, Marine Collignon, Federico Fischanger, Aurore Carrier, Daniele Trippanera, and Laura Pioli

Despite being among the most fascinating geological processes on Earth, little is still known about the charging and discharging processes taking place at geysers. We conducted a 3D geoelectrical campaign in the Haukadalur hydrothemal field, Iceland, to investigate the spatial relationships between geysers and the aquifers feeding them. We deployed 24 IRIS Fullwavers to measure the 3D resistive structure of this geyser-hosting hydrothermal field. In addition to DC resistivity measurements and induced polarization methods, we also recorded temperature variations inside Strokkur and Great Geysir geysers. We lowered multiple thermometers at different depths highlighting temperature fluctuations that point out a marked oscillatory behaviour at depth.

The electrical study is complemented with a semi-quantitative temperature distribution of the thermal springs across the hydrothermal field that has been acquired through several unmmanned aerial vehicle surveys. This combined approach highlights the strong control that extensional tectonics has on the distribution of fluids across the hydrothermal field. The inverted geoelectrical data suggest the possible occurrence of a common deep groundwater reservoir from which fluids feeding Strokkur and Great Geysir upwell. Induced polarization data are particularly effective in showing water-filled pipes, that we interpret as sub-vertical fracture zones. The geysers are located at the borders of highly resistive regions that we interpret as being vapour-saturated domains. The study shows to the best of our knowledge the first full 3D electrical structure of a geyser-hosting hydrothermal field and helps us understanding the intreplay between boiling fluids and eruption dynamics at geysers.

How to cite: Lupi, M., Collignon, M., Fischanger, F., Carrier, A., Trippanera, D., and Pioli, L.: 3D Deep electrical resistivity structure of a geyser-hosting hydrothermal field, Haukadalur, Iceland., EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9935, https://doi.org/10.5194/egusphere-egu23-9935, 2023.

X2.155
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EGU23-4847
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GMPV5.3
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Muriel Gerbault, Felipe Saez, Javiera Ruz Ginouvez, Pablo Iturrieta, Daniel Hurtado, and José Cembrano

Geothermal systems are recognized as key energy resources as well as locations where hydrothermally enhanced chemical reactions can favour mineralizations of economic interest. While fluid-fault interactions in the upper crust have received a wealth of investigations using observational, experimental and modelling approaches, the multi-parametric processes at play are still poorly constrained. While faults can alter fluid flow in their surroundings, potentially acting as barriers or conduits for fluids, magmatic and hydrothermal fluids can also modify pore pressure and alter faults resistance to slip motion. The Planchon-Peteroa geothermal system of the South Andean Volcanic Zone (Chile), illustrates at tectonic crustal scale, how strike-slip faults appear closely involved in the localization of hydrothermal fluid flow. Here, we carry a preliminary modelling approach to be considered as a proof of concept, to show how within such a tectonic setting, a strike slip fault influences fluid flow out from a geothermal reservoir. We developed an original poro-elasto-plastic Finite Element Method (FEM) based on the FEniCS library, and in which the poro-elastic and the elasto-plastic constitutive equations are implicitly coupled. Once this implementation is benchmarked, we assess the development of fluid flow due to a slipping vertical strike-slip left-lateral fault set at 5 km depth. The development of dilational and contractional domains in the fault’ surroundings lead to mean stresses and volumetric strains that range between ±1 MPa and ±10−4, respectively. The appearance of negative and positive fluid pressure in these domains lead to a time-dependent focused fluid flow, which resembles the suction-pump mechanism proposed ca. 30 years ago. We investigate the spatial and temporal evolution of this fluid flow when varying fault permeability, shear modulus, fluid viscosity, and rock frictional strength. We report a maximum fluid flux reaching 8 to 70 times the initial stationary flux. Pressure-driven fluid diffusion returns to stationary state between weeks to months after fault slip. We also show how a plasticity criterion as simple as the von Mises criterion already enhances fluid flow, locally. This transient process highlights the importance of addressing such solid-fluid coupling in studies aiming at constraining volcanic eruption triggers as well as seismic fault destabilization, and the means and pros of geothermal system development.

How to cite: Gerbault, M., Saez, F., Ruz Ginouvez, J., Iturrieta, P., Hurtado, D., and Cembrano, J.: Coupled Poro-elasto-plastic models of transient fluid flow in response to a crustal strike-slip fault : insight from a geothermal setting in the South Andean volcanic zone, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-4847, https://doi.org/10.5194/egusphere-egu23-4847, 2023.

X2.156
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EGU23-12401
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GMPV5.3
Christopher Schmidt, Rebecca Zitoun, Mark A. Lever, Julie Schindlbeck-Belo, Arne Warwel, Sofia Ramalho, Norbert Kaul, Johanna Klein, Helena Adão, Wayne Dillon, Johanna Schenk, Christian Hübscher, Pedro Terrinha, and Christian Hensen

Young oceanic plateaus are important for fluid exchange between the lithosphere and the ocean. Increased heat fluxes can lead to a large-scale upwelling of fluids that play a role in global elemental cycles. In addition, variations in fluid chemistries can potentially influence the biomass and species compositions of microbial and benthic communities in sediments exposed to subsurface fluid flow. Yet, the present understanding of these young oceanic plateaus in terms of their fluid dynamics and their biogeochemical local and global impacts is limited. The goal of RV Meteor Expedition M186 in December 2022 was to investigate how subsurface fluids on the young Azores Plateau, Central North Atlantic, vary with respect to their flow rates, chemical compositions, and the prevalent on microbial and benthic communities at and below the seafloor. First data from the São Jorge Channel (Azores Plateau) show that fluid dynamics here are diffuse rather than focused, and that fluid chemical compositions nonetheless show strong local variations, over a small spatial scale of 65 km2, that could be related to differences in fluid origins and fluid flow paths. However, the connection of fluid conduits, heat flow data and biogeochemical data as well as their relation to faults visible in seismic data are rather complex. Our first results thus indicate that diffuse fluid flow on young oceanic plateaus is highly heterogeneous despite occurring over large sediment-covered areas. Thus, the role of fluids at young oceanic plateaus as an important intermediate between the lithosphere and the ocean cannot be generalized over large spatial and possibly temporal scales.

How to cite: Schmidt, C., Zitoun, R., Lever, M. A., Schindlbeck-Belo, J., Warwel, A., Ramalho, S., Kaul, N., Klein, J., Adão, H., Dillon, W., Schenk, J., Hübscher, C., Terrinha, P., and Hensen, C.: Fluid Dynamics of the São Jorge Channel, Azores Plateau – First results of RV Meteor expedition M186, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-12401, https://doi.org/10.5194/egusphere-egu23-12401, 2023.

X2.157
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EGU23-12831
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GMPV5.3
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ECS
Daniele Spatola, Daniele Casalbore, Martina Pierdomenico, Simone Napoli, and Francesco Latino Chiocci

Mud and fluids migration producing active seepage at the seafloor is a global phenomenon documented in different geodynamic contexts. Scoglio d’Affrica islet is one of the culminations of the Elba-Pianosa Ridge (northern Tyrrhenian Sea), where submarine methane emissions have been studied since the 1960’s, sometimes evolving in violent gas outbursts such as those occurred in 2017. In the study area, the seafloor is punctuated by more than 250 small pockmarks with mean diameter of 10 m and occurring mainly between 20 and 60 m water depth. Pockmarks are characterized by planform shapes from sub-circular to elongated and U/V-shaped cross-sections. They are predominantly arranged as isolated or in clusters or minorly organised in strings-oriented about N-S, running almost parallel to the fault escarpments which represent one of the main structural features of the study area. Pockmarks have been classified on the basis of their size parameters (i.e., depth, mean diameter) according to the recent literature and they resulted to belong mainly to the morphological classes of the "unit pockmark" and minorly to the “normal pockmark”. The complex seafloor morphology of the area is also characterised by several positive features, showing very different shapes and sizes (up to 35 m high and 600 m wide). In this work, we select 67 positive features (named as M1-67) more than 2 meters high and perform on them the first morphometric analysis by means of high-resolution bathymetric data. The obtained morphometric parameters (e.g., flatness value, mean slope), which allow us to classify the positive features as mounded, flat topped and conical features, are compared with those of other submarine mud volcanoes from literature, showing often high similarity. In view of that, we suggest that M1-67 have an origin likely linked to the migration of fluidised mud or mud breccia (a mud matrix with clasts), probably from shallow mud sources, rising through the thick Eocene-Early Miocene siliciclastic succession and overlying sedimentary layers. We interpret as mud volcanoes the larger sub-circular positive features (M1-7) since they are characterised by the occurrence of lobate flows along their flanks, widespread mud-breccia and focused emissions of CH4 observed on ROV videos. Whilst, with the available data, to avoid any speculation, we propose for M8-67 an alternative and more generic explanation interpreting them as “piercement structures” formed due to the seafloor deformation associated with a rising mud diapirism. Considering the high-magnitude outburst occurred in 2017 and the shallow water setting with evidence of active fluid seepage (as vertical focused gas bubbles) documented by ROV videos, the morphometric analysis of mud and fluids migration morphologies is an important baseline study since it can provide insight for a marine geohazard assessment around Scoglio d’Affrica islet.

How to cite: Spatola, D., Casalbore, D., Pierdomenico, M., Napoli, S., and Chiocci, F. L.: Morphometric analysis of seafloor morphology revealing recent mud and fluid migration around Scoglio d’Affrica islet (Tuscan Archipelago, northern Tyrrhenian Sea), EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-12831, https://doi.org/10.5194/egusphere-egu23-12831, 2023.

X2.158
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EGU23-14662
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GMPV5.3
Kei Ogata, Annelotte Weert, Peter Betlem, Thomas Birchall, and Kim Senger

Meso-scale (sub-seismic) sedimentary injectites are inferred to play an important role in controlling subsurface fluid flow as documented in many hydrocarbon plays at various scales. Detailed characterisation of such units, usually unresolvable at the seismic scale, can be directly achieved at outcrop scale. In this framework, two sedimentary injection complexes have been analysed in the middle Jurassic-lower Cretaceous Agardhfjellet Formation exposed at Deltaneset (central Spitsbergen) at different stratigraphic levels. The upper complex comprises two main isolated, decimetres-thick clastic dykes characterized by different orientation and consolidation, tapering out vertically (up- and downward) within a stratigraphic thickness and a lateral extension of more than 50 m and 200 m, respectively. The lower complex is coarser-grained, made up by a network of interconnected dykes and sills, branching off from isolated lenticular bodies, interpreted to be linked to seafloor extrusion structures (sand volcano). Petrographic and micromorphologic analysis were used to identify the possible source of the remobilized material for both the upper and lower complexes within the over- and under-burden formations. Our results reveal that such granular material is likely sourced by the underlying coarse-grained lithologies of the late Triassic to middle Jurassic Wilhelmøya Subgroup. The lower complex was firstly emplaced during the Late Jurassic at shallow burial conditions, while the upper complex developed at higher confinement pressure, probably during the Late Cretaceous, with the progressive reworking of the same granular material. Field data allow detailed characterisation of complex structural-stratigraphic architectures of sedimentary intrusions, which can be used to constrain their spatial-temporal relationships with subsurface fluid flow.

How to cite: Ogata, K., Weert, A., Betlem, P., Birchall, T., and Senger, K.: Investigating sub-seismic sedimentary intrusions in the Middle Jurassic to Lower Cretaceous Agardhfjellet Formation (Svalbard), EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-14662, https://doi.org/10.5194/egusphere-egu23-14662, 2023.

X2.159
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EGU23-14777
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GMPV5.3
Ljegay Rupeljengan, Tzung-Ting Chen, Yu-Xuan Lin, and I-Ting Su

The rapid sedimentation of the seafloor in southwestern Taiwan in early period created the sediments which are not fully compacted and cemented. With the developing geological process, a well-developed mud diapir was formed. Linear structures such as faults or fissures were exposed on the earth’s surface to form mud volcanoes of different scales. Our study area is located at the Gunshuiping mud volcano in Yanchao District and Qiaotou District, Kaohsiung City. It is adjacent to the Qishan Fault and spans the Chegualin Fault, which is the extension of the Longchuan Fault. According to the geological map published by Central Geological Survey, MOEA, the stratum from top to down in this area can be divided into recent alluvial formation, terrace deposits formation, Qiding formation, Gutingkeng formation, etc. The mud eruption of the Gunshuiping mud volcano was chemically analyzed and the result showed that it is the product of the Gutingkeng formation. This project will use the Electrical Resistivity Tomography (ERT) to construct a complete subsurface stratum distribution map and the structure of the mud volcano, and combine the micro-tremor site exploration technology to analyze the underground structure of mud volcano. The ERT method can observe the mud reservoir content and mud channel structure under the surface and analyze the trend of mud flow, while the micro-tremor site exploration technology can observe the underground velocity structure caused by mud volcanic activity, and explore its mud accumulation thickness, fissure distribution and potential Eruption range. Therefore, the two methods can be seen as complementary and mutually corroborate each other's information. In the future, this method can be used to make plan and take precaution in advance for the activity level and the influence area of Gunshuiping mud volcanoes or other geologically sensitive area.

How to cite: Rupeljengan, L., Chen, T.-T., Lin, Y.-X., and Su, I.-T.: Integrating the electrical resistivity tomography and the microtremor exploration technology to explore the spatial distribution of the mud reservoir and the channel of the Gunshuiping mud volcano, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-14777, https://doi.org/10.5194/egusphere-egu23-14777, 2023.

Posters virtual: Tue, 25 Apr, 10:45–12:30 | vHall GMPV/G/GD/SM

vGGGS.11
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EGU23-1709
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GMPV5.3
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ECS
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Luxia Wang, Qinghai Guo, Geng Wu, Zhicheng Yu, José Miguel Léon Ninin, and Britta Planer-Friedrich

Hot springs represent a major source of arsenic release into the environment. Speciation is typically reported to be dominated by arsenite, arsenate, and inorganic thiolated arsenates. Much less is known about the relevance and formation of methylated thioarsenates, a group with species of high mobility and toxicity. In hot spring samples taken from the Tengchong volcanic region in China, methylated thioarsenates contributed up to 13% to total arsenic. Enrichment cultures were obtained from the corresponding sediment samples and incubated to assess their capability to convert arsenite into methylated thioarsenates over time and in the presence of different microbial inhibitors. In contrast to observations in other environmental systems (e.g., paddy soils), sulfate-reducing bacteria did not contribute to arsenic methylation. Methanosarcina, the sole genus of methanogens detected in the enrichment cultures, as well as Methanosarcina thermophila (DSM 1825), a pure strain within the genus, did methylate arsenic. We propose that methylated thioarsenates in a typical sulfide-rich hot spring environment like Tengchong form via a combination of biotic arsenic methylation driven by thermophilic methanogens and arsenic thiolation with either geogenic sulfide or sulfide produced by sulfate-reducing bacteria.

How to cite: Wang, L., Guo, Q., Wu, G., Yu, Z., Léon Ninin, J. M., and Planer-Friedrich, B.: Methanogens-driven arsenic methylation as a precursory process for formation of methylated thioarsenates in sulfide-rich hot springs, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-1709, https://doi.org/10.5194/egusphere-egu23-1709, 2023.

vGGGS.12
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EGU23-996
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GMPV5.3
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ECS
Xianhui Yang, Chunhui Tao, Shili Liao, Fernando Barriga, Xianming Deng, Jin Liang, Zhikui Guo, Mingxu Wang, and Weifang Yang

Hydrothermal activity in the mid-ocean ridge facilitates the chemical exchange of seawater with new oceanic crusts. This activity mostly occurs on the detachment fault of the asymmetric accretion segment in the slow-ultraslow spreading ridge, which is characterised by limited magma supply. Deep faults can readily extract heat from deeper heat sources. Moreover, the repeated movement of faults activates the permeable fluid channels of the overlying oceanic crust, thus driving long-life hydrothermal circulation. Recent studies have found that the response time of the hydrothermal activity of the intermediate-fast spreading ridges differs from that of the slow-spreading ridge to the glacial cycle, and a unified model is expected to explain it. Also, the response of hydrothermal activity to the glacial cycle must consider the differences between oceanic ridges with different spreading rates and types of hydrothermal systems.

Here, based on two sediment cores collected near the Yuhuang hydrothermal field (HF)on ultraslow-spreading Southwest Indian ridge, we obtained high-resolution sediment history records spanning three glacial periods, understood the 160 ka history of hydrothermal, volcanic and tectonic activities in the region and attempted to reveal the response mechanism of hydrothermal activities controlled by detachment faults to the glacial cycle. We discovered that in the Yuhuang HF controlled by detachment faults, hydrothermal activity increased significantly during the glacial period, and more active detachment fault activity appeared at the same time. At the end of the glacial period, both activities are reduced at the same time. We believe that in the slow-ultraslow spreading ridge, the magmatism regulated by sea level changes may regulate the evolution of detachment faults and the hydrothermal circulation, which are recorded in the sediments near the hydrothermal field.

We established a response model of Sea level change–Magmatism–Detachment fault activity–Hydrothermal activity and concluded that the magmatism of slow-ultraslow spreading ridges is more sensitive to sea level changes; with the synchronous effect of detachment faults, the hydrothermal activity responds faster to the glacial cycle.

How to cite: Yang, X., Tao, C., Liao, S., Barriga, F., Deng, X., Liang, J., Guo, Z., Wang, M., and Yang, W.: Sensitivity of mid-ocean ridge hydrothermal system controlled by the detachment fault to the glacial cycle, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-996, https://doi.org/10.5194/egusphere-egu23-996, 2023.