Martin Hovland

Fluid Venting System · Research Group

The Global Salt Cycle (GSC) model is based on the Wilson Cycle concept and predicts that deep subduction of seawater-laden oceanic crust leads to dehydration, with the expulsion of saline fluids that migrate into the overlying mantle wedge. This may result in mantle upwelling and delamination in the lower crust, which eventually leads to crustal up...

The general subject of this article deals with the term salt. Salt deposits usually con-tain chlorides, sulphates/gypsum, borates, carbonates, etc., that are seemingly part of the same system. Even though this article mainly presents data and observations on chlorides, not easily explained by the present paradigm, it should also prove relevant for...

The Global Salt Cycle (GSC) model is based on the Wilson Cycle concept and predicts that deep subduction of seawater-laden oceanic crust leads to dehydration, with the expulsion of saline fluids that migrate into the overlying mantle wedge. This may result in mantle upwelling and delamination in the lower crust, which eventually leads to crustal up...

Several studies at Arctic cold-seep locations have demonstrated a close link between geochemical signatures of seepage processes and biomass production. Especially in the Arctic, due to low temperature and light conditions, these processes result in enhanced infaunal abundance, diversity, and biomass, compared to inactive control regions. We here d...

These guidelines are based on generally accepted Norwegian and international recommendations and criteria for avoiding damage to cold-water corals on the NCS and elsewhere on the European margin. Because all large corals on the NCS are protected (red-listed), no harm must be done to them during drilling, field development, or other activities durin...

The first humans probably arrived at Sola in SW Norway just after the brutally cold Younger Dryas (YD) period, as the first neolithic tools found there are from around 11,500 years BP. This period is also called the Preboreal period, where the temperature trends upwards for over a thousand years, before suddenly plummeting again at around 8,200 yea...

Part 2 reviews some of the pertinent knowledge about ancient climate variations, from ~ 70 Ma BP until the LGM (Last Glacial Maximum), 20 ky ago. There have been four distinct states over the last 50 Ma: Hothouse, Warmhouse, Coolhouse, and the current Icehouse climate state. Humanoids (mainly Neanderthals) lived in Europe from around 120 ky BP in c...

Towards the end of the Weichsel ice age came a period with warmer climate referred to as the Late Glacial Interstadial (c.14,670 to 12,900 years BP), when the great inland ice started to retreat. This retreat was interrupted by a new period of cold climate - The Younger Dryas (YD) (c. 12,900 to 11,700 years BP). This period represented the last par...

The main objective of this communication is to describe the magmatic 'Global Salt Cycle', 8 an important addition to solar evaporative processes in the formation of salt giants. The Global Salt 9 Cycle (GSC) provides an alternative explanation for the observed volumes and composition of salts, 10 at the location where they are observed. The first s...

An investigation by Bauer et al. (2019) deals with noble gas content of brine inclusions in bedded salts from the Permian Salado formation in New Mexico. This formation and the brine inclusions are in the order of 200 Ma years old, and the brine inclusions were found to be enriched in both argon and helium relative to atmospheric values. Helium was...

Appendix 2 to the Technical Rept: The GSC-model: Formation of giant salt accumulations, - a result of subduction, ascending mantle, and fluids

APPENDIX 4 Additional material to the article: The "Global Salt Cycle": Formation of giant salt accumulations,-a result of subduction, ascending mantle, and fluids. A4.1. Properties of LCB`s Belusov (1966) describes the different zones of the upper mantle and crust. He envisions the section around 20 km depth as being composed of amphibolite-and gr...

Appendix 3 to the Technical Rept: The GSC-model: Formation of giant salt accumulations, - a result of subduction, ascending mantle, and fluids

This is the link to an album over mud volcanoes in Azerbaijan: https://www.fluid-venting-system.org/mud-volcano-azerbaijan.html Please visit this site to see the whole presentation.

The 'Holocene' time-period on the geological time scale is defined as the period following the last glaciation, about 14,000 to 15,000 years ago, until the Present. Although this is a short period in the geological sense, it is an important and defining period for the immigration and settlement by modern humans (Homo sapiens) to northern Europe/Sca...

Part 2: Transition from interglacial (Eem) to glaciation (Weichsel), to the current interglacial (warm) period, Holocene, including changing sea-levels: regressions and transgressions. https://scc.klimarealistene.com/2022/02/the-holocene-climate-change-story-witnessed-from-sola-norway-part-2/

Geophysical features such as bottom-simulating reflectors and acoustic wipe-out zones are common at locations where natural gas hydrates form in deep-sea sediments. This is also the case at two locations off mid-Norway in the Norwegian Sea: the Nyegga hydrocarbon seep area and the Husmus shallow gas location. In addition to the aforementioned featu...

The main objective of this communication is to describe the ‘Global Salt Cycle’. Giant salt accumulations are commonly found along continental margins of former rifts. The first stage in the accumulation process is saturation of newly formed oceanic crust with seawater. Final mobilisation and accumulation of the salts occurs during rifting, localis...

Gammaproteobacteria from the family Endozoicomonadaceae have emerged as widespread associates of dense marine animal communities. Their abundance in coral reefs involves symbiotic relationships and possibly host nutrition. We explored functions encoded in the genome of an uncultured Endozoicomonadaceae ‘Candidatus Acestibacter aggregatus’ that live...

These video data files were collected in the period 2004 - 2010 from the Nyegga cold-seepage site. They show an abundance of animals living there as a result of the seepage activity. There are sediment-hosted hydrate pingoes inside the pockmarks G11 and G12. This is actually a unique location for the study of carbonate precipitation and natural fer...

Raw fieldwork video

Video of the 'Ice-2' location at Nyegga G11 pockmark, showing lush animal hot-spot sitting above a seeping (semi-stable) sediment hydrate pingo between the large carbonate blocks.

This presentation describes some new ideas on how salt precipitates due to phase separation underground and how Salt Giants may develop due to recurring tectonic processes such as subduction and rifting, where endogenic heat is the main cause of initial salt production, due to phase separation (boiling and the supercritical phase) processes. Subduc...

The relative role of the various mechanisms responsible for the formation of isolated carbonate build-ups occurring on the seafloor along continental margins is still uncertain. The interpretation of an extensive seismic dataset in the central Vulcan Sub-basin (NW Australia) allowed evaluating the role of migration and seepage of deep-sourced fluid...

Carbonate platforms form informative archives for paleoclimates and their internal structures can also hold crucial information about the tectonic history and carbonate evolution of the ocean basins. The Zhongsha atoll (Macclesfield Bank) forms the largest atoll system in the South China Sea with a surface area of 23500 km². However, the internal s...

Environmental conditions influence species composition, including the microbial communities that associate with benthic organisms such as corals. In this study we identified and compared bacteria that associate with three common deep-water corals Lophelia pertusa, Madrepora oculata and Paragorgia arborea from a reef habitat on the mid-Norwegian she...

The relative role of the various mechanisms responsible for the formation of isolated carbonate build-ups occurring on the seafloor along continental margins is still uncertain. The interpretation of an extensive seismic dataset in the central Vulcan Sub-basin (NW Australia) allowed to evaluate the possible role of migration and seepage of deep-sou...

The vdeo of my presentation is at this link: https://www.youtube.com/watch?v=vWFmHFYeZEo

Recent observations of thick carpets of mobile salt slurries on the Red Sea floor (Salt Flows) and huge accumulations of salts in the sub-surface (‘Salt Walls’ and ‘Salt Ridges’), associated with topographical lows (Deeps), suggest that the Red Sea currently produces new volumes of brines and solid salts underground. The salt producing zone is focu...

Recent observations of thick carpets of mobile salt slurries on the Red Sea floor (Salt Flows) and huge accumulations of salts in the sub-surface ('Salt Walls' and 'Salt Ridges'), associated with topographical lows (Deeps), suggest that the Red Sea currently produces new volumes of brines and solid salts underground. The salt producing zone is focu...

A new type of gas chimney exhibiting an unconventional linear planform is found. These chimneys are termed “Linear Chimneys”, which have been observed in 3-D seismic data offshore of Angola. Linear Chimneys occur parallel to adjacent faults, often within preferentially oriented tier-bound fault networks of diagenetic origin (also known as anisotrop...

We suggest an alternative mechanism for the formation of chimneys; "apart from overpressured fluid (gas) creating new fractures, overpressured gas may also pass through, filling pre-existing sub-vertical cracks/fractures in the hanging wall bottoms along the main fault surface (see fig. 2 in Gaffney et al., 2007). Pre-existing vertical fractures in...

Our new hydrothermal salt model provides improved explanations for the seemingly inexplicable occurrences of salt in deep-water rift basins that were never desiccated. This is highly relevant to the Red Sea, the Mediterranean Sea, and other large salt accumulations. Aftabi and Atapour have questioned the amount of hydrothermally produced salt and r...

Subducting oceanic slabs contain large amounts of seawater/brines, confined in their fracture system, which amounts up to 25 % of the rock volume. These large volumes of brines are included in the dynamic processes at high pressures and temperatures (HTHP) in the subsurface zones. A novel Hydrothermal Salt Model and its relationship to tectonic pro...

Pockmarks in Pliocene-Quaternary continental slope deposits offshore Angola show features related to: (1) fluid leakage craters that formed repeatedly, (2) authigenic methane-derived carbonates that indicate the (former) presence of hydrocarbons and (3) erosional–depositional structures that are clearly related to current activity. Depending on top...

A new type of gas chimney exhibiting unconventional linear planform has been observed on 3D seismic data offshore Angola, and is termed Linear Chimneys. These chimneys occur in the shallow buried hemipelagic succession which was affected by syn-sedimentary remobilisation processes related to hydrocarbon migrations. Linear Chimneys are oriented para...

This chapter highlights an alternative hypothesis of gas chimney formations in hanging walls, which can be caused by fluid migrations along pre-existing vertical fractures: "Apart from overpressured fluid (gas) creating new fractures, overpressured gas may also pass through, filling pre-existing sub-vertical cracks/fractures in the hanging wall bot...

The new hydrothermal salt model predicts that salt may accumulate in the sub-surface by hydrothermal circulation of seawater and brines in locations of high heat-flow. Such conditions are primarily found along tectonic plate boundaries, with processes of subduction and rifting, associated with the Wilson cycles. Modern knowledge of the physicochemi...

The formation of large salt deposits is observed especially in areas with a geological history of high tectonic activity. Over the last decade it has become a well-established fact that heavy brines form and solid salts precipitate, due to the thermodynamic and physico-chemical properties of seawater at high temperatures and pressures encountered w...

Presentation at the ”Bubbles2017” International Training School: The role of methane in marine and terrestrial environments

Many years of shallow gas studies over the Troll field, has shown that there is active leakage of methane, ethane, and propane over the Troll field. This has resulted in the formation of thousands of pockmark craters in the seafloor, ranging in size, from Unit pockmarks, ~5m in diameter and <1m deep, to 100 m wide and 8 m deep. They also form ”fami...

Worldwide marine salt deposits ranging over the entire geological record are generally considered climate-related evaporites, derived from the precipitation of salts (mainly chlorides and sulfates) from saturated solutions driven by solar evaporation of seawater. This explanation may be realistic for a salt thickness ≤ 100 m, being therefore inadeq...

Giant marine salt deposits are found many places on Earth, particularly in zones associated with oceanization and subduction processes, where periodic tectonic unrest and hydrothermal systems occur. Both numerical modeling and recent observations in the Red Sea Deeps and the submerged Brothers volcano off New Zealand, suggest that large volumes of...

(2016 submitted version) Two new types of pockmarks were found in the Pliocene-Quaternary section of the continental slope offshore Angola. Some features inside these pockmarks were clearly due to fluid leakage, like distinct craters development that are repeated throughout their time of activity; diagenetic crusts indicating that the fluids involv...

Interesting supplementary information can be found in "Introduction" and "Discussion 5.2.1.3." in this original manuscript which was submitted to Marine Geology on 18th October 2016.

The Oceanic Crust of the Earth The deep ocean water column is stratified, with cool (high-density) water masses generally ‘hugging’ the deepest portions of the oceans. The oceans cover about 72% of our planet’s surface, and have a mean depth of ca. 3,600 m. The deepest portions of the oceans are floored by ‘Oceanic Crust’ (OC), composed mainly of t...

Methane cold seep systems typically exhibit extensive buildups of authigenic carbonate minerals, resulting from local increases in alkalinity driven by methane oxidation. Here, we demonstrate that modern seep authigenic carbonates exhibit anomalously low clumped isotope values (Δ_(47)), as much as ~0.2‰ lower than expected values. In modern seeps,...

This study integrates high-resolution surface and sub-surface geophysical data to investigate possible fluid (gas and/or liquids) migration pathways to the seafloor in Grønfjorden, west Spitsbergen. Grønfjorden is an N-S aligned tributary fjord, located in the western part of the Isfjorden fjord system. Pockmarks were identified on the bathymetric...

Salt accumulations subsea

Giant marine salt deposits form in many places on Earth, particularly in zones associated with oceanization and subduction processes, where periodic tectonic unrest and hydrothermal systems occur. The geodynamic evolution of these zones can be strongly influenced by the presence of huge amounts of salts, because of their corrosive and mechanically...

Some diatremes formed in the Hyblean Plateau in a time span from 6.5 to 9.4 Ma, producing volcaniclastic deposits, which host deep-seated xenoliths. The origin of the explosive activity that has brecciated the magma and the country rocks is controversial, two are the prevalent models: phreatomagmatic and magmatic brecciation. We propose an alternat...

The ‘MRR08’-reef at the Morvin hydrocarbon field in the Norwegian Sea is one of the several hundred deep-water Lophelia-reefs located here. The reef is situated inside a 130 m long, 80 m wide and 10 m deep pockmark depression in the seafloor. The main reef-building organism of the reef is the ahermatypic stony coral Lophelia pertusa. The MRR08-reef...

This Album contains a set of ~ 100 images of pockmarks, that have previously been published or that have never been published before. They are hereby published via ResearcGate.net. The images are from seismic, sonar, drawings, block diagrams, underwater photographs and GIS-renderings. The Album is organized with vintage images in the first half, an...

Seepage of fluids through the seafloor contain information on processes underground, including information on mineral resources: •RESOURCES: oil, fish & industry in general •Marine life: is seepage important? •Exploration: is seepage important? •Can seepage (shallow gas) be dangerous? •MAPPING AND INTERPRETATION provides key knowledge

These slides are from a presentation I made at the University of Vigo, Spain, at a Conference on "Shallow gas and METROL", Sept., 2005.

"The Beauty of the 2nd Surface" is my inaugural lecture at Sunderland University in 2000. My visiting professorship at the Geology Department at Sunderland University started in May 2000, but, unfortunately, the department was closed down one year later. This is a PDF of the lecture I held, with some newer, additional information on some slides. Of...

This is the last map in a mapseries of 6 maps constructed by use of shallow geophysical survey data from Statoil and IKU, collected during the time-period 1970 - 1982. The map series consists of the following maps: Bathymetry, Paleobathymetry, Sediment Thickness (glacimarine), Shallow Gas occurrence, Geomorphology (pockmarks), Deglaciation (streaml...

This is the fifth map in a mapseries of 6 maps constructed by use of shallow geophysical survey data from Statoil and IKU, collected during the time-period 1970 - 1982. The map series consists of the following maps: Bathymetry, Paleobathymetry, Sediment Thickness (glacimarine), Shallow Gas occurrence, Geomorphology (pockmarks), Deglaciation (stream...

This is the fourth map in a mapseries of 6 maps constructed by use of shallow geophysical survey data from Statoil and IKU, collected during the time-period 1970 - 1982. The map series consists of the following maps: Bathymetry, Paleobathymetry, Sediment Thickness (glacimarine), Shallow Gas occurrence, Geomorphology (pockmarks), Deglaciation (strea...

This is the first of a mapseries of 6 maps constructed by use of shallow geophysical survey data from Statoil and IKU, collected during the time-period 1970 - 1982. The map series consists of the following maps: Bathymetry, Paleobathymetry, Sediment Thickness (glacimarine), Shallow Gas occurrence, Geomorphology (pockmarks), Deglaciation (streamline...

Shallow gas occurrences in the northern North Sea, from a series of 6 maps constructed in 1983 on the basis of shallow geophysical data (IKU and Statoil).The map series consists of the maps: Bathymetry, Paleobathymetry, Geomorphology, Shallow Gas, Sediment Thickness, and Deglaciation (streamlines).

This is the second of a mapseries of 6 maps constructed by use of shallow geophysical survey data from Statoil and IKU, collected during the time-period 1970 - 1982. The map series consists of the following maps: Bathymetry, Paleobathymetry, Sediment Thickness (glacimarine), Shallow Gas occurrence, Geomorphology (pockmarks), Deglaciation (streamlin...