Icy ebb and flow influenced by hydrothermal activity
Release of magma from beneath earth’s crust plays significant role in earth’s climate
From the UNIVERSITY OF CONNECTICUT
The last million years of Earth’s history was dominated by the cyclic advance and retreat of ice sheets over large swaths of North America. During cold glacial intervals, ice sheets reached as far south as Long Island and Indiana, while during warm interglacial periods the ice rapidly retreated to Greenland. It has long been known that ice ages occur every 40,000 years or so, but the cause of rapid transition between glacial and interglacial periods has remained a mystery.
While conventional wisdom says that this icy ebb and flow is an interaction between the world’s oceans, the ice itself, and the earth’s atmosphere, an article appearing in the Jan. 28, 2016 issue of the journal Science sheds new light on the role that the earth itself may play in this climatological ballet.
David Lund of the Department of Marine Sciences at the University of Connecticut and his colleagues have studied hydrothermal activity along the mid-ocean ridge system — the longest mountain range in the world which extends some 37,000 miles along the ocean floor. Their research suggests that the release of hot molten rock, or magma, from beneath the earth’s crust in response to changes in sea level plays a significant role in the earth’s climate. This change is attributed to the release of heat and carbon dioxide (CO2) into the deep ocean.
Lund says, “Mid-ocean range magmatism — the release of molten rock through volcanic vents or fissures — is driven by seafloor spreading and decompression melting of the upper mantle” — the partially molten layer just beneath the earth’s crust.
“This activity is controlled by the rate of pressure release at any given location. There’s clear evidence that when ice sheets grow, sea level lowers and significant pressure is taken off the ocean ridges. This causes melting in the mantle, which should in turn promote the release of heat and carbon into the oceans — and that’s when glacial termination begins — meaning the ice starts to melt. Then, sea levels begin to rise, pressure on the ridges increases, and magmatic activity decreases.”
Well-documented sedimentary records from the East Pacific Rise (EPR) — a mid-ocean ridge extending roughly from Antarctica to the Gulf of California — show evidence of enhanced hydrothermal activity during the last two glacial terminations, the last of which took place about 15,000 years ago.
According to Lund, the southern East Pacific rise (SEPR) has the fastest spreading rate and the highest magmatic budget of any ridge in the global mid-ocean ridge system. Due to its elevated magmatism, the SEPR has over 50 known active vent sites.
He says, “The coincidence in timing between hydrothermal maxima and glacial terminations implies that there may be a direct causal relationship between hydrothermal activity and deglaciation … Our results support the hypothesis that enhanced ridge magmatism, hydrothermal output, and perhaps mantle CO2 flux acts as a negative feedback on ice-sheet size … ”
In this study, core samples from both sides of the ridge axis were analyzed and included radiocarbon and oxygen isotopic analyses of microscopic shells to provide age control for each core. Major and trace element concentrations were determined using x-ray florescence and inductively coupled plasma mass spectrometry.
The EPR results establish the timing of hydrothermal anomalies, an essential prerequisite for determining whether ridge magmatism can act as a negative feedback on ice-sheet size.
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[Update by Willis] The underlying paper in Science magazine, “Enhanced East Pacific Rise hydrothermal activity during the last two glacial terminations”, is paywalled here. From the magazine:
Searching sediment for climate signals
Sediments on the ocean floor may provide clues about the interplay between ice ages and mid-ocean ridge magma production. Lund et al. present well-dated and detailed sediment records from hydrothermal activity along the East Pacific Rise. The sediments show changes in metal fluxes that are tied to the past two glaciations. Ice age changes in sea level alter magma production, which is manifested by changes in hydrothermal systems. The apparent increase in hydrothermal activity at the East Pacific Rise around the past two glacial terminations suggests some role in moderating the size of ice sheets.
Science, this issue p. 478
Abstract
Mid-ocean ridge magmatism is driven by seafloor spreading and decompression melting of the upper mantle. Melt production is apparently modulated by glacial-interglacial changes in sea level, raising the possibility that magmatic flux acts as a negative feedback on ice-sheet size. The timing of melt variability is poorly constrained, however, precluding a clear link between ridge magmatism and Pleistocene climate transitions. Here we present well-dated sedimentary records from the East Pacific Rise that show evidence of enhanced hydrothermal activity during the last two glacial terminations. We suggest that glacial maxima and lowering of sea level caused anomalous melting in the upper mantle and that the subsequent magmatic anomalies promoted deglaciation through the release of mantle heat and carbon at mid-ocean ridges.
And here is one of their figures, with the original caption:
Fig. 4
Normalized metal fluxes at 11°S compared with EPR bathymetry.
The hydrothermal time series are from the eastern (magenta) and western (black) flanks of the EPR and include (A) Fe flux, (B) Mn flux, and (C) As flux. We normalized each record by subtracting the mean and dividing by the standard deviation of each time series to facilitate comparison between cores with different mean metal concentrations. The results include both discrete samples (thin lines) and time series smoothed with a 20-ky-wide Gaussian window (thick lines) to approximate the resolution of the bathymetry compilation at 17°S (gray lines) (4). Fluxes from 0 to 40 ky are based on the results from Fig. 2; the interval from 40 to 200 ky B.P. is based on results shown in Fig. 3.
To consider submarine geothermal influence we must consider many more features than just spreading ridges e,g, rift valleys, hydrothermal vents associated with transform faults, and the full range of volcanic styles including andesitic and silicic. We know that submarine large scale explosive eruptions do occur
The average geothermal gradient is roughly 25 °C per km of depth. Within expansion zones this progressively increases to the point of being 100 c or more at 0 crust depth. We know these exist in the submarine environment e.g. the northern extension of the East African Rift Valley
The paper here records a correlation. I do not expect that it proclaims that is has identified THE controlling mechanism. Early in my studies I was taught that progress in earth science involves “3 steps forward and 2 steps backward”. Fully accepting or rejecting a hypothesis is not the way forward. Record the observation and add it to the evidence. Fully eliminating evidence through thorough research is an important part of the process. It takes diligence and time. This is the way forward that will never be understood or adopted through the unfortunate vested interest of personal bias and politics of climate science
Submarine geothermal energy input HAS to have an influence. The jury must stay out while we undertake the many years of research required to establish its influence in quantitive terms. Questions like “does submarine geothermal flux have a part to play in ENSO events?” are important
One point regarding the proximal influence of heat within spreading ridges: The heat is most likely concentrated in fluids . This will ascend rapidly in the form of plumes
One of Earth’s systems we know least about is submarine tectonics and volcanism
Don Easterbrook
Total geofantasy! Doesn’t explain the D/O abrupt oscillations
nor the global synchroniety of climate changes.
__________________________________
But albedo can explain both of them. Albedo can deliver orders of magnitude greater insolation absorption (feedbacks) than can CO2.
R
“This activity is controlled by the rate of pressure release at any given location. There’s clear evidence that when ice sheets grow, sea level lowers and significant pressure is taken off the ocean ridges. This causes melting in the mantle, which should in turn promote the release of heat and carbon into the oceans …
Hmmnnn…
Not a new idea……
This lot looked at whether they could find an association between water pressure/glaciation and magmatism along the Australian-Antarctic ridge.
http://science.sciencemag.org/content/347/6227/1237.full
Conclusion…Maybe [more work needs to be done….quelle surprise]
What I found interesting were the illustrations of the the Earth’s orbit relative to the Sun.
This led me to consider another variable that might affect the periodicity of glaciations: the position of the Sun in our galaxy, and possibly even the position of our galaxy in the Universe.
…and so, with having no surface water to speak of to maintain sealing pressure on underlying magma, Earths land masses must be boiling cauldrons of it……………….and where are those warm currents rising almost vertically from he deep?
Doesn’t this more or less support the global warming science idea that extra CO2 can cause increases in global temp ?
Fun Tool!
http://www.glaciers.pdx.edu/Projects/LearnAboutGlaciers/ROMO/BasicsIceAges.swf
ren January 29, 2016 at 12:21 pm
“Hillier & Watts (2007) surveyed 201,055 submarine volcanoes estimating that a total of 3,477,403 submarine volcanoes exist worldwide. According to the observations of Batiza (1982), we may infer that at least 4% of seamounts are active volcanoes. We can expect a higher percentage in the case of the count taken by Hillier & Watts (2007) because it includes smaller, younger seamounts; a higher proportion of which will be active.
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Good show, ren.
More and more to find and learn about, concerning ocean hot pockets.
Like this more recent article.
Seafloor Vent System Helps Solve Mystery Of Earth Crust Heat Loss
http://www.techtimes.com/articles/121189/20160105/seafloor-vent-system-helps-solve-mystery-of-earth-crust-heat-loss.htm
By Katherine Derla, Tech Times | January 5,
The Earth’s heat loss from the planet’s crust baffled scientists for decades, until now. Scientists discovered a new class of hydrothermal vent system that could precisely explain previous global climate.
A hydrothermal vent is an opening in the seafloor out of which flows mineral-rich water that has been heated by magma. The new seafloor vent system could clear up the long-standing debate between actual observations that the Earth’s crust is losing heat and the Earth’s theoretical cooling rate.
The discovery was made by researchers from the University of Southampton and the National Oceanography Centre (NOC) in the United Kingdom. The research team used a combination of remotely operated vehicles and robot-subs to observe the vent system on the seafloor.
“Theory has long predicted that there must be more cooling in certain locations on the Earth’s crust than we could account for using the known mechanisms and this new class of hydrothermal vent system may account for that difference,” said NOC geologist Bramley Murton, who supervised the research.
Other hydrothermal vent systems use volcanic heat from magma chambers. The newly discovered hydrothermal vent system type makes use of hot rocks being pushed upward and toward the seabed by tectonic spreading centers, which are low-angle faults.
The research team believes that the new hydrothermal vent system type can be found across the globe in various tectonic seafloor spreading locations. The new vent systems will shed new light on the Earth’s cooling mechanism, added Murton.
The new hydrothermal vent system type was discovered during a Caribbean expedition at the Von Damm Vent Field. The driving process of the new vents is not completely understood, rendering them unaccounted for in existing scientific models that explain how chemistry and heat travel upward from the Earth’s crust.
The new vents are also nearly invisible to the conventional techniques utilized in searching for hydrothermal vents. The research was published in the journal Nature Communications on Dec. 22, 2015.
To measure the vent field, the team used sonar on an autonomous underwater vehicle, the Autosub6000, which then mapped the vent field. The team then sent a remotely operated vehicle (ROV) to the vents to collect mineral samples and hydrothermal fluids. The ROV’s multi-beam sonar was also utilized to produce a high-resolution map.
An analysis of the samples proved both chemistry and minerals were different form the ones taken from other hydrothermal vents. The chimneys and mounds found in other vents are mostly made up of copper sulfides and iron, while on the Von Damm Vent Field, the 50-meter-tall (almost 165 feet) chimneys and mounds are largely made up of talc, a mineral rich in magnesium.
“This research also means that ocean models of magnesium and calcium budgets will need to be updated and could lead to more accurate insights into the Earth’s past climate,” the researchers concluded.
The complete article in Nature here.
22 December 2015
Talc-dominated seafloor deposits reveal a new class of hydrothermal system
http://www.nature.com/ncomms/2015/151222/ncomms10150/full/ncomms10150.html
Matthew R. S. Hodgkinson, Alexander P. Webber, Stephen Roberts, Rachel A. Mills, Douglas P. Connelly & Bramley J. Murton
Where the South Pacific Convergence Zone and Tropical Convergence Zone meet up there is sure alot of hydrothermal venting and Volcanic Activity.
Deep-sea Vents and Volcanic Activity Discovered – 04/01/2016
http://www.hydro-international.com/content/news/deep-sea-vents-and-volcanic-activity-discovered
By the time of their return from a 28-day expedition onboard R/V Falkor in mid-December 2015, a team of scientists had more than doubled the number of known hydrothermal vent sites in the Mariana Back-arc region. This area, west of the Mariana Trench, is where plate spreading and submarine volcanism are concentrated. Several momentous findings were made, including the discovery of one of the deepest vents ever found plus volcanic activity.
The team on R/V Falkor led by NOAA Pacific Marine Environmental Laboratory Cooperative Institute scientists Dr. Joe Resing from University of Washington and Dr. Bill Chadwick from Oregon State University, were able to increase the number of known hydrothermal vent sites in the Back-arc from three to seven by discovering four new areas of activity. One of these vents is amongst the deepest ever found from the 700 vent sites known globally. Only three other vents extend deeper than this newly-found vent, detected at a depth of 4,230 metres (13,900 feet).
Another important outcome was the discovery of an extremely rare recently-erupted underwater lava field that is likely only a few months old. According to chief scientist Dr. Joseph Resing, this region probably experiences eruptions no more than once a century, making the 125m (400 feet) thick lava flows a very exceptional find. The scientists also observed cloudy warm water leaking through the still-cooling pillow lavas. At the return of AUV Sentry, imagery showed brand new lava flow on the sea floor.
The multidisciplinary group used their Woods Hole Oceanographic Institution’s Autonomous Underwater Vehicle (AUV) Sentry, operated as part of the National Deep Submergence Facility. Multibeam sonar and chemical and optical sensors were also used to hunt for the new hydrothermal oases on a track that explored a 600km (400 mile) stretch of Pacific seafloor in the vicinity of the Marianas Trench Marine National Monument. This region, best known for including the ocean’s deepest depths, is also populated with active underwater volcanoes and unique deep-sea ecosystems that provide a rich environment for uniquely adapted species.
The science team will return to this same Back-arc region one year from now to explore the newly-found hydrothermal vents with Schmidt Ocean Institute’s brand new 4,500m ROV. Armed with new maps of the recently discovered vents, the researchers will be able to better characterise the deep-sea ecosystems in and around the Mariana Trench Marine National Monument, exploring how vent species adapt to their unique chemical and geologic environment.
All data obtained during the expedition are made publicly available by Schmidt Ocean Institute. Support for this expedition was provided by the NOAA Ocean Exploration and Research Programme and NOAA’s Pacific Island Regional Office.
It is beginning to look as if a major portion of ocean heat energy gain could be from cooling magma. The old figure for ocean turnover through the vents (10 years?) was 100m year to cycle the volume of the oceans. Suppose it is 20m instead. I calculated above the heat with a difference of 300 C. Suppose it is 1000, net. There is just a heck of a lot of heat coming into the water.
The estimate above of 3-4 km^3 of new magma per year may be far too low. All these factors (according to my flawed calculations) are coming close to the total heat gained by the oceans. Wouldn’t it be amazing if it turned out there was no missing heat at all?
Keep an eye on these:
magma volume x cooling plus heat of fusion of the rocks
vent flow, total, and delta T
The ‘cooling’ of the core on the basis of heat slowly leaking out is tiny compared with the heat coming from these three.
People need to understand the size and temperature of these undersea structures… the one structure called Godzilla is in our Blob zone off Oregon.
So, one more for the road.
The 40,000-Mile Volcano
http://www.nytimes.com/2016/01/12/science/midocean-ridges-volcano-underwater.html?_r=0
By WILLIAM J. BROAD JAN. 12, 2016
Picture a volcano. Now imagine that its main vent extends in a line. Now imagine that this line is so long that it runs for more than 40,000 miles through the dark recesses of all the world’s oceans, girding the globe like the seams of a baseball.
Welcome to one of the planet’s most obscure but important features, known rather prosaically as the midocean ridges. Though long enough to circle the moon more than six times, they receive little notice because they lie hidden in pitch darkness. Oceanographers stumbled on their volcanic nature in 1973. Ever since, costly expeditions have slowly explored the undersea world, which typically lies more than a mile down.
The results can make the visions of Jules Verne seem rather tame.
The ridges feature long rift valleys and, down their middles, giant fields of gushing hot springs that shed tons of minerals into icy seawater, slowly building eerie mounds and towers that can be rich in metals like gold and silver. One knobby tower in the Pacific Ocean, nicknamed Godzilla, grew 15 stories high. Thickets of snakelike tubeworms and other bizarre creatures often blanket the hot features, as do hungry prowlers such as spider crabs.
The riot of life coexists with springs hot enough to melt lead or the plastic windows of mini submarines. With extreme care, humans and robots have measured temperatures as high as 780 degrees……
….A main question is to what extent the volcanism changes over time. The old idea was that the eruptions of oozing lava and related activity occurred at fairly steady rates. Now, studies hint at the existence of outbursts large enough to influence not only the character of the global sea but the planet’s temperature.
Experts believe the activity may carry major repercussions because the oceanic ridges account for some 70 percent of the planet’s volcanic eruptions. By definition, that makes them enormous sources of heat and exotic minerals as well as such everyday gases as carbon dioxide, which all volcanoes emit.
“It’s a whole new perspective on how the Earth works,” said Daniel J. Fornari, a senior scientist at the Woods Hole Oceanographic Institution on Cape Cod, Mass. “We’ve got our eyes and ears on a part of the seafloor that’s really dynamic.”
The source of all of this activity is the slow churning of Earth’s molten interior, which continually rearranges the planet’s two dozen or so large crustal plates. The volcanic ridges mark the places where oceanic slabs slowly pull apart, giving molten rock and gases an escape route…..
….“Discovering the Deep,” published in May by Cambridge University Press, is filled with hundreds of images of alien creatures as well as volcanic towers belching clouds of superheated water rich in metals and minerals. It profiles more than a dozen hot spots around the globe, including those on the Juan de Fuca Ridge, home to Godzilla. Oceanographers, the book says, have discovered vast swarms of unusually sturdy microbes thriving in dark volcanic waters as hot as 250 degrees — hotter than most boiling water on land….
This theory is nonsense !
What has sea level risen across the interglacial ? 200 feet ? 300 feet ?
The conversion is 2.31 feet per psi. So a 300 foot rise in sea level amounts to less than a 150 psi change in pressure at the oceans’ floor.
Thinking of it another way is 33 feet beneath the surface of a body of water is one atmosphere. A 330 foot rise in sea level is an increase of 10 atmospheres, and an atmosphere is 14.7 psi.
So a 330 foot rise in sea level would cause an increase of 147psi.
So these BOZO’s are saying that a 150 psi change in pressure at the oceans’ floor is enough to dramatically change volcanism in the earth’s mantle ???
BLITHERING IDIOCY !!!
But then, that’s what I guess can be expected from 2-3 decades of dumbed-down educational systems and Post-Normal Science.
Disgusting.
Oh, and before anyone gets cute here, including long-time posters and/or WUWT contributors, about the size of the water body or the weight of water, etc. :
A column of water is a column of water ! It does not matter if the column is the diameter of a buret, or a swimming pool or a lake or a sea or the entire ocean !!! 2.31 feet per psi is the change in pressure with the height of water – PERIOD !
So I reiterate : only an idiot would think that a 150 psi change on the earth’s surface could cause a cataclysmic change in the earth’s plate tectonics or its volcanism.
Any geologists, PhD. level, care to comment on this specifically ?