Palawan Continental Terrane. “Palawan?” According to Google Translate, it means “Sleeper Fish.”
Sleeper gpby
Sleeper gobies are members of the Eleotridae fish family, found predominantly in the tropical Indo-Pacific. There are approximately 35 genera and 150 species.
Interesting… sort of. The Palawan Continental Terrane is actually a fairly sizable chunk of material that has perplexed a few researchers as to where it came from, or how it originated. Before I yammer about that, let me point out what that word actually means… not Palawan, but “Terrane.”
A Terrane is a geologic term for a somewhat contigious block(s) of material that operate/move over geologic timescales as one unit. The boundaries are not really clear enough to call it a crust block or microplate, or microcontinent… though each of those could eventually wind up being a terrane once they get to a resting place, or are plastered onto a continent. Essentially, the material in the Terrane is related to all the other material in origin, chemical make up, and destination. Usually a Terrane originates from one crust block/plate and winds up attached to or sutured onto another. The Wrangellia Terrane is where I learned the term… that’s the region plastered to the North American craton east of where the recent Queen Charlotte quakes occurred at. If you think of bugs and windshields, you get the general idea of how terranes work and accumulate.
From the name “Palawan Continental Terrane” you would assume that it originated from some continent somewhere. According to Knittel et al., it’s a piece of the rifted margin of SE China. So where is it now? Well, it makes up a significant chunk of Mindoro in the Philippines. Mindoro is a collection of three uniquely different chunks of material. The other parts are the Philippine Mobile Belt that the Palawan Continental Terrane is sutured to, as well as a third unit that is made up of metamorphic material and a section that might indicate an ophiolitic unit… complete with gabbros. From Wikipedia: “a section of the Earth’s oceanic crust and the underlying upper mantle that has been uplifted and exposed above sea level and often emplaced onto continental crust”
Okay… so it’s a slow motion collision in process. More correctly, part of a slow motion collision in process. Why part? Well, this affects Taal and Laguna de Bay.
Mukasa et al. points out that other researchers have pinned their origin as products of the subducting plate at the Manila trench, and then further notes that the geochemistry of them has changed as they have grown older. Specifically, they differ from the other volcanoes in the northern part of that chain. (East Bataan Lineament). The reason for this, according to the authors, is the incorporation of Palawan Continental Terrane material into the magma production.
This could explain how Taal and Laguna de Bay could have become capable of making large calderas. By its nature, continental material is more silica rich than oceanic crust. The general thought is that leading shards of this material are intruding into and being caught up in the melt formation process.
As cbus20122 notes:
…It’s amazing that such a large eruption [Pinatubo] only produced a comparative blip of a caldera when looking at the other volcanic areas on the map…
Pinatubo, being on the West Bataan Lineament, is more north and further away from this source of silica rich magma.
Right next to the Taal/Laguna de Bay region is the Macolod Corridor. From the abstract of a pay to play paper by Förster et al (1990):
an approximately 40 km wide zone of still active intense Quarternary volcanism which perpendicularly crosses the Island in a NE-SW direction … we believe that the corridor is a pull-apart zone formed by a diffuse system of NW-SE oriented shearing.
And of course… a plot of sorts. Not my usual, I wanted to focus on quake depths in relation to the major players. This was put together with DivaGIS. Red Quakes are greater than 90 km deep, Blue quakes are less than 90 km deep. Somewhere around 125 km is where melt percolates off of the subducting slab. The majority of the deep spike is under and just to the southwest of the Taal parent caldera. (The one the island of Taal sits in). There are a few deep quakes up around Pinatubo, but nothing like the area around Taal. These are quakes from the USGS list back to 1975 and greater than magnitude 4.5 or so.
GEOLURKING
An after the fact addition: If you note my first graphic, there is a region that forms a “T” with the Manilla Trench that I called “Old South China Sea Spreading Center.” A closer look at this was done in “Basement structures from satellite-derived gravity field: South China Sea ridge” by Braitenberg et al (2005). You may find it of interest. It is what put the Palawan Continental Terrane where it is.
“The Macolod Corridor: A rift crossing the Philippine island arc” Förster et al (1990).
“The Nd-, Sr- and Pb-isotopic character of lavas from Taal, Laguna de Bay and Arayat volcanoes, southwestern Luzon, Philippines: implications for arc magma petrogenesis” Mukasa et al (1993)
“Permian arc magmatism in Mindoro, the Philippines: An early Indosinian event in the Palawan Continental Terrane” Knittel et al (2009)
In summary, Taal and Laguna de Bay fall into the “Large Caldera” category of volcanic systems. Both are on the margin of the McCleod Corridor which is part of the Philippine mobile belt. The McCleod Corridor is seemingly a nascent spreading region. What exact dynamics are in play is hard to nail down since like much of the Western Pacific, the Philippine islands are a geological train wreck with many tectonic forces competing for dominance. The presence of the Palawan Terrane could contribute to a higher silica content of the magmas feeding the volcanoes in the area since it is continental crust in origin. Don’t let the4 fact that much of it is underwater fool you. The Jan Mayen microcontinent is fully underwater except for a volcanic feature known as Jan Mayen island.
The important part of the animated plot is to note just how prolific the deep quakes are in the Benioff zone under the Taal area compared to Pinatubo.
BTW, Taal is probably the largest Tilapia production area in the Philippines. Earlier this year they had a large fish die off, but it wasn’t the volcano. It was a drop in dissolved oxygen in Taal lake.
There was a misunderstanding in the press. Taal was raised to 1 several months ago.
I can buy that. The purpose of the re post remains the same. 😀
That geology makes the Adriatic look like a kindergarten jigsaw.
Brrr…
Slightly off-topic: Family friend, a ship’s captain, hailed from the Philippines. After a long, careful career, he moored his last box-ship and retired to family farm. Then, like many others, he discovered his investments & pension had been lost to one of the Marcos’ machinations. He had to go back to sea. Farm was down-wind of the Pinatubo eruption, ruined by heavy ash-fall. IIRC, his family just gave up and moved away…
Don’t count the Adriatic as simple, to the east, back behind Montenegro, are several examples of “super subduction.” That’s where you get a subduction zone progressing back and forth as the geometry of it changed over millions of years from the turmoil of the Tethys Ocean being consumed.
Note the Province of Foggia. South of that jut of land in the Adriatic, the basin drops of quite deep. Directly across the Italian peninsula is the Campi – Vesuvius area. I’m pretty certain some very interesting geology occurred to create that set-up. I don’t have any proof, but I have a feeling that the 41 myr activity in the region may have been connected with a slab detachment from what was left of the Tethys ocean crust being subducted. This could also be connected with the Laschamp event which is dated to about the same time frame. Sure, it could be a coincidence, but Laschamp and Campi being so close to each other in time seem a bit too coincidental to me. After all, magnetism is caused by flowing electric charges and magma tends to be iron rich. It is not too far a reach to expect an eddy current of magma in the athenosphere to be the cause of both. Word of warning, I also hold the view that the Columbia Flood Basalts could be related to slab detachment of the subducted Farallon plate and associated eddy currents. This point of view is a bit radical and I have nothing to back it up.
Data plotting from an old article I never finished writing; Projected Yellowstone hotspot positions before “landfall”
Notice the mountinous region between the 33 myr posit and McDermit. There is an increased geothermal gradient along that path as well. This fits with the idea that the curve in the Snake River plain is not part of the Yellowstone track that some sources state. Also, the general idea is that Steens was the first caldera outbreak of Yellowstone. The hypothetical track connection to Newberry is not well established.
Projected locations were derived by tasking the current angular measurements between Yellowstone and Hawaii hotspots and applying that to previous known Hawaii hot spot locations. (essentially, I sort of DR’d the track back though time → “Dead Reckoning”) You wont find any existing sea floor evidence of the hot spot, that is plastered onto North America as the terane deposit like bugs on a windshield.
Caveat, Not a geologist, but I was a qualified CIC Watch Officer.
Steen mountain is often considered the first activity of the Yellowstone spot. The Columbia flood basalt extended further north but was fed through huge dikes which could easily have come from here. I imagine a 2-kilometer tall bulge, with dikes extending into the norther lowlands. A bit like Iceland. But where did the hot spot come from?
Sorry, I did not mean to imply the Adriatic’s underpinnings were ‘simple’, far from it !
But, that tectonic zoo around the Philippines, combined with the Australian Plate’s rapid motion, will take a *lot* of untangling. Surely no coincidence that it bears an unsettling resemblance to those very complex terranes & micro-terranes patiently mapped along the Indian Plate’s Asian convergence zone…
If I’ve understood the still-evolving data, both PF/Vesuvius and Yellowstone / Snake River Track arise from descending plates’ slab breaks. The hot stuff gets a different history to ‘simple’ subduction / arc / back-arc processes, has ‘strange’ chemistry.
Is there a third such confirmed example ?? IIRC, there may be one along the Japanese islands, spawning an ‘odd’ volcano where back-arc splits…
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With respect GL, Yellowstone seems too shallow to be the driver for a magnetic reversal. IIRC, they’re thought to start when the ‘aggregate’ core field, powered by outer-core motions, goes multi-pole. A bit like the ‘South Atlantic Magnetic Anomaly’ currently flexing its thews, but ‘going large’. Then, the ‘aggregate’ field slowly recovers its prior alignment, or settles reversed. Until the next time…
Hmmm: https://core.ac.uk/download/pdf/37458450.pdf
indicates SAMA’s core is drifting WSW, from off Brazil’s Atlantic coast circa 1900 to Paraguay circa 2005, headed for Northern Argentina…
Given its position matches neither the South African nor mid-Pacific outer-core mega-blobs recently reported, your guess is better than mine. As it is now approaching the deep tail of the vast Andean subduction system, fire-works may ensue. Or not, of course, of course !!
The coincidence between the Laschamp magnetic reversal and the large Campi eruption must be just that – a coincidence. It was 41 thousand years ago, and at a speed of centimeters per year, the plates would only have moved by 1-2 km. Slabs do nothing much on that kind of time scales. For Yellowstone, we are talking about 10 million years and that becomes more interesting – now we get proper geology. Magnetic fields come from motion in the Earth’s outer core, not the mantle, and so the slabs have no effect on these in any cases. Reversely, the field is too weak to affect continental movement. It is very useful to have a global magnetic field, for all kind of reasons, but it is very weak.
Terrestrial Super Earths with their immense internal heating and probaly very fast spinn: are likley extremely magnetic.
Entire core maybe molten on these larger worlds (more than 12 000 C in middle )
Immense pressures keeps it form vaporizing.
I can imagine the landscapes of a habitable 3X earth mass world
very geologically active with numerous ocean ridges and hyperactive spreading centers and subduction zones everywhere.
Landmasses are small twisted orogenic beltsin a huge sea.
And aliens drilling into the very very plentiful geothermal energy
I imagines continental landscapes
Completely crowded by volcanoes… like nothing we haves here on earth.
Imagine nights with glowing volcano summits everywhere
Steaming mudpots and hot water pools and sillica sinter are everywhere in belts 100 s of km long.
Im pretty soure these heavier Earth cousins have lots of fire in their hearts.
The more massive you are as a planet..the more heat you will produce.
Sucks there is no Super earth at all in our own solar system…
How are the magnetic fields on Super earths with earth- like compositions and surface temperatures? some of these worlds must spinn very fast
We don’t really know what kind of planets these are, super earths or small neptunes. Magnetic fields are likely strong in either case, but neptunes have fields that are centred in their liquid mantles so they are differently organized. Of course Earth had a fully molten core until 2-3 billion years ago. Superearths are likely to have a lot more water than we do, so expect an ocean of not 10 km but more like 100 km deep. Nice for fish.
Some of these Super Earths
Are sourely earthlike
But a 100 km deep global ocean
Will become a marine desert like Hawaii: No nutrients, No plankton
Even more nutrient poor than 6 km deep Tropical Pacific
Oceanic deep sea worlds are marine deserts?
Could be. Life in oceans is quite localized, around hot springs. I think though that floating reefs could form. Our coral reefs form in very nutrient-poor environments. Add nutrients (farm run-off) and they die.
Tangential: I’m sorta in the throes of setting a story on the mega-moon of such a big planet. ‘Thule’ is smaller than Earth, bigger than Mars, has more silica and a smaller core. Think ‘Gaia’ before ‘Theia’ impact gave us Earth/Moon pair. Host planet, tau Ceti_f, aka ‘BMF’, is at cold edge of habitable zone, but contributes tidal stirring, keeps Thule’s global magnetic field alive.
A lonnng-prior terraforming project seeded Thule’s seas with Terran photo-synthetic cyano-bacteria etc. With an oxygenated atmosphere established, Phase-Two installed a terrestrial eco-system of sorts.
Unfortunately, old data is old data. Tidal dissipation varies with orbital precession etc, ‘Thule’ is currently in a ‘seriously slushy’ phase, that dry-foot eco-system effectively restricted to several large geo-thermal ‘oases’….
The ‘sleeper-shipped’ lead-team of researcher-colonists choose the ‘least scary’ caldera for their settlement, duly tag it ‘Jellystone’…
😉
@Albert, I can see your point. Magnetic field strength being a function of the rate of charge movement. I personally don’t know of an equivalent geomagnetic anomaly dating to Steens or CFB, but I’m not ready to fully dismiss the idea until I find out more about that interaction.
Ref Japan: I read a bit a year or so ago that postulated a slab fragment somewhere under the greater Tokyo area that was reluctant to finish subducting. Per the article it was responsible for anomalous energy dissipation, making ancient quakes difficult to analyze.
Something I’ve wondered-is that the Farrallon plate as it subducted did break up. Like Lurk suggested. leaving traces of that break up.Features like the Olympic/Wallowa Lineament or OWL the Brothers Linament and others , Also as stated by several the rotation of the NW
US on the North American plate is a factor. another is the previous supervolcano history of Eastern/Central Oregon. In the last 20 or so years a picture of an major Caldera appeared. Where previously there was speculation that a series of eruptions caused the
John Day/Clarno formations , there may have been just a few..One of th eproblems was this activity was swallowed up by the Columbia river basalts..
I don’t think we yet have a clear picture of what’s going on..
Here is a bit from the Ore Bin-Oregon Geology magazine:
https://www.oregongeology.org/pubs/og/ogv69n01-crookedrivercaldera.pdf
The Cascades are full of odd lineaments like that, so that breakup of the old Farallon plate would make sense based on the geomorphology.
Geo net has an interesting quake chart on its site a the moment, something is on the move ?
https://www.geonet.org.nz/earthquake/unnoticeable
Grimsfjall acting UP now… 3.2 now
I don’t think this is Grimsvotn. It is further west, not on the Grimsvotn rift.
What would be the cause of the earthquake?
This is on the Loki ridge that is one of the two ridges extending from the Hamarinn central volcano. Earthquakes of this magnitude are not uncommon in this area.
That said, there has been quite widespread activity around Vatnajökull the last 48h. We know that Grímsvötn is inflating and that may influence stress fields around nearby faults. I also think Bárðarbunga is getting close to one of its larger quakes. There was a post here a while ago about the magma chambers under Vatnajökull acting like balloons massaging each other. To me it seems like there is a bit of massaging going on right now.
I am absolutely have no good knowledge on that phenomna, so I will be more then happy to take that solution
@ Tomas Andersson – happy end massage?
Oh, yes! The kind that ends with hot ejecta and happy volcano watchers. Grímsvötn will probably be relaxed afterwards…
This is probaly having to do with the sourge in magma from the plume in general.
1996,1998,2004,2011 and 2014 are lots of magmas
Plume pulse maybe? and its not over yet?
From 1998 to 2004 Vatnajökull inflated alot sourge in magma.
No souch data have been done on Vatnajökull from 2004 to 2014 I think?
Hmm – interesting where the earthquakes are not. Kaingaroa seems to be a quiet place in a ring of rumbling.
Sorry, in reply to karulei!
in iceland perhaps also some interesting eq:
Vatnajökull – earthquakes during the last 48 hours Total: 41
Sunday 13.10.2019 3.9 km 3.1
99.0
14.6 km E of Hamarinn
Hekla has caused IMO to raise half an eyebrow, but don’t get too excited yet:
“the Icelandic Met Office alerted both Department of Civil Protection and Emergency Management as well as Isavia, the company which operates Keflavík International Airport.”
https://grapevine.is/news/2019/10/09/hekla-rumbles-authorities-alerted/
Nice little swarm at the feature unofficially known as Greip.
A lot of seismic tension under Vatnajokull in recent days.
Earthquakes have increased in recent weeks in Grimsvotn, then a larger quake in Hamarinn and a swarm in Tungnafellsjokull central volcano, north of Bardarbunga. Now a swarm in Greip. probably a consequence of the larger quake in Hamarinn.
Yesterday´s quakes at Nýidalur remind one of the runup to Bardarbunga – there was a similar pattern before the magma went towards Bardy.
All the activity seems like a push of this proverbial cushion pushing from below that Carl was talking about.
Fireball over north China, seen a few days ago.
Albert just imagine how many fireballs and boldies the reentering Chicxlulub ejecta did after impact!
Billions of shooting stars fills the skies after hour after impact, totaly crazy.
Is this firestorm a correct view of the event?
How big was the explosion?
200 million times more powerful than Tsar Bomba was the KT impact that ended dinosaurs
An 30 km deep and 180 km wide arera of earths crust was turned into 20 000 C vaporized rock and ejected into low orbit
I wonder if there is a residue debris patch from that event that we still encounter in our orbit from time to time…
I wonder how Chicxulub crater looked like 3 weeks after impact
probaly extremely hot and thick layers of impact melt.
warm water hydrothermal systems woud go on there for tens of thousands of years after impact, resudial heat
Very unlikely. To reach orbit you need a very high velocity (faster than achievable in an explosion!), AND you need to further accelerate when on the target height. The last part is needed since otherwise you are on an elliptical orbit that will intersect the Earth surface somewhere, bringing your orbit to an immediate and premature end. To get a ring around the Earth, you need to disintegrate something at orbital distance.
Chicxulub Ejecta easly reached low orbit speed .. setting them on ballistic reentry trajectories
Low orbit speed = the speed to maintain an orbit = 7 km/s. It is NOT the speed needed to get to the height of a low-earth orbit: that can be done with a fraction of the speed. Let’s be clear what we are talking about. Lurking asked about debris in orbit, and that is not possible. Debris reaching 100 km height, that is relatively easy – even a volcano can do it. Debris reaching escape velocity (11 km/s) – that is actually possible in impacts. Debris reaching orbital speed AND going into orbit – no. That requires a velocity change in orbit which a ballistic rock can’t do.
I have another question for you:
How the heck does the rocket motors like in Saturn V and space shuttle solid boosters cope with 3300 C temps?
Everytime I watch rocket launches Im amazed why the machinery dont melt.. not only should they melt, they should vaporize!
Rockets are indeed extreme machines operating at temperatures as hot as some stars. They should melt and blow themselves up ad launch site.
Whats the cooling system? I dont understand
Im too lazy now to look at internet today
Jesper, rocket engines are generally cooled by circulating the cryogenic propellant and oxidizers through cooling passages in the engine bells and the combustion chambers.
Eruption begins at Metis Shoal in Tonga. Maybe another temporary island in the making.
Thanks for the interesting and in-depth article – great VC stuff as usual As a space and astronomy fiend loved to see Albert’s fireball news and Jesper’s usual enthusiastic comments on all subjects !