Welcome to the blog of writer and musician Andrew Martin. Here I'll post original photographs and observations as I encounter the history and culture of the San Fernando Valley, the City of the Angels, Alta California and the far-flung Pacific Rim… but mostly the Valley.
There was only one Mexican desert yellow bird-of-paradise, but it was gorgeous. The shrub is a bean, family Fabaceae, highly poisonous. Caesalpinagilliesii.
I pre-empt my promised post about the Hollywood Hills, to show what I found last week on the southern slopes of Griffith Park. I had ducked into Vermont Canyon to avoid traffic, and found a trailhead I’d never noticed. I found brave Views…
But as the boys used to say back on old Alcatraz: Views, shmiews! Here’s a real porphyry, turning marble to copper:
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The official geology (1953!) tells how this part of the park contains different rock from the other areas of the Santa Monica Mountains. Here there have been, in the last 17 million years, three different grey-blue-purple granodiorite intrusions, that is, magma chamber extrusions, up and through the sedimentary layers. Called he Vermont, the Lar, and the Feliz, each formation is a pluton, and each rose from the same magmatic chamber, emplaced deep below during the course of the Miocene. Ever since, they have risen like balloons through the heavier sediments. But along with erosion and buoyancy, the chemistry and physics of hydrothermal piping have been transforming bits of the granodiorite in those hills, shaping, raising, splitting them according to ancient groundwater ducts by leaching and dissolving and re-mineralizing deep marine sediments — maybe bits of ocean crust? — into the copper suite of minerals…and gold and lead and nickel and molybdenum et. al. And doing it before our very eyes.
The blue crystals
Are covellite
Covellite — first recorded on Mt. Vesuvius. Named 1832, after Niccolo Covelli. Secondary copper sulfide mineral formed in the supergene environment. Prized by collectors. Rare in crystal form. AKA blue copper; indigo copper. Irridescent. FIrst mineral to be identified as a superconductor.
There are clearly important networks of magma pipelines that define peaks and ridges, and many periods of intense hydrothermal alteration. I don’t think this has been very evident before now, but the yellowed, dead slopes next to healthy green ones, is too marked to ignore.
The central anticline is mineralized, the top ridge hardened and whitened. Also note the oaks in the holes; and the scallop, or crown, or Montgolfier, shape emerging from the grass in the slope facing us.
The ridge of gray rock is the biggest outcrop of Sierra-style granodiorite in Southern California.
There is some andesite, many very oxidized sedimentary layers, quartz veins, slickensides, and cliff faces glistening with very oozy, crystallized chalcopyrite. I read there was once a claim for copper in the Park; but public geology, at least, is quite silent on these glaring porphyry eyes in the hills — dark with dank ore, gritty with green sleep, weeping hydrothermal tears down the hills. [Cue: ‘OtchiTchornya’]
Right next to the big blue-and-gray marble cauldron, there is a stretch of hillside that clearly has had some porphyry action over the centuries, but, unlike its neighbor, isn’t currently doing much we can see on the surface. To the casual hiker, it’s just a rock wall. But you can discern some of the movements and adjustments of this spigot, as the earth moved around under it. You can discern them as an unusual configuration of U’s, all those folded sedimentary layers: look for a syncline stacked on top of an anticline. Or, you can discern them by unusual configurations of crowns and stars, triangles and diamond quarrels, unfolding from each other like origami points. You could even try seeing both U’s and stars at the same time; but that’s madness. It’s obvious that these features aren’t just one-off, one-time events, but important fixtures in the geology.
[Shudder.] Next we’ll take a Tour To The Stars along Mulholland Drive, and View the new copper mines of the rich and famous in the Hollywood Hills!
I went to boring-old-Griffith Park partly because I haven’t been much lately, and I thought it would be full of People, and I imagined the thrill of going unmasked somewhere where life promenades gaily.
It was a relief, actually, to find it was rather sleepy. The glens were lush with hush and cloaked by cloud cover, making for high-resolution photographs, and reflective hiking.
A bit too reflective, old chum. The topographic scale-model is wonderful, but you can barely see it. And it is the ONLY exhibit about geology left in the entire park! The Visitors’ Center is tired and small and out of date; it offers the public little interpretation of LA’s most amazing resource.
Griffith Park epitomizes the potential for a SFV Nat’l Geo. Monument. The strapped City desperately needs federal assistance to install new exhibits; encourage respectful public access to sites of awe; put more rangers on-site to support public education and awareness of earthquakes, water, and chaparral ecology; and deepen America’s understanding and appreciation of the unique geology of our region.
I went hoping to see whether the the Santa Monica Mountains might be involved in the geologic drama currently gripping the other Valley ranges — rapid groundwater changes, newly active vent formations, etc. Once more I was staggered by what I found on the ground. But before we go play in the dirt: Marine–layer–gloom + Sage–in–bloom = Aromatherapy.
Toyon in all stages, new blooms to old berries.
Holly-leafed cherries going great guns!
Prunusilicifolia
Buckwheat! But note the water differential in the onion-layered zones of the bowl…
MIKROKOSMOS, IN THREE PILES OF MUD
Nobody would look twice at any of these, nor would I have, before a few months ago. Even if you did — Just eroded sand piles, one would think; LA’s usual trashed public trails. Rubble beside a fire road. Fill dirt, bulldozed by a parking lot maintenance crew who left their job undone. Awful; burned hillside ruined by drought. Come away from there Bobby, there’s broken glass and syringes and snakes.
Understanding even the surface features of these things enough to see them, is taxing. Nobody has ever written a single word about them in Los Angeles, ever, I think. Perceiving them as essential organs of the Earth, that belong here, and that reveal the inner workings of the LA watershed, blows my mind to Cloudcuckooland. Astronomy, physics, geology and geography; hydrology, chemistry, organic chemistry, biology; paleontology, social history, economic history, industrial history; ecology, ethics, social policy. These mud piles will really kick your hyper-specialized 21st century human brain into shape.
EXAMPLE1 — Of the three formations this is the subtlest. But it’s a whole ridge full of recent activity, which, together, illustrate the themes nicely.
These structures naturally form where there were volcanoes, those familiar molten rock-one-pipe-and-lava flow volcanoes that LA isn’t supposed to have had any of, but which racked the region during the Miocene, about 17 mya. Back then our fault block was migrating north, to collide with the mainland (at the Point of the Riviera, now San Gabriel Fault); subducting gouged-off sediments down into an accretion prism, including members of the famous MontereyShale. For ages, trillions of microorganisms had been down in the shales and sediments feasting on the oozy organic goo in the layers. As the layers were folded, tilted, compressed, and broken open, first underwater, and then underground, hydrocarbons and sulfur gas gained the opportunity to release vertically to the low-pressure surface. Lava infusions (andesite? Alaskite?) roared up through weak joints in the infinite layers of shale.
Even millions of years after the infusions, the lava tubes and cracks and joints have been — are still being — infiltrated by breccia-conglomerate pipes saturated with mineral brine, under pressure and heaven-bent. Steam escapes into the first fresh air or wet sand it can find — often a creek bed, or at the crease of a road or trail cut. When the de-pressurized brine goes “pfft,” the heavy metals get jilted, emplaced on the rocks around the vents. All this, I’d barely grasped so far.
An old cauldron. The sumac in the center of the pipe, and the water it draws up, the microbes and mosses and lichens that eat some of the hydrocarbons in the water, and concentrate others, all play parts in making this geology happen. Right along with the quartzy-schisty sand of the diagonal layers, and the re-metamorphosed lava that long ago surged through those layers and formed the little synclines around the rim, like a king’s crown. Note the sumac essentially has a vase — a series of layered, lined, nested pots or chambers to hold harvestable water between them — until it boils with acid and burns the sumac. This cauldron was recently active, but not this year —you can see last year’s undisturbed leaves at the base (toasted, presumably, when Example #2 vented recently…see below).
Now a new wrinkle: some of these vents, millions of years after the host volcano has retired, and after the whole mountain has practically been eroded away, still create geo-chemical ovens that cook up the rare and valuable minerals — iron, copper, gold, silver, lead, zinc and many more. These structures are called porphyries; and they are the source of most of the copper mined today, and copper prices are soaring, and everybody in the world is looking for them in remote third-world spots, even on Mars; they plan, wherever they find them, to bribe the local dictator, strip-mine the copper with slave labor, ship it back to Earth, and get rich. Those porphyries. In Griffith Park!
Example2 is stunning — an arch with points or rays like the diadem worn by the Statue of Liberty. (Damnyou! Youblewitup!) It has several cauldron areas and several vents. These have been recently active in mineralization, but still I could barely grasp how the alteration machinery works to change rock to sand, back into ore.
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It seems to be dismantling old structures on the hillside with acid washes — carefully sorting out the rocks, vein by vein, and altering them as it washes the piles downhill…
The iron-oxidized vein of brown chert, and the sandy quartz of the sediment layers, and the Alaskite (granite) lava intrusions, have all the ingredients to make chalcophyrite, the primary copper ore. Presumably, although the porphyry is eroded away, these mingled piles or residue will still eventually sink together below the road, and get covered with other sands, until the next big rain or liquefaction earthquake. Then they might be re-washed, re-leached, re-doxed, and fuse together as a richer copper ore. The more times this happens, the more copper-rich the ore is made, secreted just below the water table (here, under the trail surface).
Turned to copper sulfate?
Porphyries were so-called by the Romans, for they found copper ore conveniently near their beds of lovely red and purple “porphyry” column marble. The name has stuck, though there is no porphyry marble in the Valley. (The chemistry doesn’t require red marble, just any limestone contact). Lime brings the carbon to a floating groundwater party that already has plenty of iron and sulfur. Heat and pressure can do the alchemy far below ground, but if certain salts and solutions are present, then all you need on the surface to get the reducing action going is for the groundwater table to rise. It could be ordinary rain, sinking through the cracks — ‘meteoric’ water circulation, leaching out metal salts. Or/and, it could be a tectonic compressive shift, like an earthquake on a thrust fault, that forces water and brine to mingle and rise, cracking rocks en route, cooking the salts, separating the dross, and adding or removing oxygen, iron, sulfur, carbon, hydrogen, etc to make metals. (The more modern term investors use is an Iron Oxide-Copper-Gold Deposit, or IOCG. But specifically copper is still called porphyry copper.)
Example3 is from a parking lot so forlorn, so uninteresting, so damaged-looking, that even in Griffith Park, with THOUSANDS of acres and THOUSANDS of visitors and only THREE parking areas, and though it’s right on Zoo Drive, is always wide-open. This time, Patient Reader, you’re on your own as far as interpretation, as I am, since I’m the only resource for researching these things. A few notes: 1) the fancy colors are likely the copper minerals bornite, chrysocolla, azurite, and cuprite. 2) This hillside is likely to repeat porphyry pots all the way to the top. 3) The Hollister Fault is just over that ridge; 4) the Montgolfier balloon shapes are tipped to the left, or east; 5) and those oaks in those old cauldrons, were likely vertical when their acorns sprouted. Maybe you can tell me what’s going on!
So: while these vents are not magmatic eruptions, they are phreatic engines which happen in, around, and because of, an old volcano. Porphyries seem to be a manifestation of late-stage volcanism. They are common around the Pacific Rim where oceanic crust has been subducted, especially in convergent continental plate collision zones like the SFV. But seriously, you ain’t seen nothin’ yet. We’re going into the Hollywood Hills next, where the rich are getting richer every time it rains — though they don’t know it, and the fumes may kill them. Comedy is easy — geology is hard.
This little puff of rare earth minerals just starting tickling the rim of my hat —
Next time, we’ll talk about what I learned after months of researching: that nobody should ever handle chalcopyrite; and we’ll discuss why if you’re looking at a rock formation, and coughing and choking uncontrollably, it isn’t the dust and you should leave the area; and why shuffling through sand piles to get close to pretty rocks, can leave chalcopyrite exhalations on your shoes!
THE CALIFORNIA FLORISTIC PROVINCE/ SAN FERNANDO VALLEY NAT’L. GEO. MON.
For Patient Reader Down East: StickyMonkey–flower!
Copper grows out of these arches; so do monkey-flowers. Below: Elsmere Canyon. Hydrocarbon petrology don’t faze them monkeys.
The golden face-pullers are a glory this month in all the SFV Canyons, and throughout the coastal Golden State. They epitomize the integral relationship of the CFP and its complex mineralized soils. Monkeys are a great example of how protecting one, protects the other. (Photos from Elsmere Canyon, Griffith Park, and Laurel Crest.)
Mimulusaurantiacus — the “little orange mime,” “little golden joker.” (Too delicate and Victorian to use the word ‘sticky’ in conversation? Call it “Bush Monkey-flower.”) It’s recently been reassigned its own genus in the Jepson Manual.
California natives in every way, monkeys prefer spots with coastal breezes and half-day sun; and elevations like eyebrows, crowns, and canyon cliff faces, where they dangle and lure zooming hummingbirds.
They are specially evolved to tolerate local conditions, including serpentine soils. And as Viewed, they have no problem coping with the mineralizing vapors of hydrothermal vents, skarns, and porphyries. In fact, they seem to seek these formations out. Blast ‘em with your copper salts, your sulfides, your ammonias and hydrocarbons and metasomatizing acid baths. Ha ha! Let the invasive brome and bracken lie slaughtered on the field, their husks bleached, chemically scorched. The hardy CFP monkeys will just peek over the edge, and laugh and laugh, their goofy heads nodding moronically.
[Sen. Alex Padilla has proposed up to a million acres in California will receive federal protection. Hurrah! He is to be congratulated for moving much faster than I can — for a whole month, I’ve been working against time and Google tech troubles to get a comprehensive SFVNatGeoMon website up, making the case for preserving the Sylmar-Pacoima-Tujunga hills. These lands are mostly already public, but currently they are orphaned, with little upkeep and almost no public services (even trail markers). Thus, it is treated as a dumping ground, a wasteland. The side canyons of Lopez are still being leased off and paved over, level by level, as parking lots for cheap parking and storage of big-rig trucks and industrial junk. Of course this completely destroys the habitats, and scares off the animals. The SFV Canyons are on a slippery slope, which are the LA watershed, seem at terminal risk of being taken over by homeless jungles, dirt bikes and off-roaders, and remaining a dangerous junkyard, forever. The City is broke, the State is broke, and may be for a while, because of Covid-19…Federal support is the only thing that will cut across multiple agencies like the City, the DWP, the Forest Service, and the MCRC. And the geological theme would both unify the disparate canyons in the public mind, giving them a positive identity, and also help encourage local use, appreciation and respect for this integral part of Los Angeles.The investment would be small, for the benefits gained. More details will appear in coming blogs, and eventually, on the website when it emerges.
Since February of 2019, I’ve taken many Views of Sugarloaf in Lopez Canyon. A headless sphinx; a kaleidoscope of sedimentary rock; crown jewel of the Land of Contrasts. A riddle, wrapped in an enigma, wrapped in buckwheat. Now, I see it as an old volcano.
There are no volcanoes in Los Angeles, is the consensus of the Internet; but that’s misleading, a partial truth. True in that there is, or has never been discovered, a volcano with a textbook, one-vertical-pipe, ash-spewing Mt. Vesuvius model. Clearly Sugarloaf is not that. But from various ages and in different geological contexts all over the foothills are evinced quiet but insistent signs of molten-lava volcanism, such as the Miocene intrusions at Limerock and Gold Creek. And related to those, there may have been much more volcanism of a different but important kind, mudvolcanism; its traces may only have been revealed in the last few years, as they have been active.
The Dec., 2017 Creek Fire was no simple brush fire, it must have been fed by methane flaring from breccia pipes in the mud volcanoes of Sylmar-Pacoima-Tujunga. Methane flaring is the common eruption of mud volcanoes.
Mudvolcanoes are well-recognized internationally, associated with petroleum and hydrocarbon districts. They are even famous throughout the solar system, for the phenomenon is found on Mars; and everybody involved in planning our invasion of the Red Planet is looking intently and expensively at them there. But they are obscure in California, despite the fact that the recent Creek Fire, the Sand Fire, and the Saddleridge fires were all almost certainly fueled by MV processes: namely, the copious methane likely to have been released from hydrothermalvents in the hills, like the formations pictured here. Government needs to put geologists and biologists on the ground here to study them, and the land needs to be protected from any other use or development than as hiking and open space, until the risk of flares and gas-offs is better understood. Also, public agencies must take this new change in the land seriously; it means understanding that except for oaks, which have deep tap-roots and may very well “lure” gas to the surface, most chaparral plants only have roots six inches deep, and don’t send up a 100-foot flare when they burn.
Below is Kagel Mountain, known for its graphite deposits but not for the breccia pipes which bring it, and the micro-organism-excreted methane created with it, to the surface. As you might discern, there is almost nothing to this face of the mountain except breccia pipes. These lead down to ‘aureoles’ in the subduction zone. Older photos don’t show the outline of the pipes as clearly as they are seen today. Just like a backyard gas fire pit filled with sand and pretty gravel, the gas has no trouble venting up these pipes and will eventually flare off if ignited. It may not happen again for a hundred years, or never again.
The Creek Fire covers the quadrant. Note the big yellow flare at right, shooting out of Dexter Park
This cartoon from a mining company shows the process, but is misleading in the one-pipe vertical model. Ours are more likely to be horizontal or diagonal.
There are many articles online about MVs on Mars; I can’t provide links like I planned, since as of yesterday Google has suddenly stopped our websites from sharing links with each other; which was the whole point of the internet. But if you do your own online search, and are willing to load your own cookies, you might find much. Luckily, I copied a few links to science articles yesterday, on the general science of hydrothermal vents and mud volcanism:
Azerbaijan….is this is what Sugarloaf looked like once? Those striations are sand ducts, conglomerate-filled feeder pipes that bring mineralizing water and gas up from the hot high-pressure subduction zone below. It may take 100 years to take the journey. The little pyramid cones are called griphones, a mangling of the Italian griffone. Maybe in English we should just call them gryphons.
Below, a few of the huge number of recently active vents, cones, dribblers, eruptions, extrusions, seeps, and chemical blasts (in Lopez, Kagel, Limerock, Little T., Elsmere…). I could show a hundred more, and will, in future posts.
Recent (since about 2000) plate tectonics models illuminate the San Gabriel Range orogeny and the whole rise of the LA Basin— block capture and convergence, in a deep-sea and in-shore continental margin environment, where migrated and rotated fault blocks captured by the Pacific Plate were thrust up over, and/or down against shallow bay-shore shales and deep marine turbidites in a shallow subduction zone, forcing them under pressure towards magma intrusion centers relatively high in the upper mantle. All this, would predict a perfect environment for mud volcanism. These are similar conditions to the shale oil zones around the world where they are found.
The keyhole-shaped crater and flow formation atop Sugarloaf is the classic mud volcano vent. Next, the shape on a cone in Azerbaijan. Below, the Sugarloaf vent seen during the Creek Fire.
A new model for volcanism in pierced soft-sediment basins like Sylmar-Pacoima-Tujunga, shows how the plumbing can diffuse, spreading horizontally while rising through the sands via shallow feeder pipes. This new model supports what is seen on the surface. Mud volcanoes start, and are seen mostly, just offshore, but many are known on land, too, for the conveyor-belt thrust of continental crust convergence pushes some sediment layers up and over, while some of the seamounts, along with the sea, sink into the subduction zone. Now that there’s no bay left, our mud volcanoes are high and dry — until rains, or a temblor, or a shift in groundwater plumbing, fills them with caustic fluids again. Wh
Sugarloaf is certainly less active, but much prettier and dressier, than its cousins in Azerbaijan, the naked-prototype mud volcanoes, near Baku, atop the Caspian Sea shale oil region. In upcoming blogs, or soon on the new website, I’ll go into more detail about what I’ve witnessed happening in the local geology, including tracing some recent activity to the July, 2020 4.4 temblor in Sylmar; and the possibility that massive uranium deposition vents are blasting the walls of Elsmere Canyon with eerie green and yellow stains — the same colors seen staining the pipes feeding the big Azeri crater. Until then, I hope Patient Reader will take away the following key points:
That the hills are incredibly beautiful and unique, and full of hydrothermal vents, with breccia pipes and conglomerate pipes and seeps, lately developed or re-activated, which have recently been gassing off and extruding fluid, metasomized minerals and gases;
That the vents are linked to the liquefaction structures, sand blows, sand murmurs, and chemical bleaching recently found in spots everywhere on the slopes; and to the numerous recent soft-sediment deformations, fissures and rifts, gozzans and skarn, strange mudpots and fumaroles, bradyseisms and griffoni, now sprouting in the canyons;
That as a result of hydrocarbon venting and related groundwater anomalies, the hills look much different today than they did historically or even a few years ago. They might be undergoing an unusual period of rapid transformation, including mass wasting of the hills, and some areas seem on a path to total denudation of all living soil.
1877, Herman Herzog
1931, George M. Hendry
Now
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Three panoramas taken last week, encompass the magnificent View of the quadrant from the vault of Sugarloaf: first, looking northwest; second, northeast; third, south over the Valley to Topanga. Expand them, and see the land.
The Valley Village View 