Santa Susana Mountains | The Valley Village View

Last week I finally found the elusive 3rd trailhead into Santa Susana State Park and it was the Gateway to Hell. It’s on something called Larwin Avenue in Chatsworth (which good luck finding) where condos and cul-de-sacs abruptly give way to wild, recently incinerated lands. The park is in the pinch point of the braid of three Transverse Mountain Ranges (the Simi Hills, the Santa Susana Mountains, and the Santa Monica Mountains.)

Google satellite View of the trailhead from what must have been this past spring, 2021. Note the chaparral looks more or less normal, not overgrown…in fact sparse, patchy or dead in spots, where the soil also appears singed. Drought, sure…but, a few rock-hollows show grey ash char. *ROCK-hollows.*

Caves around here are famous; the Chumash and Tongva and Tataviam shamans performed rituals in them, and many have cave paintings. [I’m assured that the few surviving true Chumash medicine caves are well-hidden and protected; and that all the art on the accessible cave walls is punk graffiti.]

It took a week of internet searching (“recent wildfire, Chatsworth, Larwin Street, SSSP, brushfire, Simi Hills…”) before I could find any news reports of the ”Jeffrey Fire,” last month. The capture above is from KTLA 5. There’s clearly some good fuel growing on the back slopes. But of course, that isn’t what’s burning, and its smoke would be black, I think, at least a little.

VITRIOL FALLS?

🤔It appears the scorchiest parts, and the freshest and deepest ash piles, are under rocks, between rocks, and deep inside piles of rocks. 😈Sure, tree roots smolder underground… 🤔 Why aren’t the crowns and limbs burned? And note how everywhere there’s flow of scorch, out of the holes…rivers of incinerated rock and oddly altered soil and, sure, some wood ash, and bounded or banked by badly deformed rocks?

🥺Why aren’t the rocks on top of piles of burned rocks, burned? 😈 Subterranean downdrafts. 🙄 Then why is there scorching in loose soil around seemingly emergent pillow basalts? Why does the pillow basalt appear to have wiggled its way up out of loose earth at all? Why is it that the minerally altered gravels that washed over or splashed on boulders, has become chemically fixed to their surfaces, like emory? Why is the ground under my feet still hot? 😈⚡️Erosion; homeless cookfires; turbidity currents, weathering invasive grasses. Punk kids! Drought! Dogs off leash! 😌This cliff face; there are an awful lot of different kinds of rock here from many different ages, intruded by volcanics and altered. Isn’t that a great recipe for hydrothermals, or gas releases? 😈 I only have Craig Claiborne’s recipe: too much sodium, not enough sulfur.

🤔 You’re sure there are no volcanoes in Los Angeles, right? 😈That’s right, you’re wrong. 🤭Never have been? 😈Well, if you mean the Conejo Volcanics… 🤔Oh right; where were they again, down in Orange County? 😈Maybe there, but also…..maybe, just over the hill. I mean, MILES away, five at least, past Topanga. Anyway, eight, ten million years ago. When all this was underwater! 😏 Right, making these pillow basalts! 😈Fire-fused sandbags buried after an old Western movie shoot. 😏 I wonder if anyone else has reported there are gorgeous volcanics in Santa Susana Pass. 😈It would take you YEARS to find a refrence in the geology literature online! HA ha ha ha ha ha ha ha ha. 🙄 So no Miocene pillow basalts intruding the Chatsworth Formation, at all? 😈 It concerns me that this matters so much to you. 😏…nor in the Simi Hills, no hydrothermal flows through all this basalt, no methane seeps near these fault zones, no underground mineral fires, or Vitriol Falls flowing out of those two white- and-yellow steaming mounds? 😈 Did you search for those things? 😌Yes! 😈Find anything? 🥺No. 😈THEN THERE ISN’T! 🥺Then what’s all this stuff here? 😈None of this stuff is here! HA ha ha ha ha ha! 🙄And who believes bloggers, I suppose? 😈 Welcome to the Devil’s Slide, sucker! HA ha ha ha ha ha!

YOUR OROGENOUS ZONES DEPT.

Look! Fault block mountains, there, and there…everywhere! All around! Closing in –!!

If Southern California is an Island on the Land, as Carey McWilliams dubbed it, the Transverse Ranges are the reason. They seal up the southern end of the Central Valley and separate Northern California from Southern California. The San Gabriels/Sierra Pelona division marks a key split in the northern and southern breeding populations among much of California’s wildlife. All that to do, and they’re still always on my back.

The mountains’ southerly-exposed bluffs and alluvial fans host the Foothill Alluvial Fan Chaparral and Southern Coastal Sage Scrub suites of the California Floristic Province, some of the youngest, rarest and most endangered organisms on earth.

Our microclimates are legion; this breeds diversity. Habitats feet apart, are completely different. Note the “Slope Effect” in Placerita Canyon on the back side (north side) of the San Gabriels:

Click below and fly souteasterly, over the whole Transverse Range Geomorphic in gorgeous relief:

But why do the mountain ranges trend easterly-westerly, when, as everyone knows, most of the other mountain ranges on the continent trend northerly-southerly? I asked a geologist. He didn’t get back to me, so I asked Norah and Ito. Here’s the scoop:

The cats say the reason is plate tectonics: subduction, rift zones, arc accretion, volcanics, uplift, rotation. Click on the animation by the seraphic C.R. Scotese. [Thank Thoth for his work at the Paleomap Project.] Try to spot western North America as it emerges: gasp when it does!

[Point of Awe: this is how far the plate theory has advanced since the 1970s, when the penny finally dropped for geologists and they realized it was the whole show, and had been, all along. Our generation of fifth graders were among the first kids who learned about “Gondwonaland” as basement bedrock of our knowledge. Our poor teachers must have been reeling with it, groping, grasping to understand so they could teach it to us. BLESS THEM.] But what I’ve been groping and grasping to understand lately, is that the Western Transverse Range Fault Block, Home Sweet Home, was formed all the way down by Baja. Santa Barbara and San Diego were suburbs of each other! Then it — we, the Transverse mountains and our Valley — were pushed and pulled and folded and rotated into position, transverse that is. This was quite recently indeed, and it’s still going on. It all hinges — quite literally — on the subduction of the “old Farallon Plate” and the rise of the East Pacific Rise, and the birth of the San Andreas Fault. Enjoy Tanya Atwater’s brief but brilliant video models of how it went down:

To really get an idea of this process at our very local level, consider Malibu Creek State Park. This is how it looks today:

Their resident geologist Don Kovalevsky has done a MAGNIFICENT set of illustrations tracking how this area of Santa Monica Mountains — and everything else — looked in various epochs. Click below for the whole series.

Click to access Don-Kowalewsky-MALIBU-CREEK-STATE-PARK-1.pdf

Today the Western Transverse Range Block is half covered by the ocean, with the Channel Islands the only peek-a-boo features. But the whole lump was made anyway from uplifted beach and marine sediments, bunched and folded, so even the bits that are high up in the mountains and miles from the tides, show their marine origin. I’m told you can find marine fossils, seaweed leaves and foot-wide nautilus shells, but I don’t need another solitary well-ventilated hobby…or do I?