pahavit (pahavit) wrote,

Alum Rock Park: Mineral Springs & Grottoes

Alum Rock Park: Mineral Springs & Grottoes

Last Saturday D. and I returned to Alum Rock Park to look at the mineral springs for which the park was once renowned and take some more pics. Here's mine.

On our way to the Visitor's Center, we see this lichen growing on one of the many rustic stone bridges crossing Penitencia Creek.

Inside the Visitor's Center, we find bits of Alum Rock Park's history.  Here are chunks of tile from the old natatorium, or indoor swimming pool (long since demolished).   The mineral-rich springs in the canyon were piped into separate bathhouses for men and women to "take the waters."

A mountain lion exhibit utilizing a feature from the old natatorium.

The "meteorite" is not really from outer space.

There used to be an enormous boulder two stories tall in Penitencia Creek that was said to be a meteorite and thought to weigh over 2,000 tons.  Scientists who studied it said it wasn't a meteorite but no one really wanted to believe it, so it was promoted by the Alum Rock Railroad as a tourist attraction in the canyon ("Come up and see the Meteorite!").  It wasn't really 2,000 tons either (more like 389 tons), but why let facts get in the way of a good story?  The huge boulder was broken up in 1918 to help with the war effort. Smelting yielded 39 tons of high-grade magnanese ore used in the manufacture of armor plating. This small chunk is part of what's left.

The last thing a ground squirrel ever sees.

Briones sandstone is a sedimentary rock originally formed in a marine environment.  Alum Rock Park was an ocean beach 15 million years ago.  Three kinds of ancient clam shells are embedded in the rock, cemented in place by calcium carbonate.

Wild pig skull.

A mystery skull lies on top of a display case, in need of cleaning and labeling.  My guess is it's from a deer.

This unlabeled bronze bust of an Indian in a "clutch the pearls" pose has real feathers wrapped around its head.

I have no idea who it is supposed to be.  The bust is on a base strewn with clear quartz crystals, with other semiprecious gemstones in the background.  I don't know what's going on there or what the crystals have to do with the anonymous Indian.

The whole Visitor's Center is a little odd.  Peculiar, unrelated items lie cheek by jowl in several display cases.  For example, the natatorium pieces pictured above are displayed next to Ohlone mortar rocks.  There is no connection I can see.  Here, a vintage strawberry soda can is next to railroad spikes at least a couple of generations older.  No interpretive signs explain the reason they are displayed together.  What is there relationship to each other?  We may never know. 

That Visitor's Center could use a few improvements, IMHO, starting with better edumacational signage on the display cases. 

Back outside at the creek, we see a pool full of fallen leaves.

Reflections in the creek glow like stained glass.

♪♫♪ I want to be your sledgehammer
Why don't you call my name
Oh let me be your sledgehammer ♪♫♪

It is next to the creek, almost covered by leaves.  Maybe it escaped from a display case in the Visitor's Center. 

The canopy of arroyo willows overhead.


A couple of fallen leaves, touched by autumn's hand.

There are jillions of buckeye trees in the park.

They are poisonous, don't eat! 

An arroyo willow next to the creek in the autumn sunlight.

Sycamore trunks have intricately patterned bark.

Nearly-bare sycamore branches reach across to embrace a bay tree.

These acorn woodpeckers are utilizing this dead sycamore to ready their acorn stash for the winter.  They can store as many as 50,000 acorns in a single tree.

Around a curve in the Penitencia Creek Trail, we come across the first of many springs seeping from the face of the cliff, creating a crust of minerals on the rock.  We also begin to smell a rotten egg odor, hydrogen sulfide.

The springs borrow their warmth, odors and chemistry from the rocks through which they percolate.  One of the springs is a constant 98º.  Another bears traces of arsenic (it has since been capped off).  Some of the springs are salty, some carbonated and most are sulfurous.  The sulfur in the water is the source of the rotten-egg odor which permeates the air and the water in the creek in the area of the springs.  Over 20 different mineral springs have been discovered in the park.

Around the next curve in the trail, we come across the first of many grottoes.

Tunnels were dug into the hillsides, and grottoes and decorative fonts were built to protect the different springs along the trail by craftsmen using native rock collected from the canyon.

More seeping springs, staining the rock in with their dissolved minerals and even creating little stalactites.

In spite of the noxious minerals oozing from the rock, ferns and oxalis sprout up in little pockets in the cliff face.

Another grotto.

One of the many rustic stone bridges crossing Penitencia Creek.

These tilted sedimentary rock layers alongside the creek show how this canyon was once an ocean beach that got knocked sideways by volcanic upheavals.

A peek inside a grotto whose spring is still running.

It smells bad.  I can't imagine how people drank that stuff, thinking it was medicinal. 

This field trip is brought to you by the number 12! 

This rounded mass of rock near the creek is evidence of past volcanic activity. It is deposited by minerals (mostly calcite) dissolved in the hot spring water. When the water reaches the surface, it cools and evaporates, depositing more minerals on the existing rock.

Dead fleurs along the trail.

Another grotto.

Lichen encrusts this tree trunk next to the creek.

To get to the creek, turn left at the beer can . . .

A little waterfall on the creek.

Algae mats, dead leaves and a little cress plant in the waterfall's plunge pool.

A large rock of Briones sandstone beside the creek, full of fossil clams.

The afternoon sky above the canyon's north rim.

One of the grungier grottoes along the trail.

Webby, drippy inside of grotto.

Oozy, seepy, slimy algae in grotto spring.

Grungy, gunky, seepy, oozy grotto grunge.

(Grungy, Gunky, Seepy and Oozy are the other 4 dwarves you never hear about. )

Camino Cerrado.

¿Cómo se dice "hefty fine" en español?

Black-tailed deer feeding ahead on the trail.

A look upstream toward yet another rustic stone bridge.

Some grottoes look tublike, almost like spas to soak in.  But people did not actually bathe outdoors in these tubs.  Each grotto is really a fancy little architectural showcase for that individual spring, reflecting the Victorian style prevalent at that time.  The waters were piped into bathhouses ("natatoriums") elsewhere in the park where people bathed in them.

Some grottoes are in really bad shape.

They have definitely seen better days.

Some grottoes still show fancy ornamentation.

Another little falls in the creek.

The crumbly masonry of the grottoes makes an impromptu rock garden for a sprig of oxalis.

Like most other springs along the trail, the grungy runoff from this spring flows right into Penitencia Creek.

I am really, really glad we did not try to drink from the creek downstream from here, where the water looks clear and shows no trace of the gunk pouring into it 24/7 farther up the canyon. 

A peek deep inside one grotto shows the tunnel dug into the hillside to access the spring.

This grotto has a substantial pool.

This grotto's pool is choked with leaves.

Looking up Penitencia Creek.

Lichen growing on the steps of another rustic stone bridge.

A pair of oaks up on the north rim of the canyon catch the lowering afternoon sun.

Another grotto.

This field trip is brought to you by the number 14! 

And by the number 13! 

Act up!  Fight back!  Fight erosion!

Backtracking, we decide to walk on the South Rim Trail for a while, and we get a warning.

They make it sound like a thoroughfare. (It is anything but.)

The trail begins to rise, and we get a view to the hill across the canyon.

This turkey tail fungus is growing in a rosette instead of the more usual fantail shape.

On the trail we begin to see lines cut in the pavement.

Lichen looks like whitewash and paint splashes on this live oak trunk.

We pass a lot of buckeye trees.  They go dormant and drop all their leaves in the heat of the dry summer, and their fruits are very conspicuous at this time of year among the bare branches.

There are those lines cut in the road again.

We think they were cut to install or repair a water main leading up to a fire hydrant at the summit, but who knows. 

This is an unusually gnarly buckeye trunk.  It seems to bristle with eyes.

As we near Inspiration Point, more of the north rim of the canyon comes into view.

More buckeyes.

A glimpse of the view from the top of the trail shows some smoke coming up from the valley floor.

I guess there used to be quite a view from up here, before all the surrounding brush grew up really high.  There used to be an edumacational sign here as well, apparently.

The sign probably showed the view of the valley floor below with prominent landmarks labeled and stuff, or maybe an historical photograph from the same place so you could see how much the valley has developed.  We'll never know.

Nothing says undying love more than your initials scratched into a fence with a ballpoint pen.  NOT.

Colorful lichen on boulders at the summit.

Heading back to the car, we pass through a mixed oak woodland and find this broken, rusted jar jammed into a tree at eye level. 

The mixed oak woodland.

On Penitencia Creek Trail, we pass by a mossy stone horse trough, full of leaves, sticks and dubiously-colored water.

This field trip has been brought to you by the number 2!

Tags: algae, alum rock park, beer can, bird, canopy, deer, fern, field trip, fungus, grotto, indian, lichen, maple, moss, mountain lion, owl, sign, skull, spring, step, sycamore, turkey tail fungus
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