Tales & Trails of a Traveling Wiseguy

Italy Travelog #19
Santadi, Sardinia - Wednesday, 28 May 2025, 1pm

Our organized activity at Club today was a cave tour at the Is Zuddas Grotto in Sardinia. We could have opted for ruins and wine touring, mountain biking, or horseback riding instead but chose this because it was the most up our alley. As a serendipity we learned a lot about Sardinian history from our tour guide on the van ride over here, even though at the cave she handed us over to a cave specialist.



As we started into the cave I wondered if I'd chosen the wrong activity. I mean, limestone caves are basically all the same. And we've seen a lot of them. Maybe we should have done the ruins and wine tasting tour instead... though Hawk doesn't/can't drink, so that's why.



One interesting formation we saw is "Medusa". ...Okay, maybe that's more interesting linguistically than geologically because "medusa" is the name in Romance languages for jellyfish. It's like only we stupid anglophones have a different name for jellyfish that doesn't evoke the Greek myth of Medusa. And this formation does look more like a jellyfish than a demonic woman with snakes on her head.



Anyone who's visited a bunch of limestone caverns probably looks at the photo above and puzzles for a moment, "Wait, what's going on here?" That's because stalactites and stalagmites are virtually always oriented vertically, their shapes driven by gravity. Well, what happened here is that a block of stalactites fell from the ceiling. They're at an angle because that's how the block landed when it fell to the floor of the cave. And note it fell, like, millions of years ago, because of the size of stalagmites growing atop it.



Above I noted that stalactites and stalagmites virtually always form vertically. There's a category of stalactites that don't. They're called helictites, and they can grow in crazy shapes, thin tendrils extending sideways, curving around, forming curls and "S" bends, and even forking.

"What does Science know about why helictites form in such eccentric shapes?" I politely asked the guide, who'd been getting a bit frustrated about the parallel lesson in limestone formations I'd been whispering to a colleague who'd never been in a cave before.

Strangely I'd never though to ask this before. I mean, other cave guides have pointed out helictites, so I've known what they are, by definition, but not the science behind them. To his great credit, this guide had an education answer.

First, there are multiple theories, the guide explained. That's classic science right there. Science includes uncertainty, and true scientists acknowledge when/where it exists— an unfortunate fact that is frequently exploited by demagogues nowadays to dismiss science as wild theories that are merely personal opinion, all equally valid.

The leading theory, which our guide holds, is that helictites develop in eccentric formations because their rate of water flow is so slow that water evaporates quickly. Remember, all these cave formations are driven by the action of water responding to gravity. Rain water seeping through small cracks in the rocks above dissolves limestone. It flows downward along existing formations and forms droplets at the bottom. Rock re-crystalizes from these droplets. But with helictites it's thought that the water flow is so minimal that the water doesn't even form a droplet; it evaporates before it gets to that stage. Thus limestone deposits may form on the side of an existing limestone structure, or— via capillary action— at its upper tip.

New Zealand Travelog #36
Hamilton, NZ - Fri, 19 Apr 2024, 5pm

We're back to our cozy apartment in Hamilton atfer another day of adventure. Today's adventure was a stitching together of a few paid tours plus a few completely self-guided things:

• We visited the Ruakuri Cave (vendor link) with a guided tour. On the trip we heard about a few of the features in limestone caverns, the history of the Maori people, and glowworms. The cave features part was the least interesting (to me) as those features are the same around the world, this was hardly our first cave tour, and this cave/guide wasn't the best for highlighting features. I mean, anyone can tell you what stalactites and stalagmites are. I think I learned that in 4th grade science class.... But learning about Maori history was really interesting. Our guide was Maori and descended from the chief of the tribe that settled this area 750 years ago. He really personalized what it meant to him. Plus, we were among a small group that was all adults, so we asked lots of questions about Maori language, culture, and history.


• Next we visited the Waitomo Glowworm Caves (vendor link) nearby. This one focused more on the glowworms, though we'd already learned the basics at the other cave: The "worms" are the larval stage of a species of insect— so technically they're glow-maggots, not glowworms. They grow up to a 3cm long. They glow through bioluminescence, which they use to attract other insects for food. They drop sticky lines, sticky similar to how a spider web is sticky, to catch those insects. Again, this info was all a repeat from the previous tour. That's a risk with cave tours: once you've done one you've done most of all of them. The standouts on this tour, though, were that a) there were a lot more glowworms-maggots and b) we toured part of it on a boat through an underground river. I've never done an underground boat tour before!

After these tours we were on our own and visited 3 short hiking trails in the area.

• The first of these was Mangapohue Natural Bridge. A short trail led into a beautiful stream canyon to a large overhead arch. We had the area mostly to ourselves. That's always nice when outdoors, and was doubly nice after a morning spent on paid-for tours where buses pulled up to disgorge tourists by the dozens.


• Next we hiked to Piripiri Cave. A short but steep trail leads up to the entrance to a large, single-room cave. How large? I estimate it's 80' deep and 50' across. And, yes, 80' deep because you enter it near the top. Wooden stairs descend to the bottom.


• Finally we hiked to Marakopa Falls. The weather had been crummy all day but wasn't really a factor up to this point. I mean, it almost doesn't matter if it's cloudy and drizzling outside when you're in a cave. And cloudy-and-drizzling helped with the atmospherics at the natural bridge. But here at these falls it started to be a real minus. Marakopa Falls is large, which is a big plus, but the last part of the trail to it has been washed out due to floods, and with today's rains what was left of it was too slick to traverse safely... even for experienced hikers. (And by "safely" I mean "without getting covered in mud from slipping a few times".) So we viewed the falls from across the canyon.

5 Days in the Desert travelog #15
Cima, CA - Sun, 25 Dec 2022, 5pm

I left off in my last blog entry with us descending into the bowels of the earth after an hour+ long drive to the remote lava tubes in Mojave National Preserve. I decided that after all that effort I would not be deterred by having to crawl on my hands and knees a bit, so in I went.



Well, I didn't have to crawl right away. The entryway (above) was tall enough that I could pretty much stand and walk as I carefully lowered myself down the jagged rocks. Not far inside, though....



The ceiling dropped low, not much more than 3 feet high. "Is this the end?" we wondered.

Hawk delved deeper as she was able to navigate under the low ceiling merely by bending over and squatting. It opened up again after 10 feet or so.

"C'mon," she said. "It's worth it!"



On the other side of the low ceiling was this fairly sizable chamber. Overhead are three windows to the outside. Two are obvious at the top of the picture (above), split by a small arch. The third is at the far end of the chamber, where you can see an orange light filtering down. We'd seen the split window along the trail on the surface as we walked to the tube entrance but not the smaller window.

Good new/bad news: While this chamber was a great find, the lava tube definitely ended here. And the other direction from the ladder ended in about 15' with nothing but a pile of rubble from a collapsed roof. Oh, but there was one other thing on the way out....



This rock struck me as looking something like a geode. Well, not a geode because those aren't crystals hanging down from the topside. It's a volcanic rock shell with some smoother minerals on the underside.

Speaking of underside, it was time to leave the underside of the earth and get back to its surface.

We returned to the car and picked our way carefully down the lava 4x4 trail. Back at the Subaru parking area we met another pair of visitors arriving— in a Subaru— and chatted with them about road conditions. We'd seen them arriving from the opposite direction and wanted to know how passable routes other than the Mojave Road (link to my YouTube video) are.

It turned out to be a two-way exchange of information... like the best 4x4 backcountry conversations are. Our new acquaintances were Chinese visitors who spoke limited English. But their English was better than my extremely limited Chinese.

I unfolded a paper map and used that to help frame our halting conversation. They'd come from the north on different roads than we took from the east. Their route was obviously passable, though they warned they had to drive slowly, like 5mph in some difficult parts, and never faster tha 15mph in the best parts. I cast a side eye toward their Subaru and figured that we'd do better than that. In exchange, I explained for them how to drive the Mojave Road. They were using only Google Maps on a phone... and there really wasn't any signal out here, miles from the nearest paved road.

We parted ways; they went toward the cave while we started north.



Right away the road was smoother than the Mojave Road. It was graded dirt and did not have those whoop-de-doos (YouTube video link) that had forced us to keep our speed down— otherwise we'd have been looking like stunt drivers from The Dukes of Hazzard!

There was one tough part about a mile out where we climbed a rocky hill navigating past a mostly defunct mine. Our capable 4x4 walked it. After that it was smooth sailing. We picked up a route following along utility lines (pic above). That confirmed we were headed the right way. If in doubt, follow the telephone lines back to civilization!

High Desert Weekend Trip-log #11
Red Rock Canyon State Park - Sun, 27 Mar, 2002. 1:30pm

After driving around near the falcon cliffs in Red Rock Canyon State Park we decided to head to a spot in the park simply marked "overlook" on our hand-drawn map. The trek turned out to be both less and more than we bargained for.

It was more because the map was not drawn to scale. What looked like 3 miles on the map was more like 6 in real life. And while the disinterested park range warned us about the "rough" road near the falcon cliffs— which was rough only for glorified grocery-grabbers in 20" wheels and summer tires— the road out here was genuinely rough. Our Xterra still traversed it with ease, but only because of its high clearance in addition to 4 wheel drive.

"Less" described the overlook once we found it. Meh, I thought. But there was something fascinating right next to it: a mine entrance!



This wasn't marked on our map— our not-to-scale, hand-drawn map offered by a disinterested ranger who doesn't even know the true condition of the roads in her park— but I found out elsenet it's the Old Dutch Cleanser Mine.

The deserts of California are studded with old mines. Many of them were gold and silver mining claims than never paid out. But many are for softer minerals peculiar to the desert geology, like talc, gypsum, boron, and— here— white pumice. White pumice is the gentle abrasive in old for Old Dutch Cleanser was mined here until the 1940s.



he mine shafts descend at roughly 30° angles and they are deep. Our (small) lights couldn't penetrate to the ends, or even bends, in the descending shafts. And no echo was returned. And coldness radiated up from the shafts. These mines that were used for decades were suddenly abandoned almost 75 years ago. It was kind of spooky.



The walls and floors of the mind are still covered with a soft, white mineral. At first I thought it was talc, then gypsum. But no, it's white pumice.

Elsenet there are videos of people exploring the mine deeply. We did no more than scratch the surface because we didn't have the right equipment with us— particularly helmets and stronger lights.