The Flickr Oldoreroad Image Generatr

This is the zoomed-in companion to the Part 12 image. So I'm still facing southwestward, and I'm at the same cliffside pullout from which the Part 11 cuestita photo was also taken. See the top of that description for the exact location.

This is the last photo I ever took at Big Bend National Park, and this is my last post devoted to that magnificent place. Both the times I spent exploring there and my embarking on this photographic journey so many years later have been deeply joyful and immensely productive experiences for me. I wish I could return to see that landscape one last time, but given my current circumstances that is most unlikely.

Still, instead of dissolving into a state of nostalgia or downright loss I think I'll bask in this picture and be grateful that the park gave me such a glorious sendoff in sunset colors.

I like how the foreground and middle ground are still visible enough in the fading light for their rock units to be recognizable. On the left side of the stream, where I'm standing, there's the Aguja Formation, and on the right, the more colorful Javelina Formation. Both are Upper Cretaceous in age, and both are tilted downward toward the northwest. I assume their dip is an expression of the great monoclinal structure that extends eastward over to the Sierra del Carmen.

The monocline formed as a response to crustal compression of the Laramide Orogeny. That mountain-building episode started in the Upper Cretaceous, probably not that long after the deposition of the Javelina, and continued into the Tertiary.

The Chisos Range on the horizon is 15 mi / 24 km from here. For a delineation of which peak on its jagged, back-lit silhouette is which, see the Part 12 description.

Ave atque vale.

To see the other photos and descriptions in this set, visit my my Integrative Natural History of Old Ore Road album.

Facing north-northeastward. Taken at a cliffside pullout. We'd just transited the Roy's Peak area and the McKinney Hills laccolith. This spot was 0.2 road mi / 0.3 km up from the McKinney Spring site, 7.2 road mi / 11.6 km beyond the Alto Relex locale where I took the Part 9 and Part 10 photos, and 19.6 road mi / 31.5 km from the start of Old Ore Road at its junction at Park Road 12. And we were about 7.1 road mi / 11.4 km south of that track's terminus at the Dagger Flat Auto Trail.

There I go again. In coining the word cuestita I'm shamelessly inventing more wholly unauthorized geologic terminology. But it makes sense. if a cuesta is a ridge of tilting strata with one steep side and one more gently sloped, then certainly a mini-ridge of that description must be a cuestita. A diminutive landform deserves a diminutive suffix.

I've done this before. When I first beheld the miniature drumlins near Liberty Grove in Wisconsin's Door Peninsula, I christened them drumlini (singular, drumlino). Pretty classy, eh?

No photo-posting project involving my Big Bend slides has given me greater pleasure than this image. While I distinctly remember taking this shot twenty-three years ago, I was not sure until just yesterday why or where I took it. But after a number of tries I located this wee landform, humble as it is, on Google Earth. Zooming down to road level, I was able to duplicate the view here down to the same ridge and gully patterns, with the exact same profile of the Sierra del Carmen in the background. On top of that, when I rotated in place around to the southwest, I precisely reproduced the Chisos Mountains vista the next photo in this series will show. Pretty darned nifty, if I say so myself.

No doubt I'd wanted to stop here because the cuestita, actually a detached section of a longer ridge just to its south, exposes some interesting things in the Late Cretaceous Aguja Formation that is also present in the rest of the foreground and middle ground. Basically a shaly unit deposited in a number of lowland environments—stream valleys, deltas, coastal wetlands, and so forth—it also contains some sandstone and lignite, the lowest grade of coal.

According to the current USGS bedrock map of the park (Turner et al., 2011), the Aguja dips 45 degrees westward in this locale, and indeed that's very plausible if you look at the slant of the cuestita's uppermost strata and its backslope. And come to think of it, is that a bed of lignite sticking out at the crest? If so, some of it has broken off and rolled downhill.

In this telephoto image the cuestita seems to be right next to the road, but in fact it's over 200 yd / 183 m, or two football fields, from it. Had I been by myself, I would have hiked over and seen if the dark stuff was in fact lignite. But I had a tour group with me, the sun was setting, and we needed to finish our Old Ore trek while there was still some ambient light to navigate by.

But if my surmise is correct and there is some Cretaceous carbonaceous stuff visible there, this must be the Aguja's "lower shale member." The map cited above describes it as

light-gray to dark-gray, laminated, silty, carbonaceous shale, and some brown and gray sandstone and siltstone; contains some coal and lignite, and reddish-brown concretions and oysters.

At this point everyone in the tour group was hungry, and I'm sure we would have enjoyed the oysters, had they been fresh.

To see the other photos and descriptions in this set, visit my my Integrative Natural History of Old Ore Road album.

Looking northeastward at the western face of the Sierra del Carmen. This was taken in the same locale as the Part 9 photo, which is to say we're about 5.5 road mi / 8.9 road km north of the Carlota Tinaja stop documented in Part 7 and Part 8. That equates to being approximately 12.4 road mi / 20.0 road km north of the intersection of Old Ore Road and Park Road 12. How about that for a lot of geolocation?

This is a closer, tighter view of one section of the imposing fault scarp of the Alto Relex horst. To review the Laramide-Orogeny and Basin-and-Range tectonics that went into making this impressive feature, see the Part 9 description.

The rock unit we're gazing at is the cliff-forming Santa Elena Limestone, the Lower Cretaceous formation also so dramatically displayed in the park's Santa Elena and Boquillas Canyons.

When it's near or at the Earth's surface, the Santa Elena Limestone often develops deep vertical joints (fractures where no sizeable displacement has occurred) and karst (solution features created by acidic precipitation and ground water). Some karst features visible here include caves and widened joints.

As jointed sections of the Santa Elena cliff face continue to weather, they can turn into freestanding hoodoos, which often assume a spire- or chimneylike shape. The process of hoodooification has apparently not progressed as far at Alto Relex as it has at Boquillas Canyon, but there are a few examples of weird and funky forms emerging from the bedrock. Can you find any of them in this image?

To see the other photos and descriptions in this set, visit my my Integrative Natural History of Old Ore Road album.

Special philosophic-briar-patch alert: If you're here for the geology or natural history only, stop reading after the first unitalicized paragraph to avoid a toxic dose of authorial introspection.

Taken in the same place as Part 7 of this set, but from a slightly different angle. And still looking southwestward at a small canyon of a Tornillo Creek tributary. Here at Carlota Tinaja we're about 6.9 road mi / 11.1 road km north of the intersection of Old Ore Road and Park Road 12.

To briefly review what I mentioned in the previous post, the artfully stratified stone belongs to the Upper Cretaceous Boquillas Formation. It's composed of alternating beds of limestone and various kinds of mudstone, each representing a separate pulse of sedimentation near a margin of the Western Interior Seaway. In those days, that great body of saltwater bisected North America from the Arctic all the way to what will always be known to the non-idiotic as the Gulf of Mexico.

And now I'm going to do something unforgiveable by speaking primarily to myself about my own reaction to this photo: it has always triggered in me particularly intense associations with the blessed day I stood in this spot and took it.

I remember feeling a flood of awe and curiosity and calmness that cannot possibly be related, in word or image, to any other person. I was standing in the midst of so much sheer geologic beauty, so much monumental stillness, so much rock carefully arranged by unconscious processes. No human-derived landscape has ever been half so uncontrived or perfect.

There is that experience of four-dimensional immersion in the real that only deserts offer. In that stark and arid world there is the overwhelming impression that the only way to avoid delusion is to sense the legendary nature of everything.

At least that's what this kind of place, and this kind of picture, do for me. But as noted before, it's a lesson that can't be imprinted on others. Still, in the heart of this old agnostic Gnostic the memory of having been there, at Carlota Tinaja, says something like this:

Rejoice evermore.

Pray without ceasing.

In every thing give thanks: for this is the will of God in Christ Jesus concerning you.

Quench not the Spirit.

Lest I get slapped with a plagiarism suit from the Heavenly Choir, let me note that this is 1 Thessalonians 5:16-19, straight up. I was raised on the King James Version, so there you have it, in good Jacobean prose.

To see the other photos and descriptions in this set, visit my my Integrative Natural History of Old Ore Road album.

Looking southwestward at a small canyon of a Tornillo Creek tributary.

In this location we're about 6.9 road mi / 11.1 road km north of the intersection of Old Ore Road and Park Road 12. So we're almost 5 mi (8 km) farther up this rocky track from the site of the previous, wildly popular and deeply appreciated photo in this series.

Whoever Carlota was, she certainly had quite an impact on the local landscape.

I've already shown and described Cuesta Carlota, the prominent ridge that parallels the lower portion of Old Ore Road and whose northern end terminates just east of here. And this scenic spot is known as Carlota Tinaja. That requires a bit of explaining.

It's my understanding the Spanish term tinaja denotes a large jar or other similar ceramic container. This leads me to this post's title, which is a play on the old schoolyard riddle, "When is a door not a door? — When it's ajar." Get it? When . . . it's . . a . . . jar. Of course, it loses its punch when it has to be explained.

But in this case, when is a tinaja/jar not a jar? — When it's a natural depression in the bedrock where standing water collects and wildlife and livestock come to drink. That's a nice poetic adaptation of the word, but I don't know if it has that additional meaning far and wide in Mexico and the adjacent US, or is just another of those funky things specific to the alternative universe that is Big Bend.

In any case, there must have been one of those watering holes down in that streambed.

If you've been to this park and spent some time in Boquillas Canyon and Santa Elena Canyon, you know that one of the area's big geologic stories has to do with the series of distinctly stratified Cretaceous-period formations on dramatic display. These contain a lot of limestone, but include other sedimentary rock types, too. They formed after North and South America parted company during the breakup of Pangaea.

In the big Rio Grande canyons, however, most of what you see are Lower Cretaceous units, including the massive, cliff-forming Santa Elena Limestone. Here, however there's a beatifically lovely exposure of the Upper Cretaceous Boquillas Formation. And according to the USGS map of the park I often cite (Kenzie J. Turner et al., 2011), the rock here belongs specifically to the Boquillas' San Vincente Member.

The booklet that accompanies the map describes the San Vicente as

Medium-gray, finely crystalline, thin-bedded limestone, and brownish-gray and yellowish- to light-gray claystone, calcareous shale, marl, and chalk. Limestone is argillaceous and chalky; claystone is calcareous and contains some clay minerals including kaolinite, montmorillonite, and illite; about 145 m thick.

And thin-bedded it definitely is. Such flaggy strata as these can produce striking patterns and textures.

Apparently the Boquillas Formation owes its origin to sea level rise and the establishment of the Western Interior Seaway. This great swath of seawater not only covered the Big Bend region; it transected this continent from north to south. An ambitious mosasaur or ammonite could have traveled all the way from the Arctic Ocean to the correctly named Gulf of Mexico.

To see the other photos and descriptions in this set, visit my my Integrative Natural History of Old Ore Road album.

This image shows the same plant featured in Part 5. So it was taken about 30 yd (27 m) east of Old Ore Road, on the Chihuahuan Desert floor 500 yd (457 m) east of the foot of Cuesta Carlota, and about 2.0 road mi (3.2 km) north of its intersection with the paved park road to Rio Grande Village (Park Road 12).

This specimen, a fine representative of Argemone chisosensis, otherwise known as the Chisos Prickly Poppy, does an excellent job of attracting desert pollinators to its large, five-petaled flowers. But it must also try its best to ward off hungry browsing animals. Any wildflower enthusiast foolish enough to touch its leaves is likely to suffer multiple puncture wounds.

Many online images of A. chisosensis show plants with pink or lavender blossoms, but the only examples I've seen—all from this one locale—were a chaste white instead.

Recently, having been told, more or less, that I have no photographic technique, I feel compelled to prove that point conclusively. I'm doing so by posting this shot. The wind was blowing pretty vigorously when I took it, and the four flowers visible were deflected somewhat to the right. So I failed to capture all their inner anatomy and scenic potential. Mea maxima culpa.

Had I proper photographic technique, I would have held up the tour I was leading at the time for several hours, till the breeze died down. Or I would have packed a large portable wind barrier. I would also have waited for the Earth to rotate until the lighting was perfect, and I also would have had a more expensive camera with a bagful of detachable lenses.

However, now that I know the importance of proper photographic technique, I will jettison my previous, uncreative reason for taking photos: to simply document, record, and learn something rather than be a technology-obsessed shutterbug who doesn't care to know what he's looking at.

By the way, if you'd like to see more pathetically unartistic examples of my lack of photographic technique, take a look at this and this and this and this.

To see the other photos and descriptions in this set, visit my my Integrative Natural History of Old Ore Road album.

Taken about 30 yd (27 m) east of Old Ore Road, on the Chihuahuan Desert floor 500 yd (457 m) east of the foot of Cuesta Carlota. And this spot was about 2.0 road mi (3.2 km) north of its intersection with the paved park road to Rio Grande Village (Park Road 12).

The marvelous plant on display here is a Chisos Prickly Poppy, Argemone chisosensis. The next shot in this series will show its flowers at closer range; this is the habitat shot. That said, there are two fully developed, white-petaled blossoms visible here. They're being tilted over to the right by a stiff breeze. This requires no further explanation, because it's always windy when I try to photograph wildflowers.

Chisos Prickly Poppy is an edifying example of a plant with an accurate common name. It is indeed a member of the Poppy Family (Papaveraceae); it is fearsomely armed with long prickles; and it does like to hang in and about the Chisos Mountains, which are only about 15 miles (24 km) due west of this locale.

This particular specimen seems to have built a rock garden for itself, and is nicely edged with larger chunks of what I gather are mostly Buda Limestone. There may also be some bits of the Del Rio Clay. Both formations make up this side of Cuesta Carlota, and are Upper Cretaceous in age. The smaller overlying stone fragments make up the desert pavement, a common sight in the arid places of the American Southwest.

One leading explanation of how desert pavement forms is an eminently simple one: smaller rock particles once present have gradually been blown away, and only the pebbles too heavy for aeolian transport have remained. But there are other hypotheses out there. For another view of this intriguing aspect of the desert landscape, see this post.

To see the other photos and descriptions in this set, visit my my Integrative Natural History of Old Ore Road album.

(Updated on November 17, 2024)

On the eastern side of Old Ore Road, at about 1.5 road mi (2.4 km) north of its intersection with the paved park road to Rio Grande Village (Park Road 12). Facing just about due eastward.

The base of Cuesta Carlota, and small alluvial fans splaying out from it, are visible at top. For a rundown on the tectonic episodes that created this landform and the Sierra del Carmen in general, see Part 1 of this series.

From my standpoint, some Big Bend botany is long overdue. And here it is: the two xerophytic species that are, to me at least, the most iconic plants of both the greater Chihuahuan Desert regime and this park in particular.

In the foreground, and in other clumps farther back, is that bane of hikers, and especially of those in shorts, the yellowish-green to gray, bayonet-leaved succulent, Lechuguilla, Agave lechuguilla. When I was younger, this and its fellow agaves were placed in the polyphyletic, catch-all Lily Family (Liliaceae). However, when that big assemblage was deconstructed some years ago on the basis of advanced genetic and cladistic analysis, this genus came to rest instead in the Asparagus Family (Asparagaceae).

As monocots, agaves have floral structures in multiples of threes and seeds that contain a single cotyledon or rudimentary leaf. The other featured plant here, however, is a eudicot. So it's a member of a separate evolutionary lineage that has its floral parts, usually, in fours or fives, and two cotyledons in each seed.

So what is that other plant—the ghostly gray item that looks like bunches of giant pipe cleaners? It's Candelilla, which has the rather eye-catching taxonomic name of Euphorbia antisyphilitica. And yes, the specific epithet does indeed indicate how it was employed as a traditional herbal remedy. It is a member of the morphologically diverse Spurge Family (Euphorbiaceae).

Its greater economic use, however, has been as a source of natural wax employed in various applications. When you examine Candelilla up close, you'll see why it's been harvested for that; its main moisture-saving adaptation, outside of its lack of large leaves, is the waxy sealant that coats the tubular stems.

To see the other photos and descriptions in this set, visit my my Integrative Natural History of Old Ore Road album.

Facing northeastward from Old Ore Road, at about 1.5 road mi (2.4 km) north of its intersection with the paved park road to Rio Grande Village (Park Road 12).

For a rundown on the tectonic episodes that created this landform and the Sierra del Carmen in general, see Part 1 of this series.

This slide transfer is the grainiest of the set, but I decided it was important to include it here because it's a good follow-on to my first shot of Cuesta Carlota. For its shows, as the preceding image does less clearly, the punctuated, gully-transected nature of this leaning fault block that is the westernmost section of the Sierra del Carmen.

The Spanish term cuesta, which among other things indicates a slope or incline, has been incorporated into the English-language geological lexicon. There it means what you see here: a ridge composed of tilted rock layers that create a relatively gentle slope on one side, and a steep scarp on the other. In this case, the scarp is on the far (eastern) side. The large gap in the ridgeline at right of center is one of many places an intermittent-stream channel has cut through transversely.

Cuesta Carlota's strata are composed of the Buda Limestone and Del Rio Clay Formations. Both are Lower Cretaceous in age, and were laid down at a time of high global sea level before this section of North America started getting compressed by the underriding and shallowly pitched Farallon Plate.

Considerably farther north along the road, we'll leave Cuesta Carlota behind and see the main rampart of the Sierra del Carmen, much of it Santa Elena Limestone, on our right.

To see the other photos and descriptions in this set, visit my my Integrative Natural History of Old Ore Road album.

(Updated on March 20, 2025)

Looking northeastward from the unimproved rock-and-gravel one-laner called Old Ore Road. I'm here about 1.4 road mi (2.2 km) north of the intersection with Park Road 12 to Rio Grande Village.

For those wishing to traverse this former mule-team trail, the National Park Service website has this to say, in screaming caps:

"NOTICE: The Old Ore Road is currently in a very poor, unmaintained condition. Travel on this primitive road REQUIRES High Clearance AND true Four-Wheel Drive. It is NOT passable to passenger cars, minivans, motorhomes, and tiny crossover SUVs."

I think they really mean it. When I took a small tour group here in 2002, we were in a full-sized SUV. It was 4WD and qualified as high-clearance, I guess, but its Achilles' heel was its tires, which were designed for standard vacation driving on paved roads, and not for rough-country use. However, we'd already made it into the heart of the Solitario, albeit at the cost of one flat on the way back.

I'm happy and somewhat amazed to report that here also we were lucky, and were able to trek the whole, 26-mi / 42 km way, from Old Ore Road's southern end at Park Road 12 up to Dagger Flat Auto Trail, and then over to the Main Park Road connecting Persimmon Gap with Panther Junction. And not even a flat this time. That was much farther than I had expected. Still, there were a number of places where I had to get out and scout ahead on foot to make sure the vehicle could get through. And it was a very close call more than once.

All that duly noted, here's some emphasized text of my own: Do not assume that just because I was fortunate enough to get that far twenty-two years ago, you can do so now. The NPS rangers on site know best, and in my experience are spot-on in assessing road conditions. Were I trying get up Old Ore today, I'd use a helicopter or a blimp.

- - - - - - - -

In this first shot of the set, I'm recording the local geology just a few minutes' drive up from where this very unpaved track meets Park Road 12 between the big Tornillo Creek bridge and the Cuesta Carlota tunnel. And speaking of the latter, the tilted ridge shown above is indeed the Cuesta Carlota. In Big Bend Vistas, William MacLeod notes that this is the westernmost fault flock of the Sierra del Carmen range that is such an impressive and beautiful part of the Big Bend landscape.

Composed of upturned layers of the Buda Limestone and Del Rio Clay formations, both Upper Cretaceous in age, Cuesta Carlota has, as MacLeod aptly says, "an almost corrugated appearance" when seen from above.

This is due to the fact that it's been cross-punctuated at regular intervals by gullies—a reminder that, as ironic as it seems, erosion is the dominant terrain-shaper in desert environments. It may rain rarely, but when it does, its does so dramatically. Much downcutting takes place in short bursts.

At first glance that may be difficult to sense at this angle, but careful scrutiny reveals the existence of the crosscutting ravines where the ridge's deformed strata are visible.

In those ravines, and on the alluvial fans and the Tornillo Creek Graben floor as well, grows a wonderfully adapted Chihuahuan Desert plant community. I'm seriously tempted to focus on it for the rest of this description. But I have another photo better suited for that, and besides, I should review the general structural setting first.

The Sierra del Carmen owes its existence to various factors—among them two separate and especially significant tectonic episodes. The first, the Laramide Orogeny in late-Cretaceous and early-Cenozoic time. was a compressional phase in which preexisting rock units were pushed into a generally monoclinal orientation, with the strata bent into a stair-step shape that produced uplifted blocks bounded by basins.

Then, later in the Cenozoic (25-2 my ago), a large portion of western North American underwent an extensional phase that created the Basin-and-Range and Rio-Grande-Rift topography we see today. This activity extended as far inland as far as this area. The Sierra del Carmen was stretched and thinned into an alternation of down-dropped sections bounded by normal faults (grabens) and raised blocks (horsts).

While by no means as lofty of the central spine of the Sierra del Carmen, the Cuesta Carlota horst is still an impressive indicator of the park's Basin-and-Range tectonics.

To see the other photos and descriptions in this set, visit my my Integrative Natural History of Old Ore Road album.

Some yuccas or dagger plants at the National Park.

Taken along the canyon trail at Ernst Tinaja in Big Bend National Park.

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jasonfrels.com/2020/11/01/big-bend-ernst-tinaja-and-the-b...

A scenic view while traveling up the Telephone Canyon Trail on the Old Ore Road at Big Bend National Park, Texas. This was a very nice trail that continued a couple miles up into the Dead Horse Mountains. We walked the trail until we came to an old very well built rock/mortar dam and dry pond. I don't know the history but people went to a lot of effort to build the dam. I'm sure it worked nicely in rainy weather. The trail continued and connected to another very long trail but it was getting late and we saw what we wanted. Maybe a trail for the future. Also, as we walked up this trail it crossed a drainage with a lot of ground cover and it was over 70 degrees so I was watching out for rattlesnakes at every step!!! Thank goodness we didn't see any but they had to be there!!!
:-)

This is another image of Ernst Tinaja, Big Bend National Park, Texas but from the opposite side of the canyon. This view is looking back down the drainage towards the parking area about .5 miles away. It's a short and easy hike to get to this site. The tinaja is an eroded basin in the top of the Buda limestone and the thin sedimentary layers above it is part of the Boquillas Geologic Formation. This tinaja always seems to have water even in dry weather and some people suspect there is a spring feeding it. This drainage is from Questa Carlota which is on the western side of the Dead Horse Mountains.

Thin bedded layers of claystone, shale, limestone and sandstone in the lower section of the rocks making up the Boquillas Formation are seen in this image. These thin layers sit on top of the Buda Limestone in which the tinajas are carved by erosion. The tectonic uplift and faulting of the Dead Horse Mountains caused these beds to shift over the top of the Buda Limestone creating 'folds' as seen in this image.

Ernst Tinaja is another famous place at Big Bend National Park, Texas. Tinaja is a Spanish word for 'large earthen jar' or water hole. It is located in the Dead Horse Mountains on the eastern side of the National Park via the 4x4 WD Old Ore Road. This tinaja was created in the limestone rock by erosion. The layers above the limestone are thin beds of claystone, shale from clay, sandstone, and limestone. At times the thin beds shifted and created some strange folds that can be seen as one walks the drainage to the tinaja. This last trip to Big Bend actually had three tinajas that we saw. The first two were only a foot or so deep but the tinaja in pic is deeper, probably three or four feet deep?

Candelilla (Euphorbia antisyphilitica), Big Bend National Park. Click here for more images and info.