Editor’s note, I think I wrote this chapter twice.
Frances had mail.
To: Frances Watson
From: P. J. McClintock
Subject: Inconveniently Deep Hole aka Xblanque.
Dear Frances,
I received the completed lidar scans from Merl about 12 minutes ago. Yep, that’s IDH, Inconveniently Deep Hole. We have 10 meter radar topographic scans of the Hole back to the early 2000s, and better than that for some years since. As far as I know, you’re the first ever to scan the entire surface at close range. The Pool of Xblanque, as you call it, occurs on survey maps back to the 1920s, just tagged by an elevation contour: the interior has no detail indicated at all. “Here be dragons.”
The name ‘Inconveniently Deep Hole’ crops up in cave literature around the same time, in reports of cenotes in the Yucatan. The thing about the name “Inconveniently Deep Hole” being a translation from Mayan is a myth, by the way, perhaps an invention of yellow journalism later taken as fact. No one knows what the feature was called by ancient people in the area.
Xblanque is not the largest cenote of the Yucatan, but large enough so that it displays some classic features associated with larger examples of such secondary karst structures. The trees are indeed growing on islands of collapse, connected by shallow pools above submerged breakdown resting on the cenote floor. Agree with your friend (?) Jo Stapledon that the large lighter colored mass in the center represents a flat plain on the largest of these collapse structures, largely occluded by tree canopy. A 3D rendered texture map of the reduced lidar map plus video would be of inestimable value, but the computing and staffing resources would be formidable, our own “Hilltopper” quantum computer cluster would take years to perform the analysis of your data set.
Am intrigued as to the greater scope of this research. I web searched Jo Stapledon and the only reference I could find was to a marsupial specialist in Australia. Is there another Jo Stapledon?
Best,
P. J. McClintock
Center For Karst Topgraphy Analysis
Western Kentucky University
To: MaryLiz Bender
From: Clint Lex, Ph.D.
Subject: Pool of Xblanque LIDAR model
Dear MaryLiz,
We received and unpacked your LIDAR data set this morning. Dr Groves, our emeritus director, was in to give the monthly coffee talk, but the star of the colloquium was the holographic walk through of your model, the feature you are calling the Pool of Xblanque.
It feels weird to introduce Dr Groves, who in my field (karst hydrology) needs no introduction, but Chris is a pioneer in the digital modeling of karst (cave) features, going back to the 20th century. I watched him during our 3D presentation with interest, and at one point Dr Groves turned to me and silently mouthed the word ‘Yucatan’. I understand the sensitivity of your discovery, but I nodded back.
To the question of ocean access to the cenote via air filled cave passages, sea level rise during the period 1960-2050 may indeed have inundated (filled with water) cave passages which were formerly filled with air, during periods in history when the sea level was lower than presently. But even given anthropogenic climate change, that’s not quite enough. Those cave passages have been mostly filled with water since ages past.
Generally, the limestone of the Yucatàn is far younger than comparable cave bearing rocks in Kentucky, only 65 million years old or younger. The ancient coral reefs which form the cavernous limestones of the Yucatan peninsula were lifted to the sky around ten million years ago, after approximately 55 million years of reef formation. The oldest documented passages in Yucatàn are younger still, around 175,000 years old. Sea levels have been stable in the region for approximately 5,000 years. Although climate change has led to slight increases in the last century, the bulk of cave formation in Yucatan occurred during a relative minimum in sea level as a result of a global temperature minimum locking up water ice at the poles.
Those old cave passages may or may not have been large enough to allow human beings to pass through them, even when filled with breathable air. But given the size of the cenote, the potential remains for discovery of large cave passages linking the cenote to the Gulf of Mexico.
Attached please find an expanded XYZT file, with your LIDAR data embedded in the USGS model for that segment of the Yucatan Peninsula, the Woods Hole model for the seafloor. The “T” in XYZT stands for “Time”, by the way: you can dial up any year you like, and the model will show you the water surface for that year. My students enjoy pulling up the timeframes representing storm events (hurricanes), which shows a rare negative storm surge. These momentary and local depressions in sea level have two chief causes: a slight depression of sea level occurs in regions of high atmospheric pressure. The other, dominant mechanism is easier to understand. As a violent tropical storm or hurricane blows past a small bay, the local sea level may drop, with dramatic effect, as the wind itself sucks water our of the neighboring bay. These events have a time scale of scant hours, but they are real. Such an event could, in theory, introduce air to passages normally filled with seawater,and postentially cycle breathable oxygen into air filled pockets in some cave passages.
MaryLiz, your adventures in space are known to all of us, here at the Center. I speak for all of us in reminding you that water-filled caves are among the most dangerous to explorers.
Before you enter a cave, please ensure that your team understands the risks of underwater operations in the cave environment. We are prepared to provide resources in ensuring your team’s safety, and hope to remain in the loop on any further work in this area.
Sincerely yours, Lex
Clynt Lex, Ph.D. Center for Cave and Karst Studies Western Kentucky University Bowling Green Kentucky
Bender closed the lid of the laptop. Time to unplug and think.
UNESCO, the “blue helmets” charged with protecting the Earth’s natural resources, had been reasonable, but firm. The relict population of wallabies within the Pool of Xblanque were subject to absolute protection by force of international treaties meant to give voice to the voiceless species of planet Earth. The fact that the wallabies had been purposely bred during the Cold War meant that its location was so sensitive, it was absent from the UNESCO roster, effectively a planetary state secret.
Bender’s team’s innocence and naivete in visiting the protected cenote was the only way they all could possibly have made it there to collect the precious 3D map of the cenote, now carefully annotated by the WKU team to include the surrounding geology and hydrogeography.
They had jaunted to Yucatan without a thought to publicity. If they had announced the expedition, aforehand, all of this would have ended on the Progreso Quay.
Bender sighed.
On the plus side, since their intrusion was innocent UNESCO only demanded forgiveness, since it was far too late to ask permission. Aude et Effice.
It was late at night, and Bender was starting to lose focus. What was planned for tomorrow? There was something… what?
I remember. A day of rest for the whole team. I ordered it myself.
Bender meditated. What would Neil Armstrong do? Return to basics. What is the core question?
The Wallabies. How did they get inland to the Pool of Xblanque, so many miles inland from the Gulf?
From the sea… from the sea….
Bender slept.
Bender awoke at 6 AM to the aroma of fresh coffee. A day of rest? Her crew were rising in open revolt against any semblence of a day of rest, and were showing up to work anyway. The whispers grew louder as the ranchers emboldended themselves to wake up the boss.
Bender coughed, involuntarily, and the noise outside grew still.
OK, my people. I am awake. The clock said 6:07. Bender rolled to the side of the bed and fumbled for her Tereshkova slippers, and then for the door to the mess.
The lights were all on. Bender winced.
Merl: “They’ll never let us back there.”
MaryLiz opened the door to the mess. Frances, Merl, and Jo. The coffee urn smelled of burnt coffee. Cap spoke. “We may not need them to.”
Merl looked at Cap with a conspiratorial eye. “Stealth tech?”
“Ha. I neither confirm nor deny. Stealth isn’t the right word. But ‘tech’ might be.” MaryLiz glanced at Merl, and crossed to the coffee urn, which was empty. Bender opened a drawer and drew out a new packet of coffee.
“Not stealth, or stealth tech. But perhaps cover, of a sort. Academic cover.”
Merl snorted. “Your friends with fancy degrees are goin’ to save us from the most fanatical biological conservation group ever conceived?”
Our friends at WKU looked at our scans. The Pool is only a few thousand meters from the coast. There may be cave passages between the Pool and the sea. Unfortunately, they are all full of water.” Bender frowned on purpose. The Western Kentucky University people had been adamant on the risks to human safety.
Frances broke the silence. “Does UNESCO monitor the caves, too?”
“They’d like to,” replied MaryLiz. “But caves are tough – and expensive – to monitor in real time.
The coffee was ready. MaryLiz poured her second cup. Merl was staring at the screen, at the map of the Yucatan Peninsula.
“These blue dots,” said Merl, “they’re caves?”
“Cave entrances,” said MaryLiz. “They are all over the Yucatan. They all have water at the bottom. They’re natural formations, made when underground caves get so close to the surface that the ceiling collapses, all the way to the surface. There are thousands of them in Yucatan. They call them cenotes.”
Merl stepped back from the map. “Thousands.” Merl said. The map did show thousands of sinkholes.
Merl reached both hands out towards the map, palms down, thumbs touching, outlining a crude semicircle which covered most of the blue dots. “Why are the cenotes laid out like that? That curve is so smooth. Like I’d make with a drawing compass.”
No one knew. Bender loaded fresh grounds in the coffee urn.
Bender brought the discussion back to earth. “I don’t want to go behind UNESCO’s back on this. The last thing we need is be Federal trespassing charges in Mexico. I am just wondering how much we can learn, legally, without bothering them.”