Nicolas Steno

Paleontologists argue about which living organisms were first. In exchange, we living organisms get to argue about who was the the first paleontologist. There are many potential answers: the Greek philosophers/natural scientists Xenophanes, Herodotus, & Eratosthenes all wrote about fossils and recognized that parts of the land were once under water. Likewise the Roman geographer Strabo theorized about volcanism, subduction, and, most importantly, deposition. Pliny labored to apprehend the relationships between living creatures (and how they related to vanished or mythological beasts). A Medieval Perisan Ibn Sina (known as Avicenna in Europe) came up with a theory concerning the petrification of living things while the Chinese naturalist Shen Kuo recognized that climate and ecology changed over time (based on his studies of petrified bamboo).

However, to my eyes, the first paleontologist was an altogether more peculiar figure–a Baroque Danish polymath named Nicolas Steno who lived from 1638 to 1686. The son of a goldsmith, Steno moved through the scintillant aristocratic courts of Northern Europe in his era and thus knew Spinoza, de Graaf Ruysch, Lister, and Bourdelot (along with lots of aristocrats and churchmen who were probably all-important for securing patronage back then but about whom we are no longer obliged to care). As you can probably tell from the list of names I have given, Steno was dirst an anatomist, and it is through a strange quirk of dissection that he made a name for himself as a geology/paleontology pioneer.

In 1666 two Ligurian fishermen caught a colossal shark which they presented to the Grand Duke of Tuscany, Ferdinando II de’ Medici, who had the presence of mind to order it sent to Steno for dissection. Steno dissected the shark’s head and discovered that its teeth were extremely similar to stony objects discovered within the earth (then known as “tongue stones” but now called “fossilized shark teeth”). These mysterious triangles were once thought to have been hidden by imps or to have fallen from the moon. Steno recognized they came from sharks (perhaps giant sharks killed by the Biblical flood ?) and he devised a hypothesis for how they further came to be inside of rocks. Steno devised a theory of stratigraphy (a discipline of which he is arguably the founder). His four principles of stratigraphy laid the bedrock (heh heh heh) for Lyell, Hutton, and Darwin to piece together an accurate record of events on Earth. These four principles are:

1. the law of superposition (older layers lie beneath more recent layers…just like upon a cluttered desk)
2. the principle of original horizontality: (thanks to gravity, layers are horizontal when deposited)
3. the principle of lateral continuity: (layers within a basin extend in all directions according to the manner and order of their deposition and are contiguous)
4. the principle of cross-cutting relationships: if a disconuity cuts through a layer, it must be more recent than the strata

These principles seem childishly obvious to anyone who has ever made a sand sculpture–and they are in fact beautifully brilliantly obvious. Yet nobody had stated them together in the context of natural history or applied them properly to the stones beneath us. Indeed it would take another hundred years for scientific consensus to grasp their astonishing power and scope.

Sadly, Steno became interested in theological conundrums (and in the worldly power of the church). He converted to Catholicism and was ordained a priest. Soon he became involved in the counter reformation (where he found a new role arguing with Leibniz and censoring Spinoza). Thanks to his self-abnegating piety and devotion he was even raised to the rank of auxiliary bishop. His story becomes filled with weird hagiographic details like how he sold the bishop’s ring and cross to help the poor and how he ate so little that he, um died.

Steno was not unique among geology pioneers in being a churchman. However he is unique in that he has been beatified (Pope John Paul beatified him in 1988). According to the tenants of Catholicism, if you pray to Nicolas Steno he can intercede upon your behalf in heaven! However I recommend that you do not pay attention to such holy claptrap, but instead keep looking at interesting rocks and cool fish. That is where the real beatification occurs.

Mars 2020 Mission

What with all of the excitement in the world, it is easy to lose sight of the bigger picture…and of good things which are still happening during these troubled times.  This morning at 7:50 a.m. EDT, NASA launched an Atlas V-541 rocket from Cape Canaveral Space Launch Complex 41.  On board the rocket is a Martian lander containing the most sophisticated Martian rover yet “Perseverance” along with its robotic helicopter sidekick “Ingenuity.”

Artist’s Conception of Perseverance and Ingenuity on Mars

If the mission continues to go according to plan, the lander will reach Mars in February 2021.  Coincidentally, Mars will be crowded that month, since a Chinese orbiter & lander, and a UAE orbiter are also slated to arrive.  After much trial-and-error, I have faith in NASA’s sky crane landing system but it will be most interesting to see if the Chinese rover can “stick the landing”or if it is eaten by the ghosts of Mars (I hope not: humankind needs the Chinese data too, and NASA needs some competition to keep the creative juices and the congressional funding flowing).

The ultimate destination of the Mars 2020 mission is the Jezero Crater, a nearly circular crater 49 km (30 miles) in diameter.  The ancient crater is now partially filled with sediments–including a fan delta of ancient clays.  It is believed that if evidence of ancient life is to be found anywhere on Mars this is as likely a place as any to discover the ancient fossils.

Jezero Crater

Perseverance  has onboard a 4.8 kilograms (11 lb) pellet of plutonium dioxide which will provide the vehicle (and the miniature helicopter) with abundant energy for traveling, communicating with orbiters/Earth, assaying rocks, and operating a core drill for gathering geological samples of ancient Martian rock.  Additionally the rover will conduct material experiments concerning the potential toxicity of Martian dust and the production of pure oxygen from Martian atmospheric CO2.  Perhaps most excitingly, the rover will also carefully organize and cache the precious samples it gathers in preparation for a future retrieval mission.  Such a mission would involve landing, building and launching a Mars ascent vehicle from the Martian surface up to our proposed next generation Mars orbiter which would then load the samples on am Earthbound craft.  So the Mars 2020 mission is a tremendous step towards discovering whether life ever gained a toehold on Mars AND towards building next-generation space faring capabilities (for the dull and incurious earthcentric crowd that always decries space exploration–as though Earth is located somewhere other than space!– it should be noted that such engineering breakthroughs generally confer military, technological, and economic supremacy here).

Also, special thanks to our brilliant Norwegian, Spanish, French, and Italian friends!

So best wishes for the entire armada which has left our planet this month headed for Mars, but particular good wishes to Perseverance and Ingenuity!  Let’s hope we can discover some perveverance here to make it all the way to February 2021 (right now that sounds like it might as well be some HG Wells date in the impossible future).

Mary Anning

Happy Birthday to Mary Anning (21 May 1799 – 9 March 1847).  Mary’s life was a difficult one.  Her father was a poor cabinet-maker in Lyme Regis (a coastal town in Dorset, England) who supplemented his income by selling strange petrified shells and stone bullets which he pried out of a nearby sea cliff.  Mary’s parents had ten children, but only Mary and her brother survived past early childhood.  Her name was a hand-me-down from an older sister who had burned to death at the age of four.  When Mary was 15 months old, she and three neighbors were under a tree when it was struck by lightning and only Mary survived.  Her father died while Mary and her brother were young and they kept the family afloat by selling curiosities pried from the sea cliffs.  This was dangerous business: Mary’s beloved terrier Tray was crushed in a rockslide (he’s up there sleeping with the ammonites in the painting) and Mary narrowly avoided this fate herself on multiple occasions.  Additionally, living so close to the sea carried further perils: the family nearly drowned from a flood during a great storm.  Mary Anning died of breast cancer at the age of 47.  Her final years were marked by agonizing pain from the condition which she self-treated with laudanum (which caused the community to gossip about her morals).

This is a pretty bleak biography (although in no way atypical for a working-class woman from early industrial Great Britain).  So why are we writing about Mary 172 years after her death anyway? Mary Anning was a great pioneer of paleontology, geology, ichthyology, ecology, and invertebrate zoology.  The luminaries of the English geology community relied on her indomitable fieldwork to frame their conclusions about the history of living things and to stock their museums with specimens. Mary was a religious dissenter and the daughter of a cabinet-maker in an age when geology was the near-exclusive preserve of well-to-do Anglican gentlefolk (the Geological Society of London did not even allow women to attend meetings as guests).  Yet she kept informed of the scientific literature of her day and she dissected fish and invertebrates as to better understand the nature of her excavations and discoveries. Above all, Mary Anning actually discovered the fossils which others wrote about–so she had insights and knowledge which were occluded from armchair scholars. Charles Lyell (the father of geology) wrote to her asking her opinions about cliff erosion.  Mary proposed a theory to William Buckland that some of the fossils she discovered were ingested by ichthyosaurs and the remains excreted (a concept which fascinated Buckland and became the central focus of his work). In a fair world she would have an alphabet of letters after her name and be immortalized as a statue on a plinth beside the statues of Darwin and Lyell.  Even in our fallen world, she is revered as one of the founders of the natural history and life science disciplines (although many biographies about her concentrate on the sad exigencies of her life rather than on the extraordinary discoveries she made, a tradition which I have somewhat followed).

The cliffs which Mary relied on for specimens were part of a geological formation known as the Blue Lias. These layers of limestone and shale were a shallow seabed of the Tethys Ocean during the Jurassic period (about 210–195 million years ago).  The curlicues and stone bullets were fossil ammonites and belemnites, but Mary had a knack for finding the much rarer remains of hitherto unknown creatures such as ichthyosaurs, pterosaurs, plesiosaurs and other ancient marine fauna.

In the early 19th century a debate was raging between learned churchmen who knew for certain that God’s perfect creation could never be diminished and gentlemen geologists who believed that there had once been animals which were gone from earth…”extinct” as they called this new concept.   Mary’s fossils of bizarre giant sea crocodiles and lizard dolphins gave concrete evidence to the ur-paleontologists (who were indeed proven right).  Her discoveries were seminal for the discovery of paleontology itself and paved the way to the understanding that the world’s ecosystems were once very different indeed from what they are like now.   These pieces of knowledge helped towards an understanding of the true age of the Earth and ultimately made Darwin’s discoveries possible.

Here is another painting of Mary, by the greatest living fish-artist, Ray Troll.  Troll shows Mary with fleshed-out versions of the creatures she discovered (note the ichthyosaur swallowing an ammonite).  We owe an enormous debt to Mary Anning.  Her contributions were under-appreciated in her day (when only the most learned gentleman scientists…and Mary… had inklings of the real nature of natural history and what her super sea-monsters connoted ), but those discoveries undergird our understanding the nature of the planet and of life itself.

 

Serpents in Ireland!

Saint Patrick Expelling the Snakes

Just kidding—aside from zoos and the pet trade, Ireland actually famously has no snakes.  It is one the few snake-free large islands on Earth joined only by New Zealand, Iceland, Greenland, and Antarctica (well—everywhere far enough north or south is snake-free: the reptiles don’t really thrive in places where there is permafrost or truly cold winters).  Legend has it that it was Saint Patrick who drove the snakes out of Ireland.  Standing on a great hill he lifted up his crosier and focused divine energy upon the unlucky reptiles which then writhed en masse into the sea and never returned to the emerald island.

"Ssseriously, why are you doing thisss?"

It has always been a bit unclear to me why Saint Patrick would do such a thing. Ecoystems which undergo such catastrophic changes tend to go haywire with great alacrity!  Fortunately the story is entirely a myth.  If snakes ever lived in Ireland (and it doesn’t seem like they did), they were long gone by the time the first Christians showed up.  The real reason is even more interesting than the dramatic Moses-like power of Saint Patrick, but as with most actual answers it is also more complex.

Evidence suggests that snakes evolved 130 million years ago during the Cretaceous.  At the time Ireland was, um, underwater at the bottom of a warm chalky sea.  Early snakes slithered their way across landbridges, rafted to islands on washed away logs, and swam (like the sea snakes) from island to island but, during the Mesozoic, there was no Ireland for them to go to.

Europe in the Ice Age (the pale white area was under a huge sheet of ice)

When the Mesozoic era ended in the great ball of fire, the continents again shifted.  Snakes went through a substantial evolutionary period during the Miocene and the original python-like snakes evolved into many different forms.  These new varieties of snakes slithered into grasslands, deserts, forests, and oceans around the world, but they still could not get to Ireland (now above the waves) because a cold ocean was in their way.  Then the end of the Miocene brought an ice age.  To quote the National Zoo’s essay on “Why Ireland Has No Snakes”:

The most recent ice age began about three million years ago and continues into the present. Between warm periods like the current climate, glaciers have advanced and retreated more than 20 times, often completely blanketing Ireland with ice. Snakes, being cold-blooded animals, simply aren’t able to survive in areas where the ground is frozen year round. Ireland thawed out for the last time only 15,000 years ago.

So Ireland remains snake-free because of the world’s temperamental geology. The island was underwater or covered by ice during certain eras when the snakes might have arrived–geography has conspired against serpents coming to Eire and setting up shop.  The age of humans however has been marked by numerous introduced species cropping up everywhere.  I wonder how long Ireland will be snake free when a pet shop accident or crazy hobbyist could unleash a plague of serpents on the green island.  The fact that such a thing has yet to happen seems almost as miraculous as the original myth.

Although many people construe the whole story to be an allegory of Saint Patrick driving paganism and the old gods from Ireland (as seen here).

Lake Lonar

Lake Lonar

Approximately 650,000 years ago, an outer space object–either a comet or a meteor– struck the Deccan plateau (an immense basaltic flow on the Indian subcontinent dating back to the twilight of the dinosaurs).   The resultant crater in Maharashtra is now the sight of a very interesting saltwater lake, Lake Lonar.  The geology of this region has been intensely studied because the great basaltic mass of the Deccan traps is thought to mirror the igneous geology of Mars and the moon.

Lake Lonar proper is nearly circular with a diameter of 1.2 kilometers.  The greater meteor crater rim is about 1.8 kilometers and the crater measures 500 feet deep in the deepest part of the lake.  In addition to the obvious features of an extraterrestrial impact (um, a large round hole), the region features many other unique geological signs of such an event. Maskelynite, a material only naturally known from meteorites and meteorite impact areas, is found around Lake Lonar, as are silicate minerals with planar deformation features (distinctive high-stress crystalline irregularities which have only been found in silicates from meteorites, craters, and nuclear test areas).  The deeper geology of the lake region displays shatter cones in the bedrock, and extreme deformation of the basalt layers. Finally the surrounding region has been spattered with a non-volcanic ejecta blanket. 

Lake Lonar: pink-beige indicates bare ground, blue and off-white indicate human-made structures, dark blue indicates water, green indicates vegetation, and dull purple indicates fallow fields (NASA: Terra Satellite)

By measuring the accumulated radiation in certain crystals (aka thermoluminescence) scientists had assigned an approximate age of 50,000 years to the crater. However a 2010 study of isotopic Argon in Lonar impact melt rock estimated the true time of impact to be 650,000 years ago (give or take 80,000 years).  The compelling 2010 study drily notes “The discrepancy between the thermoluminescence age and the new isotopic 40/Ar/39Ar age is flagrant.”

Daitya Sudan, a temple to Vishnu

Several abandoned temples and archaeological sights are also located around the lake.  For example, the beautiful Daitya Sudan Temple to Vishnu was built by the Chalukya Dynasty which ruled of Maharashtra from the 6th and 12th centuries.  The local town, Lonar, still has an active temple to Vishnu, the great protector of the universe who features prominently in local legend.  According to the Skanda Purana (a canon of Hindu scripture universally cited when a story is doubtful or can not be found elsewhere) a great underworld demon, Lonasur, lived where Lake Lonar is today.  From time to time the demon would venture from his subterranean abode to torment the countryside and challenge the gods. Assuming the form of an extremely beautiful young man, Vishnu…somehow convinced the demon’s sisters to divulge where the monster could be found.  The god then lifted up the countryside like a great lid and found the demon hiding in his huge circular lair. After Vishnu slew the demon, the demon’s dwelling place filled up with water made salty by the fiend’s blood.    

Although threatened by India’s ever growing sprawl, Lonar Lake is a rich wetland with abundant wildlife—particularly birds.  The jungles, fields, and lake are a birder’s paradise featuring flamingos, grebes, black-winged stilts, dabchicks, ducks, shell-ducks, shovellers, teals, herons, rollers, parakeets, hoopoes, weavers, larks, tailorbirds, magpies, robins, swallows, peacocks, coots, white-necked storks, lapwings, grey wagtails, black droungos, green bee-eaters, and tailorbirds (to name just some).

The Jungle around Lake Lonar