Landmannalaugar is at the northern tip of the Laugavegur hiking trail that leads through natural geothermal hot springs and an austere yet poetically beautiful landscape.
Sunday, 13 June 2021
LANDMANNALAUGAR: AURORA BOREALIS
Landmannalaugar is at the northern tip of the Laugavegur hiking trail that leads through natural geothermal hot springs and an austere yet poetically beautiful landscape.
Saturday, 12 June 2021
HALENDID: ICELANDIC HIGHLANDS
Sitting at the junction of the North Atlantic and Arctic Oceans is the ruggedly beautiful island of Iceland. It is Europe's second-largest island after Great Britain.
Geologically, Iceland is part of the Mid-Atlantic Ridge — a wee bit of the oceanic crust sitting just above a mantle plume, hence all the showy volcanic eruptions and lava flows.
The interior of Iceland is usually referred to as the central highlands or as the locals call it — Halendid — which roughly translates to Highlands in Icelandic. It is considered one of the last great wilderness areas in all of Europe, covering nearly 40,000 square kilometres. Truly one of the last untamed regions on earth. Halendid contains high concentrations of waterfalls, volcanoes, glaciers, and rivers. Large expanses of black sand, lava fields, and fragile vegetation are found throughout the region.
Still, one of the features that make this region so unique are the rivers. These rivers carry glacial runoff and sediment from the interior of the island to the ocean. Along the way, this mix of minerals and water produces dramatic colours, complex systems, and vibrant patterns.
Thursday, 10 June 2021
AMMONITE TIME PIECE: INDEX FOSSILS
They were prolific back in the day, living — and sometimes dying — in schools in oceans around the globe. We find ammonite fossils, and plenty of them, in sedimentary rock from all over the world. In some cases, we find rock beds where we can see evidence of a new species that evolved, lived and died out in such a short time span that we can walk through time, following the course of evolution using ammonites as a window into the past.
For this reason, they make excellent index fossils. An index fossil is a species that allows us to link a particular rock formation, layered in time with a particular species or genus found there. Generally, deeper is older, so we use the sedimentary layers of rock to match up to specific geologic time periods, rather like the way we use tree rings to date trees.
Wednesday, 9 June 2021
GORGONS: APEX PREDATORS OF THE PERMIAN
Tuesday, 8 June 2021
LIPAROCERAS IN SEPTARIAN NODULE
These photos show a delightful example of a lovely Liparoceras sp. from Robin Hoods Bay with some interesting septarian veins radiating away from the ammonite. The awesome Harry Tabiner gets full credit — and my unending respect — for the find, preparation and photo of this lovely Lower Jurassic, Lower Lias specimen.
Around Robin Hood’s Bay, well-developed platforms cut across outcrops of Liassic shales. The cliffs are primarily till resting on the Lias. Cliff falls at this location are common. The cliffs are about 50 m in height in the northern part of the bay where they are cut by two steep-sided valleys, Mill Beck and Stoupe Beck. Here the Lower Lias forms most of the slope, with near-vertical lower cliffs comprised entirely of Lower Lias rocks.
The rocks in the lower cliffs are dark grey marine shales from the Redcar Mudstone Formation. The Lias Group at Robin Hood’s Bay is represented, in ascending order, by the Redcar Mudstone Formation, Staithes Sandstone Formation, Cleveland Ironstone Formation and Whitby Mudstone Formation and contains stratotypes for several zones and horizons.
Be mindful of the tides as this location should only be attempted on a retreating tide. Minerals can be found in both the large Septarian nodules and partially replacing the many fossilized tree limbs and roots found in the sandstone blocks from higher up in the cliffs. This site can be dangerous and is not appropriate for children.
To look for fossils, search through the rocks and concretions along the foreshore. Ammonites can often be found this way, but you will need the right tools and good eye protection.
Fossils loose on the foreshore are rare. You generally need to work for finds at this location. A few good storms help with collecting here. Robin Hood’s Bay yields little during the summer months. The best time to collect is after the winter storms.
The north side of the bay is rich in ammonite remains and these can mostly be found after cliff falls. The ammonites (Platypleuroceras, Tropidoceras, Acanthopleuroceras and Androgynoceras) can be found, along with the large bivalve, Pinna. Within the calcareous shales, exposed in the low tide reefs at the centre of the bay, you can find the ammonites, Arnioceras and Caenisites.
Robin Hoods Bay Directions from the good folk at UK Fossils Network:
At Robin Hood’s Bay village, you can park in either the small car park at the top of the hill or the second larger one just a short walk away.
- From here, the best end to visit is the north side. You will find a footpath at the top of the hill, to the left of the main street leading to the beach. This winds around and passes a picnic area.
- You can also visit the south and middle part of the bay. To do this, go down into the main street at the bottom of the hill and follow round to the right. You will see some steps, which follow the sea defence and lead to the shore.
- Paleo-coordinates: 54.43442°N, 0.53079°W
Reference: Humberside Geologist No. 14, Humberside Geologist Online, The geology of East Yorkshire coast.http://www.hullgeolsoc.co.uk/hg146t.htm
Reference: https://www.mindat.org/loc-267536.html
Monday, 7 June 2021
ROCKY MOUNTAIN TRENCH
Trapper Cabin on Isaac Lake / Bowron Provincial Park |
From all descriptions, something like heaven.
The east and south sides of the route are bound by the imposing white peaks of the Cariboo Mountains, the northern boundary of the Interior wet belt, rising up across the Rocky Mountain Trench, and the Isaac Formation, the oldest of seven formations that make up the Cariboo Group (Struik, 1988).
Some 270 million years ago, had one wanted to buy waterfront property in what is now British Columbia, you’d be looking somewhere between Prince George and the Alberta border. The rest of the province had yet to arrive but would be made up of over twenty major terranes from around the Pacific. The rock that would eventually become the Cariboo Mountains and form the lakes and valleys of Bowron was far out in the Pacific Ocean, down near the equator.
With tectonic shifting, these rocks drifted north-eastward, riding the continental plate until they collided with and joined the Cordillera in what is now British Columbia. Continued pressure and volcanic activity helped create the tremendous slopes of the Cariboo Range we see today with repeated bouts of glaciation during the Pleistocene carving their final shape.
PLIENSBACHIAN APODEROCERAS OF DORSET
Apoderoceras is a wonderful example of sexual dimorphism within ammonites as the macroconch (female) shells grew to diameters in excess of 40 cm – many times larger than the diameters of the smaller microconch (male) shells.
Apoderoceras has been found in the Lower Jurassic of Argentina, Hungary, Italy, Portugal, and most of North-West and central Europe, including as this one is, the United Kingdom. This specimen was found on the beaches of Charmouth in West Dorset and prepped by the wonderfully talented Lizzie Hingley.
Neither Apoderoceras nor Bifericeras donovani are strictly index fossils for the Taylori subzone, the index being Phricodoceras taylori. Note that Bifericeras is typical of the earlier Oxynotum Zone, and ‘Bifericeras’ donovani is doubtfully attributable to the genus. The International Commission on Stratigraphy (ICS) has assigned the First Appearance Datum of genus Apoderoceras and of Bifericeras donovani the defining biological marker for the start of the Pliensbachian Stage of the Jurassic, 190.8 ± 1.0 million years ago.
Apoderoceras, Family Coeloceratidae, appears out of nowhere in the basal Pliensbachian and dominates the ammonite faunas of NW Europe. It is superficially similar to the earlier Eteoderoceras, Family Eoderoceratidae, of the Raricostatum Zone, but on close inspection can be seen to be quite different. It is, therefore, an ‘invader’ and its ancestry is cryptic.
The Pacific ammonite Andicoeloceras, known from Chile, appears quite closely related and may be ancestral, but the time correlation of Pacific and NW European ammonite faunas is challenging. Even if Andicoeloceras is ancestral to Apoderoceras, no other preceding ammonites attributable to Coeloceratidae are known. We may yet find clues in the Lias of Canada. Apoderoceras remains present in NW Europe throughout the Taylori Subzone, showing endemic evolution. It becomes progressively more inflated during this interval of time, the adult ribs more distant, and there is evidence that the diameter of the macroconch evolved to become larger. At the end of the Taylori Subzone, Apoderoceras disappeared as suddenly as it appeared in the region, and ammonite faunas of the remaining Jamesoni Zone are dominated by the Platypleuroceras–Uptonia lineage, generally assigned (though erroneously) to the Family Polymorphitidae.
In the NW European Taylori Subzone, Apoderoceras is accompanied (as well as by the Eoderoceratid, B. donovani, which is only documented from the Yorkshire coast, although there are known examples from Northern Ireland) by the oxycones Radstockiceras (quite common) and Oxynoticeras (very rare), the late Schlotheimid, Phricoderoceras (uncommon) Note: P. taylori is a microconch, and P. lamellosum, the macroconch), and the Eoderoceratid, Tetraspidoceras (very rare).
Sunday, 6 June 2021
DACTYLIOCERAS OF THE HOLDERNESS
Dactylioceras ammonite, Photo: Harry Tabiner |
Holderness is an area of the East Riding of Yorkshire, on the east coast of England. An area of rich agricultural land, Holderness was marshland until it was drained in the Middle Ages. Topographically, Holderness has more in common with the Netherlands than with other parts of Yorkshire. To the north and west are the Yorkshire Wolds.
Geologically, Holderness is underlain by Cretaceous chalk but in most places, it is so deeply buried beneath glacial deposits that it has no influence on the landscape.
The landscape is dominated by deposits of till, boulder clays and glacial lake clays. These were deposited during the Devensian glaciation. The glacial deposits form a more or less continuous lowland plain which has some peat filled depressions (known locally as meres) which mark the presence of former lake beds. There are other glacial landscape features such as drumlin mounds, ridges and kettle holes scattered throughout the area.
Dactylioceras ammonite, Photo: Harry Tabiner |
The Geology of Yorkshire in northern England shows a very close relationship between the major topographical areas and the geological period in which their rocks were formed. The rocks of the Pennine chain of hills in the west are of Carboniferous origin whilst those of the central vale are Permo-Triassic.
The North York Moors in the north-east of the county are Jurassic in age while the Yorkshire Wolds to the southeast are Cretaceous chalk uplands. The plain of Holderness and the Humberhead levels both owe their present form to the Quaternary ice ages.
The strata become gradually younger from west to east. Much of Yorkshire presents heavily glaciated scenery as few places escaped the direct or indirect impact of the great ice sheets as they first advanced and then retreated during the last ice age. This beauty is in the collection of the deeply awesome Harry Tabiner.
Thursday, 3 June 2021
CRETACEOUS AFRICA SUPER CROC
Sarcosuchus imperator |
Sarcosuchus were ambush hunters, eating anything that entered their watery homes from wee fish to large dinosaurs. These big beasties were the precursors to our modern crocodiles -- and they were big. Really big.
Wednesday, 2 June 2021
SARCOSUCHUS IMPERATOR
Strictly speaking, Sarcosuchus was not a crocodile as we know them today, but a kind of pre-crocodile. These early croc-types were Crocodylomorphs.
This crocodylian lineage (clade Pseudosuchia, formerly Crurotarsi) was a very diverse and adaptive group of reptiles. We used to lump all known living and extinct crocodiles indiscriminately into the order Crocodilia. Sometime in the late 1980s, we finally moved all living species into the order Crocodilia, segregating closely related extinct relatives such as Mekosuchus. Our true "modern" crocodiles, now all safely ensconced in the order Crocodilia without their ancient ancestors, arrived millions of years after the first crocodylomorphs, with the first members of the modern species arriving on the scene in the Upper Cretaceous.
The Crocodylomorpha were a very ancient group of animals, at least as old as the dinosaurs, who evolved into a very diverse spectrum of weird and wonderful forms you might not recognize as croc-like. During the Jurassic and the Cretaceous, marine Crocodylomorphs in the family Metriorhynchidae, such as Metriorhynchus, evolved forelimbs that were paddle-like and had a tail similar to modern fish. Dakosaurus andiniensis, a species closely related to Metriorhynchus, had a skull that was adapted to feast upon large marine reptiles. We see several (unexpected) herbivorous terrestrial species during the Cretaceous, such as the tiny and adorable Simosuchus clarki and Chimaerasuchus paradoxus, both roughly the size of a dog. During the Cenozoic, a number of lineages left their ancient river homes and became wholly terrestrial predators.
Sarcosuchus was one of the largest early crocodile-like reptiles, reaching up to 9.5 m in body length and weighing up to 8 to 10 tons. He was almost twice as long as our modern saltwater crocodiles, so one big croc! These big beasts lived and hunted in ancient rivers, grabbing and crushing prey that came too close to the water.
The first remains were discovered during field expeditions in the Sahara led by French paleontologist, Albert-Félix de Lapparent, from 1946 to 1959. Remains were found of skull fragments, vertebrae, teeth, and scutes.
In 1964, an almost complete skull was found in Niger by the French CEA, but it was not until 1997 and 2000 that most of its anatomy became known to science when an expedition led by the American paleontologist Paul Sereno discovered six new specimens, including one with about half the skeleton intact and most of the spine.
A common method to estimate the size of crocodiles and crocodile-like reptiles is the use of the length of the skull measured in the midline from the tip of the snout to the back of the skull table since in living crocodilians there is a strong correlation between skull length and total body length in subadult and adult individuals irrespective of their sex, this method was used by Sereno et al. (2001) for Sarcosuchus due to the absence of a complete enough skeleton. Two regression equations were used to estimate the size of S. imperator, they were created based on measurements gathered from 17 captive gharial individuals from northern India and from 28 wild saltwater crocodile individuals from northern Australia, both datasets supplemented by available measurements of individuals over 1.5 m (4.92 ft) in length found in the literature.
The largest known skull of Sarcosuchus imperator (the type specimen) is 1.6 m (5.25 ft) long (1.5 m (4.92 ft) in the midline), and it was estimated that the individual it belonged to had a total body length of 11.65 m (38.2 ft), its snout-vent length of 5.7 m (18.7 ft) was estimated using linear equations for the saltwater crocodile and in turn, this measurement was used to estimate its body weight at 8 tonnes (8.8 short tons). These new measurements meant Sarcosuchus was able to reach a maximum body size not only greater than previously estimated but also greater than that of the Miocene "Beak crocodile" Rhamphosuchus, the Late Cretaceous Deinosuchus crocodilian related to our modern alligators, and the Miocene Purussaurus.
However, extrapolation from the femur of a subadult individual as well as measurements of the skull width further showed that the largest S. imperator was significantly smaller than was estimated by Sereno et al. (2001) based on modern crocodilians. O’Brien et al. (2019) estimated the length of the largest S. imperator specimen at 9.5 meters and body weight at 4.7 tons based on longirostrine crocodylians skull width to total length ratio. This estimate is very close to the femur based estimate is 9.1 m (29.9 ft).
Sereno, Paul C.; Larson, Hans C. E.; Sidor, Christian A.; Gado, Boubé (2001). "The Giant Crocodyliform Sarcosuchus from the Cretaceous of Africa". Science. 294 (5546): 1516–9. Bibcode:2001Sci...294.1516S. doi:10.1126/science.1066521. PMID 11679634.
Monday, 31 May 2021
OUR EARLY ATMOSPHERE
Our early Earth was a molten world |
And arise they did. On the planet's surface, volcanoes spewed lava and volatile gasses into what would become our earliest atmosphere.
Again, in composition, it looked very different from the one we know today. Nitrogen, carbon dioxide, ammonia, methane and small amounts of water vapour made up the gassy soup surrounding our world.
But that first water would change everything. As the water vapour condensed, it came back to the surface bit by bit. Over a very long period of time, those waters pooled and gathered and became our first oceans. It was in this early ocean some 2.7 billion years ago that cyanobacteria, or blue-green algae, wonderous photosynthetic microbes, would take up that weakened sunlight and water vapour to process the carbon dioxide from the atmosphere, producing other chemical compounds and oxygen as a by-product.
Sunday, 30 May 2021
RED LIPPED BATFISH
Red Lipped Batfish, Ogcocephalus darwini |
Our world's oceans have some of the most amazing, beautiful, ugly and interesting creatures on the planet. Red Lipped Batfish are no exception. They can be found along the sandy ocean floor and reefs around the Galapagos Islands and off the shores of Peru.
Their most distinguishing feature is revealed in their name and one look at this photo gives it away — they have very distinctive bright red lips. They also have a rather fetching illicium, the dangling projection you see here. It's a lure to attract prey to those luscious lips so she can enjoy a tasty snack. Above the illicium is an esca, an unusual feature that emits a bright light. Between the light and the lure, small fish and curious invertebrates — shrimp, molluscs, crab — deep in the Southeast Pacific investigate the light and get swallowed up by those lips.
Most of their flattened flounder-like bodies are light brown and a greyish in colour with white colouring on the underside. They are roughly the size of a dinner plate. On the top side of the batfish, there is usually a dark brown stripe starting at the head and going down the back to the tail.
Their face has a definite red sheen. Comically, with the red face and bored expressions, it looks like they're perpetually unimpressed and slightly embarrassed.
Once you get past those lips, the next thing that stands out with these interesting beauties is how they move. They're not terribly good swimmers but do walk rather well on their highly adapted fins. They march or waddle across the seafloor in search of more interesting sights to practise the art of deep-sea fishing.
Batfish are descendants of lophiiform fishes. In 2011, a new genus and species of batfish, Tarkus squirei, was described from Eocene (Ypresian) limestone deposits in the celebrated locality of Monte Bolca, Italy. Tarkus squirei was a tropical batfish that inhabited the inner-shelf palaeobiotopes of the central-western Tethys Sea. Tarkus gen. nov. shows a certain degree of phenetic affinity with the extant shallow-water batfish genera Halieutaea and —more particularly — Halieutichthys. The specimens of this taxon are the first articulated skeletal remains of the Ogcocephalidae ever recorded as fossils, also representing the oldest members of the family known to date.
Reference: CARNEVALE, G., & PIETSCH, T. (2011). Batfishes from the Eocene of Monte Bolca. Geological Magazine, 148(3), 461-472. doi:10.1017/S0016756810000907
Friday, 28 May 2021
FROM RUSSIA WITH LOVE: AULACOSTEPHANUS
Kaluga is known for its most famous resident, Konstantin Tsiolkovsky, a rocket scientist who pioneered astronautic theory.
The Tsiolkovsky State Museum of the History of Cosmonautics in Kaluga is dedicated to his work and its practical applications for space research. The city's coat of arms and motto gives a respectful nod to work — the Cradle of Space Exploration.
Kaluga, founded in the mid-14th century as a border fortress on the southwestern borders of the Grand Duchy of Moscow. The city's name has changed over time. If you poke through historical records and chronicles from the 14th century, you'll see it written as Koluga — derived from the Old Russian word for bog or quagmire.
Historically, Kolunga has sat on the sidelines of history. It is the sort of place you might have a country home away from the hubbub of the bustling city. Indeed, the area has served as such for many of Russia's Royals. In the Middle Ages Kaluga was a smallish settlement owned by the Princes Vorotynsky whose relationship with the townsfolk looked more akin to how you and I might picture slaver versus a liege lord.
Over time, the village grew more prosperous and opened its first drama theatre in 1777. As in many parts of the world, the first geologic exploration and mapping were done to locate natural resources that would be used to fund monarchies, wars and infrastructure.
Kaluga is connected to Moscow by a railway line and by the ancient roadway, the Kaluga Road (now partly within Moscow — as Starokaluzhskoye Shosse - the Old Kaluga Highway — partly the A101 road. This road offered Napoleon his favoured escape route from the Moscow trap in the fall of 1812.General Kutuzov repelled Napoleon's advances in this direction and forced the retreating French army onto the old Smolensk road, previously devastated by the French during their invasion of Russia — an event that may be attributed to poor planning and tin buttons, but that is for another post.
On several occasions during the Russian Empire Kaluga was the residence of political exiles and prisoners such as the last Crimean khan Şahin Giray (1786), the Kyrgyz sultan Arigazi-Abdul-Aziz (1828), the Georgian princess Thecla (1834–1835), and the Avar leader Imam Shamil (1859–1868).
The German army briefly occupied Kaluga during the climactic Battle of Moscow, as part of Operation Barbarossa. The city was under full or partial German occupation from October 12th to December 30, 1941. In 1944, the Soviet Government used its local military buildings to intern hundreds of Polish prisoners of war — soldiers of the Polish underground Home Army — whom the advancing Soviet front had arrested in the area around Vilnius. This specimen is in the collection of the deeply awesome Emil Black. Maximum diameter of 58mm.
Thursday, 27 May 2021
FOOL'S GOLD: A PERSONAL GOLD RUSH
Someone had dumped a tailings pile near the woods where I lived and in the sun, those crushed pieces of rock sparkled. I had already been bitten by the love of minerals and fossils and so naturally I filled my pockets and brought as much home as a youngster can carry.
Where I was told that it was Fool's Gold.
But, still... it was so compelling and just so gold-like. So, secretly I continued my forays and dragged as many of those lovely sparkly bits home as I could. The pile soon amassed to what could not be concealed in a youngsters room — those socks have to live somewhere. So we struck a bargain. My folks would let me keep my gold if I kept it under the house. I suspect it is still there to this day.
I did eventually find gold up in Atlin, British Columbia — and loads of it — but none that I could keep. I met a fellow who pans for it and had built out a sluicing system to great success. He showed me an ice cream bucket full of gold nuggets that I still ponder to this day.
So, what exactly is Fool's Gold? Is it gold mixed with another mineral or something else altogether? Turns out it is pyrite which has a brass-yellow colour and metallic lustre similar to gold, but pyrite is brittle and will break rather than bend as gold does.
A good field test is to give it a streak test. Gold leaves a yellow streak, while pyrite’s streak is brownish-black.
Pyrite is named from the Greek word for fire, "pyr" because pyrite can create sparks for starting a fire when struck against metal or stone — also fun to try in the field. Pyrite was once a source of sulfur and sulfuric acid, but today most sulfur is obtained as a byproduct of natural gas and crude oil processing.
We sometimes see pyrite sold as a novelty item or made into costume jewellery. But pyrite does have its uses beyond amusing youngsters dreaming of their own gold rush.
Pyrite can sometimes help you find real gold because the two form together under similar conditions. Gold can even occur as inclusions inside pyrite, sometimes in mineable quantities depending on how effectively the gold can be recovered.
Fool’s Gold is truly pyrite or iron sulfide (FeS2) and is one of the most common sulfide minerals. Sulfide minerals are a group of inorganic compounds containing sulfur and one or more elements.
I still have a fondness for it and share a wry smile when I find it out in the field. It is remarkably common. And, I do still want it to be real gold even though my grown-up brain knows it is not.
When I am very lucky, however, I find pyritized fossils — even better than gold!
Wednesday, 26 May 2021
FOSSILS OF THE LONDON CLAY
Birds, Snakes & Mammals, London Clay |
The London Clay Formation is a marine geological formation of Ypresian (early Eocene Epoch, c. 56–49 Ma) age which outcrops in the southeast of England.
The exposures are well-known for their variety of fossil fauna. The fossils from the lower Eocene sections tell us about a moderately warm, tropical to subtropical climate.
It was with the greatest pleasure that I came across some of the wonderful fossil specimens found by Martin Rayner and his father over the better part of 40-years worth of dedicated collecting. These excellent examples of the London Clay fauna hail from Sheppey, Seasalter and Tankerton.
You may recall that Martin is a co-author of London Clay Fossils of Kent and Essex. The book is a collectors' guide to the fossil animals and plants of the London Clay from river and coastal exposures in Kent and Essex. It is known locally as the Fossil Bible.
This superb book is published by the Medway Fossil and Mineral Society and was written by four of the Society members, David Rayner, Tony Mitchell, Martin Rayner and Fred Clouter.It the essential field guide for use by both beginners and the more experienced — and likely the definitive work on the subject for many years to come.
The book includes when to collect, equipment, cleaning, preparation and preservation of specimens, sieving, storage and cataloguing, geology and a list of fourteen collecting sites — six with site location maps, access details and collecting techniques.
There is a hugely useful identification section and comprehensive terminology for the invertebrates, vertebrates and plants of the London Clay. Here you'll find all of the yummy foraminifera, bryozoa, worms, trace fossils, corals, barnacles, lobsters, stomatopods, crabs, insects, brachiopods, bivalves, scaphopods, gastropods, nautili, coleoids, crinoids, echinoids and starfish. Also included are the sharks, rays, chimaera, bony fish, otoliths, turtles, snakes, crocodiles, birds, mammals and plant material.
If you fancy picking up a copy, here is the UKGE link: https://www.ukge.com/en-ie/London-Clay-Fossils-of-Kent-and-Essex__p-3291.aspx
Photo One: Martin Rayner: Snake, Bird and Mammal finds from the London Clay, mostly from Sheppey and Seasalter, UK
Photo Two: Martin Rayner: A rare skull from the remains of the sea snake Palaeophis toliapicus.
Tuesday, 25 May 2021
EOSUCHUS OF SEASALTER
But for Martin Rayner and his father, the best finds hail from nearby Seasalter, a village in the Canterbury District on the northern coast of Kent. It was here, during the mid-1990s, that Martin found this spectacular Eosuchus sp. fossil crocodile along the foreshore.
Eosuchus or the Dawn Crocodile, is an extinct genus of eusuchian crocodylomorph, generally regarded as a gavialoid crocodilian. It might have been among the most basal of all gavialoids, lying crownward of all other known members of the superfamily, including earlier putative members such as Thoracosaurus and Eothoracosaurus.
We find their fossil remains at Seasalter in the UK, in France and along the eastern seaboard of North America in Maryland, Virginia, and New Jersey. Their remains date back to the late Paleocene and early Eocene.
Martin's Eosuchus sp. was found in-situ spread out over a small area of Seasalter's clay rich foreshore. His significant find was originally collected in hundreds of pieces, many of these fragmented and spread around before fossilization. Careful excavation, preparation and articulation over a two year period was necessary to piece them all together.
It took another year or more to reconstruct the skull and much more time again to research the find with the help of those working at the Natural History Museum in London.A few of the pieces you see here were generously donated to Martin by fellow collectors who had plucked some of the bones from the collecting site then realized each held a small part of a large important specimen.
Once fully articulated, the near complete specimen measures around 1.2 meter in length. Had all the bones been recovered, the complete specimen would likely be closer to 2m in length.
We now get to enjoy this magnificent specimen in its entirety. It also shows what can be found in the foreshore material and will hopefully encourage those used to collecting on Seasalter's beaches to give this prolific area the attention is surely deserves.
On the foreshore where the clay is exposed it is possible to find fossils in situ and washing out. The foreshore platforms are constantly eroding and at a faster rate than the nearby cliffs. It is a large area to search, but the large expanses of foreshore offer newly revealed specimens, often in stunning condition.When you visit Seasalter, you may arrive after wind and tide have scoured away the silt and exposed the fossiliferous clay. You can find nice crab fossils and other marine goodies.
There are far more London Clay sites without cliff exposures than ones with cliff exposures. As at Sheppey, Seasalter's foreshore exposures yield a large amount of fossil specimens in addition to the beach finds derived from the cliffs. Foreshore sites are scientifically significant as they provide a snapshot of a more specific time versus the fossils retrieved from cliff falls which can often span millions of years.
The photo above shows all of the bones laid out together. A frame has been created for them into which each individual vertebrae fit snug so that it can be displayed at potential shows and exhibitions.
Martin's Seasalter find helps us to understand both the anatomy of Eosuchus and place this basal gavialoid geographically. It is the occurrence of Eosuchus in the London Clay that pushes the gavialoid clade beyond the Paleocene and firmly and unambiguously into the early Eocene.
The strata from which both species of Eosuchus have been found were thought to have formed in a marginal marine depositional environment, and thus probably reflect the actual environments that these animals would have inhabited. It has been proposed that early gavialoids were originally salt-tolerant coastal forms, and the evidence seen in the case of Eosuchus is consistent with this theory.When we are lucky, the fossil evidence comes together to paint a picture of the environment and provide clues to our ancient world. One specimen of E. minor from the Aquia Formation, USNM 299730, has a fossil oyster attached to the dorsal surface of the rostrum.
The fact that the two species of Eosuchus lived on either side of the Atlantic Ocean implies that these populations may have been separated geographically from one another while not necessarily having to be separated stratigraphically (that is, if the temporal ranges of the two species coincide with one another).
More importantly, the separate biogeographic ranges of the two species may be evidence for a transoceanic dispersal event from one continent to the other. Since the presumed ages of the localities from which specimens have been found are quite similar yet inexact, it is currently unknown just what continent this dispersal event may have originated. A recent reevaluation of the holotype material of E. lerichei, which in the past has been poorly studied, suggests that it is the more basal species and thus would have been the ancestor of E. minor in Europe.
We'll likely find more Eosuchus material which will provide additional insights. More specimens will likely be found at Seasalter. The London Clay fossils at Seasalter are found out on the foreshore at low tides in the bay between Seasalter and Whitstable Harbour to the east.
If you're headed out and want to try your luck, walk the area from the bottom of the beach halfway or more toward the oyster nets. The fossil material you will find will be 50 million years old.
If you fancy a read and armchair inspiration, check out the wonderfully informative book on the London Clay Fossils of Kent and Essex by David Rayner, Tony Mitchell, Martin Rayner and Fred Clouter. These four genius minds have produced the definitive book on the area — greatly expanding our insight and understanding through their years of earned knowledge.
References:
Dollo, L. (1907). "Les reptiles de l'Éocène Inférieur de la Belgique et des régions voisines". Bulletin de la Société Belge de Géologie, de Paléontologie et d'Hydrologie. 21: 81–85.
Norell, M. A.; Storrs, G. W. (1986). "Catalogue and review of the type fossil crocodilians in the Yale Peabody Museum". Postula. 203: 1–28.
Brochu, C. A. (2006). "Osteology and phylogenetic significance of Eosuchus minor (Marsh, 1870) new combination, a longirostrine crocodylian from the Late Paleocene of North America". Journal of Paleontology. 80 (1): 162–186. doi:10.1666/0022-3360(2006)080[0162:OAPSOE]2.0.CO;2.
Michael S. Y. Lee; Adam M. Yates (2018). "Tip-dating and homoplasy: reconciling the shallow molecular divergences of modern gharials with their long fossil record". Proceedings of the Royal Society B: Biological Sciences. 285 (1881): 20181071. doi:10.1098/rspb.2018.1071. PMC 6030529. PMID 30051855.
Taplin, L. E.; Grigg, G. C. (1989). "Historical zoogeography of the eusuchian crocodilians: A physiological perspective". American Zoologist. 29: 885–901. doi:10.1093/icb/29.3.885.
Delfino, M.; Pira, P.; Smith, T. (2005). "Anatomy and phylogeny of the gavialoid crocodylian Eosuchus lerichei from the Paleocene of Europe". Acta Palaeontologica Polonica. 50 (3): 565–580.
Broom, Robert (1925). "On the South African rhynchocephaloid reptile "Eosuchus" colletti, Watson". Records of the Albany Museum. 3: 300–306.
Monday, 24 May 2021
WETTERSTEIN LIMESTONE
Ammonoid and gastropod coquina, Wetterstein Limestone |
The lovely example of the Wetterstein limestone you see here is equivalent in age to the typically creamy orange limestones from nearby Hallstatt. The Wetterstein limestones are an adjacent Ladinian to Lower Carnian reef facies that provide a window into the end of the Carnian Pluvial Event (CPE).
The Carnian Pluvial Event is sometimes called the Carnian Pluvial Episode and is also known as Reingrabener Wende (meaning Reingrabener turnover), or Raibl Event — named after the Raibl area, Friuli-Venezia Giulia region of northeastern Italy.
By any name, the Carnian Pluvial Event (CPE) was a time of major change in our global climate and biotic turnover in the early Late Triassic, between 234 and 232 million years ago. For its significance, it is all but neglected in the body of our palaeontological studies that favour other global ecosystem turnovers during the Mesozoic. It had a huge impact on marine and terrestrial ecosystems. This interval saw a climatic shift from the arid climate of the Late Triassic to the markedly more humid conditions of the Carnian Pluvial Event (CPE), then back to arid again.
A ≈1.5‰ negative shift in oxygen stable isotopes (δ18O) of conodont apatite suggests a global warming of 3 to 4 °C and a change in seawater salinity.
Major changes in organisms responsible for calcium carbonate production occurred during the CPE. In the world's oceans, we see mass biological turnover. Conodonts, ammonoids, bryozoa, and green algae were severely hit by the CPE and experienced high extinction rates.
Most noticeable were the radiations of, among other groups, calcareous nanofossils, corals, and crinoids.
This is especially interesting as ammonoids and conodonts, the two most important groups for the biostratigraphy of the Triassic, had a significant turnover.
Outside of Austria, many localities in Itlay place a primary role in our understanding of the CPE as paradigmatic examples of the geological and biotic processes that were occurring during this interesting moment in time — particularly concerning our future understanding of the evolution of shallow marine and terrestrial groups.
The collective research to date has been focussed on more global and on the deepwater records of the CRP. Italy boasts the most expanded and complete shallow-water successions in the Raible area of northeastern Italy and the most prolific amber site with reef associations in the Dolomites near Veneto.
A halt of carbonate sedimentation is observed in nearby southern Italy in deepwater settings that were probably caused by the rise of the carbonate compensation depth (CCD). High extinction rates occurred among ammonoids, conodonts, bryozoa, and crinoids.
Major evolutionary innovations followed the CPE, as the first occurrence of dinosaurs, lepidosaurs, an expansion of coniferous trees, calcareous nanofossils and scleractinian corals
After the CPE, reef growth starts again. We see this as the Dachsteinkalk — the Dachstein Formation or Dachstein Limestones — a Norian geologic formation in the Alps and other Tethyan mountain ranges in Austria
The beautiful block you see here was kindly prepared by mother nature. She did most of the prep but Andreas did the excavation, soaked it for a few days in water and carefully washed it clean to photograph. A very special thank you to him for continuing to inspire me with his wonderful eye and deep knowledge of our world.
Photo: Andreas / Size: 15 cm x 15 cm.
Sunday, 23 May 2021
TURTLE SHELLS: HOME SWEET ARMOUR
When we look to the oldest known members of the turtle lineage, Proterochersis and Proganochelys, found as fossils in 210 million-year-old outcrops in present-day Germany and Poland. Like the turtles we find today, these stem-turtles already had fully formed shells — special bony or cartilaginous shell that originates in their ribs. It is a useful adaptation to help deter predators as their soft interior makes for a tasty snack.
Turtle armour is made of dermal bone and endochondral bones from their vertebrae and rib cage. It is fundamentally different from the armour seen on our other vertebrate friends and the design creates some unique features in turtles.
Because turtle ribs fuse together with some of their vertebrae, they have to pump air in and out of the lungs with their leg muscles.
Another unusual feature in turtles is their limb girdles, pectoral and pelvic, which have come to lie within their rib cage, a feature that allows some turtles to pull their limbs inside the shell for protection.Armadillos have armour formed by plates of dermal bone covered in relatively small, overlapping epidermal scales called scutes, composed of bone with a covering of horn. In crocodiles, their exoskeletons form their armour, similar to ankylosaurs. A bit of genius design, really. It is made of protective dermal and epidermal components that begin as rete Malpighii: a single layer of short, cylindrical cells that lose their nuclei over time as they transform into a horny layer.
Depending on the species and age of the turtle, turtles eat all kinds of food including seagrass, seaweed, crabs, jellyfish, and shrimp,. That tasty diet shows up in the composition of their armour as they have oodles of great nutrients to work with. The lovely example you see here is from the Oxford Museum collections.
Saturday, 22 May 2021
JOSE BONAPARTE: MASTER OF THE MESOZOIC
We often think of those who have shaped our past and found many of the firsts of their region as living in ancient history, but José left us just this past year in February.
He was a prolific and hard-working Argentinian palaeontologist who you'll know as the discoverer of some of Argentina's iconic dinosaurs — Carnotaurus, along with Amargasaurus, Abelisaurus, Argentinosaurus and Noasaurus.
His first love was mammals and over the course of his career, he unearthed the remains of some of the first South American fossil mammals from the Mesozoic.
Between 1975 and 1977, Bonaparte worked on excavation of the Saltasaurus dinosaur with Martín Vince and Juan C. Leal at the Estancia "El Brete." Bonaparte was interested in the anatomy of Saltasaurus, particularly the armoured plates or osteoderms embedded in its skin.
Based on this discovery, together with twenty examples of Kritosaurus australis and a lambeosaurine dinosaur found in South America, Bonaparte hypothesized that there had been a large-scale migration of species between the Americas at the end of the Mesozoic period.
The supercontinent of Pangea split into Laurasia in the north and Gondwana in the south during the Jurassic. During the Cretaceous, South America pulled away from the rest of Gondwana. The division caused a divergence between the northern biota and the southern biota, and the southern animals appear strange to those used to the more northerly fauna.
Bonaparte's finds illustrate this divergence. His work is honoured in his moniker given to him by palaeontologist Robert Bakker — "Master of the Mesozoic."
If you fancy a listen, he is the honoured guest in absentia on an episode of the Fossil Huntress Podcast. You can find the link here to listen: https://anchor.fm/.../Jos-Bonaparte-Master-of-the...
Friday, 21 May 2021
KERMODE SPIRIT BEAR: GREAT BEAR RAINFOREST
Thursday, 20 May 2021
KEPPLERITES FROM THE KURSK REGION
These beauties hail from Jurassic, Lower Callovian outcrops in the Quarry of Kursk Magnetic Anomaly (51.25361,37.66944), Kursk region, Russia. Diameter ammonite 70мм.
Back in the USSR — in the mid-1980s — during the expansion and development of one of the quarries, an unusual geological formation was found. This area had been part of the seafloor around an ancient island surrounded by Jurassic Seas.
The outcrops of this geological formation turned out to be very rich in marine fossils. This ammonite block was found there years ago by the deeply awesome Emil Black. Sadly, he has not been able to collect there for some time. In more recent years, the site has been closed to fossil collecting and is in use solely for the processing and extraction of iron ore deposits.