Category: Geology

Extreme Equatorial Climates Slowed the Rise of the Dinosaurs

Climate of the Tropics too Unstable for the Dinosaurs to Dominant in the Late Triassic

The vast majority of the reptile species found today are confined to the tropics.  However, a new study undertaken by an international team of researchers suggests that during the Late Triassic as one group of reptiles came to dominate the land, the dinosaurs, they struggled to gain a foothold in the tropics due to extreme climate fluctuations.  Dramatic swings in the equatorial climate from wet and humid to extremely hot and dry checked the evolutionary development of the Dinosauria.  Such conditions may be repeated in equatorial regions in the very near future due to increased amounts of carbon dioxide in the atmosphere as a result of global warming.  What slowed the rise of the dinosaurs, could provide our species Homo sapiens with a viable model of what lies in store for us.

The Flora and Fauna of the Late Triassic (Ghost Ranch, New Mexico)

Dramatic climate changes from very wet to very dry conditions limited the range of large, herbivorous dinosaurs.

Dramatic climate changes from very wet to very dry conditions limited the range of large, herbivorous dinosaurs.

Picture Credit: Victor Leshyk

The picture above shows a typical scene representing the flora and fauna of the Late Triassic (Ghost Ranch, New Mexico).  Thick forests of primitive ,drought resistant conifers, araucaria, redwoods and podocarps dominate the landscape.  Armoured Aetosaurs (foreground and background) would have grazed upon ferns, club mosses and horsetails, whilst Phytosaurs, which superficially resemble modern-day crocodiles, would have hunted small animals and mammal-like reptiles.  The vast majority of dinosaur fossils associated with the Ghost Ranch location (Chinle Formation), relate to small, Theropod dinosaurs.

Late Triassic Equatorial Dinosaur Puzzle

What has troubled the curiosity of palaeontologists, is why so very little evidence of larger plant-eating dinosaurs have been found in rock formations that represent deposits laid down close to the Equator?  The first dinosaurs might have evolved some 240 million years ago, perhaps slightly earlier.  Although, the fossil record is far from complete, it is likely the first dinosaurs lived in the southern hemisphere.  Over the next thirty million years or so, the Dinosauria gradually diversified and spread.  At this time in our planet’s history, most of the landmasses were joined together to form a single, super-sized land mass (Pangaea or Pangea).  Fossils of Sauropodomorphs have been found in Late Triassic strata from northerly as well as southerly latitudes but very few fossils of big, herbivorous dinosaurs have been found from locations that would have been close to the Equator.  Small-bodied, meat-eaters are found, although they do not make up a huge proportion of the total fauna, least not until the latter stages of the Triassic, but there is very little evidence to suggest the presence of large, plant-eating Sauropodomorphs.

To read about the recent discovery of a new type of meat-eating, Therpod dinosaur from the south-western United States: New Theropod Dinosaur Discovery Provides Evidence of Meat-Eating Dinosaur Diversification

A Map of the World in the Late Triassic

The position of the continents during the Late Triassic.

The position of the continents during the Late Triassic.

Picture Credit: North Arizona University with additional annotations by Everything Dinosaur

The map shows the approximate location of the Ghost Ranch site (New Mexico, USA), which during the Late Triassic lay close to the Equator.

To help understand the why certain types of dinosaur may have struggled to survive in the tropics, an international team of scientists, including researchers from the University of Southampton, have created a remarkably detailed picture of the ecology and climate of the famous Ghost Ranch fossil site (New Mexico).  The colourful rock layers preserved in this part of south-western United States represent a series of continental deposits, consisting mainly of sandstones and shales.  They date mostly from the Late Triassic (Carnian and Norian faunal stages).  The research team sampled different layers and used these samples to identify microscopic trace fossils such as plant pollen and fern spores.  This provided the researchers with some understanding of the changing plant populations over time.  This data was correlated with the work of organic geochemist Jessica Whiteside (Southampton University), who analysed carbon isotopes preserved in the rocks. Dr. Whiteside identified repeated highs and lows in the amount of “heavy” carbon-13 that was recorded, signs of major changes in the ecology of the area over time.  These peaks and troughs lined up with changes in the composition of the fossil pollen and fern spores preserved  This suggests that there were wild and dramatic climate swings leading to a flipping of floras, between a dominance of water loving species suited to a humid, warm and wet environment and those species that thrived when the climate became much more arid.

Dr. Whiteside Taking Samples for Isotope Analysis

Researchers Jessica Whiteside and Maria Dunlavey taking rock samples for analysis of the isotopic signature of organic carbon at Ghost Ranch, New Mexico. These data help reconstruct ecosystem productivity and environmental changes in the Triassic.

Researchers Jessica Whiteside and Maria Dunlavey taking rock samples for analysis of the isotopic signature of organic carbon at Ghost Ranch, New Mexico. These data help reconstruct ecosystem productivity and environmental changes in the Triassic.

Picture Credit: Randall Irmis

Commenting on the implications of this part of the study, Dr. Whiteside stated that this see-sawing between wet and dry environments occurred as atmospheric carbon dioxide levels rose from around 1,200 part per million in the oldest rocks sampled up to 2,400 parts per million in the youngest rocks included in the study.  These levels are well in excess of the current CO2 levels in our atmosphere (400 parts per million), but as global warming occurs and the amount of green house gases like carbon dioxide in the atmosphere increases, then we too, are likely to experience much more extremes in world weather.

Ian Glasspool, a specialist in studying ancient plant remains, examined the layers of charcoal that could be found in those sediments associated with the drier, hotter climate.  These are the remains of trees that were caught up in forest fires that periodically swept through this part of the world in the Late Triassic.  He measured the reflectiveness of the charcoal to estimate the intensity of the wildfires that had occurred.  The suggestion is that, the greater the amount of fuel available for a fire to consume, then the greater the heat generated.  The biomass available to burn would be directly related to dry conditions, the drier the climate the greater likelihood of very hot forest fires due to the presence of so much combustible material.

The evidence from the charcoal samples support the idea of a tropical climate swinging violently from extremes.  Severe droughts and forest fires would have continually reshaped the vegetation available for plant-eating dinosaurs.  Perhaps the large bodied, Sauropodomorphs, with their much greater food demands compared to other plant-eating reptiles, were not able to cope with the changes in the flora.

 The Field Team Excavating Vertebrate Fossils

A field team excavating vertebrate fossil remains (Ghost Ranch).

A field team excavating vertebrate fossil remains (Ghost Ranch).

Picture Credit: Randall Irmis

Note the clearly defined bands of different rocks which is a hall mark of the Chinle Formation.  The layers represent different deposition environments, the red sandstones are coloured due to the amount of iron minerals that they contain.  In the published academic paper that outlines this research, the scientists conclude that extreme climate fluctuation led to ecosystem instability in the tropics, which in turn suppressed the rise of the large, plant-eating dinosaurs in these regions.

Warm-Blooded versus Cold-Blooded

This new study may go some way to explain why fossils of small Theropod dinosaurs are found amongst the vertebrate fossil assemblage, but the remains of large Sauropodomorphs are extremely rare.  Although this new research provides a fascinating insight into an prehistoric ecosystem, it throws up some intriguing but controversial ideas.  The scientists postulate that these extreme climates prevented large, active, warm-blooded herbivorous dinosaurs from becoming established in sub-tropical low latitudes until much later in the Mesozoic.  It is suggested that the higher metabolic rates of plant-eating dinosaurs which were endothermic or had a form of endothermy (warm-bloodedness), prevented them from getting a foothold.  They would have needed greater amounts of food to sustain them when compared to the other types of, presumably, cold-blooded reptile that did live in those regions.  The debate over dinosaur metabolism is not resolved and even if the majority of the Dinosauria were endothermic or even mesothermic (a combination of cold-blooded and warm-blooded features), the early long-necked dinosaurs and their descendants, the Sauropoda, may have been entirely ectothermic.

The Femur of a Small Meat-Eating Theropod Dinosaur Excavated by the Researchers

A fossilised dinosaur thigh bone (Ghost Ranch), only small dinosaurs were present close to the Equator.

A fossilised dinosaur thigh bone (Ghost Ranch), only small dinosaurs were present close to the Equator.

Picture Credit: Randall Irmis

The small scribe provides a simple scale.  The distal end of the femur is towards the left of the photograph.

To read a short article about another early meat-eating dinosaur from the Ghost Ranch site: Buck Toothed Vicious Dinosaur Daemonosaurus chauliodus

What is Oolitic Limestone?

Oolite (Egg Stone) Get up Close to Limestone

One of the joys of having Smartphones around the office is that these can be borrowed and taken out on fossil hunting expeditions.  Yes, they have all sorts of features, most of which we don’t use, but the camera has proved a boon. With twenty megapixels to play with team members have been able to take some lovely photographs of fossil discoveries and geological landscapes.  With this sort of imaging technology widely available there are more pictures of fossils being taken than ever before, but sometimes the rocks that contain the fossils can prove to be just as interesting, take oolitic limestone for example.

 A Photograph of Oolitic Limestone (Building Stone)

"egg stone" seen in a building.

“egg stone” seen in a building.

Picture Credit: Everything Dinosaur

The picture above shows Cotswold building stone (Middle Jurassic), limestone that was laid down in a marine environment and a number of small shelly fossils have been preserved along with natural casts of shells.  If you were to run your hand over this finely chiselled piece of building stone it would still feel quite rough, having the texture of coarse sand paper.  It is oolitic limestone, otherwise known as “egg stone” and close up the surface of the stone has a remarkable appearance.

A Close Up of the Limestone Material

Made up of tiny spherical shapes.

Made up of tiny spherical shapes.

Picture Credit: Everything Dinosaur

The powerful digital camera on the Smartphone can pick up fine details such as the small, bubble-like appearance of the surface of the limestone.  These are the remnants of the ooliths (sometimes also called ooids) that make up the rock.  Grains of sand or fragments of seashell are rolled around the sea floor and as they do, they collect calcium carbonate (CaCO3).  Concentric layers are formed and these give the rock its characteristic “egg stone” appearance, as the surface of the rock looks like fish roe (fish eggs). Hence the term oolitic limestone.

Oolite (egg stone) is sedimentary rock and although most ooids are formed from the collection of calcium carbonate, this is not always the case as these structures can be composed of phosphate, dolomite or even chert.  The ancient Greek word for egg is  òoion and this might be the source of the derivations associated with this geologic structure.  In geology, sedimentary rock can be classified according to the composition of the rock as well as the diameter of the “egg stone” structures that are observed within it.  For example, oolites are technically defined as being composed of ooids that range in diameter between 0.25 mm to 2 mm.  Rocks composed of ooids of a larger than 2 mm diameter are called pisolites (made up of spherical shapes called pisoids).  The terms pisolite and pisoids come from the ancient Greek word for pea, so think of the size of the spherical shapes observed in the stone like a group of small peas.

Oolitic Limestone can be Full of Fossils

Fossil shell fragments in the oolitic limestone.

Fossil shell fragments in the oolitic limestone.

Picture Credit: Everything Dinosaur

Ooids are normally formed in warm, shallow seas that contain a lot of calcium and other minerals dissolved within the seawater.  Intertidal movements or currents aid in the transport of the material which helps in the formation of the ooid structures, but oolitic material can also form in freshwater.  Fragments of shell or a sand grain can act as a “seed” giving the calcium carbonate a medium which it can form around.  As these tiny “seeds” tumble around the sea bed they accumulate layers of precipitated calcite (another term for calcium carbonate), the size of the ooid (or pisoid) formed indicates the length of time the object has been exposed to the sea water before being buried by further sediment deposition.  Therefore, pisoids, being larger than ooids have been present on the sea floor longer than ooids.  Oolites with their “egg stone” grains superficially resemble sandstone and they can be white, grey or even yellow in colour (such as Portland limestone).  Under a high powered magnifying glass (or within a 20 megapixel image), the concentric rings which form the ooids can be easily made out.

Oolitic limestones are popular building materials, for example Cotswold limestone (oolitic limestone), as they are hard, resist erosion and come in a variety of hues and colours.  As they have an even structure they can be cut or sculpted in any direction.  Take a look at some of the older, stone buildings in your town.  If you live in the UK, chances are that some of these building stones are oolitic limestone and if you have a powerful camera you can record surface details yourself and record the ooids.

Washington State 37th U.S. State with a Dinosaur?

 Which States in the USA Don’t Have Dinosaur Fossils?

Everything Dinosaur’s recent article on the describing of a dinosaur fossil bone found on Sucia Island (Washington State) set team members thinking.  The fossil, which is believed to represent the partial left femur of a tyrannosaurid was the first dinosaur bone to be scientifically described from Washington State.  A number of media sites and scientific publications that covered this story listed Washington State as the latest and thirty-seventh U.S. State to have had dinosaur fossils discovered within its boundaries.  Of the fifty States that make up the USA, more than two-thirds of them are associated with the Dinosauria, either body or trace fossils or both.

The Partial Left Femur Identified as Tyrannosaur Fossil

Details of the partial left femur.

Details of the partial left femur.

Picture Credit: PLOS One with additional annotation by Everything Dinosaur

To read Everything Dinosaur’s article on the fossil discovery: The First Dinosaur Fossil Described from Washington State

So what about the remaining thirteen States in America, those inferred not to have dinosaur fossils?  Is this a case of there being none found as yet or does the fossil discovery in Washington State represent, in all likelihood, the last State in the United States to be added to the “dinosaur club”?

Let’s look at this in a little more detail.

Which States Don’t Contain Dinosaur Fossils?

Identifying the thirteen States* that don’t contain dinosaur fossils is quite a tough ask for a company this side of the Atlantic.  However, team members at Everything Dinosaur have been putting their heads together and have come up with the following list (which may or may not be accurate).

    1. Hawaii – the Hawaiian archipelago was the fiftieth and most recent State to join the USA.  As it is almost entirely made up of volcanic rock (igneous) and since it is a relatively recent geological feature, probably less than six million years old, we can state with confidence that no dinosaur fossil material will be found in the island’s rock formations.  That’s the easiest one out of the way.
    2. Florida – the “Sunshine State” it might attract millions of tourists but there are very probably no dinosaur fossils to be found.  The landmass we know as Florida today did not form in the Mesozoic.
    3. Louisiana – in the north-western portion of the State, there are some small outcrops of marine shales that were deposited in the Late Cretaceous.  As far as we know, no dinosaur fossils have been associated with this strata (located around Bienville Parish).  It is extremely unlikely that dinosaur fossils could be found in Louisiana, but it could happen.
    4. Mississippi** – the Mississippi river and delta deposits are far to recent to provide the opportunity to find dinosaur fossils.  However, in the far north-east of the State there are small exposed areas of Upper Cretaceous aged marine deposits, predominately chalk.  As far as we know no dinosaur fossils have been found and it is extremely unlikely, however, if you were to go and look, try around Ponotoc and Union Counties – we wish you luck.  South-east USA sorted (we think).
    5. West Virginia – moving up the eastern seaboard of the United States, the next candidate is West Virginia.  As far as we know at Everything Dinosaur, there are no sedimentary rocks dating from the Mesozoic to be found in this State, erosion and other forces have removed them, therefore no dinosaur fossils.
    6. Rhode Island – the smallest State in the USA.  Triassic and Jurassic sedimentary deposits are absent (we think), very few Cretaceous outcrops present, so no dinosaur fossils.
    7. New Hampshire – erosion of sedimentary materials and intrusions of igneous and metamorphic rocks leaves virtually no Mesozoic aged sedimentary formations in the State.  We don’t think any dinosaur fossils have been found here.
    8. Vermont – Triassic and Jurassic aged sediments eroded away and very little Cretaceous aged deposits exposed.   All of these Cretaceous deposits not fossiliferous, so no dinosaur fossils as far as we know discovered in Vermont.
    9. Maine – in the far north-east of the United States there is a huge gap in the geological record with most Late Palaeozoic, Mesozoic and Cenozoic fossils eroded away (blame the glaciers and so forth).  As a result, once again, as far as we know dinosaur fossils recorded from the State of Maine = zero.  So that’s the eastern seaboard and the far north-east taken care off.
    10. Michigan – still in the Eastern Time Zone, but no dinosaur fossils have been found on either peninsula that make up this State.  Lots of invertebrates et al, but no dinosaurs (we think).
    11. Ohio – thanks to glaciation and other forms or erosion, Mesozoic aged sedimentary rocks are virtually absent.  Dinosaurs did probably roam in this part of the world but their fossils have long since be eroded away.
    12. Indiana – just like its eastern neighbour Ohio, blame the glaciers for the loss of the Mesozoic strata.  So no dinosaur fossils in Indiana either, but just like in Ohio, they did probably live in this neck of the woods.
    13. Kentucky – south of Indiana to the “Bluegrass State”.  As far as we can work out from our own notes, there are few Mesozoic rocks exposed (eroded away no doubt).  Some Cretaceous aged outcrops are present and we have some tentative notes of plant fossils from the Cretaceous, but alas, no evidence of the Dinosauria.  Hold on a minute, that should be it, but we still have some more States to go.
    14. Illinois – into the Central Time Zone but just like its eastern neighbour Indiana, erosion has led to the removal of much of the Mesozoic strata.  Some Cretaceous-aged deposits can be found in the south of this State, but as far as we know, although dinosaurs may have lived in this part of the world there is no fossil evidence for them.
    15. Wisconsin – substantial erosion has removed the dinosaur fossil bearing strata, so according to our notes and database, there are no dinosaur fossils associated with the State of Wisconsin.

States in America with Dinosaur Fossils (2015)

Dinosaur Fossils by U.S.State.

Dinosaur Fossils by U.S. State.

Picture Credit: Wikipedia Commons (map) Everything Dinosaur (annotations)

According to our research, the figure of thirteen U.S. States not having dinosaur fossils associated with them is inaccurate. Of course, our own database could be wrong but we make it fifteen States without any evidence of the Dinosauria.  Thanks to mountain building, glaciation, the construction of huge urban developments and the fact that parts of the United States simply did not exist during the time of the dinosaurs, these are the States that lack any dinosaur fossils.

We admit, we could have got this wrong and we would welcome any comments to help provide a more accurate picture.

Additional Notes

Thanks to J. Slattery for helping with this, we have received information about Late Cretaceous dinosaur fossils from Mississippi**.  It seems that in some uncovered outcrops of Upper Cretaceous age which represents shallow marine deposits, fragmentary dinosaur fossils (teeth and bones) have been found as a result of what we tend to call “bloat and float”.  A dinosaur carcase being washed out to sea and then being scavenged before sinking and settlement.

Fossil Site Threatened (Hall Dale Quarry)

Former Quarry Could be Transformed into Housing and Commercial Development

The huge Hall Dale Quarry near Matlock, Derbyshire, could be transformed, with the potential loss of an amazing fossil location, if the local authority grants permission for a mixed residential and commercial development on the site.  Hall Dale Quarry is a disused limestone quarry.  We at Everything Dinosaur, don’t know when the quarrying of limestone blocks ceased, what we do know is that the rocks exposed at this location contain a huge diversity of Carboniferous invertebrate fossils.  Fossils are extremely common at the quarry, whilst many amateur collectors split the boulders with heavy-duty chisels to access the fossil material, just a few minutes exploring the scree on the quarry floor will yield plenty of specimens.  Fossils of a variety of Brachiopods, Crinoid stems and large Corals litter the site and with careful searching some nice examples of marine Gastropods (mainly internal moulds), can be discovered too.

The strata represents a shallow, marine environment and the rocks at the quarry are part of the Eyam limestone formation.  They date from the Early Carboniferous (Visean faunal stage of the Middle Mississippian Epoch [345-328 mya]).  The site is hidden from the road and is approached via a small path leading through a wooded area, although it is just a few minutes’ drive from the bustling centre of the Derbyshire market town of Matlock, once at the quarry face, it’s a different world.  On the day Everything Dinosaur visited, the quarry was deserted, we did not see a single person for the best part of three hours.

A View from the Helicopter Pad at Hall Dale Quarry

Hall Dale Quarry (Derbyshire)

Hall Dale Quarry (Derbyshire)

Picture Credit: Everything Dinosaur

The rock strata forms a series of platforms (three in total), Hall Dale Quarry is a popular location with climbing clubs, the sheer rock faces and huge piles of stone provide plenty of different climbing routes to explore.  We would advise that fossil collectors stay on the ground level, there are plenty of fossils to be found and there is no need to climb the boulders.

Enormous Boulders at Hall Dale Quarry

Huge boulders - can you see our rucksack?

Huge boulders – can you see our rucksack?

Picture Credit: Everything Dinosaur

During our research, prior to our fossil hunting trip, we visited the excellent website of UK Fossils: UK Fossils.  As we prepared for our visit, we came across a news article from November 2014 that outlined plans for the development of this rural space, what is termed a brownfield site.  4M Property Partners had submitted plans to convert the quarry into a development consisting of mixed residential and commercial properties.  Plans had been submitted to the council to build some 220 houses, and to convert 400 square metres into a restaurant and a café.  In addition, the planning proposal contained details of some 6400 square metres of office space.  We at Everything Dinosaur are not sure exactly how fossil collecting would be affected by these developments, we are also unsure as to how the planning application has progressed.  However, we would like to express our concern that such an amazing place might be lost forever.

Whilst we can appreciate that Matlock, like many towns in the UK, may have a need for more houses and that such a development might boost the local economy, as we stood in the quarry, totally in awe of the spectacular scenery and surrounded by evidence of a tropical, marine environment that existed some 340 million years ago, it seemed such a shame that this location might soon be unrecognisable.

Many Different Types of Invertebrate Fossil can Be Found in the Scree

Fossils can be found in the scree.

Fossils can be found in the scree.

Picture Credit: Everything Dinosaur

There may be an urgent need for more local housing.  The town of Matlock might desperately require additional commercial properties.  We feel that we are unable to comment with regards to these development plans, but we sincerely hope that the developers have at least considered the need to preserve some part of this remarkable location’s fossil heritage.  There are fewer and fewer places in this country, where people can simply stop and stare and admire rock formations and the fossil treasures they contain within.  These special sites demonstrate the rich geology of our landscape and allow visitors to explore life in the past.  We hope that any development is undertaken in sympathy with the astonishing geology of this location.

A Few Minutes Collecting and So Many Fossils

A multitude of fossils can be picked out from the scree.

A multitude of fossils can be picked out from the scree.

Picture Credit: Everything Dinosaur

Wishing to express our concerns, the team member who visited the site contacted the planning department of Derbyshire Dales District Council.  A very helpful person in the department explained that the planning team could be emailed, allowing concerns about the need to develop the location in sympathy with the geology of the area to be put on record.  Everything Dinosaur subsequently did this and in addition, emailed Natural England to raise awareness of the development of this brownfield site with that organisation.

Raising Awareness About the Potential Loss of the Quarry

If you have collected fossils at Hall Dale Quarry and wish to make a point with reference to the re-development of this site and the potential loss of this fossil collecting location, then we would urge you to do so.

Planning application reference: 14/00541/OUT (please quote this reference when emailing the planning department or Natural England).

Email: planning@derbyshiredales.gov.uk to contact Derbyshire Dales District Council (we would advise that you include a contact telephone number in your email, so that a planning team member can get in touch)

Email: consultations@naturalengland.org.uk (again quoting planning reference: 14/00541/OUT) to get in contact with Natural England

Whilst we do understand the difficult and often challenging job of district councils and we aware of the potential economic benefits to the local community this project may bring.  We at Everything Dinosaur feel that it is important, to at least place on record a desire to consider the development of Hall Dale Quarry which takes into account the remarkable fossil bearing strata to be found at this location.

Please share.

The Chinese Pompeii – Dinosaur Fossils Can be Confusing

Death of Dinosaurs in the Early Cretaceous of China (Lujiatun Unit of the Yixian Formation)

At Everything Dinosaur we define science as the “search for truth” and one of the fundamental principles of scientific working is the examination and assessment of evidence which leads to conclusions being drawn and theories put forward.  However, different scientists can examine the similar evidence and come to contrasting conclusions.  Let’s illustrate this point by looking at two scientific papers published recently that both seek to explain the remarkable degree of fossil preservation seen in a sequence of Lower Cretaceous strata laid down in north-eastern China.  Let’s explore the mystery of the “Chinese Dinosaur Pompeii”.

Last year, a team of international researchers led by Associate Professor of Palaeontology and Stratigraphy at Nanjing University, Baoyu Jiang published a paper that concluded the remarkably well-preserved dinosaur, bird and mammal fossils that form part of the Jehol Biota were created “Pompeii-style” by pyroclastic flows.  A pyroclastic flow is an immense, fast-moving cloud of extremely hot gas and dust that can occur with some types of volcanic eruption.  It would have swept everything before it and killing instantly any unfortunate animal or plant that was in the way.   The research team cited evidence such as criss-crossed cracks on the edges of fossilised bones, evidence of heat stress, microscopic debris showing plant remains that had been blackened by being exposed to very high temperatures prior to fossilisation and hollow bones filled with fine quartz grains, tell-tale signs of a pyroclastic flow.  Although the fossils are some 120 million years old, the same evidence can be found in the bodies of citizens of Pompeii who perished when this Roman town was engulfed by a pyroclastic flow which erupted from Vesuvius back in 79 AD.

Evidence of Sudden and Dramatic Death – Caught in Pyroclastic Flows

Evidence for pyroclastic flows from the Jehol Biota.

Evidence for pyroclastic flows from the Jehol Biota.

Picture Credit: Baoyu Jiang

The picture above shows photomicrographs (photographs of images produced under a microscope), showing thin sections of fossilised bone of two relatively common vertebrate fossils from the strata that was investigated.  The pictures show a dinosaur, Psittacosaurus and a thin section of the bone fossil from an ancient bird, Confuciusornis (top Psittacosaurus spp. and bottom Confuciusornis spp.).  The white arrows indicate missing bone material and cracks can be seen at both the dorsal and ventral edges of the bone.  This evidence supports the idea that the bones were subjected to intense heat, such as that found in volcanic pyroclastic flows.

Victims of a Pyroclastic Flow?

a).

a = Psittacosaurus, b and c = Confuciusornis fossil material

Picture Credit: Baoyu Jiang

Note the position of the limbs in the photographs of the fossils (above), particularly those fossils representing the bird Confuciusornis.  The pose is like that of a boxer.  This pose results from the shortening of muscles and tendons that occurs postmortem and this boxer-like box has been cited as further evidence to support the idea of mass mortality as a result of a pyroclastic event.

Conflicting Views as to How these Fossils were Formed

Associate Professor Baoyu Jiang and his colleagues have studied the flora and fauna preserved in the Lower Cretaceous deposits for many years.  It had been known for some time that volcanoes were active in the area at around this time in the Cretaceous, testament to the frequent eruptions were the many layers of fine, volcanic ash that could be identified in the rock layers.  The paper citing pyroclastic flows as the reason for the remarkable, often three-dimensional preservation of vertebrates led to considerable debate amongst scientists at the time of its publication.  Now another paper has been written, which argues that the fossils of the Lujiatun Member of this Formation do not owe their existence to violent clouds of hot ash, rocks and dust travelling at hurricane speeds, but are the result of slightly more gentle, (but equally dramatic), deposition forces.

A team of scientists from Bristol University in association with the IVPP (Institute of Vertebrate Palaeontology and Palaeoanthropology – Beijing) and University College, Dublin have reassessed the “Chinese Pompeii” deposits and their fieldwork suggests that the fossils were transported in water which was choked with volcanic ash, rather than have the fossils forming as a result of sudden airborne ash fall.

A New Study Suggests Vertebrates such as Psittacosaurus were Buried by Ash that was Deposited by Water

Overcome by ash carried in water flows not pyroclastic flows.

Overcome by ash carried in water flows not pyroclastic flows.

Picture Credit: Bristol University Press Release

The fossils of the Jehol Biota come from the Lower Cretaceous Yixian and Jiufotang Formations.  Both freshwater and terrestrial creatures are found in the same horizons and some scientists have interpreted these deposits as evidence for mass mortality events.  The research group that included the Bristol-based team, set out to explore the events and mechanisms that led to the exceptional preservation.  By analysing in microscopic detail the sediments and residual fossils from the Lujiatun Member (the vicinity of Lujiatun village) and comparing the strata to fossils in the collections of Chinese museums, the scientists concluded that the beautifully preserved specimens of the Lujiatun Unit are not the result of one single, massive catastrophe caused by a volcanic eruption.  Their study suggests that the fossil-bearing sediments were remobilised and deposited by water.  If this is the case, the Psittacosaurs, other dinosaurs, primitive mammals and birds for example, were not wiped out by one huge, airborne delivery of volcanic ash, but in multiple flood events which carried very high loads of ash and other debris from volcanoes sweeping all before them and burying the unfortunate animals and plants.

One of the problems that occurs when trying to conduct a study such as this, is that many of the fossils in museum collections have been found by local farmers who then sell on the fossil material.  Not very accurate excavation records are kept and therefore it is often extremely difficult to match up a museum specimen with the actual horizon from which it originated.

Commenting on the research, lead author of the scientific paper that has just been published in the journal of “Palaeogeography, Palaeoclimatology, Palaeoecology”, PhD student Chris Rogers of Bristol University said:

“Without stratigraphic information of the fossils in the field, it was impossible to accurately establish a mode of death for these animals.  Once we established proper placement of these fossils in the sedimentary sequence it became clear that these animals had been buried by sediments that were deposited by water and not by volcaniclastic flows.”

It is likely that the debate over the nature of the Jehol Biota will rumble on (just like a pyroclastic flow), this is an example of groups of scientists building on each other’s work to better understand how certain fossils are formed.  However, they were formed, the Jehol Biota provides palaeontologists with a unique insight into the flora and fauna of this part of the world back in the Early Cretaceous, a time when the Aves were rapidly diversifying and there were important revisions undergoing in both the Mammalia and Reptilia.

Chilesaurus – A Dinosaur Designed by a Committee!

 Chilesaurus diegosuarezi – A Theropod that Took a Very Different Path

It may have been little more than three metres long and if it had been included in the forthcoming dinosaur film “Jurassic World”, this little dinosaur would not have lingered long in the film goers memory but the publication of a scientific paper on the newly described Chilesaurus (C. diegosuarezi) represents a very big deal for the scientific community.   Here is a member of the Theropod dinosaur family, distantly related to the likes of Allosaurus, Velociraptor, Spinosaurus and T. rex that evolved into a plant-eater and what a bizarre looking dinosaur Chilesaurus is.  It does look like a dinosaur designed by a committee.

An Illustration of the Newly Described Patagonian Dinosaur C. diegosuarezi

A curious little dinosaur from southern Chile.

A curious little dinosaur from southern Chile.

Picture Credit: Gabriel Lio

Theropod dinosaurs were the dominant land predators throughout most of the Mesozoic era.  It is thought that the very first dinosaurs, those that evolved perhaps as early as 240 million years ago, had very similar body plans.  They were small, fast running, agile predators that had long tails, slender legs and for the most part were entirely carnivorous.  These were the lizard-hipped dinosaurs, the Saurischia, one of two great divisions into which all the dinosaurs are divided, the other division being the bird-hipped dinosaurs, the Ornithischia.  It was a British scientist, Harry Govier Seeley, who in 1888, classed the then known dinosaurs into one of two clades based on the structure of the bones that make up their hip girdles.  Lizard-hipped forms which include the Theropods have their pubis bone projecting forward (usually see below), in contrast to the bird-hipped forms that have the pubis bone pushed backwards.

Chilesaurus is a member of the lizard-hipped clade.  It is a Theropod and palaeontologists know that the Theropoda are perhaps the most diverse Sub-order of all the Dinosauria, but no one quite anticipated such a bizarre looking dinosaur from one of the southern most parts of the South American continent.

 Classifying Dinosaurs by their Hip Structures

Classifying dinosaurs by the shape of their hip bones.

Classifying dinosaurs by the shape of their hip bones.

Picture Credit: Everything Dinosaur

The beautiful, mountainous and sparsely populated Aysén region of southern Chile was being explored by a Chilean couple, both of whom are geologists (Manuel Suarez and Rita de la Cruz), back in 2004 when the fossils of this strange dinosaur were discovered. This remote part of Chile is renowned for its extensive mineral deposits, but whilst exploring a rocky exposure near General Carrera Lake, the son, Diego, who was seven at the time, picked up a couple of odd looking objects.  The parents recognised these as a partial rib and a vertebra and the family set about searching the immediate area to find more fossilised bones.  Sister Macarena joined in and in a short while the family had collected quite a number of bones representing several individual animals.  Over the last decade or so, a team of South American scientists have been piecing together the evidence and this has led to the naming of this new and very unusual genus.

One of the lead authors of the scientific paper published in the journal “Nature”, Dr. Fernando Novas (Museo Argentino de Ciencias Naturales (Buenos Aires, Argentina), explained:

“I don’t know how the evolution of dinosaurs produced this kind of animal, what kind of ecological pressures must have been at work.  What’s surprising is that in this locality the most bizarre dinosaur is not the exception, but the rule.  It is the most abundant animal we find.”

 A Skeletal Drawing and Illustration of Chilesaurus diegosuarezi

Light, agile plant-eating dinosaur.

Light, agile plant-eating dinosaur.

Picture Credit: Gabriel Lio

 Chilesaurus ran around on long legs, each foot had four toes.  The forelimbs were less than a third the size of its hind legs, so it retained the bipedal stance of its meat-eating ancestors, but the neck was long and slender and the skull small.  The teeth had evolved, squared-off tops, adaptations to a diet of plants.  The jaw supported a beak, very reminiscent of those beaks seen in bird-hipped dinosaurs like Stegosaurus and Triceratops.  The hands were reduced and only two fingers had claws, the third finger was little more than a stump and effectively vestigial.

A spokesperson from Everything Dinosaur commented:

“Chilesaurus, shows anatomical characteristics quite unlike any other Theropod dinosaur.  For example, the pubis bone is projecting backwards, which is similar in orientation to the layout of the pelvic girdles of Ornithischian dinosaurs, but other features identify this as a member of the lizard-hipped Theropoda.”

All four toes of the hind feet supported the weight of the animal, whilst in the Theropoda, the vast majority of these animals have a tri-dactyl (three-toed stance).  It seems that this plant-eater, not having the need to pursue prey was slowly evolving a foot morphology similar to the early plant-eating Prosauropods.

Excavating Fossil Bones in the Beautiful Aysén Region of Southern Chile

A beautiful but very remote fossil dig site.

A beautiful but very remote fossil dig site.

Picture Credit: Dr. Fernando Novas

The strata in this region of southern Chile is part of the Upper Jurassic Toqui Formation and dates to around 145 million years ago.  Apart from the numerous fossils of Chilesaurus, which represent a number of individual animals at various stages of growth, the site has yielded a number of Archosaur remains as well as several Crocodyliforms and highly fragmentary remains of a few Sauropods tentatively assigned to diplodocid and titanosaurians.

How to classify this little dinosaur with its strange mix of features?  The scientists have described this dinosaur as a basal Tetanuran, a distant relative of the likes of the Tyrannosaurs, Dromaeosaurs and the Therizinosauridae, a Family of Theropods associated with Cretaceous deposits that also adapted to a herbivorous diet.  The genus name reflects the location of the fossil discovery.  Chilesaurus is the first complete dinosaur from the Jurassic geological period found in Chile and the fossils represent one of the most complete and anatomically documented Theropod dinosaurs known from the southern hemisphere.

Dr. Novas added:

“Although plant-eating Theropods have been recorded in North America and Asia [Therizinosauridae], this is the first time a Theropod with this characteristic has been found in a southern landmass.”

A Fragment of Jaw from a Juvenile Showing the Bizarre Teeth

Teeth adapted for cropping plants.

Teeth adapted for cropping plants.

Picture Credit: Dr. Fernando Novas

This bizarre Late Jurassic Theropod dinosaur really looks like it has been designed by a committee!

A Sixth Mass Extinction Event?

Capitanian Extinction Event – Suggested by Northern Hemisphere Study

A team of geologists have published a paper in the prestigious Geological Society of America Bulletin postulating that there was a major global extinction event that took place in the Permian geological period.  To be more precise the evidence for the extinction can be found in rocks laid down approximately 262 million years ago (the Capitanian stage of the Guadalupian epoch of the Permian).  The idea that there was a major extinction event amongst both marine and terrestrial organisms in the Middle Permian is not new.  Studies of the diversification of marine invertebrates recorded in Mid Permian strata from lower latitudes indicated that several families of mollusc and Brachiopod had died out during this time in Earth’s history.  It had been thought that global cooling had resulted in the loss of so many types of marine animal from the tropics.  However, this new study indicates that the Middle Permian extinction is manifested in the fossil record preserved at higher latitudes.

To assess the extent of the extinction, the research team, led by Dr. David Bond (University of Hull) travelled to the remote Norwegian island of Spitsbergen to explore the Kapp Starostin Formation, a layer of marine strata that is up to four hundred metres thick.  These rocks were laid down over a period of around 27 million years and cover the crucial period of the Guadalupian epoch.   By assessing the number and type of Brachiopod fossils found in the rock layers, the scientists were able to demonstrate that there were two severe extinctions amongst Brachiopods in northern latitudes in the Middle to Late Permian.  These extinction events are separated by a recovery phase, a time when the diversity of Brachiopods increased.

Many Rhynchonellid Brachiopod Fossils Found Together

Study suggests global mass extinction event in the Permian.

Study suggests global mass extinction event in the Permian.

Picture Credit: Everything Dinosaur

Brachiopods, superficially resemble shelled molluscs like clams and mussels, but they have a very different body plan.   They are not closely related to the Mollusca and the Brachiopoda is an entirely separate phylum.  These little creatures first evolved in the Cambrian and they are still around today.  Most can be found in deep water and they are benthic (live on the sea floor), they are not found in freshwater.  There are more than a dozen or so species to be found in the waters surrounding the British Isles.  Brachiopods are sometimes called “lamp shells” as some of them resemble the shape of oil lamps used by the Romans.  Shells are usually made from calcium carbonate, but some form phosphatic shells.  The shells which protect the soft tissues consist of two parts (valves), one part is always bigger than the other part.  They are often the commonest fossil to be found in Palaeozoic marine limestones that represent shallow water deposits, as a result there are a number of Brachiopod biostratification zones.

An Illustration of a Group of Brachiopods

Brachiopods anchored themselves securely using a pedicle.

Brachiopods anchored themselves securely using a pedicle.

Picture Credit: Everything Dinosaur

Strontium isotope analysis coupled with examination of trace metals and magnetic polarity preserved within the strata, correlated the time of the formation of the layers that show a distinct decline in Brachiopod diversity to about 262 million years ago (Capitanian stage).  Older rocks show that Brachiopods dominated the fossil record, but there is an 87% fall in fossil Brachiopod diversity in the middle of the Capitanian-aged rocks.  Younger rocks do have preserved remains of Brachiopods but they are different from the ones in the Capitanian strata, in addition, the younger rocks show a change in the fauna, there are many more bivalves (molluscs) preserved as fossils.   This suggests that there was a catastrophic event that lasted tens of thousands of years which led to a dramatic change in the benthic  invertebrate populations, as recorded by the fossil evidence.  The research team visited Spitsbergen three times to conduct the research from 2011 to 2013, working in the month of July, taking advantage of the 24 hours of daylight available and the slightly warmer weather.  Polar bears were still a danger and the expedition had to be on the look out in case a curious bear came into their camp.

The existence of a separate and distinct global extinction event around 262 million years ago, remains controversial.  Just a few million years ago, the biggest mass extinction event known occurred, resulting in the loss of something like 96% of all sea-dwelling creatures.  The event is known as the end Permian mass extinction.   The vast majority of the invertebrates recorded in the rocks after the Capitanian event became extinct.  The authors of the paper, published in the Geological Society of America Bulletin, suggest that their research shows that the Capitanian extinction event devastated fauna in both the tropics and in northern latitudes.  They conclude that this extinction was not limited to the warmer areas of the planet but much more wider ranging, deserving the status of a global mass extinction event.

What Caused this Extinction?

Molluscs and Brachiopods need calcium to make their shells (most of them), Dr. Bond believes massive volcanic eruptions in what is now the Chinese Province of Sichuan released huge amounts of carbon dioxide which in turn, acidified the oceans locking up the calcium.  In addition, depletion of oxygen on the sea floor may also have contributed to the extinction event.

Today, April 22nd is designated “Earth Day”, a day in which we recognise the plight of our planet, issues like global warming, extinction and loss of habitat.  It is apt for us to be considering the evidence for a sixth mass extinction event recorded in the Phanerozoic Eon (visible life).

Scientists Set Out to Explore Chicxulub Impact Crater

Impact Crater from Dinosaur Extinction Event to be Explored

Plans are in place for a team of international researchers to drill into the seabed off the Yucatan peninsula (Mexico), so that they can explore the composition and structure of the Chicxulub impact crater, the site where around 66 million years ago, a huge rock from space crashed into our planet.  The impact was so immense that the devastation and climate change events that this collision caused may well have resulted in (or at least assisted with), the extinction of the dinosaurs.  The scientists intend to drill into the crater, which is buried under sediments over fifteen hundred metres thick and study the elevated sections called the “peak ring”.  These rocks were forced up by the impact and form the boundary of the impact site, these topographically elevated rings are present in nearly all extraterrestrial impacts and the scientists hope to learn more about the Chicxulub impact itself as well as gaining a better understanding of such impact events and their effect on our our rocky planet.

An International Research Team Plan to Explore the Chicxulub Impact Crater

The end of the Age of Dinosaurs.

The end of the Age of Dinosaurs.

The Cretaceous mass extinction event is one of the most researched areas of science.  Improving our knowledge of how the climate change affected life in the past is helping to shape current policies as our planet experiences a period of exceptional warming.  Whether or not the extraterrestrial impact was the cause of the extinction of about 70% of terrestrial life, marking the end of the Age of Dinosaurs, is still debated.  Recent research from Glasgow University dates the impact at approximately 66,038,000 years ago +/- 11,000 years (margin of error).  This date according to many scientists is about 300,000 years before the Dinosauria extinction.  Whether the impact is the single cause, or whether it contributed to the mass extinction which occurred as a result of a number of factors remains when one of the hottest topics in palaeontology.

It was father and son team Luis and Walter Alvarez, who in 1980, publicised the discovery of a layer of clay with high levels of the rare Earth element iridium which mark the Cretaceous/Tertiary boundary (the K-T boundary).  They argued that the iridium was deposited as a result of an impact event where a meteorite or some other rocky body crashed into our planet.  The discovery of the Chicxulub crater that dated from the end of the Cretaceous provided “the smoking gun” evidence that just such an event had occurred.

The scientists involved in this new research project gathered in the city of Merida (Mexico) last week.  Merida, is within the 125 mile wide impact site that marks the Chicxulub event.  Scientists have estimated that the extraterrestrial object, perhaps an asteroid or even a comet, was at least six miles wide and it was travelling about eight times faster than a bullet when it hit the Earth.  About £6 million GBP has been set aside for funding, approved by the European Consortium of Ocean Research Drilling (ECORD).  Sean Gulick, who holds many academic posts including Associate Professor at the UT Jackson School of Geosciences, is part of the research team and has spent many years studying the geology of the Yucatan peninsula.  He hopes to acquire samples from the crater in a bid to learn more about the impact and its consequences.

Explaining the purpose behind the planned expedition, which is due to start next year, Sean stated:

“What are the peaks made of?  What can they tell us about the fundamental processes of these impacts, which is this dominant planetary resurfacing phenomena?”

The Associate Professor and long-time co-worker, Professor Joanna Morgan (Imperial College, London) have collaborated on a number of research projects exploring the Chicxulub impact crater, to read more about their research and earlier explorations of the geology of the Yucatan peninsula, click the link below:

To read more about this earlier research by the University of Texas: Getting to the Bottom of the Chicxulub Crater

A Geophysical Map Outlining the Impact Crater and the Crater Peaks

A geophysical map of the impact crater.

A geophysical map of the impact crater.

Picture Credit: NASA

The picture above shows a colour coded geophysical gravity map of the Yucatan peninsula.  The white dots represent “Cenotes”, these are sink holes which were formed as a result of the impact event.

The international research team are keen to explore the traces of microscopic life that may have lived inside the peak rocks of the crater.  The geophysical maps of the region indicate that these rocks are porous and they may have acted as miniature environments for types of extremophiles to thrive in the hot, chemically enriched area surrounding the crater.  In addition, core samples should provide evidence of the earliest recovery of marine life after the extraterrestrial impact, providing scientists with an idea about how life on Earth bounces back from such cataclysmic events.

Commenting on the search for evidence of life, Associate Professor Gulick stated:

“The sediments that filled in the crater should have the record for organisms living on the sea floor and in the water that were there for the first after the mass extinction event.  The hope is, we can watch life come back.”

Working from an offshore platform, the expedition is likely to last eight weeks and the cores taken will be the first to be extracted from the impact site.  The first papers on the analysis of these core samples are expected at the end of next year, we at Everything Dinosaur, look forward to this analysis of the “Alvarez smoking gun”.

William Smith Map – Re-discovered

Founding Father of Geology and His Remarkable Map

One of the very first editions of arguably one of the most significant maps in the history of the study of our planet has been re-discovered.  A pristine copy of William Smith’s 1815 map of the geology of England, Wales and parts of Scotland has been found in the archives of the Geological Society (London).  It seems that the map was placed in storage, carefully sealed inside a leather wallet but just where in the vast archive it was stored had not been recorded.  Ironic really, when you consider the dedication and attention to detail shown by Smith, the son of a blacksmith who so meticulously mapped the strata of most of the British Isles.

The archives of the Geological Society are vast, after all, it is the oldest body of its kind in the world (founded in 1807).  This year marks the bicentenary of the publication of William Smith’s great geological survey, only about 370 or thereabouts were ever produced and with this re-discovery, it is estimated that at least seventy are still in existence, not bad considering this map first went into production in the same year as the battle of Waterloo.  It is believed that this particular copy last saw the light of day around forty years ago.

Indexing the map, which comprises of fifteen sections would not have been easy.  It was customary in Georgian times to use very long titles for scientific publications, a trend that in some academic institutions still exists today.  Try cataloguing a map with the catchy title of:

“A  Delineation of the Strata of England and Wales with part of Scotland, exhibiting the collieries and mines, the marshes and fen lands originally overflowed by the sea, and the varieties of soil according to the variations in the substrata, illustrated by the most descriptive names by W. Smith.”

It is thought that William Smith, nick-named “strata-Smith” by his contemporaries spent fifteen years travelling the United Kingdom and carefully recording the rock formations exposed on the surface of the land.  His map when published, helped land owners and mining companies exploit this nation’s natural resources as the map helped surveyors identify potential areas for drainage, sites for new building work and most importantly which layers of strata indicated the presence of coal seams nearby.

Commenting on the discovery, John Henry (Chairman of the Geological Society’s History of Geology Group), stated:

“It just wasn’t where people expected it to be.  I guess the person who put it away knew where it was, but then they left and that was it, it became lost.”

Having been hidden away in the archives the map, which was printed from copper plate engravings with the details painted in with water colours, has not faded and the colours depicted are as vivid today as when the map was first completed.  Archivists are puzzling over just what number in the sequence of maps produced might this copy be?  There is the exquisite hand finished painting with the lower edge of each formation saturated and then the paint is faded to indicate the formation’s edge, a technique used by Smith to make his maps easier to read, but the map itself, unlike later editions, has no serial number.

Geologists are aware that the very first maps produced were not numbered.  Another clue as to just when this map was made can be seen in how the geology of the Isle of Wight is depicted.  Over the production period of Smith’s map, the way in which the geology of the Isle of Wight was shown changed several times.  This map shows a very early effort to map the geology of the island.  All this suggests that this particular example of cartography might be amongst the first dozen or so ever produced.

A Clue to the Age of the Map – The Strata of the Isle of Wight

The Isle of Wight illustrations suggests an early print.

The Isle of Wight illustrations suggests an early print.

Picture Credit: The Geological Society (London)

The Geological Society has had the map fully restored and digitised.  As from today, it will be available to view on line on the Geological Society’s website.  This copy of the map itself will be stored back in the archives, this time properly catalogued.  A paper copy of the “Smith map” will be put on display in Burlington House, (London) the home of the Geological Society.

The Beautifully Illustrated Geological Map of the Cotswolds (William Smith)

Beautifully illustrated geological map.

Beautifully illustrated geological map.

Picture Credit: The Geological Society (London)

To see the map and other important geological images on line: The Picture Library of the Geological Society

Now, we at Everything Dinosaur don’t want to be cynical but today, March 23rd, is the anniversary of the birth of William Smith.  He was born on this day in 1769 in the county of Oxfordshire.  We think the timing of this announcement regarding the re-discovery has a lot to do with publicising an event taking place later on today, when Sir David Attenborough will be unveiling a plaque in tribute to the “Father of English Geology” at his former London residence – 15 Buckingham Street.  During his life, as William Smith strived to forge a reputation amongst academics, his lowly beginnings as the son of a blacksmith meant that his views and findings were often disregarded by those who perceived themselves to be of a higher class.  Class distinctions blighted the lives of many pioneers in geology and palaeontology during the Georgian and Victorian times.  However, William Smith and his contribution to our understanding of the world is now recognised and his map of England, Wales and parts of Scotland remains one of the most significant maps ever produced.

Why was the Map So Important?

The map certainly helped landowners and that part of Georgian society that owned mines.  It helped stoke (literally) the Industrial Revolution but it did something else, as William Smith traversed the British Isles making his map, he noticed that certain types of sedimentary rock, although far apart contained the same types of fossils.  We shall let John Henry explain just how significant this realisation was:

“The concept which enabled him to do the mapping and that drove him along almost obsessively was this realisation that specific fossils were unique to a specific stratum, and that you knew where you were in a sequence if you could see what the fossils were.  That was the breakthrough.  People had been collecting them for a long time and naming them in the Linnaean way, but without any real idea that they were in a sequence.  But Smith knew it.”

Smith explored the deep excavations taking place as canals and other major works were being constructed and found that he could correlate apparently dissimilar and geographically dispersed strata based on the fact that they contained similar fossils.  Going up through the strata, William Smith observed a succession of different fossils and proposed that each stage of this succession represented a specific period in the history of the Earth.  This is termed the “principle of faunal succession”.  In this way, the relative age of rocks could be determined and the types of fossils that characterise strata led to the concept of biostratigraphy.  Smith developed and built on the idea of a Law of Superposition, postulated by the great scientist Nicolas (sometimes spelled as Nicolaus), Steno in the 17th Century.

To read more about the work of Nicolas Steno: Google Doodle Commemorates Nicolas Steno

The 1815 Geological Map of England, Wales and Parts of Scotland

Can you see the geology in your part of the world?

Can you see the geology in your part of the world?

Picture Credit: The Geological Society (London)

Originally produced as a map in fifteen sheet sections, the geological map of the British Isles (most of it) measures approximately 180 cm by 250 cm.  We at Everything Dinosaur, don’t know why northern Scotland was not mapped by Smith, we suspect it was much more difficult to travel the highlands and islands of northern Scotland and during the early 19th Century, there was simply not the demand for detailed geological maps of that part of the British Isles.

Spring Low Tides Uncover French Dinosaur Footprints

The Dinosaur Footprints at Veillon Beach (Vendée)

The low tides brought about as a result of the spring equinox has exposed a remarkable series of Early Jurassic trace fossils, giving residents of the town of Talmont-Saint-Hilaire the chance to go “Walking with Dinosaurs”.  The exceptional low tides on France’s North Atlantic coast have revealed 200 million year old footprints as well as ripple marks preserved in the mudstone and sandstone which were laid down at the very beginning of the Jurassic (Hettangian faunal stage).  The site represents an estuary, or shallow bay area and this was criss-crossed by many different types of dinosaurs.  Hundreds of footprints have been recorded, a large number have been removed to prevent further damage by erosion, but at very low tides, especially in the spring when the seaweed and algae growth is not extensive, many three-toed prints can still be seen.

“Walking with Dinosaurs” – Some of the Footprints Revealed at Low Tide

One of the many three-toed prints that can be seen at very low tide.

One of the many three-toed prints that can be seen at very low tide.

Picture Credit: GeoWiki

The site was discovered in 1963 by a local engineer and chemist Gilbert Bessonnat, but it was not until March 1965 when a team of French palaeontologists mapped the area in earnest that the full significance of the location was revealed.  The mapping project begun on March 19th that year, taking advantage of the very low tide associated with the spring equinox, allowed the scientists to discover what has turned out to be the largest single concentration of dinosaur ichnofauna in the whole of France.  Dinosaur trace fossils from the Lower Jurassic are exceptionally rare, the site is protected and no fossil collecting is allowed.  After all, the sandstones and mudstones preserved here record terrestrial life shortly after the End Triassic extinction event, those footprints were made some fifty million years before the likes of Stegosaurus and Diplodocus and other iconic Jurassic dinosaurs roamed the Earth.

In all, about a dozen different ichnospecies have been identified, including large and small Theropods.  Some footprints may not represent dinosaurs, for example, some trace fossils have been assigned to the Order Rauisuchia and ascribed to the Postosuchus genus (a type of ancient, terrestrial Crocodylomorph).  Ichnospecies associated with the site include: Eubrontes veillonensis tentatively described as a Megalosaur, Talmontopus tersi which could be a bipedal Ornithischian dinosaur and several dinosaurs assigned to the coelophysids (ichnogenus Grallator).

It seems that low tides on the North Atlantic coast of France, are providing scientists with a unique opportunity to learn about life in the Early Jurassic, well at least over the spring and autumn equinox anyway.

A Close Up of One of the Many Hundreds of Dinosaur Footprints Preserved at the Site

This print has been assigned to the ichnospecies Eubrontes.

This print has been assigned to the ichnospecies Eubrontes.

Picture Credit: GeoWiki

Staypressed theme by Themocracy