Bat's Head to Mupe Bay Mapping

In the final part of the Dorset fieldtrip I would like to discuss the section of coast between Bat's Head and Mupe Bay. This will include Durdle Door, Lulworth Cove and Stair Hole. This part of the fieldtrip was the main mapping task and therefore took two and a half days to complete.

This is an odd bit of the Dorset coast as it is nestled between two large outcrops of upper Jurassic Kimmeridge Clay, with Osmington Mills to the West and Kimmeridge Bay to the East. The geology between Bat's Head and Mupe Bay are latest Jurassic to Upper Cretaceous, the only explanation as to why this area is now surrounded by older rock is faulting and uplifting. This area is heavily faulted, as we will see, and therefore the older Kimmeridge Clay has been thrown down preserving the rock above.

Bat's Head to Mupe Bay

Map of east Dorset showing the location of Lulworth Cove. (Source: 
Google Maps)

Map of the stretch of coastline that was mapped between Bat's Head and Mupe
Bay (Source: Google Maps)

Durdle Door viewed from the Chalk ridge to the north.
(Source: Saffron Blaze www.mackenzie.co)

The basic geology of this section of coastline is relatively simple. The geological boundaries typically run west-east. The oldest unit is the limestone closest to the sea is the Portland Limestone and is only really accessible at Durdle Door and Lulworth Cove. Resting on this is the Lulworth Formation, another limestone unit, forming the lower part of the Purbeck Group. The upper part of the Purbeck Group, Durlston Formation, is separated by the Cinder Bed. This is recognisable from the bluish purple colour of the mud matrix that holds thousands of small bivalve shells. It is in the Purbeck Group that we find the Jurassic-Cretaceous Boundary.

The Lulworth Crumple seen from the west end of
Stair Hole. (Source: Stuart Chettleburgh
http://www.bournemouthweather.co.uk/gallery.php?
image=2010-07-01-095124Stair%20hol
e,Lulworth%20Cove.jpg&caption=
Stair%20hole,%20Lulworth%20Cove%20-
%20Taken%20by%20Stuart%20Chettlebu
rgh&curPage=2&id=68&rating=4.3&
totalratings=14)

Moving above this is the Wealden Group, which includes the dinosaur bearing Wessex Formation. You can quickly identify this unit by the orange sands and clays that typically form the topographical lows of this length of coast, being the softest of the units. There is another unit that is rarely seen, this is one outcrop at St Oswald's Bay. This is the Gault Clay, a soft black clay that is faulted out in most of the succession. This unit marks an intermediate stage of a marine transgression between the river facies of the Wealden Group and the marine facies of the Greensand and Chalk.

This brings us onto the Greensand, which like its name suggests is green and sandy. This is usually a thin unit at most exposures, the largest being St Oswald's Bay due to the angle of the erosion of the bay.

Lulworth Cove viewed from the viewpoint to the west.
(Source: Gregg M. Erickson)

The most obvious and youngest unit the outcrops here is the Chalk. This forms the back wall of the bays that are dotted along the coast and also forms the large ridge that runs across east Dorset to north of Swanage.

Mupe Bay viewed from the chalk ridge to the north, with
Mupe Ledge and Mupe Rocks in the distance. (Source:
https://www.geograph.org.uk/photo/1707606)

When you look at the succession, the best place to do this is either Durdle Door or Lulworth Cove, you will see that the angle that the rock dips changes from south to north. The Portland and Purbeck limestones dip approximately 50 to 60 degrees to the north. Moving to the Wealden Group the beds are near vertical, so the dip is getting steeper and steeper to the north. This dip continue to steepen until the chalk becomes overturned and begins dipping to the south.

This deformation is best seen at Stair Hole with the Lulworth Crumple. This is the folding of the Purbeck Group. The folds are more dramatic here due to the faulting of the beds. Deformation along this coastline was the result of the collision of the African plate into the Eurasian plate, the same collision that formed the Alps in Southern Europe.

The chalk cliffs in the north of Mupe Bay viewed from the
south. (Source: Jim Champion)

At Mupe Bay there is the opportunity to see the hydrocarbon potential of the Wealden Group. The sands of the Wealden Group, are stained black with oil. This has seeped up from much lower down in the Jurassic, possibly the Blue Lias, and been stored in the porous sands.

Lyme Regis (and a passing visit to Charmouth)

In this second part to the Dorset Fieldwork I will show you all the world famous Lyme Regis Lias outcrops. These were incredibly interesting both geologically and palaeontologically. Our trip leader, Professor David Martill found something very exciting when making our way back to the coach.

We visited the beach to the west of the town of Lyme Regis, Monmouth Beach.

Lyme Regis (with a quick stop at Charmouth):

Map of West Dorset showing the location of Monmouth Beach.
(Source: Google Maps)

The alternating succession of shales and argillaceous
limestones at Monmouth Beach. (Source:
https://www.shutterstock.com/video/clip-5416676-stock-
footage-the-blue-lias-beds-and-limestone-pavement-on-
monmouth-beach-cliffs-lyme-regis-on-the-jurassic.html)

The limestone ammonite pavement, or ammonite
graveyard. (Source: https://chandlerscottage.co.uk/1
125x750-lyme-regis-0772/)

In the morning after a rather lengthy drive from Swanage, we arrived in Charmouth. Although we didn't actually go onto the beach to see the cliffs up close, we got a pretty good view of the geology. I have also visited this site a number of times and will post the fossils I found in my collection series.

When standing at the Charmouth Heritage Centre, if you were to look to the west towards Lyme Regis those dark clay cliffs are called Black Ven. To the east you have Stonebarrow and the Golden Cap.

Charmouth is a Jurassic succession being deposited during the Sinnemurian to Pliensbachian ages of the lower Jurassic, approximately 190 Ma.

Black Ven is highly fossiliferous with ammonites being the most common fossil you will find. If you are very lucky you can also find crinoids, Ichthyosaur and Plesiosaur remains. A complete dinosaur, Scelidosaurus, has also been found here and is on display in the Charmouth Heritage Centre. Another must see is in the fossil shop, where they have on display a large Temnodontosaurus skull.

This is also one of the sites that Mary Anning collected from, finding marine reptiles and the pterosaur, Dimorphodon macronyx, later described by Sir Richard Owen.

After this brief talk we then drove a bit further west into Lyme Regis and walked down onto Monmouth Beach. Here you will notice, similar to Kimmeridge Bay, a repeating pattern in the cliffs between shales and argillaceous limestones, another example of Milankovitch Cyclicity.

But the really interesting thing to see here is in the wave cut platform that is formed by one of these bands of limestone. It is covered in hundreds of ammonites, the majority are of the genus Coroniceras. This was a single event where all of these ammonites died at the same time, this was gradual, possibly they returned to the same site seasonally. Ammonites won't be the only fossil you find here, you can also spot nautiloids, crinoids and gastropods. A complete Plesiosaur was even found in the pavement some years back.

If you wet the limestone around an ammonite you will find dark marks in the rock. These are fossilised burrows. Some are branching 'Y' shapes, this is formed by a shrimp, the name given to these burrows is Thalassinoides. Others will be two circles next to each other (Diplocraterion), straight burrows (Planolites), and some very fine burrows. These very small burrows are called Chondrites and show that the water had become anoxic for a period.

On the walk to the next locality, Professor Andy Gale found a large nautilus, preserved in three dimensions, a very nice find indeed. It was picked up by a course mate on the way back to the coach.

The next site was geologically of interest. This was the boundary between the limestone dominated White Lias, to the shale of the Blue Lias. The interesting part is, lithologically speaking the boundary is very clear, you can see a pale limestone become a dark shale. You would be forgiven for thinking that this is simply the boundary between the Rhaetian of the Triassic and the Hettangian of the Jurassic.

But to date the rock to confirm this is very difficult. The use of lavas of similar ages are regularly used to radiometrically date rock, however, there are no lavas to use. So dating could be done with the fossils, using relative dating. The change in the ammonites present between the White and Blue Lias represents a biological boundary. This is higher in the succession than the lithological boundary.

On the way back, Professor Dave Martill came across some Ichthyosaur remains in a limestone band of the Blue Lias. Unfortunately I did not see it but there was enough articulated material to warrant him going back to recover it.

Kimmeridge Bay and Etches' Collection

In this series I want to share three residential fieldtrips that I went on during my time at University. In these I will discuss the geology and palaeontology of the site and also if anything interesting was found. I won't be discussing every site we visited either because there were a lot of small ones or there just isn't too much to say about a particular site. Any information has come directly from my notes made in the field.

At the start of the second year we spent a week based in Swanage, Dorset. Here we were being trained to construct accurate geological maps of the coastline between Bat's Head and Mupe Bay, this included the world famous Durdle Door and Lulworth Cove. We also had the chance to visit a number of sites that yield some particularly interesting fossils.

Unfortunately I haven't got any photographs of the localities (any photographs will be credited in the caption). The finds were a little scarce, I managed to collect an echinoid spine, bivalve and Perisphinctid ammonite from Black Head, near Osmington Mills (I'll photograph these for when I do a piece on my collection). There was a single fragment of dinosaur bone found in an outcrop of the Wessex Formation at Dungy Head and some large ammonite fragments from the uplifted Kimmeridge Clay at the same locality. Also 2 Lepidotes scales were found in a mudslide in the Wessex Formation at Lulworth Cove.

Kimmeridge Bay and the Etches Collection:

Map of East Dorset showing the location of Kimmeridge Bay (Source: Google Maps)

The wave cut platform at Kimmeridge Bay showing the
 localised thrust structures, these are found in the east
of the bay where the cliff debris and beach material has been
removed. (Source:
https://www.geoexpro.com/articles/2009/06/
where-does-it-all-come-from)

The first visit of this fieldtrip was Kimmeridge Bay. This is a Jurassic locality, dating back to the Kimmeridgian age of the Late Jurassic (~157 to 152 Ma). Unfortunately the only fossils that were found here were flattened and very delicate ammonites, what was more interesting was the sedimentology.

View of the cliff at Kimmeridge Bay. The anticline peaks at
this point in the succession, making it suitable for hydrocarbon
exploitation. (Source:
http://www.discoveringfossils.co.uk/kimmeridge_fossils.htm)

When visiting Kimmeridge Bay you will notice immediately that there are two types of bed. One that is a dark bluish colour and another that is a rusty orange colour. The blue rock is a friable clay and the orange rock is a clay that has been cemented with calcium carbonate. This alternation is caused by Milankovitch Cyclicity. In essence this the variations in environmental and/or astronomical conditions that causes a repeating succession of rock.

At the top of the cliff you will see that one of these beds is very prominent (middle right), making it a useful marker bed when constructing field sketches and making observations. If you follow this marker bed with your eyes to the west of the bay you will notice that it drops down (roughly where the MOD flag is at the top of the cliff). This is a fault, a weakness in the rock caused by the upwards thrusting of the Kimmeridge Clay within the bay itself. The structure that this marker bed highlights is called an anticline, a gentle fold in the rock.

The Etches Collection Museum, well worth a visit to
appreciate the magnificent finds that Steve Etches has
collected himself. (Source: http://www.dorsetlife.co.uk/2017/06/
from-beach-to-museum/)

In the west of the bay there is a wave cut platform made of a pale rock (above right). This platform is covered in raised structures, these are localised thrusts. This was caused by expansion. At the time of deposition of this particular bed the waters had an elevated level of magnesium, this reacted with the calcium carbonate in the rock thus forming dolomite. The rock now has now increased its volume by 10%, forcing it to fracture and overlap itself.

Kimmeridge Bay is not only known for its exceptional fossil and geological record but it is also a source of hydrocarbons. The Kimmeridge Well has been pumping oil since the 1950's and continues to this day. The Kimmeridge Clay is not the rock that is producing the oil however, the oil is coming up in fractures in the underlying Oxford Clay, however this is not the source. Although, the source of the oil is not completely clear it is likely to be migrating from the Blue Lias (the rock that outcrops at Lyme Regis and Charmouth to the West). The reservoir does not appear to be slowing down on production, hinting that maybe it is being replenished by a source deeper than the Lias.

The presence of hydrocarbons aids us in the palaeoenvironmental analysis of the area. Oil forms when organic matter is preserved and broken down by anaerobic bacteria, after diagenesis this becomes Kerogen, another process, catagenesis, turns this into oil. Should temperature and pressure continue to increase a process called metagenesis will take place forming gas.

We also had the privilege of viewing the private collection of Steve Etches before it was taken to his new museum in the village of Kimmeridge (below right). Etches is a local fossil hunter who has tirelessly devoted himself to finding Kimmeridge fossils. He has found everything, from a set of giant pliosaur jaws to complete Ichthyosaurs and Pterosaurs, even dinosaur bones from large sauropods that would have been washed out to sea during the Jurassic. His collection is something to be marvelled at, words cannot justify the significance of his finds. The Etches Collection Museum is now open and I highly recommend a visit if fossils are an interest.

Getting Back on Track

Lately, I have neglected this blog completely, all due to being in my final year of my Palaeontology degree, but now that is all done with I can get some posts together and get back on track.

My plans for this blog are to go over some fieldwork that I have done during my time at University and show off some of the fossils that were found there. I'll also be doing some more posts about my work with foraminifera at Whitecliff Bay on the Isle of Wight.

I have also got plans to write about some of my favourite fossil localities in the UK, so I'll be covering some sites on the South coast of England and also a quarry that I have visited over the past year or so.

I got some good feedback on my Difference between... series, so I will look into doing some more of those.

If there is anything in particular that you would like to see in particular just leave a comment on this post, I'm always grateful to hear what you all think.

The Thames Group of Whitecliff Bay

After completing my dissertation fieldwork at Whitecliff Bay on the Isle of Wight, I will cover the sedimentology and palaeontology of the Thames and Bracklesham groups, starting with the Thames Group. All images are my own. rock is older moving to the right in images.

The Thames Group exposed at Whitecliff Bay. The
Harwich and Reading formations are located out of
frame to the left. Approximately 100m of strata shown.

The Eocene is an epoch in the Palaeogene Era and spans from around 56 to 34 million years ago. This epoch is characterised by peaks in global temperatures, known as thermal events, the larger of which are referred to as hyperthermal events. The Palaeocene-Eocene boundary is marked by the Palaeocene Eocene Thermal Maximum (PETM), this was the peak in temperatures where a large volume of Carbon Dioxide was released into the atmosphere, increasing the temperature by approximately 8 degrees celsius above today's levels. Although there are several more thermal events caused by the release of Carbon Dioxide, the general trend for temperatures was that of decline throughout the Eocene, culminating in the Icehouse conditions of the Eocene-Oligocene boundary. This is the point where there is evidence for the expansion of the Antarctic Ice Sheet over the South Pole.

At Whitecliff Bay the older rocks are found in the South, as is the general trend for all the geology of the Isle of Wight. The soft clays of the Eocene rest unconformably on the Upper Cretaceous Chalk of Culver Down, the succession then stretches North until it reaches the earliest Oligocene with the exposure of the Bembridge Marls. The stratigraphy here is vertical in the south of the bay, this makes it very easy to log as all of the strata is at beach level. The strata in the north of the bay becomes more horizontal, to approximately a 5 degree dip angle at the top of the Solent Group. The reason for the geology being this way is that during the Miocene, the African plate collided with the Eurasian plate causing the Alpine orogeny, the impact was felt in the UK, with the chalk and clays buckling and being forced vertical.

The clasts in the Harwich Formation
approximately 50cm above the base.

Above the Chalk is the Reading Formation. This is a very soft red clay, and is almost always found to be slipped both at Whitecliff Bay and Alum Bay in the West of the Island. This is a completely unfossiliferous clay and was deposited as a result of a river flowing from the North. In other exposures around the London Basin, lignite and fossilised plant material can be found.

The upper boundary of the Reading Formation is marked by a brown clay with large clasts supported by the grains. This conglomerate also contains small red clay clasts that have been eroded and reworked into the conglomerate, this is evidence that this bed is a transgressive surface. As the sea level rose in the Hampshire Basin 56 Ma the soft clay was eroded and lithified as clasts. This is the Harwich Formation and is only approximately 2 to 3 metres thick but marks the start of the Thames Group. 

The next 130m of cliff are part of the London Clay Formation. this is a sequence of alternating sands and clays marking the transition from high to low energy and the gradual shallowing and deepening of the marine environment. 

This part of the succession is heavily bioturbated, this is where burrowing organisms destroy sedimentary structures and oxygenate the sea bed. This is also evidence for the oxygenation of the sea bed during the Eocene. This can be further supported by the presence of microfossils called foraminifera, a group of single celled organisms that are both benthic and planktic, with infaunal and epifaunal species as well. 

The assemblages of foraminifera in the London Clay Formation's clay beds exhibit various morphologies. A study in 1988 by Corliss and Chen on modern foraminifera showed that foraminifera can be divided into 9 morphogroups based on the shape of their test. It was established that those with elongated tests are infaunal and the rounded trochospiral foraminifera are those of epifaunal. Note that this only applies to small benthic foraminifera. 

In the brownish clays of the London Clay Formation the elongate textulariid foraminifera are more abundant, notably Bolivinopsis adamsi and Textularia agglutinans. This is evidence for the oxygen levels in the sediment being relatively oxygenated, oxic to dysoxic conditions within the first few centimetres of the sediment and just above the sediment-water interface. The sediment can also be referred to as being mesotrophic, meaning that the nutrients available are of a moderate level. It would be expected to see more of the epifaunal trochospiral forms if the sediment was oligotrophic, allowing animal life to thrive due to the reduced plant material.

The diagonal structures in these sand beds
are indicative of cross lamination
showing a gentle flow to the south when the
strata was horizontal. Approximately
4m of strata shown.

At approximately 40m above the base of the Harwich Formation the strata disappears beneath beach level. It was here that the Planktonic Foraminiferid Datum Point was discovered. This was where the marine environment deepened, upwelling here provided the habitat for planktic foraminifera. This brief occurrence of planktic foraminifera shows us that there is an abundance of nutrients being bought up into the water column through the upwelling.  

At the top of the London Clay Formation, there is a division that is made up entirely of sands. Fossils are not regularly found here. But interesting sedimentary structures can be seen in the cliff. The cross lamination of some of these sands provides us with evidence of flowing water, albeit of a very low velocity. This water was flowing gently to the south and was the result of a river to the north bringing sediment into the basin. The freshwater input made it difficult for organisms such as foraminifera to survive. The grian size of this strata is coarser than that of the underlying clays, showing an increase in velocity of flow. A higher velocity is needed to transport the larger and thus heavier grains. This is further evidence for the presence of a river to the north.

The top of the London Clay Formation and
the base of the Wittering Formation,
separated by the thin conglomerate.
Approximately 10m of strata shown.

The top of the formation is marked by a thin 30cm conglomerate. The large pebbles in the bed are evidence that the succession has reached beach level. In the foreshore exposures there are a number of conglomerates that aren't found in the cliff, showing that the sea had regressed before this point, however, this conglomerate is the most prominent. It is also made more evident by the yellowish orange sands below it and the purplish blue sandy clays above in the Wittering Formation.

Close up of the conglomerate at the top of the London
Clay Formation

Mammoth Extinction

The extinction of the Pleistocene megafauna is a heavily debated topic, was it over hunting by man or was it climate change? We now have the answer thanks to the University of Adelaide.

By analysing ancient DNA, using radiocarbon dating and other geologic analysis methods, the University of Adelaide has shown that short rapid warming events, known as interstadials, experienced during the past ice age at the end of the Pleistocene coincided with major extinction events even before man became dominant.

Professor Alan Cooper says that "abrupt warming had a profound impact on climate that caused marked shifts in global rainfall and vegetation patterns". It was therefore sudden warming not extreme cold that killed the Woolly Mammoths in Eurasia.

However, Professor Chris Turney believes that "man still played an important role in the disappearance of megafauna".

The culminating factors of rapid warming and the constant pursuit of man pushed the Mammoth's over the edge as they were already under extreme stress with a lack of tundra shrubs and grasses available as the ice retreated further north, this would have lowered reproduction success and limited the sizes of the herds as the food could not support the animals.

Let me know what you think of this, do you think the Mammoth's extinction was a result of the rapid warming of the climate or did early man hunt the Mammoths to the point of extinction?

http://www.sciencedaily.com/releases/2015/07/150723181113.htm?utm_source=feedburner&utm_medium=email&utm_campaign=Feed%3A+sciencedaily%2Ffossils_ruins%2Fpaleontology+%28Paleontology+News+--+ScienceDaily%29

Pleistocene Settlement at Creswell Crags

Creswell Crags in Derbyshire, UK, is a limestone gorge where settlements from the Pleistocene have been discovered. Although the caves were the primary shelters, there would have been man made huts made from animal skin and bones. But why did Creswell Crags prove to be an ideal site for prehistoric settlements? 

Creswell Crags Cave, Derbyshire, UK. Image Credit
hedgeduid.com

It is possible that early humans visited the Crags with the seasons in order to track herds of reindeer and horse. This was due to the herds being a vital source of food for early humans. They would have then returned to the South as the winter arrived. A stream ran nearby to the crags, water is a vital resource for humans and the herds of animals, providing a source of prey. Caves and rock overhangs would have sheltered early humans from the elements. But living in caves would have been dangerous as lions and bears also used caves as shelter. It is possible that the humans would have settled on top of the gorge's cliffs away from predators and the insects near the stream. The crags could have also been a meeting place, where information was shared and products traded. 

The settlements could be improved with simple amenities. Large rocks and post holes are found at the crags, this is evidence of primitive windbreaks being built from skins and wooden posts. Fire would have also been used for warmth and cooking. Fire also scares off animals. 

The caves are south facing, this allows for more sunlight to enter the caves. We find larger archaeological deposits in south facing caves because of this reason.

Mammoth cave painting, Roufignac, France. Image
credit mammoth.psu.edu

Many caves are found with early paintings. The purpose of cave paintings is not known. They are not believed to be decoration as the caves don’t show signs of long term habitation. Paintings are similar around the world they show mostly animals. Humans typically appear as hand stencils that were made by blowing pigment on a hand held on the wall. There are a number of theories behind the paintings; Henri Breuil interpreted the paintings as being hunting magic; meant to increase the number of animals present in the area to make hunting better. David Lewis-Williams developed the theory that suggests that the paintings were made by shamans. The shaman would enter the cave and enter a trance, then paint images of their visions.

The Fossilisation Process

When a land dwelling vertebrate dies its carcass is commonly disarticulated, this means its limbs are removed, often by predators and scavengers alike. Most of the decomposition of the organic material is done by bacteria that will feast on the rotting flesh that remains on the bones. Some bones are completely stripped clean of flesh and bleached in the sun. Others might be carried off or gnawed by rodents. Sometimes, disarticulated remains are trampled and scattered by herds of animals.


Sooner or later the bones are either destroyed or buried. If they aren’t digested their destruction can come from weathering; this is when the minerals in the bone begin to break down and the bones disintegrate. But the weathering can be stopped by rapid burial, it’s at this point fossils are formed. A body fossil is part of an organism that is buried and a trace fossil is an impression left behind in the ground by the organism.


Bone is made out of calcium-sodium hydroxyl apatite, this mineral weathers easily, this means that the mineral is no longer present once a bone becomes fossilised. This mineralogy can remain intact if the bone doe not come into contact with any fluids during its burial, something that is extremely rare.

It is possible to find tissues of extinct animals. Since bones are porous, the spaces once occupied by blood vessels and nerves fill up with minerals. This is called permineralisation.

Fossil of Archaeopteryx. Image credit Humboldt
Museum Fur Naturkunde Berlin

Pristine fossils can be found in geological lagerstatte, feathers of dinosaurs are known from these lagerstatte. Most famously the early bird Archaeopteryx is known from the Solnhofen lagerstatte in Germany.

Ammonite shells are originally made of aragonite, this is unstable so when fossilisation begins the aragonite becomes the more stable calcite. This calcite creates a cast of the shell and this is what we find today.

Woolly Mammoths and Woolly Rhinos have been discovered mummified in the permafrost in Siberia and Alaska. Soft tissue of a Tyrannosaurus Rex has even been found which allowed palaeontologists to see that the animal was female, within the fossil, red blood cells and connective tissues were found.

Natural mummies have been found in a variety of locations around the world; bog deposits or tar pits, deep inside caves, glacier ice and in the permafrost of Alaska and Siberia. A Woolly Rhinoceros was found mummified after it was covered in salty ground water that essentially pickled the carcass, preventing bacteria and microorganisms digesting the flesh by altering the pH of the environment which means that microorganisms cannot survive in these acidic conditions.

Mummified dinosaurs have been found, good examples of these mummies come from Brachylophosaurus and Edmontosaurus. Leonardo, the Brachylophosaurus that features in the palaeoart post, had skin impressions, muscle impressions that showed an excess of tissue around the neck, even parasites are found on Leonardo.


The permafrost is also effective as the low temperature prevents the bacteria from respiring by removing any moisture on the carcass through freezing. However, once the mummy is excavated the bacteria become active and decomposition begins.

Buttercup the Mammoth

Natural mummies have been found in a variety of locations around the world; bog deposits or tar pits, deep inside caves, glacier ice and in the permafrost of Alaska and Siberia. A Woolly Rhinoceros was found mummified after it was covered in salty ground water that essentially pickled the carcass, preventing bacteria and microorganisms digesting the flesh by altering the pH of the environment which means that microorganisms cannot survive in these acidic conditions.


The permafrost is also effective as the low temperature prevents the bacteria from respiring by removing any moisture on the carcass through freezing. However, once the mummy is excavated the bacteria become active and decomposition begins.


In May 2013, scientists from the Siberian North-eastern Federal University took an expedition to Maly Lyakhovsky, an island in the far north of Siberia, whilst acting on information that there was a Mammoth in the permafrost. Indeed they did find two tusks exposed and as they excavated the animal they found that it also had three legs intact, most of the body and part of the head and trunk was still attached as well.

Buttercup the Mammoth mummy. Image credit techentice.com

During the excavation, the carcass released a dark red liquid. The carcass still had fresh blood inside it, this was unique as mummies have only yielded dry specks of blood containing no complete DNA.


The researchers took the Mammoth, nicknamed Buttercup, to Yakutsk where a group of experts were to study the specimen for three days before the find was refrozen to prevent rotting. Carbon dating shows that the Mammoth lived around 40,000 years ago, tests on the animal’s teeth reveals that it died between the age of 50 and 60.


Faeces and bacteria in the lower intestines of the animal, reveal a diet of ice age grasses, buttercups and dandelions. Tooth marks on the Mammoth’s bones enabled the scientists to determine how she died, she was eaten alive by predators after becoming trapped in the peat bog that had assisted in her mummification.


More blood was found in the Mammoth’s elbow, analysis of this blood showed that the cells were broken, but some still contained haemoglobin, the protein that carries oxygen within the red blood cell. Unlike humans, the Mammoths had evolved haemoglobin that was more resistant to freezing temperatures.

Pleistocene Mammal Defences

Tusks:
A Mammoth could have used its tusks to defend itself like the modern day African Elephant. They would have been used to keep predators at bay; this would have made the young and oldest members of a herd particularly vulnerable as they wouldn’t have the strength or tusks to repel attack. Due to their curvature, the tusks were not suitable for stabbing at predators.

Mounted Woolly Mammoth tusk. Image credit
geoclassica.com

The tusks could also be used in the mating season. The adult males would battle each other to earn the right to breed. These animals may have also had to defend their territories from other herds. The size of the tusks may have been used as an intimidation tool, and physical contact being the final resort.


Communication:
Communication between modern day animals can be transferred onto extinct Pleistocene mammals. Mammoths may have communicated in a similar way to modern day elephants. They communicate over long distances using infrasound. This is inaudible to human hearing, which can detect sound between 20 and 20,000 hertz. However, over shorter distances they may have used louder bellows to warn of predators or to seem more threatening. This is a form of defence as the herd can escape or fight off the predator more efficiently than if it was attacked without warning.


Early humans had also developed speech in order to coordinate hunts. Without communication it is unlikely that hunts would have been so successful. It was 7 million years ago that hominids began to show signs of primitive speech, therefore by the time the Ice Age occurred, communication would have been more efficient, but not as evolved as present day speech.


Numbers:
Safety in numbers in the ice age would have been a major survival tactic. Even large animals such as Mammoths travelled in herds as a form of protection, this ensured that the young would reach an age where they are able to produce the next generation, the population would then thrive and either grow or remain constant.


Humans also survived in numbers. Cooperation between the tribe members would have ensured their survival. Food preparation, hunting and construction would have been shared between all members of the tribe, providing defence from the harsh conditions of the Ice Age as well as the predators that they share the land with.


Size:
Giant animals do not always need to be a part of a herd. The solitary Megatherium, could stand at a maximum height of six metres tall, it would have been intimidating to even a pack of Smilodon. At only 1.2 metres tall, Smilodon would have been dwarfed by Megatherium and therefore only the young and the weak would have been vulnerable. This is similar to the Mastodons and Mammoths.


Tools:
Humans developed the use of stone tools at the start of the Pleistocene, 2.5 million years ago. This included knives, spearheads and axes, all would have been used in everyday life to build shelters and hunt for food. This made humans more successful due to their coordination and range of tools.

Early humans harvesting meat, bone and skin from a mammoth. Image credit
humanorigins.si.edu

Humans also used animals as tools. The use of domesticated dogs was a key to the Homo sapiens outdoing their relatives the Neanderthals. The energy burden was now taken by the dog and not the human aiding in the taking down larger prey that essentially helped the humans to survive the harsh winters.

Coping With the Cold of the Ice Age

In cold climates, plant material is rather scarce. It is usually limited to grasses, low lying shrubs and coniferous forests. Woolly Mammoths would have survived on eating mainly grasses. This is evident from the adaptation of its teeth; the enamel ridges were not suited to grinding twigs and leaves. To access this grass, the Mammoth would have had to clear snow away. Palaeontologists know that Mammoths did this because tusks have been found with a small patch of smoothed ivory on the underside that would have been closest to the ground. The tusk would have been smoothed by the constant abrasion against the ground.

Reconstruction of Woolly Mammoth herd. Image credit news.chicago.edu

In contrast to the Mammoth’s ridged teeth, the Mastodon displays a different adaptation. As the Mastodon lived in more southern regions of North America there were more deciduous trees to feed on, therefore the Mastodon has more conical teeth to deal with the grinding of twigs and leaves.


The fur of animals such as the Woolly Mammoth and Coelodonta were specially adapted to cope with the freezing temperature of the ice age. The coat consisted of two layers; the outer layer was a coarse layer that would protect the second layer. The hair on the outer layer was between 30 centimetres long and 90 centimetres long depending on where about on the body it came from. The denser inner layer was much shorter at only 8 centimetres long; it was this wool that provided the greatest amount of insulation for the animals. It is believed that the Mammoth had sebaceous glands under its skin which would secrete oils onto the hair to make it greasy; this would provide yet more insulation for the Mammoth.


As discussed before, it is necessary for an animal such as the Mammoth to have a small surface are to volume ratio in order to preserve heat. This is the reason behind the size of its ears and tail. By shortening these, the Mammoth is able to reduce its surface area to volume ratio, therefore there is less surface to heat to be lost to the external environment. African elephants have larger ears so they can increase their surface area to volume ratio which allows them to lose more heat during the day. Also by minimising the size of its tail and ears, the Mammoth is able to prevent frostbite.


The Woolly Mammoth also had very wide and flat feet. This was to increase the animal’s grip on the snow and ice. Polar bears have the same adaptation; acting like snow shoes they spread the weight of the animal over a larger area, providing more stability than a smaller foot.

Smilodon Hunting

The prehistoric predator, Smilodon, was an apex predator in North and South America. The animal would have hunted large prey such as bison, camels, horses, ground sloths and mammoths. Isotopic studies of dire wolf and American lion bones show that there is an overlap in prey with the Smilodon; this suggests that they were competitors.


It is believed that Smilodon was an ambush predator, concealing itself in the vegetation. Then, using its massive body strength it would wrestle its prey to the ground.


Smilodon’s hunting has been compared to its closest relatives, the big cats that still roam Africa and Asia. Lions and tigers have smaller canines than Smilodon, a mere 3.5 inches compared to a massive 8 inches, but they are still able to bring down prey that is six times larger than itself. The lion would use its claws and teeth to pull itself up until they can get to the throat. They would then clamp down on the throat.


A lion’s bite force is relatively mild and so a lions choke hold rarely punctures the skin. Scientists have assumed that they are simply strangling their victims. However, Dr Frank Mendel believes that they squeeze vital arteries that feed the brain, causing the prey to pass out in 3 to 5 seconds. A lion would then apply a kind of sleeper hold on its prey which must be sustained for five minutes, depriving the brain of oxygen rendering it brain dead; the prey will therefore not fight back. This poses a problem for lions as the scent of a fresh kill will attract other predators, including crocodiles and hyenas.


The Smilodon bite force is even less than that of a lion and due to a greater number of scavengers and larger prey, a five minute choke hold seems unlikely. The fossil record has produced evidence that shows the massive 8 inch canines could have easily broken in a struggle or if they were to hit bone.


In an experiment, Mendel recreates the jaws and bite-force of a Smilodon and mounts it on an articulator. He then uses the carcass of a cow to demonstrate how the Smilodon could have used its canines.


The first theory is that Smilodon would have given a bite to the abdomen; there are no ribs here, only the abdominal wall so the canines wouldn’t be damaged. The gape of a Smilodon is approximately 110º, but this still only leaves 3 inches of clearance between the mandible and the tip of the canine. The mandible is able to gather a mouthful of skin but the canines do not make contact with the carcass. Therefore this is not a plausible hypothesis.


Mendel’s hypothesis is that the Smilodon would puncture the neck rather than the abdomen. The gape easily clears the neck. The canines also puncture the neck with ease, leaving big holes. To gain further evidence that the prey would be killed quickly, Mendel opened up the throat to examine the damage.

Several arteries were damaged, indicating that the animal would have been killed in seconds. This shows that Smilodon was able to kill its prey quicker than modern day big cats.

A pack of saber toothed cats attack a young Columbian Mammoth. Art by Mauricio Anton

This artist’s impression of a pack of Smilodon hunting a juvenile Columbian Mammoth is rather accurate. It shows the Smilodon in the foreground, pinning the calf to the ground and using its canines to puncture the throat. Other impressions show Smilodon biting the hide or limbs of its prey. This would not have occurred during a hunt as damage would have been sustained to the canines.


The belief that Smilodon was a social animal is further supported by the discovery of Smilodon fossils with healed injuries; this would suggest that individuals depended on others to provide food while it was injured. Also juvenile Smilodon had smaller canines which have led palaeontologists to believe that they would have been fed after a kill until they could participate in the hunt itself.

Mammalian Dentition

Diagrams of the three types of
mammalian teeth. Image credit Pearson
Education Inc.

The teeth of a carnivore consist mainly of sharp teeth. What is typical of carnivorous dentition is that there are no flat molars as these are characteristics of herbivores and omnivores. The most prominent feature of carnivorous teeth are large canines.


There are four canines in the oral cavity; two on the upper jaw (maxillary) and two on the lower jaw (mandibular). Canines are also found in omnivores including humans; however in humans the canines are much smaller. These canines act as knives that slice deep into flesh and cut chunks away. It should be noted that unlike human teeth, the teeth of a carnivore are widely spaced to prevent debris getting caught.


Carnivores have rather undeveloped molars in the sense that they are not flat and remain pointed. These molars act as scissors, slicing the flesh into smaller pieces in an up and down motion.


While herbivores and omnivores have enzymes in their saliva to aid with digestion of plants, carnivores do not possess an enzyme that breaks down proteins as they would damage the interior of the mouth. Therefore carnivores must swallow their food in chunks which requires a strong digestive system.


Carnivores have a large hole behind each eye socket; this is called the temporal fenestrae. This allows the jaw muscles to grow larger, therefore the larger the hole, the more powerful the bite. The bite of a hyena is strong enough to crush bone making it a successful scavenger, when food is scarce the animal can eat bone to survive.


Although impressive, the oversized canines of the Smilodon, or saber toothed tiger, were not strong enough to bite through bone; they were extremely fragile compared to most canines. Depictions of Smilodon hunting are usually inaccurate as the canines would be more commonly used on the throat as opposed to the shoulder or hide of its prey.


In the herbivorous mandible it is clear to see that there are no canines at all. A herbivore only possesses incisors and a large number of molars. This is because the teeth are not designed for slicing through meat but rather plant matter. Plant matter is difficult to digest which requires strong, grinding molars. This is the prototype for a herbivores oral cavity, however there are variations.


The teeth of a Woolly Mammoth for instance. They are not individual molars, the teeth were a large mass with sharp enamel ridges that were not worn down easily over the animal’s lifetime; this allowed it to eat large quantities of vegetation, making the animal successful in the colder climate.


Herbivores, unlike carnivores, can chew their food. The reason that vegetation is chewed is that it releases the digestible insides of the plant. Chewing also exposes the food to enzymes, aiding to speed up digestion.




Omnivores display characteristics of both herbivores and carnivores in the sense that they have canines and flat molars. The human canines are not very large. This is because around 3.6 million years ago, when Australopithecus afarensis first evolved, human dentition began to change. One theory suggests that Australopithecus were not as reliant on raw meat as a food source, either because they ate more vegetation or they had developed the ability to cook their meat using fire, however this theory has not been proven.


In comparison, the skull of a Chimpanzee displays much larger canines but very similar molars to that of a human’s. The reason for the difference in canine size is that Chimpanzees are still reliant on raw meat, which requires sharp teeth to tear through.

Omnivores have the same enzymes that herbivores do in order to aid with the digestion of vegetation. The stomachs of omnivores are similar to carnivores, as omnivores have to digest meat as well, as they are unable to produce the enzymes that break down protein in the mouth as it would damage the interior of the oral cavity. Therefore, omnivores and carnivores have a stomach acid that has a very low pH of 1 or 2.


Omnivores have proven to be rather successful in the wild. This is because if one source of food was to vanish, the animal could still eat the remaining source, for example if an animal that was prey to a Chimpanzee was to become extinct, it could still survive on plants until another source of meat became available.

Mammalian and Human Evolutionary Timeline

I did some work for Peterborough Museum and looked at the evolution of mammals and then humans so I am going to do a post on a timeline of this evolution.

Mammal Evolution:
256 Ma - Wuchiapingian age, Lopingian epoch, late Permian period, Palaeozoic era:

Dimetrodon, an example of a pelycosaur. Image credit
extinctanimals.org

Shortly after the first appearance of reptiles in the Carboniferous period, two evolutionary branches split. The first branch is the Sauropsids, which later become the birds and reptiles of the modern day, the first example of the sauropsid is the Hylonomus. Synapsida is the other branch which gives rise to the mammals.

Both of these branches have temporal fenestrae (openings) behind the orbit which allows for larger jaw muscles. 

The earliest mammal-like reptiles are the pelycosaurs. These animals were the first to have temporal fenestrae. The pelycosaurs gave way to the therapsids, the direct descendants of mammals. The temporal fenestrae of therapsids are larger and more mammal-like than pelycosaurs.  

220 Ma - Norian age, Upper Triassic period, Mesozoic era:
The cynodonts were a subgroup of therapsids and bore the most mammal-like features; it's jaws for example resembled the modern jaws of mammals. It is likely that with in the cynodonts, the direct ancestor to all mammals can be found. 

Artist's impression of Juramaia sinensis alongside
skeleton. Image credit Mark A. Klingler

From Eucynodontia came the first mammals. These were very small, shrew-like animals that fed on a diet of insects. They evolved the neocortex region of the brain and so it is unique to animals.

160 Ma - Oxfordian age, Upper Jurassic period, Mesozoic era:
The earliest known mammal fossil of Juramaia sinensis comes from the Jurassic period, this is the first true mammal that we know of.

100 Ma - Cenomanian age, Upper Cretaceous, Mesozoic era:
The last common ancestor of mice and humans is found here in the Cretaceous period.

Primate Evolution:
85 to 65 Ma - Santonian to Maastrichtian age, Upper Cretaceous, Mesozoic era:
A group of small, insect eating mammals called Euarchonta evolved at the end of the late

Reconstruction of a group of Plesiadapis. Image credit
odec.ca

Cretaceous. This group would give rise to primates, treeshrews and lemurs. Plesiadapis is an animal from the subdivision primatomorpha and lived on the lower branches of trees feeding on fruits and leaves. Plesiadapiformes are very likely to contain the species that are the ancestors of the primates.

63 Ma - Danian age, Palaeocene epoch, Palaeogene period, Cenozoic era:
Primates diverge into strepsirrhini, wet nosed primates, and haplorrhini, dry nosed primates.

Strepsirrhini contains ancestors to lemurs and lorises. The haplorrhines include prosimian tarsiers, simian monkeys and apes. Haplorrhini metabolism lost the ability to make its own Vitamin C, this means that the descendants had to include fruit in their diet. 

30 Ma - Rupelian age, Oligocene epoch, Palaeogene period, Cenozoic era:
Haplorrhini splits into two; platyrrhini and Catarrhini. 

Platyrrhini are new world monkeys that had prehensile tails. It is believed that they migrated to South America, floating on a raft of vegetation is one possible hypothesis for this migration. 

25 Ma - Chattian age, Oligocene epoch, Palaeogene period, Cenozoic era:

Replica skull of Proconsul africanus. Image
credit Don Hitchcock

Catarrhini splits into two groups; old world monkeys, ceropithecoidea, and apes, hominoidea. 

The trichromatic vision had its genetic origins in this period. Proconsul africanus is a possible ancestor of great and lesser apes, including humans.

Hominidae Evolution:
15 Ma - Langhian age, Miocene epoch, Neogene period, Cenozoic era:
Hominidae ancestors speciate from the ancestors of gibbons.

13 Ma - Serravallian age, Miocene epoch, Neogene period, Cenozoic era:
Hominidae ancestors speciate from the ancestor of Orang-Utans. 

The common ancestor of the great apes and humans is believed to be Pierolapithecus catalaunicus. Like humans it had a wide, flat rib cage, a stiff lower spine, flexible wrists and shoulder blades on its back rather than its side. 

10 Ma - Tortonian age, Miocene epoch, Neogene period, Cenozoic era:
The human lineage and the genus of Pan (chimpanzees and bonobos), speciates from the ancestors of gorillas.

7 Ma - Messinian age, Miocene epoch, Neogene period, Cenozoic era:
Hominina speciate from the ancestors of the chimpanzee. 

In the first two years of life, ancestral humans and chimpanzees have a larynx that repositions itself to between the pharynx and lungs; a feature that enabled speech in humans.

3.6 Ma - Piacenzian age, Pliocene epoch, Neogene period, Cenozoic era:
Australopithecus afarensis is evidence for full time bipedalism in early hominids. this ancestor had reduced canines and molars, although still larger than modern humans.

A study of the lower vertebrate of Australopithecus afarensis suggests that in females, changes had been made so that bipedalism could be sustained throughout pregnancy.

3.5 Ma - Piacenzian age, Pliocene epoch, Neogene period, Cenozoic era:
Kenyanthropus platyops is a possible ancestor of Homo, and it emerges from the Australopithecus genus.

3 Ma - Piacenzian age, Pliocene epoch, Neogene period, Cenozoic era:
A loss of body hair takes place in Australopithecines while they evolve on the savannahs of Africa.

Homo Evolution:
2.5 Ma - Gelasian age, Pleistocene epoch, Quaternary Period, Cenozoic era:
Appearance of the genus Homo. Homo habilis and Homo ergaster lived side by side in the lower Pleistocene. The first stone tools were used here.

1.8 Ma - Calabrian age, Pleistocene epoch, Quaternary period, Cenozoic era:
Homo erectus evolves in Africa. Homo erectus resembles more modern day humans, the forehead is less sloping and the teeth are smaller.

Homo georgicus is the oldest hominid fossil outside of Africa, showing that they had the ability to travel long distances, probably following herds of animals.

The evolution of dark skin came with the loss of hair. The brain evolved to be larger and therefore tool crafting was more successful. They could then hunt bigger prey such as wild horses.

1.2 Ma - Calabrian age, Pleistocene epoch, Quaternary period, Cenozoic era:
Homo antecessor may be a common ancestor of humans and Neanderthals. Humans share 99% of their DNA with the now extinct Neanderthals.

600,000 years ago - Middle Pleistocene epoch, Quaternary period, Cenozoic era:
Homo heidelbergensis was found in Italy, it had a larger brain case and was therefore more intelligent than its ancestors, but more muscular than modern humans.

200,000 years ago - Middle Pleistocene epoch, Quaternary period, Cenozoic era:
Earliest fossils of anatomically modern humans found in Ethiopia dating back 0.2 Ma.

60,000 years ago - Upper Pleistocene epoch, Quaternary period, Cenozoic era:
Homo sapiens migrate out of Africa. Homo sapiens interbreed with the Neanderthals that they encounter.

50,000 years ago - Upper Pleistocene epoch, Quaternary period, Cenozoic era: 
Homo sapiens migrate to Southern Asia.

40,000 years ago - Upper Pleistocene epoch, Quaternary period, Cenozoic era:
Homo sapiens migrate to Australia and Europe. The European Homo sapiens known as Cro-Magnon.

25,000 years ago - Upper Pleistocene epoch, Quaternary period, Cenozoic era:
Neanderthal lineage becomes extinct.

20,000 to 10,000 years ago - Upper Pleistocene epoch, Quaternary period, Cenozoic era:
Homo floresiensis dies out, leaving Homo sapiens as the only species of Homo still surviving. Evolution of light coloured skin in Europeans took place around this time.