Geology - Part 6

24 05, 2020

The Most Dangerous Place and Time in the Cretaceous

By Mike|2024-02-21T05:23:45+00:00May 24th, 2020|Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Geology, Main Page, Palaeontological articles, Photos/Pictures of Fossils|0 Comments

A Comprehensive Guide to the Fossils from the Kem Kem Beds of Eastern Morocco

A team of international researchers have documented the fossil vertebrates associated with the early Late Cretaceous (Cenomanian-Turonian) of the famous Kem Kem beds of eastern Morocco. They conclude that with the abundance of hypercarnivores such as Spinosaurus, abelisaurids, Carcharodontosaurus and Deltadromeus, several large pterosaurs and a multitude of giant fish and crocodyliforms, no comparable modern terrestrial ecosystem exists with a similar bias toward large-bodied carnivores.

Arguably, the sediments that make up the Kem Kem Group, which is composed of the lower Gara Sbaa and upper Douira formations, represent the most dangerous place and time in the whole of the Cretaceous.

Examples of Theropod Teeth Associated with the Kem Kem Group of Eastern Morocco

Indeterminate theropod teeth from the Kem Kem Group. — Indeterminate theropod teeth from the Kem Kem Group with (H) showing the denticles of (F) and (N) close up view of denticles in (M). Scale bar equals 2 cm in A-C and I-M whilst 3 cm in D and 5 mm in H and N.

Picture credit: Ibrahim et al (ZooKeys)

An Ambitious Target

The researchers which included Nizar Ibrahim and Paul Sereno (University of Chicago), David Unwin (University of Leicester), Samir Zouhri (Université Hassan II, Casablanca, Morocco) and David Martill (University of Portsmouth), had an ambitious objective. The scientists set out to document and summarise the taxonomic status of the fauna that had been described based on the major collections of Kem Kem fossils, as well as to report on the geological age of the various strata and to plot the palaeoenvironment of this part of north Africa during the early stages of the Late Cretaceous.

The team’s comprehensive report has been published with free access in the journal ZooKeys.

The Changing Palaeoenvironment Represented by the Kem Kem Group Sediments

The palaeoenvironment of the Kem Kem Beds. — Schematic paleoenvironmental stages depicting the Kem Kem region during the Cretaceous. Stages: (1) wide rivers, (2) large river systems with substantial sandbanks, (3) deltaic conditions and (4) rise of the limestone platform.

Picture credit: Ibrahim et al (ZooKeys)

A Very Dangerous Place to Be (Large Crocodyliforms and Pterosaurs)

The strata have provided evidence of large number of crocodyliforms from one-metre-long insectivores, herbivorous forms to giant predators such as Sarcosuchus imperator. Several different types of pterosaur are also associated with these deposits. The first pterosaur remains recovered consisted of isolated teeth collected in the late 1940s and early 1950s but at the time their affinity with the Pterosauria was not recognised. For an article from Everything Dinosaur about recent pterosaur discoveries from Morocco: Pterosaurs, Pterosaurs and Even More Pterosaurs.

Cervical Vertebra (Bone from the Neck) Ascribed to an Azhdarchid Pterosaur

Third cervical? attributed to an azhdarchid pterosaur. — Near complete third cervical? of an azhdarchid pterosaur from the Kem Kem Group. FSAC-KK 3088 in (A) ventral, (B) dorsal, (C) right lateral, (D) left lateral, (E) anterior and (F) posterior view. Scale bar equals 5 cm.

Picture credit: Ibrahim et al (ZooKeys)

In addition, the first tapejarid pterosaur from Africa was reported recently (Afrotapejara zouhrii), the trivial name honours Professor Samir Zouhri, one of the authors of the extensive review. To read an article about Afrotapejara: The Fourth New Moroccan Pterosaur – Afrotapejara.

Lots and Lots of Dinosaurs – A Bias Towards the Theropoda

Dinosaurs are strongly associated with these strata, but there is only very fragmentary evidence of ornithischians including a single, large footprint. This suggests that bird-hipped dinosaurs were present but, in contrast to most other Cretaceous biotas, they seem very much underrepresented by the fossil material. Sauropods such as the rebbachisaurid Rebbachisaurus garasbae and titanosaurs are known from both the Douira and Gara Sbaa formations, however, it is theropod specimens that dominate the Dinosauria associated with the Kem Kem Group. There is evidence to support one medium-sized to large Kem Kem abelisaurid and the discovery of single neck bone (cervical vertebra) indicates a Noasauridae presence.

Huge hypercarnivores such as Carcharodontosaurus saharicus and Spinosaurus aegyptiacus have been reported. The habitat seemed to have an overabundance of large, carnivorous dinosaurs, although extensive niche partitioning is proposed by several authors.

Perhaps the Most Famous African Dinosaur of them all – Spinosaurus aegyptiacus

Spinosaurus aegyptiacus skull and skeleton. — *Skull and skeletal reconstruction of Spinosaurus aegyptiacus. Scale bars equal 40 cm in A and B, whilst in C the scale bar is 1 metre.*

Picture credit: Ibrahim et al (ZooKeys)

Deltadromeus agilis

One of the most mysterious of all the theropods from Morocco is Deltadromeus agilis. The taxonomic position of this meat-eater remains controversial. A partial skeleton (UCRC PV11), was discovered in a coarse sandstone layer in the upper portions of the Gara Sbaa Formation. The bones were found in association with teeth of the huge sawfish Onchopristis as well as teeth from crocodyliforms. Fossils associated with D. agilis from eastern Morocco show a resemblance to isolated material recovered from the roughly contemporaneous Bahariya oasis in the Western Desert of Egypt by the German palaeontologist Ernst Stromer.

The Egyptian fossils were assigned to the taxon Bahariasaurus ingens, but the Moroccan and Egyptian material could represent the same genus. If this is the case, then D. agilis would become a senior synonym of B. ingens. A single thigh bone from the Bahariya oasis measures 144 cm long. This suggests that whatever sort of carnivore Deltadromeus/Bahariasaurus was, it was huge. Some commentators have suggested that based on femur proportions Deltadromeus could have been only slightly shorter (but more lightly built), than Tyrannosaurus rex.

Holotype of D. agilis (A) and Compared in Size to the Egyptian Femur Specimen (B)

Deltadromeus agilis skeleton reconstruction. — Deltadromeus agilis from Morocco and Egypt. A (A) revised reconstruction based on UCRC PV11 (B) holotype compared to a large femur (now lost) referred to the genus and species from the Bahariya Formation, Egypt. Known elements in white. Scale bars: 1 m.

Picture credit: Ibrahim et al (ZooKeys)

Sadly, like much of Stromer’s material from the Egyptian expeditions, the femur has been lost.

It is very likely that there were lots of smaller predatory dinosaurs too. Dromaeosaurid teeth have been reported from several localities but bones are exceptionally rare and the only positively identified dromaeosaurid skeletal elements are some foot bones found in Sudan and recovered from Cenomanian-age rocks.

A Predominance of Aquatic Predators

The authors state that the Kem Kem assemblage is dominated by aquatic and subaquatic invertebrates and vertebrates, the majority of which are predators. They suggest that as most of the taxa are exploiting aquatic food resources, then like modern marine food chains, the habitat is predator dominated. As to the overabundance of carnivorous dinosaurs compared to plant-eating ones, the researchers conclude that this is not due to sampling bias or preservation factors. Large theropods in the food web were supported primarily in the case of Spinosaurus or secondarily in the case of the terrestrial carnivores by the huge amount of aquatic protein sources.

For models of Carcharodontosaurus, Spinosaurus and other theropod dinosaurs: PNSO Age of Dinosaurs Models and Figures.

The dissected deltaic plain and nearshore environments may have enhanced aquatic resources while limiting, or rendering patchy areas of available vegetation for large-bodied dinosaurian herbivores. Hence the bias towards carnivores when it comes to assessing the fossilised remains of dinosaurs from the Kem Kem beds.

The Presence of So Many Carnivores could be Explained by the Abundance of Aquatic Food Sources such as Small Fish

*Serenoichthys kemkemensis from the Douira Formation. Scale bar equals 1 cm. The abundance of predators could be explained by the large amount of aquatic protein sources present in the environment.*

Picture credit: Ibrahim et al (ZooKeys)

The scientific paper: “Geology and paleontology of the Upper Cretaceous Kem Kem Group of eastern Morocco” by Nizar Ibrahim, Paul C. Sereno, David J. Varricchio, David M. Martill, Didier B. Dutheil, David M. Unwin, Lahssen Baidder, Hans C. E. Larsson, Samir Zouhri and Abdelhadi Kaoukaya published in ZooKeys.

Visit the Everything Dinosaur website: Everything Dinosaur.

23 05, 2020

Explaining the Principle of Superposition

By Mike|2024-02-20T21:00:41+00:00May 23rd, 2020|Educational Activities, Geology, Main Page, Teaching|0 Comments

Explaining The Principle of Superposition

Everything Dinosaur received an enquiry earlier this week from a young student studying rocks and fossils at their school as part of a geology project. The student asked, “what is the law of superposition?” Our team members were happy to provide a short explanation.

The principle of superposition, often referred to as the law of superposition is an observation that sedimentary layers of rock at the bottom of a sequence if they undeformed, then they must be older than those at the top. The bottom layers must have been in existence in order to permit the upper layers to have been deposited on top of them.

Layers of Sedimentary Rock Demonstrating the Principle of Superposition

The Church cliffs at Lyme Regis. — *Fossil hunting can be fun but beware of the cliffs. The Church cliffs at Lyme Regis are notoriously unstable and dangerous but they do help to demonstrate the law of superposition.* *Picture credit: Everything Dinosaur.*

Picture credit: Everything Dinosaur

A Fundamental Principle of Geology

The law of superposition is regarded as one of the fundamental principles that underpins modern geology, although this principle is very much applicable in other research fields such as archaeology. It helps to provide a basis for the relative dating of strata. As the oldest strata will always be found at the bottom of an undeformed, observable sequence of sedimentary rocks. It is extremely helpful when considering stratigraphical dating, which is governed by the proposition that a layer cannot be older than its constituents.

The introduction of this principle is accredited to the Danish polymath Nicolas Stenos (1638-1686), often referred to as the “father of modern geology”. In 2012, Nicolas Stenos was honoured with the creation of a Google doodle demonstrating his principle complete with illustrations of fossils.

The 2012 Google Doodle Honouring Nicolas Stenos

*Remembering the Contribution of Nicolas Stenos. Danish scientist honoured with a Google doodle.*

Picture credit: Google

This geological principle was popularised by the famous English geologist William Smith (1769-1839), who used this law to create the first ever map showing the geology of a landscape. In 1815, the year of the battle of Waterloo, William Smith published a map outlining the geology of England, Wales and parts of Scotland.

The “Ground-breaking” First Geological Map to be Published

The William Smith Geological Map (1815). — *Can you see the geology in your part of the world?*

Picture credit: The Geological Society of London

Visit the Everything Dinosaur website: Everything Dinosaur.

22 05, 2020

13,000 Edmontosaurus an Astonishing Dinosaur Bonebed

By Mike|2024-02-18T13:47:44+00:00May 22nd, 2020|Adobe CS5, Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Geology, Main Page, Palaeontological articles, Photos/Pictures of Fossils|0 Comments

Massive Edmontosaurus Bonebed Provides Data on Dinosaur Decomposition

A team of scientists have produced a study mapping an astonishing dinosaur bonebed that has so far yielded a staggering total of 13,000 individual fossil elements. In truth, the bonebed contains many more fossils, but individual dinosaur teeth, ossified tendons and other fragmentary elements under five centimetres in length have not been counted.

Edmontosaurus annectens

The site is located in eastern Wyoming and consists almost entirely of the preserved remains of a single type of dinosaur, a hadrosaur (Edmontosaurus annectens). The bonebed study has not only provided a great deal of information about this duck-billed dinosaur but shed light on how death assemblages consisting of a large number of corpses are formed and how various bones of differing sizes might be transported before final deposition.

Dinosaur Bonebeds such as the Danek Edmontosaurus regalis Bonebed in Edmonton Have Yielded Thousands of Fossil Bones

Excavating an Edmontosaurus. — *The Danek Edmontosaurus bonebed is typical of an Edmontosaurus-dominated bonebed which are widespread in the Upper Cretaceous (Campanian to Maastrichtian) of western North America).*

Picture credit: Victoria Arbour

The Hanson Ranch Bonebed (Lance Formation)

Writing in the on-line, open access journal PLOS One, the scientists which include Keith Synder of the Biology Dept. of the Southern Adventist University, Tennessee, document the taphonomy and depositional history of an extensive E. annectens bonebed known as Hanson Ranch, in the Lance Formation of eastern Wyoming. The bonebed includes five main quarries and three exploratory quarries. Approximately 13,000 elements including around 8,400 identifiable bones, have been recovered in 506 square metres of excavated area in twenty years (1996-2016).

Virtually all the fossils are located within a fine-grained (claystone to siltstone) bed that has a maximum depth of two metres.

Mapping the Stratigraphy of the Main Bonebeds at the Hanson Research Station (Wyoming)

The Stratigraphy of the Hanson Research station. — *Local stratigraphy associated with the main bonebeds at the Hanson Research station. The green arrow indicates position of main bonebed.*

Picture credit: Synder et al (PLOS One) with additional annotation by Everything Dinosaur

Edmontosaurus annectens Fossils in an Excellent State of Preservation

Almost all the fossils recovered from the site exhibit exquisite preservation with little or no abrasion, breakages or signs of weathering prior to deposition. All the material is disarticulated and scattered although over a relatively confined area. This evidence in conjunction with analysis of the sediments associated with the fossils indicates that the bones were moved and buried after a period of initial decay and decomposition of the Edmontosaurus carcasses.

Mapping the Distribution of Fossil Bones in a Bonebed

A map showing the distribution of fossil material in an Edmontosaurus bonebed. — *A map showing typical disarticulated fossil bone distribution in a bonebed.*

Picture credit: Synder et al (PLOS One)

Gaining a Better Understanding of Edmontosaurus Biostratigraphy

The thousands of fossil bones represent mainly adult or sub-adult specimens. Due to the huge number of fossils associated with the Hanson Research site, the scientists have been able to gain a deeper understanding of Edmontosaurus biostratigraphy including how elements from the skeleton can be transported over distances prior to deposition. The most abundant fossil bones are ischia, pubes, scapulae, ribs and limb bones. In contrast, vertebrae, ilia and chevrons are rare.

Explaining the Composition of the Bonebed

When it comes to cranial material lower jaw bones (dentaries), nasals, quadrates and jugals are prevalent whilst premaxillae (upper jaw bones), predentaries and bones associated with the braincase are seldom found. The researchers suggest that following decay and break-up of the carcase, water action sorted and removed the articulated sections such as the backbone and the smaller bones such as the digits and toes, before, or at the same time, the remaining material was swept up in a subaqueous debris flow that created the final deposit.

The scientists suggest that similar processes may have been at work that created the other hadrosaurid-dominated Upper Cretaceous bonebeds associated with such geological formations as Hell Creek, Two Medicine, Horseshoe Canyon, Prince Creek as well as the Lance Formations of western North America. It is noted that there is a remarkably similar skeletal composition among the fossil bonebeds studied. It is also noted that there is a significant correlation between the hadrosaurid bonebeds and fluvial assemblages representing thanatocoenosis* events seen with modern-day vertebrate death assemblages.

Thanatocoenosis* Explained

Thanatocoenosis refers to a site where a collection of fossils representing a variety of organisms are found together. Such sites are often referred to as death assemblages. The organisms represented at the location may not have been associated in life, but their remains have been transported and deposited together thus forming a fossil bed composed of an extensive amount of fossilised material.

Not All of the Dinosaur Fossils are Edmontosaurus

The bonebed can be described as monodominant as the vast majority of the fossil material found can be assigned to just one species Edmontosaurus annectens. Non-dinosaurian terrestrial taxa identified include mammals and squamates along with the remains of many aquatic creatures such as crocodiles, turtles, gar and other fishes and numerous molluscs. Some other types of plant-eating dinosaur are represented notably, ceratopsids, pachycephalosaurs, nodosaurs and members of the family Thescelosauridae. Numerous shed theropod teeth are also associated with this location.

Everything Dinosaur will post up a separate article detailing one rather special theropod fossil associated with a quarry close to the Hanson Research station in the near future.

A Life Reconstruction of the Hadrosaurid Edmontosaurus

Wild Safari Prehistoric World Emontosaurus model. — *The new for 2020 Wild Safari Prehistoric World Edmontosaurus dinosaur model.*

The picture (above) highlights the 2020 Wild Safari Prehistoric World Edmontosaurus dinosaur model.

To view this range: Wild Safari Prehistoric World Models.

The scientific paper: “Over 13,000 elements from a single bonebed help elucidate disarticulation and transport of an Edmontosaurus thanatocoenosis” by Keith Snyder, Matthew McLain, Jared Wood and Arthur Chadwick published in PLOS One.

Visit the Everything Dinosaur website: Everything Dinosaur.

18 05, 2020

Tiny Crystals Can Stop Contaminants in their Tracks

By Mike|2024-02-20T20:30:56+00:00May 18th, 2020|Adobe CS5, Geology, Main Page|0 Comments

Tiny Crystals Plug Gaps Limiting the Uptake of Contaminants in Rocks

Research published today by a UK-based team of scientists has shown for the first time that the mobility of potentially harmful contaminants in crystalline rocks over long periods of time may be severely limited due to the presence of tiny crystals, meaning contaminant movement is likely to be focused to water-bearing fractures only. Movement of contaminants through rocks below ground can act to spread contamination, an issue relevant to the geological disposal of some wastes. Scientists and academics undertake studies to enhance their understanding of how this process works, helping to reduce uncertainties and to assess potential environmental risks.

Tiny Crystals

These new results shed light on the difficult problem of how contaminants may move over extremely long time periods and should improve our ability to calculate long term risks. This study, published in the academic journal “Scientific Reports”, examined crystalline (granite) rock samples from an underground system in Japan (Upper Cretaceous Toki Granite) and the results imply that in many cases the importance of “rock matrix diffusion” may be minimal. Additional analyses of a contrasting crystalline rock system (Carnmenellis Granite, from the UK) confirm and corroborate these results.

The Japanese samples were taken from the Toki Granite pluton which was formed around 70 million years ago.

CT-Scans Permitted the Researchers to Map Voids and Fractures in the Granite Samples

Pore space analysis in the igneous rocks. — *Pore sizes and pore distributions within the Toki and Carnmenellis granite proximate to primary fractures (indicated by solid blue regions at upper surfaces) as determined via X–ray CT analysis.*

Picture credit: Wogelius et al published in “Scientific Reports”

Published in “Scientific Reports”

These findings, which apply to long-lived systems, build on previous field studies and laboratory assessments over short periods of time which also suggested that contaminant mobility in crystalline rocks, such as granite, will be limited to short distances in parts of the rock that are away from large fractures.

This new work has examined rocks from ancient crystalline rock systems in Japan and the UK to show that even over immensely long periods of geological time the movement of elements within such crystalline rock is indeed small, in large part because the formation of large quantities of small crystals during the aging of the rock acts to seal small openings and limit fluid access to only a few millimetres of the rock bordering fractures.

Professor Roy Wogelius, the senior author on this paper, commented:

“We set out to test exactly what we could resolve in terms of fluid access to the matrix of these rocks and we were amazed at the extremely limited volume involved. But what was most amazing to us was the distribution of tiny crystals of carbonate minerals throughout what we usually think of as a uniform block of crystalline rock. Here, unexpected little crystals of calcite appear throughout the rock plugging up all the tiny openings. These crystals clog everything up and keep most of the fluid in large cracks with no access to smaller openings. This effectively shuts down contaminant access to the rock mass, meaning any contaminant movement would likely focus in rock fractures only. “

Helping Geologists

This study in combination with other collaborative research projects will help geologists to produce more accurate models of how pollutants and other contaminants can persist in the environment and threaten groundwater.

The work was completed by researchers from UK academia (The University of Manchester and the University of Leeds), in partnership with the British Geological Survey, two environmental consultancies – Quintessa and NSG – and was funded as part of collaborative work with the UK organisation Radioactive Waste Management.

Everything Dinosaur acknowledges the help and assistance of a media release from the University of Manchester in the compilation of this article.

The scientific paper: “Mineral reaction kinetics constrain the length scale of rock matrix diffusion” by R. A. Wogelius, A. E. Milodowski, L. P. Field, R. Metcalfe, T. Lowe, A. van Veelen, G. Carpenter, S. Norris and B. Yardley published in Scientific Reports.

The Everything Dinosaur website: Everything Dinosaur.

17 01, 2020

Extra-terrestrial Impact Wiped Out the Dinosaurs

By Mike|2024-01-13T08:42:51+00:00January 17th, 2020|Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Geology, Main Page|2 Comments

Mass Extinction Event Caused by Impact Event

One of the greatest controversies surrounding the Dinosauria is what actually caused the demise of the non-avian dinosaurs? Around the end-Cretaceous mass extinction event, there was an enormous extra-terrestrial impact in the Gulf of Mexico. A worldwide layer of clay, saturated in the rare Earth element iridium, marking the K-Pg geological boundary was first publicised by American father and son Luis and Walter Alvarez. They postulated that an Earth impact event had resulted in this deposition and it was speculated that such a catastrophic event might have been responsible for the extinction of the dinosaurs.

New Study Suggests Dinosaur Extinction Due to the Extra-terrestrial Impact Event

Asteroid impact event. — *An extra-terrestrial impact event.*

Picture credit: NASA

The “Smoking Gun” Evidence

Such an impact would have left an enormous crater, the search was on to find the “smoking gun” to support the theory regarding a meteorite, asteroid or perhaps a comet hitting the Earth. Most researchers now agree, that the Yucatan peninsula in the Gulf of Mexico was ground zero. However, there is a problem, as scientists are aware of a number of other potential candidates responsible for the extinction of a large amount of the planet’s biota some sixty-six million years ago. For example, the Late Cretaceous was characterised by extensive volcanism.

Huge amounts of lava from the Deccan traps led to the formation of thousands of miles of flood basalt. The out-pouring of noxious gases as a result of this extensive volcanism could well have played a significant role in the extinction of many different kinds of organisms too.

Asteroid impact theory challenged: Blame the Deccan Traps.

In a new paper, a team of international researchers led by Dr Celli Hull from Yale University, conclude that the volcanism did not play a huge role in the extinction, but it may have played a significant role in shaping the rise of different species after the extinction event had occurred.

Impact Event the Most Likely Cause of End-Cretaceous Mass Extinction

Extinction of the dinosaurs. — *The K-Pg extinction event was exacerbated by the high levels of sulphur at the extraterrestrial impact site that led to prolonged global cooling. Picture credit: James McKay.*

Picture credit: James McKay

Analysis of Ancient Ocean Sediments

In order to disentangle the relative effects of the volcanism and the impact event, the scientists analysed deep sea sediment sections drilled from the North Atlantic, Pacific and South Atlantic Oceans. They found that volcanic activity in the Late Cretaceous period caused only a gradual global warming of about two degrees Celsius, but this had no significant effect on marine ecosystems, and cooler conditions had returned prior to the extinction.

Hull et al investigated the timing of the Deccan outgassing by modelling in several scenarios, the effects of the gases ejected by volcanoes (sulphur and carbon dioxide). Their results suggest that more than half of the total Deccan outgassing occurred well before the impact event, not just before it. The scientists concluded that the timing of most of the atmospheric pollution from the extensive volcanism, just did not fit the extinction event. The major volcanism is likely to have occurred at least 200,000 years before the extinction event.

One of the co-authors of the study, Professor Paul Bown (University College London), explained.

“Most scientists acknowledge that the last, and best-known, mass extinction event occurred after a large asteroid slammed into Earth 66 million years ago, but some researchers suggested volcanic activity might have played a big role too and we’ve shown that is not the case.”

The team’s models showed that the changes in the carbon cycle that resulted from the volcanism was mitigated by the oceans absorbing vast quantities of CO2. This would have limited any global warming.

Fellow co-author Professor Paul Wilson (Southampton University), added:

“There’s been a big row about the cause of the mass extinction for decades. The demise of the dinosaurs was the iconic event but they were large animals and there weren’t really that many of them so it’s tough to use them to figure out the cause.”

Professor Wilson added:

“We studied microscopic marine organisms called foraminifera and there are thousands of them in a teaspoon-full of ocean sediment. To get them we drilled into the sea bed in waters nearly 5 kilometres deep not far from the watery grave of RMS Titanic off the coast of Newfoundland using a sort of geology time machine – a drill ship called the JOIDES Resolution run by one the world’s most successful international scientific collaborations, the International Ocean Discovery Program.”

The authors postulate that the volcanism may have played a role in shaping the evolution of Palaeogene species in the aftermath of the end-Cretaceous extinction event.

What About Hell Creek – Were Dinosaurs Already in Decline?

From a scientific perspective, it makes much more sense to examine the fossil record of planktonic foraminifera. Relying on the non-avian dinosaurs as an indicator of palaeo-climate change some sixty-six million years ago is fraught with difficulties. For instance, although many different types of life were affected by the end-Cretaceous extinction event, it is often only the dinosaurs that are mentioned by the media. It is worth remembering that many other lifeforms died out.

There are not that many windows into the end of the Maastrichtian and the earliest part of the Palaeocene (Danian faunal stage). One such example is the Hell Creek Formation, which provides a record of the last few million years of the Mesozoic.

Studies of the number and variety of dinosaur fossils excavated from the Hell Creek Formation and other slightly older geological formations, suggest that in the last ten million years of the Cretaceous, the number of dinosaur species fell by more than fifty percent.

An analysis of the youngest fifteen metres of sediments from the Hell Creek Formation, revealed just eleven different types of dinosaur. In the uppermost strata, the last three metres of the Hell Creek Formation representing the end of the Cretaceous, only three types of dinosaur were recorded.

Difficulties in Dating Strata

Whilst it can be difficult to accurately date and assess the chronology of strata, the study of dinosaur fossils from Hell Creek suggests that the Dinosauria may have been in decline (at least in this part of Laramida), prior to the impact event. This decline, if it was a decline, could have been caused by the environmental effects of the extensive volcanism, or other factors for that matter.

We suspect that just like the Deccan Traps, this debate is going to rumble on for a considerable period of time.

The Everything Dinosaur website: Everything Dinosaur.

15 01, 2020

Unique Ediacaran Fossil Site Gains Protection

By Mike|2024-01-13T06:54:56+00:00January 15th, 2020|Dinosaur and Prehistoric Animal News Stories, Geology, Palaeontological articles, Photos/Pictures of Fossils|0 Comments

South Australian Fossil Site Purchase Supported by Billionaire

With so much bad news about the environment coming out of Australia due to the devastating bush fires, it is pleasing to report on a conservation success story. A $1 billion (USD), nature fund has been used to buy a vast tract of outback South Australia containing some of the oldest animal fossils on Earth. The acquisition safeguards an extremely important fossil site and helps support the Australian Government’s plans to gain World Heritage Site status for the area.

The Nilpena Fossil Fields (South Australia)

Picture credit: Jason Irving

The Unique Ediacara Fossil Site

The 60,000-hectare (150,000 acre) Nilpena West property is 370 miles (600 kilometres), north of the South Australian capital Adelaide and was previously part of Nilpena Pastoral Station. The property includes the Ediacara Fossil Site (Nilpena), which is listed on Australia’s National Heritage List and records a remarkable marine biota, documenting some of the earliest, large, multicellular creatures to have evolved on Earth.

Global not-for-profit organisation The Nature Conservancy, sourced funding from an anonymous donor in October 2019 to allow the purchase and protection to go ahead after the South Australian Government announced in March that it had reached an agreement with the land’s owners to purchase the site. The purchased land is adjacent to the Ediacara Conservation Park and increases the size of the protected area ten-fold.

The Importance of the Flinders Range

Strange fossils, preserved in the sandstone of the Ediacaran hills of South Australia provided the first substantial evidence for the existence of complex life in the late Precambrian. In 1946, Australian geologist Reginald Spriggs discovered fossilised impressions in this part of the Flinders Range, his unexpected discovery failed to enthuse the scientific community at first, his paper outlining the discovery was rejected by the academic journal “Nature”. However, the significance of these exquisitely preserved fossils and what they represented – organisms associated with an ancient marine community, was soon realised.

An Example of Dickinsonia – One of the Fossilised Ediacaran Organisms Associated with the Nilpena Fossil Fields

Dickinsonia costata fossil. — *The Ediacaran fossil Dickinsonia costata, specimen P40135 from the collections of the South Australia Museum. The disc-like Dickinsonia is one of the creatures preserved at the Nilpena fossil site.*

Picture credit: Dr Alex Liu (Cambridge University)

To read an article about the bizarre Dickinsonia: Dickinsonia Definitely an Animal.

The Wyss Campaign for Nature

The sale has now been finalised with The Nature Conservancy announcing this week that funding from the Wyss Campaign for Nature, the once anonymous donor, had helped secure the acquisition. The Wyss Campaign for Nature was founded two years ago, by the wealthy, Swiss-born philanthropist Hansjörg Wyss. The purchased land will be permanently protected and managed by the South Australian Government. It will be formally allocated to the Ediacara Conservation Park later this year.

A Map Showing the Location of the Nilpena Fossil Fields Relative to the Ediacara Conservation Park

A map of the Nilpena fossil fields site. — *Nilpena fossil fields site. The Nilpena Station purchase will greatly increase the protected area for the fossils.*

Picture credit: The Government of South Australia

The South Australian property is now permanently protected and managed for conservation by the South Australian Government. It will be added to the Ediacara Conservation Park later this year.

Ediacaran Fossils Represent Scores of Species

Palaeontologists have excavated many hundreds of specimens representing three dozen different species, most of which are more than 550 million years old. The fossils provide the first evidence of locomotion and sexual reproduction. The space agency NASA, has examined the Ediacaran biota in a project to assess how life could evolve on other worlds.

The Nature Conservancy’s Australian Director of Conservation Dr James Fitzsimons explained that this purchase which would permit the formal protection of the 60,000 hectare property was a big win for conservation in South Australia.

He commented:

“The property contains significant biodiversity values including two threatened ecological communities and a number of threatened species. Most critically, the property also covers extremely important sites that contain the oldest fossilised animals on Earth.”

South Australian Environment and Water Minister David Speirs said Nilpena West would soon be added to the South Australian public protected area estate and managed by the Department for Environment and Water.

The minister added:

“Its inclusion in the conservation estate will link the Ediacara Conservation Park to the Lake Torrens National Park and will support our nomination for the listing of areas of the Flinders Ranges as a World Heritage Site.”

When did life on land evolve? An Ediacaran related article: When Did Life on Land First Evolve – Does the Ediacaran Biota Provide the Answer?

A recent article about how computerised tomography and other sophisticated research techniques are providing new insights into how the first animals evolved: Chinese Fossils Suggest Animal-like-embryos Evolved Before Animals.

Everything Dinosaur acknowledges the assistance of a press release from The Lead South Australia in the compilation of this article.

The Everything Dinosaur website: Everything Dinosaur.

23 11, 2019

A Quick Guide to the New CollectA Models (Part 4)

By Mike|2024-01-05T10:25:59+00:00November 23rd, 2019|Adobe CS5, Dinosaur Fans, Everything Dinosaur News and Updates, Everything Dinosaur Products, Everything Dinosaur videos, Geology, Main Page, Photos of Everything Dinosaur Products, Press Releases|0 Comments

A Short Video Highlighting New for 2020 CollectA Models (Part 4)

Yesterday, Everything Dinosaur in collaboration with our chums at CollectA, revealed the latest collection of prehistoric animal models for 2020*. Naturally, we put up a blog post providing a little more information about each replica, specifically the new hunting Mapusaurus dinosaur model, the Pleuroceras ammonite, the belemnite and the beautiful horseshoe crab model. Team members are committed to helping to inform and educate our customers, so in this spirit, we have produced a short video providing a little more information about each of these exciting new figures.

A Quick Video Guide to the New CollectA Prehistoric Animal Models (Part 4)

Video credit: Everything Dinosaur

CollectA Age of Dinosaurs – Popular Size Hunting Mapusaurus

The first model to be featured in this short video (it lasts a little over five minutes in length), is the only dinosaur figure announced in this batch, a replica of a hunting Mapusaurus. CollectA originally introduced a model of this giant, South American member of the Carcharodontosauridae (Giganotosaurini tribe), back in 2012. This model was subsequently modified and a base added. Already represented in the CollectA Deluxe range (a 1:40 scale Mapusaurus was added in 2018), the new hunting Mapusaurus model, which measures a fraction under 23.5 cm long, will be available from Everything Dinosaur in the middle of 2020.

The Evolution of CollectA Mapusaurus Models

Evolution of Mapusaurus replicas within the CollectA model range. — *The changing Mapusaurus models 2012 – 2020 (CollectA).* *Picture credit: Everything Dinosaur.*

Picture credit: Everything Dinosaur

CollectA Ammonite (Pleuroceras) and the CollectA Belemnite Model

Fossil collectors have two new models for 2020 to get particularly excited about. CollectA will be adding an ammonite model and a belemnite to their Age of Dinosaurs range. These two superb cephalopods help to demonstrate what the actual living animal looked like.

New for 2020 the CollectA Ammonite and Belemnite Models

Picture credit: Everything Dinosaur

The CollectA Horseshoe Crab Model

The fourth replica that we discuss in our short video is the horseshoe crab replica. Everything Dinosaur will be stocking this fifteen centimetre long model of an ancient arthropod, often described as a “living fossil”.

Horseshoe crabs are fascinating creatures, despite their name they are not closely related to crabs, as members of the Arthropoda phylum they are more closely related to spiders and the extinct sea scorpions (eurypterids). All four living species are vulnerable to extinction due to loss of habitat, overfishing (they are caught and used as bait) and from the harvest of their blue-coloured blood which has medical applications. It is great to see a horseshoe crab model added to the CollectA range.

New for 2020 The CollectA Age of Dinosaurs Popular Size Horseshoe Crab Model

CollectA Horseshoe Crab model. — *CollectA Age of Dinosaurs Popular Size Horseshoe Crab.*

Picture credit: CollectA

2020* To read our blog post from yesterday about these four new CollectA Age of Dinosaurs – popular size models: New CollectA Models for 2020 (Part 4).

To view the range of not-to-scale CollectA prehistoric animal models and figures available from Everything Dinosaur: CollectA Prehistoric Life.

The Everything Dinosaur website: Everything Dinosaur.

6 10, 2019

New Species of Crocodile Honours Researcher

By Mike|2023-12-30T20:51:11+00:00October 6th, 2019|Animal News Stories, Geology, Main Page, Photos|0 Comments

Crocodylus halli – A New Species of Crocodile is Announced

The crocodile family has undergone yet another revision. It seems that the Crocodylidae are a more specious family than previously thought. The New Guinea Crocodile (Crocodylus novaeguineae), is actually two species and not one and the second species has been named Crocodylus halli after Philip Hall, a University of Florida researcher who sadly, passed away before his work on these three-metre-long reptiles could be completed.

A New Crocodile Species has been Discovered – Hall’s Crocodile (Crocodylus halli)

New crocodile species discovered. — A new crocodile species has been discovered. The picture (above), shows Jen Brueggen, Park social media manager, researchers Caleb McMahan, Christopher Murray and John Brueggen, Park director, with a specimen of Crocodylus halli, that seems rather reluctant to pose for a photograph.

Picture credit: Southeastern Louisiana University

Crocodile Nesting Behaviour Hinted at Different Species

The late scientist Philip Hall, noticed subtle differences in osteoderm patterns on the backs of crocodiles and in the nesting behaviours of crocodile populations in the north and the south of the island of New Guinea. He speculated that there could be two species living on New Guinea, but unfortunately, he died before his research could be completed. Southeastern Louisiana University Assistant Professor of Biology Christopher Murray and his co-author Caleb McMahan (Field Museum, Chicago), were inspired to continue this research and they have published their findings in the academic journal “Copeia”, the journal of the American Society of Ichthyologists and Herpetologists.

A chain of high hills and mountains known as the Central Highlands divides the island of New Guinea. It is thought this geological feature was formed in the last 8 million years or so. Geographically isolated crocodile populations, each living on different drainage basins that came about as a result of the uplift, have been identified as different species.

The Island of New Guinea

Distribution of crocodile populations on New Guinea. — *The Central Highlands of New Guinea permits two distinct drainage basins to form. This geographical barrier has led to the evolution of two distinct species of crocodile.*

Picture credit: Copeia/Murray and McMahan with additional annotation by Everything Dinosaur

The illustration of the island of New Guinea (above), shows the location of the Central Highlands and the red dots south of the mountain chain denote sampling areas for C. halli in the study, whilst the brown dots north of the chain indicate sampling sites for C. novaeguineae.

Careful analysis of museum specimens along with a study of the crocodiles kept in captivity at the St Augustine Alligator Zoological Park (Florida), confirmed the hypothesis. Subtle differences in the shape of bones and the observed behaviour differences indicates the presence of two distinct species on the island. This has been confirmed by molecular analysis.

Difference in the Shape of the Skull and Jaws

Comparing Crocodile Skulls from Papua New Guinea. — Dorsal view of skulls from New Guinea crocodiles. Crocodylus novaeguineae (left) with its extended maxilla and proportionately reduced postcranial elements compared with two examples of Crocodylus halli (middle and right). In contrast, the C. halli skulls show much shorter maxillae and proportionately enlarged postcranial elements.

Picture credit: Copeia/Murray and McMahan

The Importance of Museum Specimens

The researchers comment that this new insight into the Crocodylidae would not have been possible without access to the collections from numerous museums. The museums involved in this research included The Field Museum (Chicago), the Smithsonian National Museum of Natural History, the Museum of Comparative Zoology at Harvard University, the American Museum of Natural History (New York), Queensland Museum, Louisiana State University Museum of Natural Science and the Florida Museum of Natural History.

The careful curation and collection of a large number of specimens permitted the scientists to build up a substantial database on crocodilian skull morphology that allowed them to tease out the subtle differences between the two species.

Crocodylus halli – Hall’s Crocodile

Newly described crocodile species from New Guinea Crocodylus halli. — *One of the residents at the St. Augustine Alligator Farm Zoological Park – Crocodylus halli.*

Picture credit: Copeia/Murray and McMahan

Implications for Crocodile Conservation

Identifying a separate species has important implications for the conservation of both populations of crocodile.

Commenting on the significance of this discovery, Caleb McMahan stated:

“Now that we know the evolutionary history of these species, we need to re-inform the conservation status of them given that the distribution has changed and conservation threats are different in different areas.”

24 09, 2019

Dust from a Giant Asteroid Collision Caused Ordovician Ice Age According to New Study

By Mike|2023-12-30T17:09:32+00:00September 24th, 2019|Dinosaur and Prehistoric Animal News Stories, Geology, Main Page, Palaeontological articles|0 Comments

Global Climate Change in the Ordovician Caused by Dust from a Giant Asteroid

Scientists have been aware for some time that during the Middle Ordovician, our planet endured a prolonged but gradual period of global cooling. The average temperature on Earth fell and this opened up new ecological niches that permitted those animals and other organisms around at the time to adapt and to become more specious.

The cause of this world-wide ice age, one that started around 466 million years ago, is a mystery, but a team of scientists writing in the journal “Science Advances” think that they may have found the answer. They postulate that the global cooling was triggered by huge amounts of dust deposited in the atmosphere from an extraterrestrial asteroid collision.

An Enormous Impact in Outer Space

Colliding asteroids in outer space. — *An artist’s impression of an extraterrestrial asteroid impact. Excessive amounts of dust in the atmosphere may have contributed to global cooling.*

Picture credit: Don Davis, Southwest Research Institute

Dust from Outer Space

The Earth’s atmosphere is constantly bombarded by extraterrestrial space dust, but normally it only makes up a tiny proportion of all the dust in the atmosphere. Most of these tiny particles come from other sources such as volcanoes, forest fires, fine sand grains from deserts, pollution or from sea salt. However, the research team, which included scientists from the University of Chicago and Sweden’s Lund University postulate that the break-up of a 93-mile-wide asteroid in the asteroid belt between Mars and Jupiter led to the deposition of much more than just the normal background dosage of space dust.

Large amounts of dust would have interrupted the filtering of solar radiation to the surface of our planet and led to a period of dramatic global cooling.

Philipp Heck (University of Chicago), one of the co-authors of the paper published in “Science Advances” explained:

“Normally, Earth gains about 40,000 tons of extraterrestrial material every year. Imagine multiplying that by a factor of a thousand or ten thousand. Our hypothesis is that the large amounts of extraterrestrial dust over a timeframe of at least two million years played an important role in changing the climate on Earth, contributing to cooling.”

Giant Asteroid has Global Impact

If large amounts of ice were formed due to this cooling effect, then sea-levels would have fallen as evidenced by the geological record of strata that was formed during this time in Earth’s turbulent history. Falling sea levels would have changed ecosystems, potentially opening up new environments for organisms to exploit.

Lead author of the research paper, Birger Schmitz of Sweden’s Lund University added:

“Our results show for the first time that such dust, at times, has cooled Earth dramatically. Our studies can give a more detailed, empirical-based understanding of how this works, and this in turn can be used to evaluate if model simulations are realistic.”

Searching for the Evidence

The researchers analysed Ordovician rocks looking for rare Earth particles that could be associated with cosmic dust. Tiny micrometeorites collected from Antarctica were used to provide a base level of normal cosmic deposition. Evidence of rare helium isotopes along with other rare Earth metals confirmed that dust deposits were extraterrestrial in nature.

The Middle Ordovician cooling period could therefore have been caused by this excessive dust. The amount of water in the Earth’s oceans influences the way that rocks on the seabed form, and the rocks from this time period show signs of shallower oceans, an indication that some of the Earth’s water was trapped in glaciers and sea ice. Schmitz and his colleagues are the first to show that this ice age correlates with the extra dust in the atmosphere.

A Fragment of a Meteorite Preserved in Ordovician-aged Rock (Note the Orthocone Fossil)

Fragment of a meteorite preserved in sandstone dating from the Ordovician. Note the orthocone fossil (above). — *A fragment of a meteorite preserved in red sandstone dating from the Ordovician. Note the orthocone fossil (above).*

Picture credit: John Weinstein/Chicago Field Museum

Gradual Climate Change Could Have Benefitted Life on Earth

Whilst the authors note that sudden and dramatic climate change can be very detrimental to ecosystems, the Middle Ordovician cooling could have proved to have been extremely beneficial.

Associate Professor Heck argues:

“In the global cooling we studied, we’re talking about timescales of millions of years. It’s very different from the climate change caused by the meteorite 65 million years ago that killed the dinosaurs, and it’s different from the global warming today—this global cooling was a gentle nudge. There was less stress.”

Rocks from Southern Sweden Record the Dramatic Increase in Cosmic Dust

The grey horizontal line marks the deposition of the cosmic dust from the asteroid collision in outer space. — These are cliffs made of sedimentary rock that was once an ancient seabed. The grey horizontal line in the rock shows where the dust from the asteroid collision fell. These deposits provide “smoking gun” evidence of the outer space asteroid collision.

Picture credit: Philipp Heck (University of Chicago)

Everything Dinosaur acknowledges the assistance of a press release from the University of Chicago in the compilation of this article.

Visit the Everything Dinosaur website: Everything Dinosaur.

2 09, 2019

Ammonite Biozones and the Biostratigraphic Column

By Mike|2023-12-29T16:10:23+00:00September 2nd, 2019|Geology, Main Page, Photos/Pictures of Fossils|0 Comments

Ammonite Biozones and the Biostratigraphic Column

It was the English engineer William Smith (1769-1839), who pioneered the idea that different strata located in different places could be correlated using the fossils that were contained therein. Although, his astonishing feat of compiling the world’s first geological map did not receive all the recognition it deserved, after all, it was only later in his life that his achievements gained prominence in scientific circles, William Smith is regarded by many as the “father of geology”.

As he examined different layers of rock he perceived that any succession of fossils could represent particular periods of geological time. Furthermore, the age of widely separated strata could be compared and correlated using the fossils that they contained. These fossils helped to indicate the relative age of various rock formations. Thus, Smith helped to lay the foundations for the science of biostratigraphy. ammonites and other invertebrate fossils are extremely important in the relative dating process.

Different Fossils of Ammonites Associated with Different Layers of Rock – Building a Biostratigraphical Column

Picture credit: Everything Dinosaur

Ammonite Biozones

The above photograph was taken by an Everything Dinosaur team member on a recent visit to the Naturmuseum Senckenberg (Frankfurt, Germany), it demonstrates that different types of ammonite fossils are associated with different layers of rocks in a sequence of deposition. The stratigraphic column can therefore be divided into zones (biozones), that are characterised by one or more particular type of fossil. The sequence of these biozones in the correct order, creates a biostratigraphical column.

Ammonites are ideal zone fossil candidates. These cephalopods were ubiquitous in Mesozoic marine deposits, their shells formed abundant fossils and ammonites evolved rapidly into many distinctive types (species). We congratulate the Museum for such a beautifully created and instructive display.

The Everything Dinosaur website: Everything Dinosaur.