Take me to the rocks

Dr Sebastian Lüning (Germany) I am a geologist by profession. Everyday of my working life, I have worked with rocks, from nine to five, for 19 years, looking for oil and gas in the Sahara. Sometimes this is stressful, sometimes really enjoyable and sometimes simply annoying – just like any other job. However, I’ll tell you a little secret about what I do in my limited spare time to refresh my mind and recharge my batteries for another day. I am so in love with my rocks that I am also a hobby geologist. I just cannot keep away from the rocks. There are plenty of interesting fields open to amateur geologists and palaeontologists to indulge in. Most popular are probably collecting minerals and fossils, including visiting quarries and searching beaches for new specimens. However, my hobby is focused on regional geology. I love to understand the earth history of a particular area, by visiting its outcrops and reading the regional geological descriptions that have been published about it. That is, I like to look behind the scenes of a modern landscape to understand how it was shaped and what lies underneath. I drive and walk through my object of study to understand its dimensions, distances and height. At one moment, I can pay attention to millimetre-sized fossils and, a few minutes later, be enjoying a panorama across kilometre-scale valleys shaped by ice. I am convinced there are many other amateur geologists, who share my passion for an integrated view … Read More

To access this post, you must purchase Annual subscription, 12 Month Subscription or Monthly subscription.

Encrinus liliiformis – a crinoid from the Triassic that made a career for itself: Germany’s fossil of the year, 2019

Jens Lehmann (Germany) Despite their common name ‘sea lilies’, crinoids are animals but not plants, although they look like a flower (Fig. 1). They are related to the sea urchins, sea cucumbers and starfish, groups that are unified as echinoderms (see, for example, Broadhead and Waters, 1980). Crinoids consist of a “root”, a stem built of many disc-shaped elements (columnals) and a crown. Fig. 1. A crown of the famous crinoid, Encrinus liliiformis, from a Muschelkalk quarry in Northern Germany. The fossil shows a slightly opened crown, with a number of arms besides each other. The name “sea lily rock” is often associated with the basal plates of fossilised crowns that resemble a lily flower and were collected as “Lilienstein” (“lily rock”) by gentlemen collectors in Central Europe, particularly in the nineteenth century (Fig. 2). In fact, crinoids were encountered for many hundred years and thus were already known by the famous Swiss and German scientists (respectively), Conrad Gessner and Georgius Agricola, in the sixteenth century. However, these early geoscientists only found the fossils, since living crinoids can only be found in the deep sea and were not known by the scientific community before the eighteenth century. This is the reason why the isolated stem elements called columnals occur in millions of specimens in the German Muschelkalk (Middle Triassic) were mystically called “Boniface pennies” or “Witch money”, before they were recognised as parts of crinoids. Fig. 2: Even details of Germany’s “Fossil of the Year 2019” are beautiful, like these … Read More

To access this post, you must purchase Annual subscription, 12 Month Subscription or Monthly subscription.

Caught between two mass extinctions: The rise and fall of Dicroidium

Chris Mays and Stephen McLoughlin (Sweden) In the aftermath of Earth’s greatest biotic crisis 251.9 million years ago – the end-Permian mass extinction – a group of plants arose that would come to dominate the flora of the Southern Hemisphere. Recovery of the vegetation from the end-Permian crisis was slow; but steadily, one group of seed plants, typified by the leaf fossil Dicroidium, began to diversify and fill the dominant canopy-plant niches left vacant by the demise of the Permian glossopterid forests (Fielding et al., 2019). Eventually, Dicroidium re-established a rich peat-forming vegetation across Gondwana through the Late Triassic, dominating the flora between 30°S and the South Pole (Kustatscher et al., 2018). Indeed, few fossil plant assemblages of this age can be found in Gondwana that do not contain this plant. The importance of Dicroidium is not just its role in showing biogeographic and tectonic linkages between southern lands or its value in determining the age of continental strata. Dicroidium and its associated plant groups were so successful that they were major contributors to the development of thick coal seams in the Late Triassic that are now mined to produce electricity. Although Dicroidium is generally envisaged as a plant of cool temperate climates, the very first fossils that might belong to this group are from the Permian-Triassic transition of Jordan, located near the palaeoequator (Blomenkemper et al., 2018). Nevertheless, the distribution of Dicroidium soon shifted to high southern latitudes in the Early Triassic and they overwhelmingly dominated the southern vegetation … Read More

To access this post, you must purchase Annual subscription, 12 Month Subscription or Monthly subscription.

Akal Wood Fossil Park, Rajasthan, India

Khursheed Dinshaw (India) The Akal Wood Fossil Park is located about 18km from the desert city of Jaisalmer in Rajasthan, India. It has preserved fossil evidence dating back to the Jurassic Period (Fig. 6) indicating a hot and humid climate characterised by dense forests. In particular, 180-million-year-old fossils of animals and plants are preserved here. Fig. 1. The fossilised logs have been protected by iron grill cages with overhead tin sheds. The Jaisalmer Basin formed part of the southern shelf of the Tethys Ocean during Jurassic times. The area is well known for its rich geo-diversity, both in terms of landscapes and outcrops of rock types, and the variety of fossils that these rocks have preserved. When I spoke to him, Dr Sudesh K Wadhawan, who is Adviser (Geosciences) and Visiting Faculty, Director General (Retired), Geological Survey of India, explained that, “Lithostratigraphy of the geologically mapped formations displays an array of Jurassic siliciclastic, mixed carbonate-siliciclastic and carbonate rocks that range in age from Lower Jurassic to Upper Jurassic in geological timescale. A variety of depositional environment, ranging from continental fluvial to near-shore and off-shore deep marine, are interpreted and well documented in the Jaisalmer basin”. Fig. 2. Fossilised tree trunks lying scattered in an area of 21 hectares. The fossil logs, representing gymnosperms, belong to the dicotyledonous stems of these trees (Figs. 7 and 8). (In such stems, the vascular bundles are arranged in a ring, with pith concentrated at their core, rather than being scattered throughout the plant interior.) … Read More

To access this post, you must purchase Annual subscription, 12 Month Subscription or Monthly subscription.

Shining hill in the Arizona desert

Deborah Painter (USA) In the area east of the small community of Bagdad and on the northeast edge of the Arrastra Mountain Wilderness of central Arizona in the USA, my friends, Terril, Yvette and David, stood with me at the base of a vision in the desert of a rockhound’s dream. This was a colourful, irregularly shaped hill, standing alone in the arid wildlands, its bright whites, reds and greens standing out against a blue and white March sky. The entire hill seemed composed entirely of loose stones of quartz, caliche (a mineral deposit of gravel, sand and nitrates found in dry areas of the USA), basalt, travertine, green quartzite, tuff and gabbro. One whole side of the hill was white from quartz. We had attempted to climb this amazing thing. But, like wonderful things in a dream, most of it eluded us. We could climb but a metre or so, before we slid back down, unable to secure a foothold. However, the four of us collected about a bucket full of the rocks on this Bureau of Land Management land. Fig. 1. Our eyes were transfixed by a shining green, brown, red and white hill (a volcanic neck), standing alone in the Central Highlands of Arizona. The side facing east (to the right in this photograph) was white from quartz. (Credits: Deborah Painter.) Just across the roadway to the south, we had hiked a short distance across an arroyo (a Spanish word for a dry creek or stream bed). … Read More

To access this post, you must purchase Annual subscription, 12 Month Subscription or Monthly subscription.

Golden Dinosaur from the depths of the London Mine: Mystery of Genevieve

Steven Wade Veatch and Teresa L Stoiber (USA) The legend of “Genevieve”, a fossilised dinosaur not only made of stone — but also of gold — began on 3 July 1932. That was the day WK Jewett, owner of the London Mine near Alma in Colorado, stopped at the Antlers Hotel in Colorado Springs and made the official announcement of its unearthing. The story was picked up by the news services and word of the fantastic find spread through the scientific world like a prairie fire. The golden dinosaur was discovered by William White, 700 feet (213m) underground — deep in the London Mine (WK Jewett, 1932). Curiously, the miners had been using the creature’s nose as a lamp holder, not realising there was a ‘dinosaur’ (if that is what it was) there. White, a hard rock miner, believed at first he was looking at two stumps. In reality, it was a dinosaur lying on its back with its limbs at an angle of 75 degrees. Eager to retrieve it from its rocky tomb, miners blasted it out of rock at the 700-foot level of the London Mine with dynamite. The blast shattered the specimen. Bits and pieces of the dinosaur were hoisted to the surface, where curious crowds gathered to see the prehistoric monster. As the story goes, a geology professor at Colorado College, Robert Landon, travelled to Alma so he could examine Genevieve – an extraordinary record of a former world. The measurements he made revealed that the … Read More

To access this post, you must purchase Annual subscription, 12 Month Subscription or Monthly subscription.

Geo junkets: New Zealand, North Island (Part 1)

Jesse Garnet White (USA) Fig. 1. Legend/Key:1 = Sediments (Cretaceous and Cenozoic).2 = Greywacke (Permian and Triassic).3 = Schist (Carboniferous to Cretaceous).4 = Volcanic rocks (Cretaceous and Cenozoic).5 = Sediments and ophiolites (Northland and East Coast allochthon) (Cretaceous and Oligocene).6 = Pyroclastic rocks (Triassic and Jurassic).7 = Limestone, clastics and volcanic rocks (Central and Eastern sedimentary zone) (Cambrian to Devonian).8 = Granitoids (Paleozoic and Cretaceous).9 = West Fiordland metamorphic zone (Paleozoic and Cretaceous).10 = Ophiolites and pyroclastics (Permian).11 = Volcanic rocks (including pyroclastics) (Permian).12 = Mafic and ultramafic complexes (Paleozoic and Cretaceous).13 = Greywacke (Western sedimentary zone) (Cambrian to Ordovician). Auckland and the AVF In a thick brain fog, crusty eyed and yawning, I sat up in bed at 4:30 am. I was in Auckland, New Zealand. It was still dark outside when I drove to Mount Eden (Maungawhau), where I hiked up a narrow dirt trail lined by tall grass stippled with dew. Coming out of the verdure, my shoes, socks and shorts were soaked through. On top of the hill, a shadow-black grouping of trees blocked the creeping morning light from behind the Hanua Ranges. The burnt orange sunrise, obstructed by cumulous, lit up like a distant mountain wildfire. Auckland city centre was under puffy, lavender-white cirrus clouds, reflecting pastel colours across the harbour. Alone in the cool and crisp pre-dawn air, I viewed the various scoria cones in the Auckland Volcanic Field (AVF) bursting through the city neighbourhoods. Fig. 2. Map of New Zealand showing place names. … Read More

To access this post, you must purchase Annual subscription, 12 Month Subscription or Monthly subscription.

Pistol shrimps: How to recognise them in the fossil record

Matúš Hyžný (Slovakia), Andreas Kroh (Austria), Alexander Ziegler (Germany) and John WM Jagt (The Netherlands) Alpheid shrimps, colloquially referred to as “pistol shrimps”, exhibit a remarkable anatomical adaptation. These tiny marine crustaceans use their enlarged and highly modified claw to ‘shoot’ at their prey – hence their name. It is astonishing that the snapping claw evolved at least 30 million years ago. How do we know that? Because the fossils tell us. Fig. 1. Habitus (body form) of alpheid snapping shrimps, exemplified by the extant species Alpheus thomasi from the Caribbean Sea. (Photo: Arthur Anker.) The famous snapping claw Alpheid pistol shrimps represent a super-diverse group of benthic marine crustaceans (that is, living on the bottom of the sea, including the sediment surface and some sub-surface layers). There are more than 600 living species, nearly half of which belong to the genus Alpheus. Its representatives possess a snapping claw, a multifunctional tool used for various types of behaviour such as aggression, warning or defence, as well as for hunting prey. Although snapping claws evolved independently several times within various decapod crustaceans, only in pistol shrimps did this organ attain true perfection. Fig. 2. Pistol shrimps ‘shoot’ with an enlarged, modified claw. (Photo: Arthur Anker.) The process of snapping involves a cracking sound reaching up to 210 decibels, one of the loudest produced by any animal. This noise originates from the collapse of a cavitation bubble in front of the claw, which, in addition, is accompanied by a short flash of … Read More

To access this post, you must purchase Annual subscription, 12 Month Subscription or Monthly subscription.

Geology in Leonardo’s ‘Virgin of the Rocks’

Steven Wade Veatch (USA) Leonardo da Vinci (1452-1519), considered one of the greatest painters of all time, used his knowledge of geology to inform his art. Leonardo was also noted for his work in sculpture, anatomy, mathematics, architecture, and engineering during the Italian Renaissance (about 1330 to 1450). From a geological perspective, Leonardo da Vinci’s paintings present a realistic portrayal of nature. In his Virgin of the Rocks (1483-1486), on display in the Louvre in Paris (Fig. 1), the geological accuracy is striking (Pizzorusso, 1996). The painting’s subject is both the Virgin and the rocks. The Virgin sits in front of a grotto or cave, various aspects of which, according to geologist Ann Pizzorusso (1996): “… are rendered with astounding geological accuracy. Leonardo has painted a rich earthscape of rock eroded and sculpted by the active geological forces of wind and water. Most of the rock formations … are weathered sandstone, a sedimentary rock”. Fig. 1. Leonardo da Vinci’s Virgin of the Rocks (1483-1486). From his studies of geology, Leonardo learned how the Earth works and improved the realism of his paintings. Location: Louvre, Paris. Oil on panel transferred to canvas. Height: 199cm. Width: 122cm. (The image is in the public domain.) What looks like basalt, an extrusive igneous rock formed by the cooling of lava, appears above Mary’s head and at the top right of the picture. Leonardo even painted the columnar joints formed by the cooling of the rocks. Also, just above her head is a precisely painted … Read More

To access this post, you must purchase Annual subscription, 12 Month Subscription or Monthly subscription.

Brihadeeswarar Temple, India

Khursheed Dinshaw (India) Construction of the Brihadeeswarar Temple (also spelt Brihadisvara or Brihadeshwara), which is in Thanjavur in the state of Tamil Nadu, India, began in 1003 AD by Rajaraja I and was completed in 1010 AD. It is made of blocks of granite that were sourced from around 50km away. Almost 130,000 tonnes of granite were used to build this temple. The popular theory of how the blocks were transported is that they were gradually rolled here with the help of elephants. The design of the temple is meant to represent a cosmic structure called Mahameru, which symbolises energy from the universe, including from living as well as inanimate beings. The temple is dedicated to Lord Shiva in the form of a lingam (that is, a symbol of divine generative energy often in the form of a phallus), which is 3.66m high. The courtyard inside which the temple is built measures 240m by 120m. The Brihadeeswarar Temple, also known as the Big Temple, is an architectural marvel in stone of the Chola dynasty. It is also a UNESCO World Heritage Site. The tower, which is built over the sanctum, has a height of about 66m and has 13 storeys (Fig. 1). Fig. 1. The tower built over the sanctum has a height of 217 feet and has 13 stories. There are eight sikharas (spires), which are also made of stone and weigh about 81 tonnes. There are two circumambulatory passages. The walls of the lower passage are decorated with … Read More

To access this post, you must purchase Annual subscription, 12 Month Subscription or Monthly subscription.

Urban geology: The Boxtel wall game

Stephen K Donovan (The Netherlands) The Netherlands is a land of museums, approximately 1,200 of them in a country the size of southeast England. Although the major cities have an ample supply – about 30 in Amsterdam, for example – there are many and varied museums dotted throughout the country. (I remember, in 2003, being driven to Arnhem and seeing a German Panther tank parked outside a small military museum – be ready for the unexpected.) For the geologist, one of the gems is Het Oertijdmuseum (= The Prehistoric Times Museum; formerly De Groene Poort) in Boxtel, in the province of Noord Brabant, north-north-west of Eindhoven. As may be deduced from Fig. 1, the museum has a specialist collection of dinosaurs and other saurian – replicas in the gardens around the main building and mounted skeletons inside. Fig. 1. Welcome to Het Oertijdmuseum! I presume any visitor spots the glass fibre Tyrannosaurus before reading the notice on the right. Other saurians are lurking in the undergrowth around the main museum building, much to the delight of children of all ages. I am a walker and I prefer to saunter from the station through the attractive town of Boxtel to Het Oertijdmuseum rather than take a bus. The walk is a long 30 minutes. As you near the museum, the route passes a most extraordinary building, Bosscheweg 107, ‘Den Daalder’. This appears to be an entirely conventional office block until you reach the end closest to the museum, when all is … Read More

To access this post, you must purchase Annual subscription, 12 Month Subscription or Monthly subscription.

Rock paintings of Bundi, India

Khursheed Dinshaw (India) The River Rewa bifurcates into the Ghoda Pachad and Mangli Rivers while flowing through the region that is located 33km to the south of Bundi, in the state of Rajasthan, India.Probably the world’s largest rock paintings can be found in the rock shelters along the banks of the Mangli River here. They belong to the Mesolithic and Middle and Upper Palaeolithic periods, and depict hunting scenes – the life of gatherers, human stick figures, bulls, antelopes and wildlife (Fig. 1). Cultural scenes portray dancers, musicians and daily life. There are also inscriptions made from the plant Brahmi on the sandstone rocks lining the River. The rock shelters stretch across a distance of almost 35km. Fig. 1. Animals depicted in one of the rock shelters, which is part of the world’s largest rock painting site. Om Prakash Sharma, also known as Kukki, a local resident of Bundi is credited with discovering this site, as well as nearby sites. On 4 December 1993, he explored a Chalcolithic (Neolithic) mound in the village of Namana, where he found terracotta toys, an axe and chisel. While investigating these discoveries, a historian suggested that he try to locate rock paintings. As a result, for three years, he spent most of his time near rivers and boulders in the hope of locating rock paintings, but with no success. Not one to give up, he continued looking. Even in his dreams, it was always mountains and rock paintings that he envisioned. In one of … Read More

To access this post, you must purchase Annual subscription, 12 Month Subscription or Monthly subscription.

Geomodels in engineering: An introduction

Peter Fookes, Geoff Pettifer and Tony Waltham (UK) This article is based on the introduction to the newly published book Geomodels in Engineering Geology – An Introduction. What, why and when? The Earth is an active planet in a constant state of change. These changes can take place over both long and short periods of geological time (thousands or millions of years) or much more quickly on an engineering timescale (minutes, hours or days). Geological processes continually modify the Earth’s surface, destroying old rocks, creating new ones and adding to the complexity of ground conditions: the so-called ‘geological cycle’. The all-important concept that drives this geological plate tectonics. The benefits geologists bring to construction projects must exceed the cost of their services — that is, they must accurately improve the engineer’s ground knowledge more cheaply and effectively than any other method. They must reduce the risk of geological hazards by anticipating situations perhaps unseen by the engineers and also help to determine effective ways of dealing with risks and any problems arising during design and construction. The main role of the engineer geologist is to interpret the geology and ground correctly. Creating an initial model for the geology of the site is an excellent start. Geology (the study of the Earth) and its closest geo-relative, geomorphology (the study of the Earth’s surface), are concerned with changes over time and any geomodel has to build in any changes likely to occur in the near future, especially when the construction project may … Read More

To access this post, you must purchase Annual subscription, 12 Month Subscription or Monthly subscription.

Duria Antiquior: A nineteenth-century forerunner of palaeoart

Steven Wade Veatch (USA) Fig. 1. Duria Antiquior. A watercolour painted in 1830 by Henry De la Beche, who conjured up a vivid picture of an ancient world. It is now in the National Museum of Wales and another copy can be seen at the Sedgwick Museum in Cambridge. (Image is public domain.) In a breath of inspiration in 1830, English geologist, Henry De la Beche (1796–1855), while exploring new intellectual territories in the emerging fields of palaeontology, painted Duria Antiquior (meaning “a more ancient Dorset”), a representation of a prehistoric Dorset coast. De la Beche’s work was ground breaking – his artwork combined science and art in the first artistic rendering of a paleontological scene, while laying bare the secrets of the past. Before 1830, art depicting the prehistoric world did not exist and these realms were unknown to the public (Porter, n.d.). While it is true that scientists made drawings of fossil animals and exchanged them with each other in private letters, the public had no concept of how prehistoric animals looked. This painting opened people’s imagination to new visions, thoughts and beliefs. De la Beche’s painting also laid the foundation for a new genre that would later be known as palaeoart, an artistic genre that reconstructs prehistoric life according to the fossil record, scientific understanding and artistic imagination. De la Bache’s brushstrokes of prehistoric time included (literally) all the information known at that time about ancient life and soon became the first teaching graphic used in the … Read More

To access this post, you must purchase Annual subscription, 12 Month Subscription or Monthly subscription.

Concretions in sandstones of the Inner Hebrides, Scotland

Mark Wilkinson (UK) Concretions are a common feature in many sedimentary rocks, yet they seem sometimes to be misunderstood. So, how do concretions form? As well-studied examples, let’s look at the ones found in some of the sandstones of the Scottish Inner Hebrides, notably the islands of Eigg and Skye. The concretions are found in several formations, but perhaps the largest and most spectacular are in the Valtos Sandstone Formation of the Great Estuarine Group. This was originally named the Concretionary Sandstone Series after the prominent metre-scale concretions. It is Bathonian in age (Middle Jurassic) and is interpreted as having been deposited in a coastal environment. The Great Estuarine Group is becoming famous for its abundant dinosaur footprints and much rarer skeletal material. The concretions themselves vary from spherical to elongate volumes of rock and are typically from around 50cm to one metre or more in diameter. They are also often coalesced into groups (Fig. 1). Inside the concretions, the spaces between the sand grains are filled completely with a calcite cement. The concretions are resistant to weathering compared to the host sandstone, which is fairly soft, so stick out from the cliff in a sometimes rather alarming manner as you walk below them. I’ve been visiting the concretions sporadically for around 30 years and some of the ones that I photographed in the cliffs in the 1980s are now lying loose on the beach. None of them have fallen while I’ve been there, touch wood. Fig 1. Concretions on … Read More

To access this post, you must purchase Annual subscription, 12 Month Subscription or Monthly subscription.

Rudists: A fossil story

Jack Shimon (USA) This article is adapted from a presentation given at the Denver Gem Show, September 17, 2016 by me, Jack Shimon. When I was six and a half years old, my Grandpa took me fossil hunting in central Texas. We went to a Carboniferous Limestone quarry that he had visited earlier and was given permission to enter and collect from. This was one of my first fossil hunting trips and I really enjoyed it. The ancient reef we went to (now a quarry) had huge boulders of limestone and tube-like things in it we later to be found to be rudist bivalves. This article is all about these finds and the efforts we went to, to find out what they were. Fig 1. The author at the quarry. (Photo credit: Mike Hursey.) Fig. 2. This Google satellite image shows the reef we collected from. Two of the three lobes have been excavated for limestone. You can also see smaller pinnacle reefs marked with the short arrows. All of the reefs rise above the flat Texas landscape. (Permission from Google.com: ‘Special Use Guidelines’.)Fossils We spent a lot of time at the quarry observing the massive specimens onsite and then collected some smaller pieces to bring home and look at closer. A simple way of thinking about fossils is to consider them either as a cast or a mould. A mould is formed when an object is placed into a soft substrate and then decomposes or is washed away leaving … Read More

To access this post, you must purchase Annual subscription, 12 Month Subscription or Monthly subscription.

Collecting sharks’ teeth at Herne Bay, Kent

Les Lanham (UK) Just to the east of Herne Bay in Kent, on the way to Reculver at Beltinge, there is a small area on the foreshore where fossils of shark and other fish remains can be found on a good low tide. As this is a beach location, success will depend on good, local conditions but, if favourable, a good number of fossil teeth can be found. In fact, Beltinge is one of the best areas in Britain to collect such teeth and it is not unusual to find 20 to 30 persons on the beach on very low tides. Even so, everybody there could end up with a good haul of material by the end of the day. Fig. 1. Four keen geological groups meet for the annual extreme low tide event. I have set out directions at the end of this article detailing where to start your day. From this starting point, go as far out as the tide will let you and shark teeth can be found. Indeed, the chances of finding teeth improve the further out the tide goes. Broadly speaking, the collecting area is in the section of beach between the groynes either side of the concrete steps. Here, when the tide has gone out quite a distance, there appears to be a “stream” running out to sea. This is the junction between the clay beds to the west and the shingle to the east. Fig. 2. Thanet Beds exposed east of Herne Bay. … Read More

To access this post, you must purchase Annual subscription, 12 Month Subscription or Monthly subscription.

Important Green River Formation fossils come to New York

Stuart Wilensky and Douglas Miller (USA) In the early Eocene Epoch, drainage from the newly uplifted Rocky Mountains filled an inter-mountain basin to form what geologists call Fossil Lake. The climate of Fossil Lake was subtropical, similar to the climate of Florida today. The lake persisted for about two million years, and was home to palm trees, turtles, birds and an abundance of fish. On numerous occasions, unique conditions came together to result in some of the best-preserved fossils ever discovered. The sediments of Fossil Lake were first discovered in the 1860s, near the town of Green River Wyoming, and the area was named the “Green River Formation,” which is well-known in the scientific community and by amateur collectors. Palaeontologists have long theorised that the lake was deep enough to be anoxic (devoid of oxygen) at the bottom. This prevented scavengers from disturbing the plants and animals, and inhibited decomposition. Algae, and other plant and animal life, would die and fall to the bottom as in lakes and ponds today. Storms brought runoff from the mountains, covering the flora and fauna with mineral-rich material that would ensure their preservation. Recently, scientists have asserted that a kind of “red tide” may have been responsible for the many perfectly preserved fossils found. (“Red tide” is a common name for algal blooms, which are large concentrations of aquatic microorganisms, such as protozoans and unicellular algae. These can cause a severe decrease oxygen levels in the water column, leading to mass mortality events.) We … Read More

To access this post, you must purchase Annual subscription, 12 Month Subscription or Monthly subscription.

Extinction of the mammoth and the Clathrate Gun

Joanne Ballard and André Bijkerk (USA) In this article, we will argue that the extinction of megafauna on the mammoth steppes of the Northern Hemisphere may ultimately have been caused by the release of massive quantities of methane in the North Atlantic Ocean at the Amazon Fan near the Brazilian coast and also from the Ormen Lange gas field off the coast of Norway. We will suggest that these events caused significant changes in the flow of water at the surface of the ocean that, in turn, led to very rapid changes in the levels of rainfall. Scientists have already recognized that increased precipitation gave rise to changes to ecosystems (or, more precisely, to biotopes) that destroyed the mammoth steppe. However, much of the evidence we will use in this article to support our argument has been used to support other sorts of explanation for the extinction. Therefore, this primary evidence now appears to be in need of revision. Introduction About 11,000 years ago, all of the remaining herds of mammoths suddenly disappeared. During the Pleistocene, these mammoths once thrived on a vast, megafauna steppe stretching across the Northern Hemisphere. It may have resembled the African steppes of today with lions, hyenas and several species of large grazers being present. However, the debate about the cause(s) of the extinction continues. In North America, things appear to be simple – the appearance of early humans on that continent seems to coincide with the downfall of the megafauna. However, there are also … Read More

To access this post, you must purchase Annual subscription, 12 Month Subscription or Monthly subscription.

Urban geology: A failed example of gabions as false urban geology from the Netherlands

Stephen K Donovan (The Netherlands) The provinces of Noord and Zuid Holland, including much of the Dutch North Sea coast and adjacent inland areas, are devoid of rocky exposures. In a region of flat-lying Pleistocene siliciclastic successions (Burck et al, 1956), there are no quarries, cliffs or other man-made or natural exposures of lithified rocks. The topography is slight, with the highest natural structures being the coastal sand dunes, in part preserved as a national park (Jelgersma et al, 1970). To offset this lack of geological ‘furniture’, the Dutch have enterprisingly imported and installed sundry rocks that fill what may be an unattractive void in the environment. These rocks vary from the minimalist, such as roadside boulders (in part, possibly erratics) (Donovan, 2015), to reconstructions of structures such as a replica of a natural bridge in Mississippian limestone slabs (Donovan, 2014). But, in some instances, reconstructions are unsuccessful or, at least, inaccurate, such as the false (Pennsylvanian) Coal Measure strata without identifiable coal beds in the national railway museum (Het Spoorweg Museum) in Utrecht (Donovan, 2018a). In this article, I describe further mock geological structures that fail in the details. Gabions are tools of the engineering geologist. Yet, when packed with cobbles of imported, grey Mississippian limestone, they may make convincing false sedimentary ‘beds’, at least from a distance, and are a not uncommon feature of the environment of Noord and Zuid Holland (Donovan, 2018b). (Vertical, dyke-like structures are rarer and are less successful as false geology; Donovan, research in … Read More

To access this post, you must purchase Annual subscription, 12 Month Subscription or Monthly subscription.

Prominent figures of the 1800s who gave rise to vertebrate palaeontology

Megan Jacobs (UK) For centuries, the creatures of the past, from the terrifying theropod dinosaurs to the tiny early mammals, have captured the imaginations of millions. However, the people who put those beasts into the limelight are rarely acknowledged for their work and, in many cases, remain unknown. So here is a short account of some of the first prominent names in the world of vertebrate palaeontology, their contributions to the field, and an insight into the often eccentric behaviour that came with it. Georges Cuvier (1769-1832) Fig. 1. Georges Cuvier.Georges Cuvier was a French naturalist and zoologist, and is regarded as the ‘’father of palaeontology’’. He was one of the finest minds in history, founding vertebrate palaeontology as a scientific discipline. For example, in 1800, he identified Pterodactylus as the first known pterosaur from a print published by Alessandro Collini. Shortly after, he described the first mosasaur, a giant marine reptile that was brought to France by Napoleon after he conquered the Netherlands. Going against his old Christian (Catholic) upbringing, Cuvier believed the Earth was immensely old and, during its history, underwent abrupt changes that Cuvier called ‘revolutions’, in which large numbers of species were wiped out. This was the first recognition that extinctions were facts. Cuvier also rightly speculated that there had been a time where reptiles had been the dominant animals on the planet. Indeed, the decades after his death yielded spectacular finds that confirmed his theory. After a study comparing modern elephant species, he worked on … Read More

To access this post, you must purchase Annual subscription, 12 Month Subscription or Monthly subscription.

Mysteries of time: A quest for the age of the Earth

David Alexander Gardiner (UK) The question of the age of the Earth and its former inhabitants is one of great interest to us all. Most are aware that the Earth is understood today to be approximately 4.6 billion years in age, but what is the story of the momentous quest – to unravel the mystery of time? Many early speculations as to the age of the universe abounded in ancient and medieval times. We are all familiar with the literalist understanding of the Old Testament, from which Archbishop Ussher famously calculated a 4004 BC date for the beginnings of the Earth. Yet, this was one of the shortest chronologies in existence: the Babylonians spoke of many hundreds of thousands; the Egyptians of many tens of thousands; and the Hindus many billions of years in their cosmological speculations of the past. However, all these early traditions were not scientific in basis. Rather, they were religious or philosophical and not based upon experimentation and observation. It would not be until after the Renaissance that people started employing scientific methodologies to unravel the mystery. Various early scholars speculated upon the Earth’s geological history, including Leonardo da Vinci, the universal genius. Leonardo noted that fossils had once been actual living creatures and that the ocean must have once covered the land. As regards the age of the world, however, few people dared to challenge the conventional wisdom based upon the Genesis narrative – one wonders what da Vinci’s own view might have been. However, … Read More

To access this post, you must purchase Annual subscription, 12 Month Subscription or Monthly subscription.

Clarkia Flora: 16-million-year-old plants offer a window into the past

Margret Steinthorsdottir and Helen K Coxall (Sweden) Near the small town of Clarkia in Shoshone County, Idaho in the USA, exists a rich and unique fossil deposit. The Clarkia fossils, or Clarkia Flora, as the deposit is mostly called due to the abundance of fossil plants, is so well preserved that the assemblage is referred to as a “lagerstätte”, a scientific term reserved for the world’s very finest fossil deposits. The Clarkia fossils are found in sediments that are now known to be about 16 million years old and belong to a period in Earth history called the Miocene. By this time, the (non-avian) dinosaurs were long extinct (the last of these dinosaurs disappeared about 66 million years ago), the Earth’s continents were more or less in the same position as today, and many of the animals and plants would have started looking familiar to modern humans (who emerged much later, about 200,000 years ago). Fig. 1. The entrance to the “Fossil Bowl” motocross racetrack and fossil locality near Clarkia, Idaho. Among the Clarkia fossils can be found various insects, fish and occasionally the remains of small mammals. However, most striking is the wealth of plant fossils in the form of exceptionally well-preserved leaves, nuts, seeds and wood. Impressively, one can find leaves of oak, laurel, pine and birch that look virtually identical to those we find today. If you look quickly when a new fossil is newly exposed from within the host sediments, you may occasionally even see the … Read More

To access this post, you must purchase Annual subscription, 12 Month Subscription or Monthly subscription.

Geological transformation of Sharjah, United Arab Emirates

Khursheed Dinshaw (India) In this article, I will briefly deal with the fascinating and relatively recent geological transformation of the Sharjah region of the United Arab Emirates (UAE). Sharjah needs no introduction in terms of it being a popular tourist destination, especially for families. However, very few know how it was formed and subsequently transformed. In this article, I hope to explain this fascinating aspect of Sharjah. From the beginning At the beginning of the Miocene Period, 23 Ma, Arabia finally split from Africa along the Red Sea and the Gulf of Aden became a separate plate. This new plate moved in a northerly direction and collided with, and was subducted under, the Eurasian continent (Fig. 1). The Strait of Hormuz also closed as the remains of the Tethys Ocean formed a rapidly subsiding basin in which thick layers of salt were deposited. Large scale folding and faulting took place in the UAE producing hills of folded rock, such as Jebel Fai’yah and Jebel Hafit. Fig. 1. Granite from continental drift. In the eastern part of the UAE, uplift of the Al-Hazar Mountains began. This continued into the Pliocene Period, from 5 to 2 Ma. In the late Miocene and Pliocene, the Sharjah region finally rose above sea level and the landscape we see today was formed. Fig. 2. Various rock exhibits at the Sharjah Natural History and Botanical Museum. When the region known as Sharjah rose above sea level, it allowed the area to be covered by the moving … Read More

To access this post, you must purchase Annual subscription, 12 Month Subscription or Monthly subscription.

Carbonate platforms and coral reefs: The Coralline Oolite of the Yorkshire Upper Jurassic – a prime source of palaeontological information

Keith Eastwood (UK) The Malton Oolite Member of the Coralline Oolite Formation (Corallian Group), as exposed in the Betton Farm South Quarry (TA00158555) at East Ayton, near Scarborough (Fig. 1), provides a wealth of fascinating palaeontological and sedimentological information. Examination of outcrops within this small quarry enables the geologist to reconstruct the palaeoenvironment of deposition of the Betton Farm Coral Bed, a localised system of patch, ribbon and framework reefs that developed during the Upper Jurassic. Fig. 1. Locality map of the Betton Farm and Spikers Hill quarries. Geological outcrops from BGS Sheet 54 (Scarborough) (1998), (Wright, 2001, p.157, fig.4.20). Total image © Joint National Conservation Committee; geological outcrop map – British Geological Survey © NERC. Redrawn and reproduced with permission. The lithology and textural characteristics of the Malton Oolite Member provide a sedimentological basis for the interpretation, but the fossil content adds definitive ecological and climatic insights. The Malton Oolite is the upper of two oolite members in the Coralline Oolite Formation (Fig. 2). The lower one, the Hambleton Oolite Member, is not seen in the Betton Farm Quarries (which consist of two quarries: Betton Farm North Quarry and Betton Farm South Quarry, north and south of the A170, respectively) but is fully exposed in the Spikers Hill Quarry (SE 980863) just 3km to the WNW (Fig. 1). This location is important in providing a regional depositional context for the Betton Farm deposits, even though the upper surface of the intervening Middle Calcareous Grit Member is a minor unconformity. … Read More

To access this post, you must purchase Annual subscription, 12 Month Subscription or Monthly subscription.

Pale white dot

Steven Wade Veatch (USA) and Vishwam Sankaran (India) “There’s nothing new under the sun” goes a famous saying and these words are very apt when trying to understand Earth’s climate trends. Thanks to numerous discoveries made about Earth’s ancient past, we now know that our climate has never been static. According to geological and palaeontological records, climate change has affected the Earth throughout geologic time. In this context, this is the second of a series of articles about climate change over geological time. The first is A warming medieval climate supports a revolution in agriculture by Steven Wade Veatch and Cheryl Bibeau. To understand climate change today, researchers study past climates and events that affect climates, such as volcanic activity, solar radiation, sunspot activity, astronomical changes and other factors that influence climate. Once we understand the dominoes that have fallen during the past climate change events, we can understand and predict – to some degree – the kind of patterns that may follow current trends. To do this, scientists piece together clues from past climates provided by rock formations. Scientists likewise examine fossil records that yield climate signals from the past. These fossils range from prehistoric pollen to dinosaurs. Putting both geological and fossil records together reconstructs ancient climates and environments. More recent climate change is studied through climate records held in polar ice caps and ice sheets, ice cores, glaciers, isotopes of elements (like oxygen, carbon and sulphurfur), soil sediments and tree rings. When we think of the term … Read More

To access this post, you must purchase Annual subscription, 12 Month Subscription or Monthly subscription.

Carbon Capture and Storage (CCS): Using geology to fight climate change

Mark Wilkinson (UK) Practically everyone has an opinion on climate change by now, although for the vast majority of scientists, the weight of evidence is overwhelming – emissions of carbon dioxide and other greenhouse gases are causing climate change, sometimes referred to as global warming. One possible technology for fighting climate change is Carbon Capture and Storage (CCS) in which geology plays an important role. In fact, future generations of geologists may be employed searching for CO2 storage sites in the subsurface, rather than for the more traditional search for oil and gas. The aim of CCS is simple – to allow the continuing use of fossil fuels while reducing the emissions of greenhouse gases into the atmosphere. In the long term, the burning of fossil fuels will probably cease, but until we can rely on renewable sources of energy, we are stuck with these fuels as a cheap and reliable energy source. CO2 is emitted during many activities, including driving cars and heating homes, but the largest single sources are fossil fuel power plants, which generate electricity, followed by industries, such as steel works and cement plants. It is these that most research has been focussed on. And, in principle, the technology is simple – capture the CO2 from a source (such as a power plant; Fig. 1) before it gets into the atmosphere, then transport it to a suitable storage site and inject it into the ground where it will remain for tens of thousands of years. Fig. … Read More

To access this post, you must purchase Annual subscription, 12 Month Subscription or Monthly subscription.

Other mass extinctions

Neal Monks (UK) The extinctions at the Cretaceous-Tertiary (K/T) boundary make up what is probably the most famous geological event in popular culture. This is the point when the great reptiles that characterise the Mesozoic went extinct. Alongside the dinosaurs, the giant marine reptiles died out too, as did the pterosaurs, and a whole host of marine invertebrates, including the ammonites and belemnites. What happened? Some geologists argue the climate changed over a period of a million years or more, thanks to the massive volcanism that created the Deccan Traps in India. Others maintain that the K/T extinctions happened suddenly, pointing to evidence of a collision between the Earth and an asteroid. Perhaps there wasn’t a single cause, but rather a variety of factors: volcanism, climate change, asteroid impact, underlying changes in flora and fauna, and perhaps even variation in the output of the Sun and resulting weather patterns. That life on Earth can be wiped out this way is the stuff of disaster movies as much as TV documentaries. However, what comes as a surprise to many people is that there wasn’t just one mass extinction at the K/T boundary, but a whole series of them that can be observed throughout the fossil record. One of them, the Permo-Triassic extinctions, appear to have been even more catastrophic than the K/T extinctions, and at least three other extinction events are comparable in scale. In between these five big extinctions were lots of smaller extinctions that aren’t well studied, but had … Read More

To access this post, you must purchase Annual subscription, 12 Month Subscription or Monthly subscription.

Alternative view on climate change

Joe Shimmin (UK) Before you start shouting at your magazine, don’t worry, you’re not going to read that I think climate change isn’t happening or that human beings aren’t contributing to it. However, I am going to try to show that the version of climate change that we are always being shown may not be all that we should be thinking about. If you look at the timescale over which human-influenced climate change has been happening – and compare it with geological time – it is such a tiny period. However, people do not live over geological time periods, so it is natural that we concentrate on the present, with little regard for the past. In fact, with today’s human influenced climate change taking up all of the limelight, anyone would think that climate change was solely a human invention and that before the industrial revolution, the climate had been stable. But this is not the case. Fig. 1. A Map of Europe during the last glacial maximum. Blue areas are covered by ice. Green areas are land. White shows oceans and seas. In the event of a glaciation, could the influx of people migrating from the north be mitigated by the growth of the land masses due to a drop in sea level? Picture credit: Kentynet. A quick glance at Figs. 2 and 3 shows massive changes in average global temperature across the millions of years of geological time. The y axis of the graph shows change in average … Read More

To access this post, you must purchase Annual subscription, 12 Month Subscription or Monthly subscription.

History shows current climate change is normal

Tim Ball (Canada) Those who I refer to as ‘the new deniers’ keep trying to repair the infamous climate “hockey stick”. This is a term coined for a chart of temperature variation over the last 1,000 years, which suggests a recent sharp rise in temperature caused by human activities. The chart is relatively flat from the period AD 1000 to 1900, indicating that temperatures were relatively stable for this period of time. The flat part forms the stick’s ‘shaft’. However, after 1900, temperatures appear to shoot up, forming the hockey stick’s ‘blade’. Those who support the hockey stick focus on the blade, but it was not the major issue originally. The bulwark claim of the anthropogenic global warm (AGW) hypothesis and the objective of the stick are that current global annual average temperatures are the warmest ever. This meant that the upturn of the blade in the twentieth century was only relevant if it was higher and steeper than any previous record. Earlier warm periods were not a threat in the first reports of the Intergovernmental Panel on Climate Change (IPCC). Their mandate required that they only look at human causes, which they interpreted to mean the industrial period. However, as experts who were denied participation in the IPCC process began to examine what was said, they identified earlier warmer periods, especially the Medieval Warm Period (MWP) dating from 900AD to 1300AD, and more rapid temperature increases. Fig. 1. Temperatures for Europe plotted against the 20th century average. (Source: Based … Read More

To access this post, you must purchase Annual subscription, 12 Month Subscription or Monthly subscription.