This category can only be viewed by members. To view this category, sign up by purchasing Annual subscription, 12 Month Subscription or Monthly subscription.

From the wet clays of Peterborough to the sunny Caatinga of Brazil

David M Martill (UK) After several gruelling years of working in the sticky wet Jurassic clay pits of the Peterborough district for their gigantic marine reptiles and even more massive fishes, it was a refreshing change to fly south and investigate the sun-baked Caatinga of South America. The Chapada do Araripe, on the borders of the Brazilian states of Ceará, Pernambuco and Piaui, had always fascinated me (Fig. 1). Fig. 1a (left). A map showing the location of the Chapada do Araripe in the northeast of Brazil. Fig. 1b (above). Detail of the Chapada do Araripe. This is one of the most important sites in the world for Cretaceous Gondwanan fossil fauna and flora. I had seen specimens of the fabulous fossil fishes (I hope you like the alliteration) in limestone concretions (Fig. 2) that kept turning up in European fossil shops, but what had really caught my eye was a short letter to the scientific journal Nature that described fossil ostracods from those very same concretion horizons. Fig. 2. A typical concretion from the Santana Formation, with a not so typical fish. This is one of the rare fossil rays. I am not an aficionado of ostracods: who is? They mostly look like small baked beans, and it is so tedious trying to mount them on stubs so that you can see them under the electron microscope. No, it was the remarkable quality of their preservation that caught my eye. The specimens in question were described by Ray Bate, … Read More

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

Shear zones: Natural laboratories of rock deformation and mineral alteration

Robert Sturm (Austria) During the last few decades, the interest of diverse geosciences has increasingly focussed on the examination of so-called ‘shear zones’, because the displacements between two lithological blocks represent natural ‘laboratories’, within which the phenomena of mineral alteration and deformation are clearly shown for the purposes of scientific study. Many shear zones are only a few centimetres in size, meaning that their examination is relatively easy. Others, like the San Andreas Fault, have a width of several hundreds of metres, which requires a bit more effort to investigate (Fig. 1). Fig. 1. Some selected examples of shear zones with different dimensions: (a), (b) small-scale shear zones in the Zillertal/Austria, (c), (d) medium-scale shear zone in the Bohemian Massif/Austria, and (e) the San Andreas Fault. Shear zones – definitions and main characteristics Broadly speaking, along a shear zone, two lithological units – ranging in size from several square metres to the size of continentals – are displaced against each other. The movement has to be exclusively evaluated in terms of plate tectonics and often represents the cause of earthquakes. Depending on their orientation, three main types of shear zones can be distinguished (Fig. 2): The normal fault is characterised by the lowering of a lithological block with respect to its neighbouring tectonic unit. If the face of displacement between the two blocks has only a small angle of inclination, the shearing process is accompanied by crustal extension which is most impressively seen in the Rhinegraben and the East African … Read More

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

The “thick-shelled mussel” Pycnodonte (Phygraea) vesiculare: Germany’s “Fossil of the Year” 2017

Jens Lehmann (Germany) Thick-shelled oysters of the species Pycnodonte (Phygraea) vesiculare (Lamarck, 1806) are among the most common fossils of the late Cretaceous period of Europe. They are also known as “thick-shelled mussels” in the popular wisdom and the reason for this name is obvious when you have a look at a typical example (Fig. 1). Fig. 1. A large specimen of Pycnodonte (Phygraea) vesiculare, as typically occurring in the latest Cretaceous of Europe. From the Campanian of Haldem near Lemförde in Germany. This is an historically important specimen, because it belongs to the reference material of Arnold (1968) from this famous locality, which has produced many type specimens of fossils. GSUB L559. They can be seen in many museums, but, even more often, they are encountered during walks along the beaches under the chalk cliffs of England or around the Baltic Sea in continental Europe. A famous locality is the island of Rügen in Germany, where tourists can easily spot them (Fig. 2). Fig. 2. Collecting Pycnodonte from Late Cretaceous (early Maastrichtian) chalks is popular among tourists on the Isle of Rügen (Promoisel pit near Saßnitz) in northeastern Germany. (Photo by Martin Krogmann, 2014.) Therefore, it is not surprising that this extinct oyster species was selected as “Fossil of the Year” 2017 by the German Palaeontological Society (Paläontologische Gesellschaft) due to its ease of recognition (Kutscher 2017). Further reasons for the vote include its scientific and scientific-historical significance. This is the second time the society voted for a fossil … Read More

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

Hard work breaks no bones: A bone from the Wealden facies gets revealed

Jens Lehmann (Germany) The recent find of a big slab of Early Cretaceous lumachelle limestone of the Wealden facies containing a bone (Figs. 1 and 2) made for a time-consuming and technically ambitious preparation process. (Lumachelle limestone is a compact limestone or marble containing fragments of shells, encrinites and other fossils, which are sometimes iridescent, and display a variety of brilliant colours.) The specimen looked disappointing at first sight, but the end result made the hard work worthwhile, as I discuss below. Indeed, the following is intended as an example of the technical aspects of palaeontology, which are too often forgotten or ignored. The specimen was discovered in a loose, but very heavy slab on the beach. Therefore, efforts were made to reduce the size of the rock in the field to make it easier to carry, but, unfortunately, it broke into two pieces (Figs. 1 and 2). Fig. 1. A bone in a limestone from the Early Cretaceous (Barremian, Wealden facies), broken while preparing the slab in the field. Fig. 2. Reverse side of the limestone slab, with masses of freshwater bivalves making up most of the boulder. The original surface of the bone was completely worn – with no details preserved (Fig. 3A) and therefore a transfer preparation had to be planned. On the other side, the cross section (Fig. 3B) gave me a pretty good idea of the shape of the bone before preparation and the exact thickness of the rock that would have to be removed … Read More

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

Fabulous folds: Variscan tectonics in southwest England

Jens Lehmann (Germany) Plate tectonics drove the continent-continent collision of Euramerica and Gondwana, roughly 280 to 380mya. This mountain-building phase of the late Palaeozoic era is referred to as the Variscan Orogeny and eventually formed the supercontinent Pangaea. This was largely complete by the end of the Carboniferous and many of today’s secondary mountains in Europe are ascribed to the Variscan phase. In the UK, this event formed a couple of spectacular places for geotourism at the boundary between Devon and Cornwall. When visiting southwest England, you should not miss these spots – they are surely among the most impressive places in the world showing the effects of tectonics. A tiny settlement but tremendous in geology A tiny settlement on Cornwall’s coast gives the name for surely the most famous spot for folded sedimentary rocks in the UK – Millook Haven. A narrow, winding road leads down the hillside, with a gradient of 30° (Fig. 1). Fig. 1. At the top of the winding road down to Millook Haven. But, after surviving the journey downhill, you are rewarded by a cliff with spectacularly folded Carboniferous sediments (Fig. 2). Fig. 2. A group of geology students visiting the spectacular Millook Haven cliffs. On a global scale, coal swamps are typical of the late Carboniferous period. However, in Cornwall and Devon, no economically viable coal was deposited. In southwest England, alternating sand- and claystones, which had been transported by submarine currents with material mainly in suspension, were formed in an environment far … Read More

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

Ammonites of the Ampthill Clay, Lincolnshire

John P Green (UK) The Ampthill Clay Formation of the UK, of Late Jurassic (Oxfordian) age, represents a series of highly fossiliferous marine mudstones that form part of the Ancholme Clay Group in North Lincolnshire (Gaunt et al, 1992); but are almost unexposed in the county other than at an excellent exposure of the Ringsteadia pseudocordata zone at South Ferriby Quarry (SE 992204). Therefore, this shortage of natural exposures means that any information, which can be obtained from other exposures in this county, is of the utmost significance. Minor stream exposures at Kingerby Beck, North Owersby in North Lincolnshire (TF 0519 9340) have revealed a rich and well-preserved fossil fauna. These minor exposures have been placed by Gaunt et al (1992) within the Amoeboceras glosense zone, therefore lying at a differing stratigraphical horizon to the South Ferriby Quarry. Also, in contrast to the latter locality, the fossils exhibit a much higher degree of preservation and are therefore easier to collect. Fig. 1. Kingerby Beck, North Owersby. Minor exposures of the Jurassic Ampthill Clay. Unfortunately, biostratigraphical bed-by-bed collecting is largely impractical at Kingerby Beck, due mainly to the very minor nature of the exposures; indeed, the majority of fossils have been collected from patches of clay exposed on the stream bed. The Ampthill Clay Formation, where exposed, is present as undifferentiated pale grey mudstones, with scattered calcareous concretions. It is these that are the major source of the prolific and well-preserved fossil faunas, particularly ammonites. Some of these concretions are very … Read More

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

The geology and fossils of the Burnham Chalk Formation (Upper Cretaceous, Upper Turonian stage) of North Ormsby, Lincolnshire

John P Green (UK) The large, disused quarry at North Ormsby [O.S. grid ref. TF2893], north of Louth in Lincolnshire, displays an important sequence of beds of the Burnham Chalk Formation (Upper Cretaceous, Upper Turonian stage) and, at present, constitutes the best exposure of the beds in the county. Similar beds exposed at Ulceby Vale Pit [TA104133] in North Lincolnshire have described in terms of both stratigraphy and palaeontology, by Wood (1992) and, more recently, by Hildreth (1999, and in press). Fig. 1. North Ormsby disused quarry; an important sequence of beds of the Burnham Chalk Formation. The North Ormsby section was measured and described in stratigraphical terms by Wood and Smith (1978), although little information on the macrofauna was published. Hill (1902) was the first to identify the S. plana biozone of the Burnham Chalk Formation in this area, and Rowe (1929) provided an admirable macrofaunal list in his account. Therefore, my aim is to build on the work of previous authors, and place the recorded macrofossils in a stratigraphical context. In addition, Wood and Smith (1978) established important flint and marl marker horizons for the chalk of Lincolnshire and Yorkshire, and these shall be referred to in this account. Fig. 2. Closeup of the Burnham Chalk Formation. The Burnham Chalk, as exposed at this locality, consists in general terms of thick bedded chalk, interbedded with marl seams and marl layers, and beds of predominantly tabular and semi-tabular flint bands. About halfway up the sequence, above the level of … Read More

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

Book review: Geology of south Dorset and south-east Devon and its World Heritage Coast, The British Geological Survey

I don’t normally review BGS memoirs – they are excellent publications, but largely written for the professional or the seriously committed amateur geologist. (I have to admit to owning several, which cover my favourite fossil collecting areas of the UK.) However, this is one ‘Special Memoir’ that I am quite willing to make an exception for.

Ammonites and belemnites from the Early Cretaceous Claxby Ironstone formation of Nettleton Hill

John P Green (UK) The Early Cretaceous succession in Lincolnshire consists of a series of shallow water marine sandstones, ironstones, clays and limestones, not unlike those deposited elsewhere in the UK during early Jurassic times. In the north of the county, at Nettleton Hill, near the village of Nettleton, minor exposures of the Claxby Ironstone Formation are present. Fig. 1. Nettleton Hill, showing former site of workings for Spilsby Sandstone and the overlying Claxby Ironstone, now restored. This deposit, approximately 5.7m thick, rests unconformably on the eroded Late Jurassic Spilsby Sandstone Formation of Volgian age. The age of the ironstone ranges from the Lower Valanginian to the Lower Hauterivian stage, and is of particular interest due to the ammonite and belemnite faunas it contains. My studies over a number of years have brought to light a series of cephalopod faunas that are also prevalent in Speeton, East Yorkshire, as well as northern and southern Europe. Prominent contributors to the study of the cephalopod faunas of this formation include Lamplugh (1918), Swinnerton (1935), Casey (1973), Wright (1975) and Kemper et al (1981). The ironstone is divided into two members: the Lower and Upper Claxby Ironstone Formations. Both these formations are characterised by a brown to purple clay matrix, rich in prominent iron ooliths, and which is highly fossiliferous. Excellent exposures were formerly present in opencast and deep mines around Nettleton (TF 1140 9868, TF 1164 9870). However, these sections are now unfortunately filled in. The current exposures at Nettleton Hill, while … Read More

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

Tauern gold: The history of gold mining in the Central Alps

Dr Robert Sturm (Austria) Exploitation of gold deposits in the Hohe Tauern, in the Central Alps of Austria, has a long history: occurrences of this noble metal were explored for the first time about 2,000 years ago. Since the fourteenth century, the search for gold has been conducted on an industrial level, resulting in the production of 130km of tunnels and shafts, with the main centres of medieval gold production being the Gastein Valley, Rauris, Heiligenblut, Fusch and, later on, Schellgaden. In the second half of the fifteenth century, all of the gold found in the Central Alps was sold to Venice, but from the year 1501, the noble metal was exclusively used for indigenous minting and, therefore, all gold mines came under the archbishop’s control. Fig. 1. Map showing the position of the Hohe Tauern National Park (green) in Austria and the main locations of historical and current gold exploration. The economic zenith of gold exploitation in the Central Alps was reached in the middle of the sixteenth century. At this time, three families – the Weitmosers, Zolts and Strassers – dominated the mining industry in the Gastein Valley and in Rauris. In 1557, 830kg of gold (corresponding to about 27,000 ounces) and 2,723kg of silver were hauled from the mines. However, 50 years later, gold mining ceased completely. The main reason for this economic collapse was the total exhaustion of all lodes of ore that had been exploited in the Hohe Tauern until that time. Furthermore, only ‘visible’ … Read More

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

Skye: Island of Dreams

Anthony Rybek (UK) Having lived on the Isle of Skye since 2007, I consider myself to be very fortunate to have every day opportunities to fulfil my hunger for the wilderness, natural world and two of my greatest passions, fossil hunting and geology. So, it was of no surprise to me that, during these times immersed in this dramatic and mostly unspoiled landscape, yet another passion would evolve – oil painting. Fig. 1. Anthony Rybek, working on a painting. Like all my pursuits, I am self-taught and, as I began to learn and practice painting techniques, it soon became clear that I had a degree of aptitude for this art form. I found it similar to my earliest fossil hunting trips where, once I tasted success and the thrill of discovering new and amazing fossils, the desire to learn more and improve my skills grew deeper and deeper. My painting is no different. It wouldn’t take long before the subject matter for my landscape paintings would cross paths with fossil hunts and geology. Skye has an abundance of iconic geological landmarks and I feel privileged to have a basic understanding of the geological processes that help shape these formations. And it is these dramatic scenes that are the main influence of many of my paintings. The Trotternish Ridge In the northern half of Skye, this is the dominant feature of the Trotternish Ridge, which runs like the spine of an ancient creature between the islands capital Portree and the infamous … Read More

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

Book review: Geology of the Jurassic Coast: The Red Coast Revealed – Exmouth to Lyme Regis, by Richard A Edwards; and Geology of the Jurassic Coast: The Isle of Purbeck – Weymouth to Studland, by Paul Ensom and Malcolm Turner

The Jurassic Coast Trust is certainly producing some good books these days. I have alraedy reviewed one (The Jurassic Coast: An Aerial Journey through time by Peter Sills) and I think these two might even be better. As is well known, in recognition of its wonderful geology, the coast between Orcombe Rocks in southeast Devon and Old Harry Rocks in south Dorset was granted World Heritage status in December 2001.

Siwalik Fossil Park, Himachal Pradesh State, India: Part 2

Khursheed Dinshaw (India) In the first part of this article (see Siwalik Fossil Park, Himachal Pradesh State, India: Part 2), I introduced Siwalik Fossil Park, its geology and some of the animals and plants whose fossilised remains have been found there. In this second and last part, I cover some more of the mega fauna that once lived here. In fact, the Siwalik Fossil Park, in the state of Himachal Pradesh, India is a significant step towards the preservation of prehistoric animal sites, conserving and repairing the current natural environment and utilising them for scientific and educational purposes. In fact, the park is a rich geological heritage. The environment and climate was highly favourable for the development of elephants in the Siwalik region between 20 and 1.5mya (Figs. 1 and 2). Approximately 22 fossil species have been found, but all became extinct one million years ago with the beginning of the Ice Age. Fig. 1. The section displaying elephant fossils. Fig. 2. The proximal end of an elephant’s femur, which became extinct 1myrs ago at the beginning of the ice age. Nowadays, only one species is found in India (the Indian elephant, Elephas maximus indicus). The fossil skulls, jaws, teeth and bones of extinct species are displayed at the museum along with a life-size fibre glass model of the extinct giant species, Stegodon ganesa (Figs. 3 and 4). Fig. 3. The cranium of Stegodon insignis, which existed during the Plio-Pleistocene period. Of the species that existed during the Plio-Pleistocene period, … Read More

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

Plenty of geological fun at Cornwallis’ Cave

Deborah Painter (USA) Cornwallis’ Cave, a feature along the bluffs overlooking the York River in historic Yorktown, Virginia in the USA, is not a real cave and may not even have sheltered British General Charles Cornwallis during the final weeks of the American War of Independence. The National Park Service, which oversees the feature, has little historical evidence that Cornwallis ever used it as a meeting place or as shelter. He probably used a bunker located elsewhere along the river. It is one of the United States’ best-known man-made ‘caves’ and, though composed of Pliocene epoch coquina – a type of sandstone composed mainly of fossil shells – it is unrelated to actual karst features in the area. This feature is a cultural resource that contains holes carved in the stone cave walls for wooden beams to enable storage of supplies during the later American Civil War and is part of the Colonial National Historical Park encompassing many hectares. The cultural history Cornwallis’ Cave is approximately 12.19m in length. It has been sealed off partially by the National Park Service and one can only enter approximately a meter into the cave and view its interior through a wrought iron gate. Were it not for the historic value of the feature and its proximity to the site of testing of mid-nineteenth century hot air balloon warfare, the ‘cave’ might have been levelled long ago. Thankfully, it has not. It is rich in fictional lore, including its reputation for ghosts. A regular … Read More

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

Siwalik Fossil Park, Himachal Pradesh State, India: Part 1

Khursheed Dinshaw (India) The Siwalik Fossil Park is located amidst the scenic Siwalik Hills in the district of Sirmaur in the state of Himachal Pradesh, India. On 23 March 1974, the park was established by the Geological Survey of India in collaboration with the Himachal Pradesh Government. It contains many life-size, fibreglass models. These models are outside in the park and are based on the study of the fossils that have been found here and a field museum. The models are of prehistoric animals, which thrived in the area from to 1 to 2.5mya. The museum displays Siwalik vertebrates collected from the area. A catalogue of all the fossils and specimens displayed in the museum has now been documented providing their photographs, taxonomic status and locality, along with collectors’ names and the field season during which they were collected. Fig. 1. Fossil wood found in Siwalik, where a prehistoric animal site is being preserved. The Siwalik rocks are famous the world over for the remains of various vertebrate animals and plants. There are varied geological formations of the park, like the Jarasi, Spiti and Giumal Formations. The Jarasi consists of red purple shale with gypsum bands and are Neo-proterozoic to Ediacaran in age. Fig. 2. This rock from the jarasi formation is neo-proterozoic to ediacaran in age. The Spiti Formation is one which has fossiliferous shale containing ammonites, belemnites, bivalves and brachiopods. Its broad age is Oxfordian to early Valanginian. The Guimal Formation has fossiliferous sandstone with shells and it … Read More

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

Historically important unconformities in Scotland and Northern England

Mark Wilkinson (UK) Scotland has a number of sites of historical interest to geologists. I described one of these, Hutton’s Unconformity at Siccar Point near Edinburgh (see Hutton’s unconformity and the birth of ‘Deep Time’). James Hutton described several Scottish unconformities in his book of 1795 and, while the one at Siccar Point is easily the most dramatic and most easily accessible, there is another unconformity on the Isle of Arran that is well worth a visit if you are on the island. There is a third unconformity in the Scottish Borders that is sufficiently well known to be actually called ‘Hutton’s Unconformity’, but is on private land and is thought to be presently inaccessible. There are also a number of other locations that Hutton described, but which have sunk in the mists of time back into obscurity. It would make an interesting project to resurrect these. It was on the Isle of Arran that Hutton first observed an actual unconformity surface, in 1787. Arran is the seventh largest Scottish Island at around 32km long, lying in the Firth of Clyde some 64km to the southwest of Glasgow. Sometimes described as ‘Scotland in miniature’ due to the range of scenery, Arran has both highland and lowland landscapes. This is because the varied scenery reflects the underlying geology, with rocks typical of the Highlands of Scotland, and the lowlands. There is a good range of sedimentary, igneous and metamorphic rocks, many of which have well-exposed field relationships, as well as areas … Read More

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

Plant macrofossils and palaeoclimates

Jack Wilkin (UK) Palaeoclimatology is the study of past climates and environments using climate proxies, that is, the preserved physical characteristics of past, rather than using direct measurements of variables, such as temperature, levels of CO2 and so on. Many different types of proxies are used including, but not limited to, ice cores (Petit et al., 1999), lake and ocean sediments (Cehn et al., 1999), and fossil data. Many fossil groups have specific environmental and ecological tolerances and so can be used to determine palaeotemperatures and palaeoclimates (Jones, 2006). It is the data collected using dendroclimatology and other plant macrofossils that will be examined in this article. Dendroclimatology Dendroclimatology is the use of tree rings to determine long-term climatic trends. This is in contrast to dendrochronology, which is dating using tree ring data. Dendroclimatology is used extensity to study the climate during the Holocene (Fig. 1) but has also been applied to the Late Cretaceous of Alaska and even the Permian of Antarctica (Taylor et al., 2009). The thickness of the tree rings helps scientists work out how much the trees had grown within a given year. Then, by comparing the rate of growth to members of the same, or closely related, genera or species, they can determine the palaeoenvironment. Fig. 1. Variations in tree ring width translated into summer temperature anomalies for the last 7,000 years, based on samples from Siberia. Source: Institute of Plant and Animal Ecology https://upload.wikimedia.org/wikipedia/commons/5/53/Yamal50.gif. Dendroclimatology can also be used to gather isotopic data. As … Read More

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

Along the Chain of Craters Road, Big Island, Hawaii: Part 5

Dr Trevor and Chris Watts (UK) This is the last of five articles on the ‘Chain of Craters Road’ on Hawaii’ Big Island. The articles are in the form of a road trip that you can follow if you are lucky enough to go to this wonderful part of the world to see its volcanic scenery. Being a road trip in the USA, distances along the road and by foot are given in yards and miles, while measurements are provided in more European and scientific metric units. Hawaiian pronunciationA word about Hawaiian pronunciation – Hawaiians do not say ‘Morna Ulu’ for the Mauna Ulu volcano. They split most vowels up separately: thus, ‘Mah ooner Oo loo’. Similarly, ‘Kill ow eh uh’, for Kilauea; and, ‘Halley mah oomer oo’, not ‘Halley mow mow’, for Halema‘uma‘u; and, ‘Poo ooh Poo ah I’, for Pu’u Pua’i.3.7 miles: the pahoehoe flow Adjacent to the road, this is a wide-spreading series of flows dating mainly from 1969 to 1974, from Mauna Ulu. In the southern part, the lavas also originate from the smaller volcano of Mauna Loa o Mauna Ulu. These are varied, but mainly formed as thin, smooth sheets. They were often broken up after solidifying by being pushed upwards into low mounds by fresh lava invading beneath them and also by the lava beneath them draining away, causing the thin skin to collapse. The forest that existed here is now seen as tree moulds. These are generally in an excellent, fresh condition, and … Read More

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

Along the Chain of Craters Road, Big Island, Hawaii: Part 4

Dr Trevor and Chris Watts (UK) This is the fourth of five articles on the ‘Chain of Craters Road’ on Hawaii’ Big Island. The articles are in the form of a road trip that you can follow if you are lucky enough to go to this wonderful part of the world to see its volcanic scenery. Being a road trip in the USA, distances along the road and by foot are given in yards and miles, while measurements are provided in more European and scientific metric units. Hawaiian pronunciationA word about Hawaiian pronunciation – Hawaiians do not say ‘Morna Ulu’ for the Mauna Ulu volcano. They split most vowels up separately: thus, ‘Mah ooner Oo loo’. Similarly, ‘Kill ow eh uh’, for Kilauea; and, ‘Halley mah oomer oo’, not ‘Halley mow mow’, for Halema‘uma‘u; and, ‘Poo ooh Poo ah I’, for Pu’u Pua’i.3.7 miles: Mauna Ulu A short road to the east finishes in a large car park. The trail continues eastwards through the woodland (Fig. 1) for a few hundred yards until it opens out to a view of the twin peaks of nearby Pu’u Huluhulu and the more distant, and much higher, Mauna Ulu (Fig. 2). Fig. 1. A side trail into the forest close to Mauna Ulu car park. Fig. 2. Where the trail divides left and right. The dark a’a lava spreads across the lighter ash and lapilli flow. The twin peaks form Mount Pu’u Huluhulu; the more distant low rise is the shield volcano, Mauna … Read More

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

Along the Chain of Craters Road, Big Island, Hawaii: Part 3

Dr Trevor and Chris Watts (UK) This is the third of five articles on the ‘Chain of Craters Road’ on Hawaii’s Big Island. The articles are in the form of a road trip that you can follow if you are lucky enough to go to this wonderful part of the world to see its volcanic scenery. Being a road trip in the USA, distances along the road and by foot are given in yards and miles, while measurements are provided in more European and scientific metric units. Hawaiian pronunciationA word about Hawaiian pronunciation – Hawaiians do not say ‘Morna Ulu’ for the Mauna Ulu volcano. They split most vowels up separately: thus, ‘Mah ooner Oo loo’. Similarly: ‘Kill ow eh uh’, for Kilauea; and, ‘Halley mah oomer oo’, not ‘Halley mow mow’, for Halema‘uma‘u; and, ‘Poo ooh Poo ah I’, for Pu’u Pua’i.2.6 miles: the Hi’iaka lava field and lava tree forest This is just across the road from the Hi’iaka Crater and is the later (May 1973) lava flow. It is very extensive and is little explored beyond the first 100 yards from the road. Before the eruption, there was a forest here, mainly of ʻŌhiʻa trees, but, on 5 May 1973, a series of fissures opened up and vast amounts of lava gushed forth (Fig. 1). Spreading over several miles, it devasted the forest, filled several former collapse craters, became ponded up at the Koa’e Fault cliff, and flowed away. It drained back almost to the original surface … Read More

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

Along the Chain of Craters Road, Big Island, Hawaii: Part 2

Dr Trevor and Chris Watts (UK) This is the second of five articles on the ‘Chain of Craters Road’ on Hawaii’s Big Island. The articles are in the form of a road trip that you can follow if you are lucky enough to go to this wonderful part of the world to see its volcanic scenery. Being a road trip in the USA, distances along the road and by foot are given in yards and miles, while measurements are provided in more European and scientific metric units. Hawaiian pronunciationA word about Hawaiian pronunciation – Hawaiians do not say ‘Morna Ulu’ for the Mauna Ulu volcano. They split most vowels up separately: thus, ‘Mah ooner Oo loo’.Similarly: ‘Kill ow eh uh’, for Kilauea; and, ‘Halley mah oomer oo’, not ‘Halley mow mow’, for Halema‘uma‘u; and, ‘Poo ooh Poo ah i’, for Pu’u Pua’i.Down the Chain of Craters Road 0.3 miles: the July 1974 flow This flow, which was mostly pahoehoe lava, covered several hectares. It came from the nearby cone of Ma’una Ulu, a subsidiary cone of Kilauea. The eruption began in May 1969 and lasted until July 1974. It featured many periods of spectacular fire fountains, including one that reached 300m high on 30 December 1969 (Fig. 1). Fig. 1. Mauna Ula fire fountain 1968. (Source: USGS.) Spreading as far as the sea, it added 94 hectares of new land to Big Island – more than 230 hectares. In addition to spreading across the surface, much lava sank, returning into … Read More

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

Along the Chain of Craters Road, Big Island, Hawaii: Part 1

Dr Trevor and Chris Watts (UK) This is the first of five articles on the ‘Chain of Craters Road’ on Hawaii’s Big Island. The articles are in the form of a road trip that you can follow if you are lucky enough to go to this wonderful part of the world to see its volcanic scenery. Being a road trip in the USA, distances along the road and by foot are given in yards and miles, while measurements are provided in more European and scientific metric units. Introduction Kilauea volcano dominates the southeast of Hawaii’s Big Island. At 1,247m high, it is by no means the biggest or highest of Hawaii’s peaks, but it is easily the most active. It doesn’t have a peak. Instead, there is a caldera – a huge, oval-shaped collapse crater that formed 500 years ago in the space of a few days – perhaps a few hours. It now measures about 5km long by 3km wide, and is 165m deep (Fig. 1). Fig. 1. Regional sketch of Kilauea’s caldera and the Chain of Craters Road. Its appearance and dimensions have changed considerably over the years as different parts of the caldera have erupted at different times and in different ways. The most spectacular event in the past century was the 600m-high, fire-fountain episode in 1959, which filled the caldera floor with a lava lake and created the ‘side caldera’ of Kilauea Iki. The main eruptive point now is the fire pit known as Halema‘uma‘u that … Read More

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

The Geologists’ Association: An overview

Diana Clements (UK) The Geologists’ Association (GA) was formed in 1858 and, from its inception, was an inclusive organisation set up to embrace both professional and amateur geologists, unlike the Geological Society, some 50 years older, which was only intended for professionals. Women were accepted from the beginning – similar organisations of the time were habitually men only. It was intended as a meeting-place for like-minded people and fieldtrips were always an important part of the Associations’ activities. As early as 1895, Local Groups around the country were set up to extend activities nationwide; now we have 17 Local Groups with a further 72 other geologically-related societies that are affiliated with the GA. The aims that we adhere to now were developed gradually and foremost among them is to make geology available to a wider public. The Proceedings of the Geologists’ Association first appeared in 1859, only a year after its formation, and included written papers presented first to members at the Friday lectures and the write-ups from the early fieldtrips. These are often important historical documents of geology in a bygone age, no longer visible, particularly in urban environments. Fig. 1(a) A fieldtrip to Gilbert’s Pit, Charlton in 1913, when the quarry was operating. Fig. 1(b) The same face in 2016, with steps erected to view the remaining exposure of geological interest. As well as the images in the write-ups, the GA possesses a large archive of photographs and associated ephemera documenting the activities of the Association since the … Read More

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

Book review: Hutton’s Arse: 3 billion years of extraordinary geology in Scotland’s Northern Highlands (2nd edition), by Malcolm Rider and Peter Harrison

If you can see past the somewhat robust title (a reference to James Hutton’s discomfort riding around Scotland on horseback during his geological investigations), this is an interesting read, combining both geological science and humour in just about the right measures.

Peñon de Ilfach: Did it jump or was it pushed?

Mark Wilkinson (UK) The Spanish coastal town of Calpe is dominated by the towering massif of the Peñon de Ilfach (Fig. 1). The 332m, steep-sided summit is surrounded by the Mediterranean Sea on three sides and connected to the land by a relatively narrow neck, rather like a gigantic sea stack. Unless you are prepared to do some serious rock climbing, the summit is accessible only through a tunnel bored for the purpose, complete with rope hand-rails. The half-hour walk to the summit, through a small nature reserve and visitors centre, gives fantastic views of the surrounding coast and mountains. Fig. 1. The Peñon de Ilfach with Calpe in the foreground. Tower blocks for scale. To the geologically minded, the Peñon offers another aspect. It gleams white in the Mediterranean sunshine, so it’s not too difficult to guess that it is made of limestone. But bedding is quite tricky to spot, especially from a distance. I’ve often wondered as to how such an isolated feature came to be there – and why is the bedding so hard to see? It was almost a relief to purchase the Geologists Association guide to the area and discover that “even experienced geologists may find the bedding hard to locate”. Phew, it’s not just me then! And how did the Peñon come to be so isolated from the other limestone hills in the area, the nearest of which is several kilometres away? Was there a massive sheet of limestone, which has simply been eroded … Read More

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