STROMATOLITES IN CROSS SECTION

Stromatolites are a major constituent of the fossil record of the first forms of life on earth. They peaked about 1.25 billion years ago and subsequently declined in abundance and diversity so that by the start of the Cambrian they had fallen to 20% of their peak. 

The most widely supported explanation is that stromatolite builders fell victim to grazing creatures — the Cambrian substrate revolution — implying that complex organisms were common over a billion years ago. Another possible culprit are the protozoans. It is possible that foraminifera were responsible for the decline.

Proterozoic stromatolite microfossils (preserved by permineralization in silica) include cyanobacteria and possibly some forms of the eukaryote chlorophytes — green algae. One genus of stromatolite very common in the geologic record is Collenia.

The connection between grazer and stromatolite abundance is well documented in the younger Ordovician evolutionary radiation; stromatolite abundance also increased after the end-Ordovician and end-Permian extinctions decimated marine animals, falling back to earlier levels as marine animals recovered. Fluctuations in metazoan population and diversity may not have been the only factor in the reduction in stromatolite abundance. Factors such as the chemistry of the environment may have been responsible for changes.

WEE BABY FOSSIL OCTOPUS

Look at this adorable one! It is a wee baby fossil octopus. This specimen is a particularly exquisite example of Keuppia levante, an extinct genus of octopus that swam our ancient seas. 

Keuppia is in the family Palaeoctopodidae and one of the earliest representatives of the order Octopoda. These marine cuties are in the class Cephalopoda making them relatives of our modern squid and cuttlefish.

There are two species of Keuppia — Keuppia hyperbolaris and Keuppia levante — both of which we find as fossils. We find their remains, along with those of the genus Styletoctopus, in Cretaceous-age Hâqel and Hjoula localities in Lebanon. 

For many years, Palaeoctopus newboldi (Woodward, 1896) from the Santonian limestones at Sâhel Aalma, Lebanon, was the only known pre‐Cenozoic coleoid cephalopod believed to have an unambiguous stem‐lineage representative of Octobrachia Fioroni. 

With the unearthing of some extraordinary specimens with exquisite soft‐part preservation in the Lebanon limestones, our understanding of ancient octopus morphology has blossomed. 

The specimens are from the sub‐lithographical limestones of Hâqel and Hâdjoula, in north‐west Lebanon. These localities are about 15 km apart, 45 km away from Beirut and 15 km away from the coastal city of Jbail. The cutie you see here was collected earlier this year & is about 5 cm long.

STROMATOLITES: RECORDS OF ANCIENT LIFE

Stromatolites are layered mounds, columns, and sheet-like sedimentary rocks that were originally formed by the growth of layer upon layer of cyanobacteria, a single-celled photosynthesizing microbe.

Fossilized stromatolites provide records of ancient life on Earth. Lichen stromatolites are a proposed mechanism of formation of some kinds of layered rock structure that are formed above water, where rock meets air, by repeated colonization of the rock by endolithic lichens.

Stromatolites are layered biochemical accretionary structures formed in shallow water by the trapping, binding and cementation of sedimentary grains by biofilms — microbial mats — of microorganisms, especially cyanobacteria. They exhibit a variety of forms and structures, or morphologies, including conical, stratiform, branching, domal, and columnar types. Stromatolites occur widely in the fossil record of the Precambrian, the earliest part of Earth's history, but are rare today. 

Very few ancient stromatolites contain fossilized microbes. While features of some stromatolites are suggestive of biological activity, others possess features that are more consistent with abiotic (non-biological) precipitation. Finding reliable ways to distinguish between biologically formed and abiotic stromatolites is an active area of research in geology. 

Some Archean rock formations show macroscopic similarity to modern microbial structures, leading to the inference that these structures represent evidence of ancient life, namely stromatolites. However, others regard these patterns as being due to natural material deposition or some other abiogenic mechanism. Scientists have argued for a biological origin of stromatolites due to the presence of organic globule clusters within the thin layers of the stromatolites, of aragonite nanocrystals — both features of current stromatolites — and because of the persistence of an inferred biological signal through changing environmental circumstances.

NEUTRINOS AND PRECIOUS METALS

Deep inside the largest and deepest gold mine in North America scientists are looking for dark matter particles and neutrinos instead of precious metals.

The Homestake Gold Mine in Lawrence County, South Dakota was a going concern from about 1876 to 2001.

The mine produced more than forty million troy ounces of gold in its one hundred and twenty-five-year history, dating back to the beginnings of the Black Hills Gold Rush. 

To give its humble beginnings a bit of context, Homestake was started in the days of miners hauling loads of ore via horse and mule and the battles of the Great Sioux War. Folk moved about via horse-drawn buggies and Alexander Graham Bell had just made his first successful telephone call. Wyatt Earp was working in Dodge City, Kansas (he had yet to get the heck outta Dodge) and Mark Twain was in the throes of publishing “The Adventures of Tom Sawyer.”  — Ooh, and Thomas Edison had just opened his first industrial research lab in Menlo Park.

The mine is part of the Homestake Formation, an Early Proterozoic layer of iron carbonate and iron silicate that produces auriferous greenschist gold. What does all that geeky goodness mean? If you were a gold miner it would be music to your ears. They ground down that schist to get the glorious good stuff and made a tiny wee sum doing so. But then gold prices levelled off — from 1997 ($287.05) to 2001 ($276.50) — and rumblings from the owners started to grow. They bailed in 2001, ironically just before gold prices started up again.

But back to 2001, that levelling saw the owners look to a new source of revenue in an unusual place. One they had explored way back in the 1960s in a purpose-built underground laboratory that sounds more like something out of a science fiction book. The brainchild of chemist and astrophysicists, John Bahcall and Raymond Davis Jr. from the Brookhaven National Laboratory in Upton, New York, the laboratory was used to observe solar neutrinos, electron neutrinos produced by the Sun as a product of nuclear fusion.

Davis had the ingenious idea to use 100,000 gallons of dry-cleaning solvent, tetrachloroethylene, with the notion that neutrinos headed to Earth from the Sun would pass through most matter but on very rare occasions would hit a chlorine-37 atom head-on turning it to argon-37. His experiment was a general success, detecting electron neutrinos,  though his technique failed to sense two-thirds of the number predicted. In particle physics, neutrinos come in three types: electron, muon and tau. Think yellow, green, blue. What Davis had failed to initially predict was the neutrino oscillation en route to Earth that altered one form of neutrino into another. Blue becomes green, yellow becomes blue... He did eventually correct this wee error and was awarded the Nobel Prize in Physics in 2002 for his efforts.

Though Davis’ experiments were working, miners at Homestake continued to dig deep for ore in the belly of the Black Hills of western South Dakota for almost another forty years. As gold prices levelled out and ore quality dropped the idea began to float to repurpose the mine as a potential site for a new Deep Underground Engineering Laboratory (DUSEL).

A pitch was made and the National Science Foundation awarded the contract to Homestake in 2007.  The mine is now home to the Deep Underground Neutrino Experiment (DUNE) using DUSEL and Large Underground Xenon to look at both neutrinos and dark particle matter. It is a wonderful re-purposing of the site and one that few could ever have predicted. Well done, Homestake. The future of the site is a gracious homage to the now-deceased Davis. He would likely be delighted to know that his work continues at Homestake and our exploration of the Universe with it.

MIGUASHA BOTHRIOLEPIS CANADENSIS

A stunning replica of Bothriolepis canadensis from Upper Devonian (Frasnian), Escuminac formation, Parc de Miguasha, Baie des Chaleurs, Gaspé, Québec, Canada.

Over the past 170 years, the Late Devonian Miguasha biota from eastern Canada has yielded a diverse aquatic assemblage including 20 species of lower vertebrates (anaspids, osteostra-cans, placoderms, acanthodians, actinopterygians and sarcopterygians), a more limited invertebrate assemblage, and a continental component including plants, scorpions and millipedes.

Originally interpreted as a freshwater lacustrine environment, recent paleontological, taphonomic, sedimentological and geochemical evidence corroborates a brackish estuarine setting. Over 18,000 fish specimens have been recovered showing various modes of fossilization, including uncompressed material and soft-tissue preservation. Most vertebrates are known from numerous, complete, articulated specimens. Exceptionally well-preserved larval and juvenile specimens have been identified for 14 out of the 20 species of fishes, allowing growth studies. Numerous horizons within the Escuminac Formation are now interpreted as either Konservat– or Konzentrat–Lagerstätten.

This replica was purchased at the Musée d'Histoire Naturelle, Miguasha (MHNM) and is in the collection of the deeply awesome John Fam.

Great Canadian Lagerstätten 4. The Devonian Miguasha Biota (Québec): UNESCO World Heritage Site and a Time Capsule in the Early History of Vertebrates, Richard Cloutier, Département de Biologie, Chimie et Géographie, Université du Québec à Rimouski, 300 allée des Ursulines, Rimouski, QC, Canada, G5L 3A1, richard_cloutier@uqar.ca, http://dx.doi.org/10.12789/geocanj.2013.40.008

ZEACRINITES: CRINOID

This lovely specimen is Zeacrinites magnoliaeformis, an Upper Mississippian-Chesterian crinoid found by Keith Metts in the Glen Dean Formation, Grayson County, Kentucky, USA.

Crinoids are unusually beautiful and graceful members of the phylum Echinodermata. They resemble an underwater flower swaying in an ocean current. But make no mistake they are marine animals. Picture a flower with a mouth on the top surface that is surrounded by feeding arms. Awkwardly, add an anus right beside that mouth. That's him!

Crinoids with root-like anchors are called Sea Lilies. They have graceful stalks that grip the ocean floor. Those in deeper water have longish stalks up to 3.3 ft or a meter in length.

Then there are other varieties that are free-swimming with only vestigial stalks. They make up the majority of this group and are commonly known as feather stars or comatulids. Unlike the sea lilies, the feather stars can move about on tiny hook-like structures called cirri. It is this same cirri that allows crinoids to latch to surfaces on the seafloor. Like other echinoderms, crinoids have pentaradial symmetry. The aboral surface of the body is studded with plates of calcium carbonate, forming an endoskeleton similar to that in starfish and sea urchins.

These make the calyx somewhat cup-shaped, and there are few, if any, ossicles in the oral (upper) surface called a tegmen. It is divided into five ambulacral areas, including a deep groove from which the tube feet project, and five interambulacral areas between them. The anus, unusually for echinoderms, is found on the same surface as the mouth, at the edge of the tegmen.

Crinoids are alive and well today. They are also some of the oldest fossils on the planet. We have lovely fossil specimens dating back to the Ordovician.

MEET ARAUCARIA FAMII

In 1993, John Fam and his father were collecting from outcrops exposed at the Motorcross track near Brannan Lake in Nanaimo, British Columbia, Canada when something unusual caught John's eye. 

This was a weekly father-son event to get outdoors and explore nature and dig into our ancient world. 

The site is one of the classic Vancouver Island fossil localities with outcrops from the Santonian-Maastrichtian, Upper Cretaceous Haslam Formation. Here we find well-preserved nautiloids and ammonites — Cadoceras, Pseudoschloenbachia, Epigoniceras — the bivalves — Inoceramus, Sphenoceramus — gastropods, and classic Nanaimo Group decapods — Hoploparia and Linuparus. 

On rare occasions, we find fossil fruit and seeds which tell the story of the terrestrial history of Vancouver Island. And it was one of these seeds that John unearthed back in 1993. On this particular day, John picked up a tasty looking concretion whose shape foretold the possibility of ancient life hidden inside. Always one with a keen eye, he carefully packed it up and took it home. 

The next day, he cracked it open and a beautiful fossil cone met his eyes. He had found a cone from an ancient family of coniferous trees. 

Knowing it was unusual and important, he kept it safe and eventually met and donated it to Dr. Ruth Stockey, a palaeontologist who specializes in plants and seeds. 

Their collaboration just came full circle — the seed was indeed a new species and was published today in the American Journal of Botany. Meet Araucaria famii. Congratulations to Ruth and team for studying and writing up this important find. A huge congrats to John and his amazing father for their curiosity, collaboration and providing role-models for us all. 

John kept a few of the fossilized seeds & was gifted a cast of the cone from Stockey. His seeds might have cool embryos in them, you never know.  It sure would be nice to look at the x.s. to see for sure how many cotyledons are inside. These are the embryonic leaves in seed-bearing plants, one or more of which are the first leaves to appear from a germinating seed. 

It sure looked like two. Ruth Stockey & team are on it. I’m sure they’ll update us when they know for sure.

I was recently on a fossil field trip with John and it warmed my heart to see him, now a father himself, sharing that passion with his eldest son. We may well have more Famii's to look forward to. I'm thinking we will. 

Here is the link to this paper: 

https://www.researchgate.net/publication/343186795_Diversification_of_crown_group_Araucaria_the_role_of_Araucaria_famii_sp_nov_in_the_mid-Cretaceous_Campanian_radiation_of_Araucariaceae_in_the_Northern_Hemisphere

FIRST BC DINOSAUR WEST OF THE ROCKIES

This dapper fellow is a pine needle and horsetail connoisseur. He's a hadrosaurus — also known as "duck-billed" dinosaurs. They were a very successful group of plant-eaters that thrived throughout western Canada during the late Cretaceous, some 70 to 84 million years ago.

This beautiful specimen graces the back galleries of the Courtenay and District Museum on Vancouver Island, British Columbia, Canada. I was very fortunate to have a tour this past summer with the deeply awesome Mike Trask joined by the lovely Lori Vesper. 

The museum houses an extensive collection of palaeontological and archaeological material found on Vancouver Island, many of which have been donated by the Vancouver Island Palaeontological Society.

Hadrosaurs lived as part of a herd, dining on pine needles, horsetails, twigs and flowering plants. They are ornithischians — an extinct clade of mainly herbivorous dinosaurs characterized by a pelvic structure superficially similar to that of birds. They are close relatives and possibly descendants of the earlier iguanodontid dinosaurs. They had slightly webbed, camel-like feet with pads on the bottom for cushioning and perhaps a bit of extra propulsion in water. They were primarily terrestrial but did enjoy feeding on plants near and in shallow water. There had a sturdy build with a stiff tail and robust bone structure. 

At their emergence in the fossil record, they were quite small, roughly three meters long. That's slightly smaller than an American bison. They evolved during the Cretaceous with some of their lineage reaching up to 20 meters or 65 feet.

Hadrosaurs are very rare in British Columbia but a common fossil in our provincial neighbour, Alberta, to the east. Here, along with the rest of the world, they were more abundant than sauropods and a relatively common fossil find. They were common in the Upper Cretaceous of Europe, Asia, and North America.

There are two main groups of Hadrosaurs, crested and non-crested. The bony crest on the top of the head of the hadrosaurs was hollow and attached to the nasal passages. It is thought that the hollow crest was used to make different sounds. These sounds may have signalled distress or been the hadrosaur equivalent of a wolf whistle used to attract mates. Given their size it would have made for quite the trumpeting sound.

Dan Bowen, Chair of the Vancouver Island Palaeontological Society, shared the photo you see here of the first partly articulated dinosaur from Vancouver Island ever found. The vertebrate photo and illustration are from a presentation by Dr. David Evans at the 2018 Paleontological Symposium in Courtenay.  

The research efforts of the VIPS run deep in British Columbia and this new very significant find is no exception. A Hadrosauroid dinosaur is a rare occurrence and further evidence of the terrestrial influence in the Upper Cretaceous, Nanaimo Group, Vancouver Island — outcrops that we traditionally thought of as marine from years of collecting well-preserved marine fossil fauna.

The fossil bone material was found years ago by Mike Trask of the Vancouver Island Palaeontological Society. You may recall that he was the same fellow who found the Courtenay Elasmosaur on the Puntledge River.

Mike was leading a fossil expedition on the Trent River. While searching through the Upper Cretaceous shales, the group found an articulated mass of bones that looked quite promising.

Given the history of the finds in the area, the bones were thought to be from a marine reptile.

Since that time, we've found a wonderful terrestrial helochelydrid turtle, Naomichelys speciosa, but up to this point, the Trent had been known for its fossil marine fauna, not terrestrial. Efforts were made to excavate more of the specimen, and in all more than 25 associated vertebrae were collected with the help of some 40+ volunteers. Identifying fossil bone is a tricky business. Encased in rock, the caudal vertebrae were thought to be marine reptile in origin. Some of these were put on display in the Courtenay Museum and mislabeled for years as an unidentified plesiosaur.

In 2016, after years collecting dust and praise in equal measure, the bones were reexamined. They didn't quite match what we'd expect from a marine reptile. Shino Sugimoto, Fossil Preparator, Vertebrate Palaeontology Technician at the Royal Ontario Museum was called in to work her magic — painstakingly prepping out each caudal vertebrae from the block.

Once fully prepped, seemingly unlikely, they turned out to be from a terrestrial hadrosauroid. This is the second confirmed dinosaur from the Upper Cretaceous Nanaimo Group. The first being a theropod from Sucia Island. The partial left thigh bones the first dinosaur fossil ever found in Washington state.

Dr. David Evans, Temerty Chair in Vertebrate Palaeontology, Department of Natural History, Palaeobiology from the Royal Ontario Museum, confirmed the ID and began working on the partial duck-billed dinosaur skeleton to publish on the find.

Now fully prepped, the details of this articulated Hadrosauriod caudal vertebrae come to light. We can see the prominent chevron facets indicative of caudal vertebrae with it's a nice hexagonal centrum shape on anterior view.

There are well-defined long, raked neural spines that expand distally — up and away from the acoelous centrum. 

Between the successive vertebrae, there would likely have been a fibrocartilaginous intervertebral body with a gel-like core —  the nucleus pulposus — which is derived from the embryonic notochord. This is a handy feature in a vertebrate built as sturdily as a hadrosaur. Acoelous vertebrae have evolved to be especially well-suited to receive and distribute compressive forces within the vertebral column.

This fellow has kissing cousins over in the state of New Jersey where this species is the official state fossil. The first of his kind was found by John Estaugh Hopkins in New Jersey back in 1838. Since that time, we've found many hadrosaurs in Alberta, particularly the Edmontosuaurs, another member of the subfamily Hadrosaurine.

In 1978, Princeton University found fifteen juvenile hadrosaurs, Maiasaura ("good mother lizard") on a paleontological expedition to the Upper Cretaceous, Two Medicine Formation of Teton County in western Montana. 

Their initial finds of several small skeletons had them on the hunt for potential nests — and they found them complete with wee baby hatchlings!

Photo One: Fossil Huntress / Heidi Henderson, VIPS

Photo Two / Sketch Three: Danielle Dufault, Palaeo-Scientific Ilustrator, Research Assistant at the Royal Ontario Museum, Host of Animalogic. 

The vertebrate photo and illustration were included in a presentation by Dr. David Evans at the 2018 BCPA Paleontological Symposium in Courtenay, British Columbia, Canada.

Photo Four: Illustration by the talented Greer Stothers, Illustrator & Natural Science-Enthusiast.

ATURIA ANGUSTATA: MIOCENE NAUTILOID

Aturia angustata, Lower Miocene, WA

This lovely Lower Miocene nautiloid is Aturia angustata collected on the foreshore near Clallam Bay, Olympic Peninsula, northwestern Washington. 

Aturia is an extinct genus of Paleocene to Miocene nautiloid within Aturiidae, a monotypic family, established by Campman in 1857 for Aturia (Bronn, 1838), and is included in the superfamily Nautilaceae (Kümmel,  1964).

There are seven living nautiloid species in two genera: Nautilus pompilius, N. macromphalus, N. stenomphalus, N. belauensis, and the three new species being described from Samoa, Fiji, and Vanuatu (Ward et al.). We have specimens of fossil nautiloids dating to the Turonian of California, and possibly the Cenomanian of Australia. There has also been a discovery of what might be the only known fossil of Allonautilus (Ward and Saunders, 1997), from the Nanaimo Group of British Columbia, Canada.

Aturia in the Collection of Rick Ross, VIPS

The exquisite shell preservation of many Nanaimo nautilids has opened up a lens into paleotemperatures and accurate Nitrogen isotope analyses. 

Nautilus and all other known Cretaceous through Paleogene nautiloids were shallow water carnivores. We may see their shells as beautiful bits of art and science today, but they were seen in our ancient oceans as small yet mighty predators. Preferring to dine on shrimp, crab, fish and on occasion, a friendly cousin nautiloid to two.

Aturia lived in cooler water in the Cenozoic, preferring it over the warmer waters chosen by their cousins. Aturia, are commonly found as fossils from Eocene and Miocene outcrops. That record ends with their extinction in the late Miocene. This was a fierce little beast with jaws packed with piranha-like teeth. They grew at least twice that of the largest known Nautilus living today. 

Aturia is characterized by a smooth, highly involute, discoidal shell with a complex suture and subdorsal siphuncle. The shell of Aturia is rounded ventrally and flattened laterally; the dorsum is deeply impressed. The suture is one of the most complex within the subclass Nautiloidea. Of all the nautiloids, he may have been able to go deeper than his brethren.

Nautiloids are known for their simple suturing in comparison to their ammonite cousins. This simplicity of design limited their abilities in terms of withstanding the water pressure experienced when several atmospheres below the sea. Nautiloids were not able to compete with their ammonite cousins in this regard. 

Instead of elaborate and complex sutures capable of withstanding the pressures of the deep, nautiloids have simpler sutures that would have them enfold on themselves and crush at depth.  

Aturia angustata; Rick Ross Collection

It has a broad flattened ventral saddle, narrow pointed lateral lobes, broad rounded lateral saddles, broad lobes on the dorso-umbilical slopes, and a broad dorsal saddle divided by a deep, narrow median lobe. 

The siphuncle is moderate in size and located subdorsally in the adapical dorsal flexure of the septum. Based on the feeding and hunting behaviours of living nautiluses, Aturia most likely preyed upon small fish and crustaceans. 

I've found a few of these specimens along the beaches of Clallam Bay and nearby in a local clay quarry. I've also seen calcified and chalcedony — microcrystalline quartz — agatized beauties of this species collected from river sites within the Olympic Peninsula range. In the bottom photos, you can see Aturia from Washington state and one (on the stand on the left) from Oregon, USA. These beauties are in the collections of the deeply awesome Rick Ross, Vancouver Island Palaeontological Society.

References: Ward, P; Haggart, J; Ross, R; Trask, P; Beard, G; Nautilus and Allonautilus in the Nanaimo Group, and in the modern oceans; 12th British Columbia Paleontological Symposium, 2018, Courtenay, abstracts; 2018 p. 10-11

DEVONIAN CORAL

Devonian Coral, Kootenay Rockies, BC

This fellow is a coral from a Devonian reef site near the Bull River in the Kootenay Rockies. 

Corals are marine invertebrates within the class Anthozoa of the phylum Cnidaria. They typically live in compact colonies of many identical individual polyps. Corals species include the important reef builders that inhabit tropical oceans and secrete calcium carbonate to form a hard skeleton.

A coral group is a colony of myriad genetically identical polyps. Each polyp is a sac-like animal typically only a few millimetres in diameter and a few centimetres in height. A set of tentacles surround a central mouth opening. Each polyp excretes an exoskeleton near the base. Over many generations, the colony thus creates a skeleton characteristic of the species which can measure up to several meters in size. Individual colonies grow by asexual reproduction of polyps. 

Corals also breed sexually by spawning: polyps of the same species release gametes simultaneously overnight, often around a full moon. Fertilized eggs form planulae, a mobile early form of the coral polyp which when mature settles to form a new colony.

Modern coral reefs begin to form when free-swimming coral larvae attach to submerged rocks or other hard surfaces along the edges of islands or continents. As the corals grow and expand, reefs take on one of three major characteristic structures — fringing, barrier or atoll. Back in the Devonian, reefs were formed from corals and stromatoporoids which formed on top of carbonate banks.

Modern Thriving Coral Community

Corals reappeared during the Devonian period, around 410 million years ago. It is around this time that they began to form extensive reef systems. 

These early coral reefs were predominantly composed of coral-like stromatoporoids (reef-forming sponges), tabulate corals (mounds, branches, and organ shapes), rugose corals (horn-shaped), and predecessors of the modern-day coralline algae (encrusting multi-coloured algae seen on rock surfaces). 

It was towards the end of this period that scleractinian or ‘stony’ corals first appeared that populate coral reefs today. 

350 million years ago corals briefly disappeared from the geological record. The reason for this is not clear but evidence points towards rapid fluctuations in sea levels and a rapid reduction in atmospheric carbon dioxide. It has been a long stretch of good conditions for corals but with global warming, we are beginning to alter our oceanic conditions and not to the liking of our beautiful corals.

EAGER FORMATION AT KTUNAXA NATION

There is a small roadcut exposure of the Eager Formation on the Ktunaxa Nation lands. The Lower Cambrian Eager Formation outcrops at a few localities close to Fort Steele, many known since the early 1920s, and up near Mount Grainger near the highway. 

This particular outcrop is on First Nations land. We wanted to take photographs of the site and be respectful of who live on and own the land now. This is the Ktunaxa traditional territory and while their history does not intersect directly with the fauna who lived here half a billion years ago, their boundaries need to be respected.

We stopped for about 10 minutes to photograph the exposures. I hopped out to look at a few pieces and photograph this specimen. The Olenellus trilobite bits & pieces were moults & remains that had a slight deformation or warping — perhaps laid down in a seabed with high action, active turbidity.

Olenellus are a genus of trilobites — extinct arthropods  — common in but restricted to Early Cambrian rocks some 542 million to 521 million years old and thus a useful guide fossil for the Early Cambrian. Olenellus had a well-developed head, large and crescentic eyes, and a poorly developed, small tail. The cephalon you see here was likely a moult as this particular specimen grew and shed his snug earlier head shield.

WEE EURYPTERID

This adorable wee baby with his teeny aquatic mittens on is a eurypterid from exposures in New York, USA. This fellow is just under a centimetre in length but his cousins grew larger than a human. Eurypterids were the largest known arthropods to ever live. 

More commonly known as sea scorpions, eurypterids are an extinct group of arthropods that lived during the Paleozoic Era. We saw the first of their brethren during the Ordovician and the last of them during the End-Permian Mass Extinction Event. The group Arthropoda includes invertebrate animals with exoskeletons, segmented bodies, and paired joint appendages. Eurypterids had six sets of appendages. You can clearly see the segmented body on this cutie, which is one of the defining characteristics of arthropods. 

The first set was modified into pinchers which are used for feeding. The largest appendage visible in this fossil is a broad paddle that E. tetragonophthalmus used to swim. 

This first eurypterid, Eurypterus remipes, was discovered in New York in 1818. It is an iconic fossil for this region and was chosen at the state's official fossil in 1984. An excellent choice as most of the productive eurypterid-bearing outcrops are within the state's boundaries.

MAOTUNIA FROM NORTHERN CHINA

This lovely is Maotunia sp. from the Drumian Changhia Formation of China. You can see the 3D phosphatized gut glands still stuck to the underside of the dorsal carapace. 

Wang et al. published a paper in December 2018 on the fossilized gut of the trilobite Lioparia bassleri and the distribution of exceptional preservation in the Cambrian Stage 4-Drumian Manto Formation of northern China. 

Photo: Rudy Lerosey-Aubril

SOLAR WINDS: THE MAGNETOSPHERE

The Earth has a magnetic field with north and south poles. The magnetic field of the Earth is surrounded by the magnetosphere that keeps most of the particles from the Sun from hitting the Earth.

Some of these particles from the solar wind enter the atmosphere at one million miles per hour. 

We see them as one of the most beautiful of all-natural phenomena — Earth's polar lights, the aurora borealis in the north and the aurora australis, near the south pole. The auroras occur when highly charged electrons from the solar wind interact with elements in the Earth's atmosphere and become trapped in the Earth's magnetic field. We see them as an undulating visual field of red, yellow, green, blue and purple dancing high in the Earth's atmosphere — about 100 to 400 kilometres above us.

This image shows the parts of the magnetosphere. 1. Bow shock. 2. Magnetosheath. 3. Magnetopause. 4. Magnetosphere. 5. Northern tail lobe. 6. Southern tail lobe. 7. Plasmasphere.

Photo credit: Magnetosphere_Levels.jpg: Dennis Gallagherderivative work: Frédéric MICHEL - Magnetosphere_Levels.jpg, Public Domain, https://commons.wikimedia.org/w/index.php?curid=9608059

HOPLOSCAPHITES NEBRASCENSIS

This sweet beauty with lovely oil in water colouring is a Hoploscaphites nebrascensis (Owen, 1852) macroconch. This is the female form of the ammonite, her larger body perfect for egg production by the smaller males, or microconchs of the species.

Hoploscaphites nebrascensis is an upper Maastrichtian species and index fossil. It marks the top of ammonite zonation for the Western Interior. 

This species has been recorded from Fox Hills Formation in North and South Dakota as well as the Pierre Shale in southeastern South Dakota and northeastern Nebraska.

It is unknown from Montana, Wyoming, and Colorado due to the deposition of coeval terrestrial units. 

It has possibly been recorded in glacial deposits in Saskatchewan and northern North Dakota, but so far this is just hearsay.

Outside the Western Interior, this species has been found in Maryland and possibly Texas in the Discoscaphites Conrad zone. This lovely one is in the collection of the deeply awesome (and enviable) José Juárez Ruiz. A big thank you to Joshua Slattery for his insights on the distribution of this species.

SHELTER POINT FOSSIL CRAB SITE

This lovely fossil crab is Longusorbis cuniculosus from the Upper Cretaceous ) Late Campanian, Northumberland Formation near Campbell River, British Columbia. This photo was featured in the 2004 BCPA Calendar.

Shelter Point on northern Vancouver Island is a lovely beach site where clastic strata are exposed in the intertidal platform of Oyster Bay. 

The site is located just off the Island Highway, about 10 km south of downtown Campbell River and 4 km farther south along the lower Oyster River. Haggart et al. presented an abstract on this locality at the 12th British Columbia Paleontological Symposium, 2018, Courtenay, abstracts; 2018 p. 28-30. I'll pop a link below if you'd like to give it a read. 

Shelter Point has been collected since the 1970s. No pre-glacial strata were recognized in this area by Muller and Jeletzky (1970). Richards (1975) described an abundant fauna in the beds at Shelter Point, approximately 2 km north of the Oyster Bay exposures, including the crab Longusorbis and associated ammonites and inoceramid bivalves, and he assigned these beds to the Spray Formation of the Nanaimo Group. This information, combined with the very low dip of the Oyster Bay strata and their general lithological similarity with the coarse clastic strata found commonly in the Nanaimo Group, suggested a Late Cretaceous (Campanian) age of the Oyster Bay strata.

Beginning in the 1980s, fossil collectors from the Vancouver Island Palaeontological Society began amassing significant collections of fossils from the strata of southern Oyster Bay that are found several hundred metres southeast of the local road called Appian Way, thus providing the informal moniker Appian Way Beds for these localized exposures. 

While these collections included a great diversity of gastropod, bivalve, nautiloid, scaphopod, echinoderm, and coral specimens, as well as impressive collections of plant materials, much previously undescribed, no taxa found commonly in Campanian strata of the Nanaimo Group were noted in these collections; particularly lacking were ammonites and inoceramid bivalves. For this reason, the hypothesis began to emerge that the Appian Way Beds of Oyster Bay were of younger, post-Cretaceous, age than thought previously. 

Just how young, however, has been a source of some controversy, with different parties continuing to favour the traditional Campanian age — based on lithostratigraphy — others a Paleocene age, and still others an Eocene age — based on plant macrofossils.

Fossil Collecting at Shelter Point:

Fossil Collecting at Shelter Point

At the northern end of Shelter Bay, turn east onto Heard Road, which ends at a public access to Shelter Point. 

Low tide is necessary in order to collect from these shales. Some friends are looking to explore this site over the next week. If you see some keen beans on the beach, check to see if they are the New family, Chris and Bonnie. Welcome them — they are lovely folk!

Industrious collectors unwilling to wait for the tide have employed rubber boots to wade through knee-deep water — rubber boots are highly recommended in any case — and even headlamps to capitalize on low tides during the night. Bring eye protection and sunscreen to safely enjoy this lovely family trip.   

The fossils, mainly the crab, Longusorbis and the straight ammonite Baculites, occur only in the gritty concretions that weather out of the shale. You'll need a rock hammer to see the lovelies preserved inside. Best to hold the concretion in your hand and give it one good tap. Aside from the fossils, check out the local tide pools and sea life in the area. Those less interested in the fossils can look for seals and playful otters basking on the beaches.

References:

Haggart, J. et al. 58 million and 25 years in the making: stratigraphy, fauna, age, and correlation of the Paleocene/Eocene sedimentary strata at Oyster Bay and adjacent areas, southeast Vancouver Island, British Columbia; https://geoscan.nrcan.gc.ca/starweb/geoscan/servlet.starweb?path=geoscan/fulle.web&search1=R=308471

ANDROGYNOCERAS LATAECOSTA

This gorgeous Lower Pliensbachian macroconch of the ammonite Androgynoceras lataecosta was found as a nodule from the Green Ammonite beds, Lower Pliensbachian, Stonebarrow Marl Member, Charmouth Mudstone Formation (190 MYA) at Charmouth Beach, Dorset Coast. 

This specimen was found, prepped and photographed by the lovely and talented Lizzie Hingley of Stonebarrow Fossils. 

And what a delightful surprise! It is quite a small nodule to contain a macroconch of this species. Generally, these smaller concretions contain the diminutive male microconchs of Androgynoceras (Hyatt, 1867) if you are lucky — sometimes a Tragophylloceras loscombi (Sowerby, 1814) — or nothing at all if you are not. 

We see a great variation in this species and the ammonite species that make up this population. Murray Edmunds from Chipping Norton, UK shared some of his insights on why we see such variation and how a phylogenetic species concept may be masking a continuum that tells a very different story.  

We are starting to recognise that these could all be variants of one interbreeding population — with a highly variable duration of a juvenile Capricorn stage. Palaeontologists use a phylogenetic species concept as you cannot test reproductive isolation in any but the most recent of fossils.

By definition, individuals within an interbreeding population cannot belong to different species, let alone different genera. In palaeontology we can only interpret what we see with reference to what we understand of biology. 

In the Davoei Zone Liparoceratidae we have a single lineage that evolves into Oistoceras. The microconchs (putative males) are small Capricorns, and the macroconchs (putative females) are very variable: they have a Capricorn juvenile stage that can be expressed for only a few mm (or not at all), or for many cm. But eventually, the adult macroconch body chamber acquires liparoceratid ornament — inflated and bipinnate with numerous secondary ribs. 

Unfortunately, the green ammonite beds at Charmouth preserve only juvenile macroconchs so we don’t get to appreciate the similarity of the mature adult shell form. We see them at a size where individuals can look very different from each other. 

Historically, this difference in appearance led to all the individuals — both micro and macroconchs — with prolonged Capricorn morphology being assigned to Androgynoceras and those macroconchs lacking the juvenile Capricorn stage (as is typical in their Ibex zone ancestors) to be called Liparoceras. 

Different species were named for different variants. But this is a purely morphological approach to nomenclature and does not reflect the taxonomy used for extant organisms where we try to reflect phylogeny.

But as more and more examples are collected, we start to see that these specimens form a continuum. And as we follow them up through time, we see that all of them (microconchs and macroconchs, regardless of the extent of the Capricorn stage — although that tends to become more prolonged through time — simultaneously evolve progressively forwardly projected ribs across the venter, culminating in Oistoceras. 

This simultaneous evolutionary change across the entire Liparoceratid population more or less proves that we have a single interbreeding clade. And that it is separate from Becheiceras – through that’s another story! And they all go extinct simultaneously too, whereas Becheiceras carries on into the Margaritatus Zone. If you're a grad student looking to do your thesis, there is a very interesting story you could tell!

If you fancy a web stroll through some beautifully prepped specimens from Jurassic Coast, UK, or if you'd like to get some prepped, you can check out Lizzie's superb skill here: https://www.stonebarrowfossils.co.uk/  / Photos: Lizzie Hingley, Stonebarrow Fossils

ORYGMASPIS SPINULA OF THE MCKAY GROUP

This calcified beauty is Orygmaspis (Parabolinoides) spinula (Westrop, 1986) an Upper Cambrian trilobite from the McKay Group near Tanglefoot Mountain in the Kootenay Rockies. 

Orygmaspis is a genus of asaphid trilobite with an inverted egg-shaped outline, a wide headshield, small eyes, long genal spines, 12 spined thorax segments and a small, short tail shield, with four pairs of spines.

The outline of the exoskeleton Orygmaspis is inverted egg-shaped, with a parabolic headshield — or cephalon less than twice as wide as long. 

The glabella, the well-defined central raised area excluding the backward occipital ring, is ¾× as wide as long, moderately convex, truncate-tapering, with 3 pairs of shallow to obsolete lateral furrows. 

The occipital ring is well defined. The distance between the glabella and the border (or preglabellar field) is ±¼× as long as the glabella. This fellow had small to medium-sized eyes, 12-20% of the length of the cephalon. These were positioned between the front and the middle of the glabella and about ⅓ as far out as the glabella is wide. 

The remaining parts of the cephalon, the fixed and free cheeks — or fixigenae and librigenae — are relatively flat. The fracture lines or sutures — that separate the librigenae from the fixigenae in moulting — are divergent just in front of the eyes. These become parallel near the border furrow and strongly convergent at the margin. 

From the back of the eyes, the sutures bend out, then in, diverging outward and backward at approximately 45°, cutting the posterior margin well within the inner bend of the spine — or opisthoparian sutures. 

The thorax or articulating middle part of the body has 12 segments. The anteriormost segment gradually narrows into a sideward directed point, while further to the back the spines are directed outward and the spine is of increasing length up until the ninth spine, while the spine on the tenth segment is abruptly smaller, and 11 and 12 even more so. 

This fellow has a wee pygidium or tail shield that is only about ⅓× as wide as the cephalon. It is narrowly transverse about 2× wider than long. Its axis is slightly wider than the pleural fields to each side, and has up to 4 axial rings and a terminal and almost reaches the margin. Up to 4 pleural segments with obsolete interpleural grooves and shallow pleural furrows. The posterior margin has 3 or 4 pairs of spines, getting smaller further to the back. 

References:

Chatterton, Brian D. E.; Gibb, Stacey (2016). Furongian (Upper Cambrian) Trilobites from the McKay Group, Bull River Valley, Near Cranbrook, Southeastern British Columbia, Canada; Issue 35 of Palaeontographica Canadiana; ISBN: 978-1-897095-79-9

Moore, R.C. (1959). Arthropoda I - Arthropoda General Features, Proarthropoda, Euarthropoda General Features, Trilobitomorpha. Treatise on Invertebrate Paleontology. Part O. Boulder, Colorado/Lawrence, Kansas: Geological Society of America/University of Kansas Press. pp. O272–O273. ISBN 0-8137-3015-5.

TRIASSIC BEAUTY: ALBERTONIA

Triassic Fossil Fish, Albertonia sp. 

This beauty with the graceful sail-like fins is the Early Triassic ganoid fish, Albertonia sp., an extinct bony fish from British Columbia, Canada. 

Specimens of this lovely have been found in the Vega-Phroso Siltstone Member of the Sulphur Mountain Formation near Wapiti Lake in British Columbia and the Lower Triassic Montney Formation of Alberta. 

Early Triassic fish have been described from several outcrops in the Western Canada Sedimentary Basin of the Rocky Mountains. The best known and most prolific of these are from sites near Wapiti Lake in northeastern British Columbia. Here specimens of bony fish with their heavy ganoid and cosmoid scales are beautifully preserved. Four genera of Early Triassic fishes — the ray-finned actinopterygians Albertonia, Bobasatrania, Boreosomus, and the lobe-finned coelacanth (sarcopterygian), Whiteia — are found in abundance in the Wapiti Lake exposures.

This particular species is one of my favourites. Albertonia is a member of the ganoid fish family Parasemionotidae, which is amongst the most advanced and abundant of Triassic subholostean families of fish. The preservation here really shows the beauty of form of this species who likely died and was preserved in sediment at the bottom of an ocean with an anoxic environment. 

These fellows lived in deep marine waters, dining on plankton & other small organisms. Most specimens are 35-40cm in length. They have a large, sail-shaped dorsal fin and rather smallish ventral fins. Their pectoral fins were incredibly long compared to the rest of the body, and they too resembled sails. The preservation here is quite remarkable with each square-shaped scale preserved in minute detail.

ANCIENT ARTHROPOD FROM PAIWU

This large, showy bivalved arthropod is a Tuzoia sinesis (Pan, 1957) from Cambrian deposits of the Balang Formation. The Balang outcrops in beautiful Paiwu, northwestern Hunan Province in southern China. 

The site is intermediate in age between the Lower Cambrian Chengjiang fauna of Yunnan and the Lower to Middle Cambrian, Kaili Lagerstätten of Guizhou in southwestern China.

This specimen was collected in October 2019 and is one of the many new and exciting arthropods to come from the site. Balang has a low diversity of trilobites and many soft-bodied fossils similar in preservation to Canada's Burgess Shale. 

Some of the most interesting finds include the first discovery of anomalocaridid appendages — Appendage-F-Type. These were found along with the early arthropod Leanchoiliids — with his atypical frontal appendages and questionable phylogenetic placement — and the soft-shelled trilobite-like arthropod, Naraoiidae.

While the site is not as well-studied as the Chengjiang and Kaili Lagerstätten, it looks very promising. The exceptionally well-preserved fauna includes algae, sponges, chancelloriids, cnidarians, worms, molluscs, brachiopods, trilobites and a few non-mineralized arthropods. It is an exciting time for Cambrian palaeontology. The Balang provides an intriguing new window into our ancient seas and the profound diversification of life that flourished there.

THE DUDLEY BUG

Calymene blumenbachii, Theresa Paul Spink Dunn

A lovely example of the trilobite Calymene blumenbachii from outcrops in the UK. This wee rolled beauty is in the collections of Theresa Paul Spink Dunn. This Silurian trilobite is from the Homerian, Wenlock Series, Wrens Nest, Dudley, UK.

Calymene blumenbachii, sometimes erroneously spelled blumenbachi, are found in the limestone quarries of the Wren's Nest in Dudley, England. This locality name was charmingly highjacked by an 18th-century quarryman birth the nickname the Dudley Bug — both a symbol of the town and a key feature on the Dudley County Borough Council Coat-of-Arms. Calymene blumenbachii is commonly found in Silurian rocks — 422.5-427.5 million years ago — that formed near shallow water, low energy reefs.

This particular species of Calymene — a fairly common genus in the Ordovician-Silurian — is unique to the Wenlock series in England and comes from the Wenlock Limestone Formation in Much Wenlock and the Wren's Nest in Dudley. These sites seem to yield trilobites more readily than any other areas on the Wenlock Edge. The rock here is dark grey and quite fossiliferous. Just a few miles away in Church Stretton and along other parts of the Edge, it is yellowish or whitish — an indication that there were local changes in the environment in which the rock was deposited. The Wenlock Edge quarry is closed to further collecting but may reopen for future research projects.

THALASSINA ANOMALA: MUD LOBSTER

This fellow is the scorpion mud lobster, Thalassina anomala (Herbst, 1804), a species of decapod crustacean in the family Thalassinidae. He's a little sweetie with very interesting anatomy. 

Lobsters have their brains in their throats and they breathe and listen with their legs. To top all that wackiness off, they taste with their feet.

These fellows are not as desired as their larger cousins as food for us hoomins. True to their name, they taste a bit muddy. 

Thalassina anomala is an important member of the mangrove ecosystems in which they live. They are night borrowers who excavate om their search for tasty organic material to snack on. They push organic-rich soil from deep in the ground back up to the surface — creating huge mounds. Their burrowing also helps to aerate tidal waters. 

The mud mounds they build are pretty massive in scale in comparison to these fellows. The specimen you see here is 6.5 cm long but others can grow up to 30 cm and build mounds up to 3 metres in height. These mounds provide important habitat for other animals including Odontomachus malignus (an ant), termites, Episesarma singaporense (tree-climbing crab), Wolffogebia phuketensis (mangrove mud shrimp), Acrochordus granulatus (file snake), and plants such as the tree Excoecaria agallochoa and ferns.

Lobsters are members of the phylum Arthropoda, Euarthropoda. They are crustaceans, like crabs, crayfish, krill, shrimp and prawns. Crustaceans belong to the arthropods, a group of animals with an armoured external skeleton (an exoskeleton), a segmented body and jointed legs. The hard exoskeleton is the part that’s preserved as a fossil. This fellow has the typical tall, ovoid carapace and presumably, a short rostrum — though his rostrum is partially hidden in the matrix. 

The specimen you see here hails from Pleistocene deposits near Gunn Point, an outer rural locality sandwiched between the Howard and Adelaide Rivers east of Darwin in the Northern Territory of Australia. His cousins can be found burrowing in the muds of brackish mangrove swamps and estuaries of the Indian Ocean and the western Pacific Ocean today. 

HOMARUS KARELSNSIS: LOBSTER FROM LEBANON

An artfully enhanced example of Homarus hakelensis, an extinct genus of fossil lobster belonging to the family Nephrophidae. Homarus is a genus of lobsters, which include the common and commercially significant species Homarus americanus (the American lobster) and Homarus gammarus (the European lobster).

The Cape lobster, which was formerly in this genus as H. capensis, was moved in 1995 to the new genus Homarinus.

Lobsters have long bodies with muscular tails and live in crevices or burrows on the seafloor. Three of their five pairs of legs have claws, including the first pair, which are usually much larger than the others.

Highly prized as seafood, lobsters are economically important and are often one of the most profitable commodities in coastal areas they populate. Commercially important species include two species of Homarus — which looks more like the stereotypical lobster — from the northern Atlantic Ocean, and scampi — which looks more like a shrimp — the Northern Hemisphere genus Nephrops and the Southern Hemisphere genus Metanephrops. Although several other groups of crustaceans have the word "lobster" in their names, the unqualified term lobster generally refers to the clawed lobsters of the family Nephropidae.

Clawed lobsters are not closely related to spiny lobsters or slipper lobsters, which have no claws or chelae, or to squat lobsters. The closest living relatives of clawed lobsters are the reef lobsters and the three families of freshwater crayfish. This cutie was found in Cretaceous outcrops at Hâdjoula. The sub‐lithographical limestones of Hâqel and Hâdjoula, in north‐west Lebanon, produce beautifully preserved shrimp, fish, and octopus. The localities are about 15 km apart, 45 km away from Beirut and 15 km away from the coastal city of Jbail. 

PHYLLOCERAS VELLEDAE

Lovely defined sutures on this rather involute, high-whorled ammonite from the middle part of the Lower Albian in the Mahajanga Province, northwestern Madagascar. This specimen of Phylloceras velledae (Michelin) has a shell with a small umbilicus, arched, acute venter, and at some growth stage, falcoid ribs that spring in pairs from umbilical tubercles, disappearing on the outer whorls.

While the large island of Madagascar off the southeast coast of Africa is known more for exotic lemurs, rainforests & beaches, it also boasts some of the world's loveliest fossils.

This specimen is from a quarry near the top of an escarpment, 3 km to the west of the village of Ambatolafia (coordinates: Lat. 16.330 23.600 S, Long. 46.120 10.20 E). Judging from plate tectonic reconstruction (Stampfli & Borel, 2002), the area was located in middle latitudes within the tropical-subtropical climatic zone at palaeo-latitudes of 40E45.S in the late Early Cretaceous of the early Albian approximately 113.0 ± 1.0 Ma to 100.5 ± 0.9 Ma. 

Madagascar was carved off from the African-South American landmass early on. The prehistoric break-up of the supercontinent Gondwana separated the Madagascar–Antarctica–India landmass from the Africa–South America landmass around 135 million years ago. Madagascar later split from India about 88 million years ago, during the Late Cretaceous, so the native plants and animals on the island evolved in relative isolation. It is a green and lush island country with more than it's fair share of excellent fossil exposures. 

Along the length of the eastern coast runs a narrow and steep escarpment containing much of the island's remaining tropical lowland forest. If you could look beneath this lush canopy, you'd see rocks of Precambrian age stretching from the east coast all the way to the centre of the island. The western edge is made up of sedimentary rock from the Carboniferous to the Quaternary. The beauty you see here is from sedimentary exposures from northwestern Madagascar and is in my personal collection. There is an exceptionally well-preserved and unusually large specimen in the collections of João Da Costa that I'll photograph and include in a future post.

SULPHATES AND CLIMATE CHANGE

The main direct effect of sulfates on the climate involves the scattering of light, effectively increasing the Earth's albedo. The term albedo was introduced into optics by Johann Heinrich Lambert in his 1760 work Photometria.

Albedo is the measure of the diffuse reflection of solar radiation out of the total solar radiation and measured on a scale from 0, corresponding to a black body that absorbs all incident radiation, to 1, corresponding to a body that reflects all incident radiation. The average albedo of the Earth from the upper atmosphere, its planetary albedo, is 30–35% because of cloud cover, but widely varies locally across the surface because of different geological and environmental features.

This effect is moderately well understood and leads to cooling from the negative radiative forcing of about 0.4 W/m2 relative to pre-industrial values, partially offsetting the larger (about 2.4 W/m2) warming effect of greenhouse gases. The effect is strongly spatially non-uniform, being largest downstream of large industrial areas.

% of Diffusely Reflected Sunlight

The first indirect effect is also known as the Twomey effect. Sulfate aerosols can act as cloud condensation nuclei and this leads to greater numbers of smaller droplets of water. Many smaller droplets can diffuse light more efficiently than a few larger droplets. 

The second indirect effect is the further knock-on effects of having more cloud condensation nuclei. It is proposed that these include the suppression of drizzle, increased cloud height, to facilitate cloud formation at low humidities and longer cloud lifetime. Sulfate may also result in changes in the particle size distribution, which can affect the clouds radiative properties in ways that are not fully understood. 

Chemical effects such as the dissolution of soluble gases and slightly soluble substances, surface tension depression by organic substances and accommodation coefficient changes are also included in the second indirect effect.

The indirect effects probably have a cooling effect, perhaps up to 2 W/m2, although the uncertainty is very large. Sulfates are therefore implicated in global dimming. Sulfate is also the major contributor to a stratospheric aerosol formed by oxidation of sulfur dioxide injected into the stratosphere by impulsive volcanoes such as the 1991 eruption of Mount Pinatubo in the Philippines. This aerosol exerts a cooling effect on climate during its 1-2 year lifetime in the stratosphere

Diagram: The percentage of diffusely reflected sunlight relative to various surface conditions. By CC BY-SA 2.5, https://commons.wikimedia.org/w/index.php?curid=1060378

References: 

• Lewis, Gilbert N. (1916). "The Atom and the Molecule". J. Am. Chem. Soc. 38: 762–785. doi:10.1021/ja02261a002. (See page 778.)
• Pauling, Linus (1948). "The modern theory of valency". J. Chem. Soc.: 1461–1467. doi:10.1039/JR9480001461.
• Coulson, C. A. (1969). "d Electrons and Molecular Bonding". Nature. 221: 1106. Bibcode:1969Natur.221.1106C. doi:10.1038/2211106a0.
• Mitchell, K. A. R. (1969). "Use of outer d orbitals in bonding". Chem. Rev. 69: 157. doi:10.1021/cr60258a001.

PYRITE PRESERVATION

Ammonite Preserved in Pyrite. Fossil Huntress

We sometimes find fossils preserved by pyrite. They are prized as much for their pleasing gold colouring as they are for their scientific value as windows into the past. Sometimes folk add a coating of brass to increase the aesthetic appeal. Though this practice is frowned upon in paleontological communities.

Pyrite is a brass-yellow mineral with a bright metallic lustre. It has a chemical composition of iron sulfide (FeS2) and is the most common sulfide mineral. It forms at high and low temperatures usually in small quantities, in igneous, metamorphic, and sedimentary rocks.

When we find a fossil preserved with pyrite, it tells us a lot about the conditions on the seabed where the organism died. Pyrite forms when there is a lot of organic carbon and not much oxygen in the vicinity. 

The reason for this is that bacteria in sediment usually respire aerobically (using oxygen), however, when there is no oxygen, they respire without oxygen (anaerobic) typically using sulphate. Sulphate is a polyatomic anion with the empirical formula SO2−4. It is generally highly soluble in water. Sulfate-reducing bacteria, some anaerobic microorganisms, such as those living in sediment or near deep-sea thermal vents, use the reduction of sulfates coupled with the oxidation of organic compounds or hydrogen as an energy source for chemosynthesis.

High quantities of organic carbon in the sediment form a barrier to oxygen in the water. This also works to encourage anaerobic respiration. Anaerobic respiration using sulphate releases hydrogen sulphide, which is one of the major components in pyrite. So, when we find a fossil preserved in pyrite, we know that it died and was buried in sediment with low quantities of oxygen and high quantities of organic carbon.

AMMOLITE

Ammolite is an opal-like organic gemstone found primarily along the eastern slopes of the Rocky Mountains of North America. It is made of the fossilized shells of ammonites, which in turn are composed primarily of aragonite, the same mineral contained in nacre, with a microstructure inherited from the shell. It is one of few biogenic gemstones; others include amber and pearl.

The chemical composition of ammolite is variable, and aside from aragonite may include a mix of calcite, silica, pyrite or other minerals. The shell itself may contain a number of trace elements based on the chemical composition of the original sediments. They can include aluminium, barium, chromium, copper, iron, magnesium, manganese, strontium, titanium, and vanadium. 

Its crystallography is orthorhombic. Its hardness is 3.5–4.5, and its specific gravity is 2.60–2.85. The refractive index of Canadian material (as measured via sodium light, 589.3 nm) is as follows: α 1.522; β 1.672–1.673; γ 1.676–1.679; biaxial negative. Under ultraviolet light, ammolite may fluoresce a mustard yellow.

Ammolite comes from the fossil shells of the Upper Cretaceous disk-shaped ammonites Placenticeras meeki and Placenticeras intercalare, and to a lesser degree, the cylindrical baculite, Baculites compressus. The ammonites that form our Alberta ammolite inhabited a prehistoric, inland subtropical sea that bordered the Rocky Mountains — this area is known today as the Cretaceous or Western Interior Seaway. As the ammonites died, they sank to the bottom and were buried by layers of bentonitic mud that eventually became shale. Many gem-quality ammonites are found within siderite concretions. These sediments preserved the aragonite of the shells, preventing it from converting to calcite.

Ammolite from the Bearpaw Formation

An iridescent opal-like play of colour is shown in fine specimens, mostly in shades of green and red; all the spectral colours are possible, however. The iridescence is due to the microstructure of the aragonite: unlike most other gems, whose colours come from light absorption, the iridescent colour of ammolite comes from interference with the light that rebounds from stacked layers of thin platelets that make up the aragonite. 

The thicker the layers, the more reds and greens are produced; the thinner the layers, the more blues and violets predominate. Reds and greens are the most commonly seen colours, owing to the greater fragility of the finer layers responsible for the blues. When freshly quarried, these colours are not especially dramatic; the material requires polishing and possibly other treatments in order to reveal the colours' full potential.

Ammolite itself is very thin. It is generally 0.5–0.8 millimetres (0.02–0.03 inches) thick. This thin coating covers a matrix typically made up of grey to brown shale, chalky clay, or limestone. 

Frost shattering of these specimens is common. If left exposed to the elements the thin ammolite tends to crack and flake. Prolonged exposure to sunlight can also lead to bleaching of the generally intense colouration. The cracking results in a tessellated appearance, sometimes described as a "dragon skin" or referred to as a stained glass window pattern. 

Ammolite mined from deeper deposits may be entirely smooth or with a rippled surface. Occasionally a complete ammonite shell is recovered with its structure well-preserved: fine, convoluted lines delineate the shell chambers, and the overall shape is suggestive of a nautilus. While these shells may be as large as 90 centimetres (35.5 inches) in diameter, the iridescent ammonites (as opposed to the pyritized variety) are typically much smaller. Most fossilized shells have had their aragonite pseudomorphously replaced by calcite or pyrite, making the presence of ammolite particularly uncommon.

In 1981, ammolite was given official gemstone status by the World Jewellery Confederation (CIBJO), the same year commercial mining of ammolite began. It was designated the official gemstone of the City of Lethbridge, Alberta in 2007.

Ammolite is also known as aapoak — Kainah for "small, crawling stone" — gem ammonite, calcentine, and Korite. The latter is a trade name given to the gemstone by the Alberta-based mining company Korite. Roughly half of all ammolite deposits are contained within the Kainah (Kainaiwa) reserve, and its inhabitants play a major role in ammolite mining. Marcel Charbonneau and his business partner Mike Berisoff were the first to create commercial doublets of the gem in 1967. They went on to form Ammolite Minerals Ltd.

FOSSIL PRESERVATION: REPLACEMENT

Ancient life can be preserved as fossils in a number of ways. Replacement is one of the ways both shellfish and wood can be preserved as fossils. Replacement occurs as the original atomic composition of the living organism is replaced cell by cell by a new chemical structure. 

It is the chemical composition of the groundwater that determines what the composition of the fossil will be. A common type of replacement is silification. Silification is the process by which silica minerals such as quartz, chalcedony, and opal fill pores or replace existing minerals, rock, or wood.

Silicification occurs in the earth’s interior through the action of hydrothermal and cold water saturated with silica. As aluminosilicate rock is weathered, a great deal of silica is freed and dissolves. Much of the dissolved silica is carried to the sea, but in places, it moves downward and replaces various rock. 

Hydrothermally silicified carbonate rock is frequently associated with ores of mercury, antimony, and other nonferrous metals. At ordinary temperatures, loose rock on the bottom of lakes and seas is subject to silicification, as is solid rock; this occurs most frequently with limestones and dolomites, more rarely with clays and phosphorites. 

Accumulations of fine-grained quartz form when carbonate rocks are replaced and aggregates of quartz and chalcedony develop when clayey rock is replaced. The presence of fine-grained quartz and quartz and chalcedony aggregates in ultrabasic rock indicates that deposits of silicate ores of nickel and cobalt may be found. Excellent examples of silification are fossil molluscs and petrified forests.