Wooster Geologist in Wales and England (June 2018)

June 20th, 2018

I spent two weeks in wonderful places making presentations, doing research, scouting for student Independent Study projects, and seeing friends and colleagues. Here is a guide to the blog posts by date —

June 6: Bryozoologists gather in Wales
June 7: Bryozoologists on the rocks in South Wales
June 8: Last day of the Larwood meeting: Museum collections and a coal mine tour
June 9: A Smith Map in Wales
June 10: A Wooster Geologist in Wales (continued)
June 11: A narrow-gauge train trip in Mid Wales
June 12: Bored marbles, slate mines, and a castle in North Wales
June 13: Last day for this Wooster Geologist in Wales … for now
June 14: Stone cannon balls from Aberystwyth Castle
June 15: Wooster Paleontologist in London (again)

Thank you to Caroline Buttler, Tim and Caroline Palmer, and Paul Taylor for being such excellent, generous and creative hosts!

Wooster Geologists on Helvellyn

June 4th, 2018

The black mountain icon indicates the location of Helvellyn in the Lake District.

During the last two weeks of May, Dr. Alley and were in the UK.  Part of the experience involved complaining about the inadequate width of UK roads, but there was also some undeniably beautiful geology.  One such location was Helvellyn, in the Lake District of England. This is one of the “top walks” in the UK, but note that the term “walk” has a very loose definition in British English.  Really, this is a hike, with a climb of nearly 3000 ft in about 4 mi.  If you’re a fan of glacially carved, open landscapes, it deserves the hype. 

The exposed rocks of the Helvellyn Range are part of the Borrowdale Volcanic Group. The volcanics here transitioned from primarily intermediate lava flows (andesite) to more silica-rich magma that resulted in pyroclastic flows and ignimbrite deposits.  This all occurred around 450 million years ago (Ordovician) — around the same time as the Taconic Orogeny in North America (most notably in New England).

That’s the raw material for the terrain, but the carving is much more recent.  Glaciers from the last glacial advance have gouged out the sides of these mountains into deep u-shaped troughs with steep sides and wide bottoms. Below Helvellyn sits a deep bowl called a cirque. This is where a large mountain glacier once originated, digging out a hole from which it later advanced.

Look back at Helvellyn Cirque from Birkhouse Moor.

If you go up into the cirque today, that depression has been filled with a small lake called a tarn. Tarns sits at the headwaters of watersheds, and the outlets are often some of the cleaner water you can find (although they may be turbid from lots of sediment).  This tarn, though, had a large number of sheep around it.  So I’d be a little more suspicious.

Red Tarn below Helvellyn.

Actually, the sheep are a more important aspect the the geology than you might think.  Looking down from Helvellyn, you can see the “Striding Edge”.  This is an arête, a sharp ridge that, thousands of years ago, was the boundary between two parallel glaciers.  The glaciers would have been flowing away from you in the image below.

View eastward from Helvellyn overlooking Striding Edge (an arête) and Red Tarn.

Finally, when walking along the northwest side of the mountain, you go by the Greenside Mine. In the 19th century, veins along a normal fault through the mountain were mined for the mineral galena (PbS), which also contains impurities of silver. 

Wooster’s Fossils of the Week: Tiny athyridide brachiopods from the Lower Carboniferous of the West Midlands of England

September 9th, 2016

1 Hustedia radialis 585These little brachiopods were also in the recent gift package from Clive Champion, our English brachiopod expert and friend. They tested my photographic skills, being too large for our photomicroscope and at the limit of resolution for my camera with its extension tubes. They are the athyridide Hustedia radialis (Phillips, 1836) from the Chadian-Arundian Limestone (Viséan, Lower Carboniferous) exposed near Wetton, Staffordshire, England. Brachiopods of this size are often referred to as “micromorph“, with some debate as to whether they are dwarfed adults or juveniles. With this fauna the consensus is the former.

Athyridide brachiopods are “spire-bearing”, meaning they have complexly-spiraled lophophore supports (brachidia) inside their shells. The lophophore is a tentacular device that creates a water current and traps organic bits from it for nutrition. These tiny critters thus had surprisingly elaborate feeding systems. The first paleontologist to grind through these minuscule shells to sort out the twists and turns of their microscopic brachidia is a hero of science.
2 John Phillips (1800-1874)Hustedia radialis was named in 1836 by one of the most important English geologists of the 19th Century, John Phillips (1800-1874). He originally called it Terebratula radialis, a common genus name applied at the time to biconvex brachiopods with pedicle openings (the hole for the attaching stalk visible at the pointy end of the shell).
3 Geology of YorkshireHe named it in the second volume of his Geology of Yorkshire series.
4 Brachs PhillipsSee if you can find the two figures of Terebratula radialis in Plate XII of the book. (Hint: small, triangular and ribbed!)

John Phillips was born in Wiltshire in 1800. His mother was a sister of the famous William “Strata” Smith, another founding father of modern geology. Phillips father and mother died when he was only seven years old, so William Smith took over raising him, despite his genteel poverty. Phillips traveled with Smith throughout England in the course of making Smith’s famous 1815 map. Phillips had a spotty formal education, but was clearly a quick study. By 1824 he was organizing museum fossil collections in Yorkshire, and in 1826 he became keeper of the Yorkshire natural history museum. Phillips then advanced very quickly, helping organize the new British Association for the Advancement of Science, becoming a professor of geology at King’s College London, and then at the age of 34 he was elected a Fellow of the Royal Society. All the while he kept up a prodigious rate of publication. The honors and positions continued for Phillips, with him eventually becoming a Reader of Geology at Oxford University. A remarkable career with such an unpromising start.
5 Phillips 1841 160Phillips published the first geological time scale in 1841, inventing the term “Mesozoic” in the process. The above clip is from Phillips (1841, p. 160).
6 Phillips 1860 time scaleHere is his 1860 version of the geological time scale (Phillips, 1860, p. 51).

After an April 1874 dinner at All Souls College in Oxford, John Phillips fell down a flight of stone steps, dying the next day. No doubt but for this fall he would have continued producing geological work into the next decade.

References:

Brunton, C.H.C. 1984. Silicified brachiopods from the Viséan of County Fermanagh, Ireland (III). Rhynchonellids, spiriferids and terebratulids. Bulletin of the British Museum (Natural History), Geology 38: 27–130.

Brunton, C.H.C. and Champion, C. 1974. A Lower Carboniferous brachiopod fauna from the Manifold Valley, Staffordshire. Palaeontology 17: 811–840.

Mottequin, B., Sevastopulo, G. and Simon, E. 2015. Micromorph brachiopods from the late Asbian (Mississippian, Viséan) from northwest Ireland (Gleniff, County Sligo). Bulletin of Geosciences 90: 307-330.

Phillips, J. 1836. Illustrations of the geology of Yorkshire, Part 2. The mountain limestone district. 253 pp. John Murray, London.

Phillips, J. 1841. Figures and Descriptions of the Palaeozoic Fossils of Cornwall, Devon and West Somerset. 231 pp. Longman, Brown, Green and Longmans, London.

Phillips, J. 1860. Life on the earth: its origin and succession. 224 pp. Macmillan and Company, London.

7 Gould bookplateFun feature of that last reference: Google Books scanned a personal copy of Stephen Jay Gould, a famous American paleontologist and evolutionary theorist.

8 Darwin quoteOn one of the front pages is this penciled note: ‘Unreadable, dull’ – Charles Darwin to [unknown] 15/1/61. [UPDATE: See comment from Katherine Marenco below.]

Wooster’s Fossils of the Week: Mystery fossil solution — an oyster from the Middle Jurassic of southern England

August 30th, 2016

Mystery fossils 081916 585Last week I gave my students in Wooster’s Invertebrate Paleontology course a fossil to identify (shown above), using any techniques they want. This was their first task in the course, so it was difficult for most of them. I hope it was a good introduction to practical paleontology and the mysteries of taxonomy. One student, Josh Charlton, nailed it all the way to the species. Several other students got close.

These are Middle Jurassic oysters properly identified as Praeexogyra hebridica (Forbes, 1851). I collected them many years ago from the Frome Clay (Bathonian) at Langton Herring along the coast of Dorset, southern England. They are extremely common fossils there, crunching underfoot as they erode out into the surf. These oysters lived in estuaries, where there was a mix of fresh and marine waters. In 1976, John Hudson and our friend Tim Palmer sorted out the systematics and  evolution of this oyster species, moving it from Ostrea and Liostrea to the genus Praeexogyra.
Forbes diagramThis oyster species was originally described in 1851 as Ostrea hebridica by Edward Forbes (1815-1854) from Jurassic sediments on the Scottish Isle of Skye in the Inner Hebrides (hence the name). As was typical of many nineteenth century fossil descriptions, the illustrations (above) and diagnoses are not particularly helpful. Forbes (1851) wrote, “Being very familiar with the oysters of the Wealden and Purbeck I cannot admit this identification, nor can I refer the Loch Staffin shell to any known fossil, although, as usual in this variable genus, it is difficult to express in words its marked distinctions.” We wouldn’t get away with such a conclusion for a new species today, but to be fair, oysters are notoriously difficult to describe. Forbes knew that this species “inhabited brackish water” in the Jurassic.

Forbes bust to useEdward Forbes FRS, FGS (above) was born on the Isle of Man in 1815, the year of Waterloo. He was, as they said then, a sickly child unable to attend a regular school for long. He traveled to London when he was 16, though, to study art. That didn’t work out, so he became a medical student at the University of Edinburgh. Forbes was intrigued more with natural history than medicine (a common story!), so he dropped his medical plans and set out to become a naturalist skilled in paleontology, mineralogy, zoology, anatomy and botany. His younger brother David became a well-known mineralogist. Edward Forbes caught on quickly. In 1838 he published a summary of the mollusks found on the Isle of Man. He was 23 years old. Forbes traveled widely, accumulating more observations, experiences and colleagues. He had many publications and advocated numerous hypotheses about the distribution of life forms. Some had lasting value (like the distribution of flora before and after glaciation intervals) and others were a bit naive (such as his idea that there is no marine life below 300 fathoms). He was a president of the Geological Society of London (1853), and in 1854 became the Professor of Natural History at Edinburgh, his driving ambition. Unfortunately his health problems caught up with him and he died that year at age 39.

Edward Forbes played a critical role in the history of science by being a mentor of Thomas Henry Huxley. Forbes advised Huxley as a young man and helped him publish his earliest works. Forbes introduced Huxley to his circle of colleagues, which eventually led to the latter’s election to the Royal Society while only 26 years old. Huxley wrote a touching obituary for his young friend Edward Forbes.

References:

Anderson, F.W. and Cox, L.R. 1948. The “Loch Staffin Beds” of Skye; with notes on the molluscan fauna of the Great Estuarine Series. Proceedings of the Royal Physical Society of Edinburgh 23: 103-122.

Anderson, T.R. and Rice, T. 2006. Deserts on the sea floor: Edward Forbes and his azoic hypothesis for a lifeless deep ocean. Endeavour 30: 131-137.

Forbes, E. 1851. On the Estuary Beds and the Oxford Clay at Loch Staffin, in Skye. Quarterly Journal of the Geological Society 7(1-2): 104-113; plate 5, figs. 4a-4c.

Hudson, J.D. and Palmer, T.J. 1976. A euryhaline oyster from the Middle Jurassic and the origin of the true oysters. Palaeontology 19: 79-93.

Wooster’s Fossil of the Week: An ammonite from the Middle Jurassic of southern England

July 8th, 2016

Leptosphinctes microconch Jurassic Dorset 585We’re featuring just a workaday fossil this week because of other summer activities. This is the ammonite Leptosphinctes Buckman 1929 from the Inferior Oolite (Middle Jurassic) at Coombe Quarry, Mapperton, Dorset, southern England. Cassidy Jester (’17) and I collected it last month during our 2016 England research expedition. Our friend Bob Chandler generously identified it. It popped out of a rock we were pounding into submission, providing a direct application of ammonite biostratigraphy to our work. As with many ammonites, the group is well known but the names are still a bit dodgy.

This specimen is a microconch, meaning it is the smaller version of a species pair, the larger being the macroconch. It is presumed that this is sexual dimorphism and that the microconch is the male because it didn’t need to carry resources for egg-laying. This is one reason why the taxonomy of these ammonites is in perpetual revision.

References:

Buckman, S.S. 1909–1930. Yorkshire Type Ammonites & Type Ammonites. Wesley & Son, Wheldon & Wesley, London, 790 pl.

Chandler, R B., Whicher, J., Dodge, M. and Dietze, V. 2014. Revision of the stratigraphy of the Inferior Oolite at Frogden Quarry, Oborne, Dorset, UK. Neues Jahrbuch für Geologie und Paläontologie-Abhandlungen 274: 133-148.

Galácz, A. 2012. Early perisphinctid ammonites from the early/late Bajocian boundary interval (Middle Jurassic) from Lókút, Hungary. Geobios 45: 285-295.

Pavia, G. and Zunino, M. 2012. Ammonite assemblages and biostratigraphy at the Lower to Upper Bajocian boundary in the Digne area (SE France). Implications for the definition of the Late Bajocian GSSP. Revue de Paléobiologie, Vol. spéc, 11: 205-227.

Wooster’s Fossils of the Week: Iron-oxide oncoids (“snuff-boxes”) from the Middle Jurassic of southern England

July 1st, 2016

1 Snuffbox colection BBThese fossils (in the broad sense!) are inevitable for our weekly feature considering how much time we spent studying and collecting them during last month’s fieldwork in Dorset, southern England. “Snuff-boxes” are the subject of Cassidy Jester’s (’17) Senior Independent Study project, so here we’ll just broadly cover what we think we know about them.

These discoidal objects are called “snuff-boxes” because their carbonate centers (usually a bit of limestone or shell) often erode faster than their iron-oxide exteriors, making them weather a bit like boxes with lids.
2 Quote from Buckman 1910 67This quote from Buckman (1910, p. 67) is the earliest reference I can find to the snuff-box term. Snuff-boxes were sometimes works of art in the 18th and 19th centuries, although quarrymen probably had more homespun varieties in mind.
1 Snuffbox serpulidssWe’re counting these snuff-boxes as fossils here because they formed through biotic and physical processes. The cortex of a snuff-box has layers of serpulid worm tubes, as shown above.
4 Palmer Wilson Fig 3There are also cyclostome bryozoans embedded within the iron-oxide layers, as shown in this image from Palmer and Wilson (1990, fig. 3).
3 Snuff-box horn 061716We believe the snuff-boxes grew by accretion of microbially-induced layers of iron-oxide formed on their undersides, which would have been gloomy caverns on the seafloor. They then would have occasionally turned over and grew layers on the other side. Many snuff-boxes have extensions on their peripheries that look in cross-sections like horns, as seen above. The layers are separate from those that formed around the nucleus. They may have grown after the snuff-box became too big to be overturned by currents or animals.
6 Platy minerals pdt19573Paul Taylor and I looked at the cortex of a snuff-box with Scanning Electron Microscopy (SEM) and had the above surprising view. The odd platy materials may be limonite, an iron-oxide that is amorphous (non-crystalline).
7 Hebrew letters pdt19572Sometimes the plates look like they’ve partially evaporated, leaving remnants that resemble Hebrew letters!
8 iron ooid pdt19576Associated with the snuff-boxes are small “iron ooids” that are about sand-size. They too have the platy materials, and so their origin may be similar to that of the snuff-boxes.

Cassidy has an interesting project ahead of her testing various origin hypotheses and sorting out the paleontology, mineralogy and geochemistry.

References:

Buckman, S.S. 1910. Certain Jurassic (Lias-Oolite) strata of south Dorset and their correlation. Quarterly Journal of the Geological Society 66: 52-89.

Burkhalter, R.M. 1995. Ooidal ironstones and ferruginous microbialites: origin and relation to sequence stratigraphy (Aalenian and Bajocian, Swiss Jura mountains). Sedimentology 42: 57-74.

Gatrall, M., Jenkyns, H.C. and Parsons, C.F. 1972. Limonitic concretions from the European Jurassic, with particular reference to the “snuff-boxes” of southern England. Sedimentology 18: 79-103.

Palmer, T.J. and Wilson, M.A. 1990. Growth of ferruginous oncoliths in the Bajocian (Middle Jurassic) of Europe. Terra Nova 2: 142-147.

Wooster Geologists in England: Team Dorset

June 19th, 2016

Cassidy Bridport Sands 060716Cassidy Jester (’17) and I have now finished our fieldwork in southern England this month. Cassidy traveled through Britain afterwards, and I went on to London and the Natural History Museum. It was all a success thanks to my friends and colleagues Tim Palmer and Paul Taylor, with critical help from our new friends Bob Chandler and John Whicher. Our daily blog entries can be accessed at the UK2016 tag.

Team Dorset 0n Hive BeachTim Palmer, Cassidy Jester (’17) and Mark Wilson on Hive Beach, Burton Bradstock, Dorset, England.

Here is a table of our locality information for reference:

GPS# Latitude Longitude Location
138 50.96268903 -2.503268039 Frogden Quarry
139 50.96319797 -2.501848983 Frogden Quarry older
140 50.93710503 -2.601833018 Babylon Hill
141 50.94292902 -2.556813983 Louse Hill
142 50.79496597 -2.71623401 Coombe Quarry, Mapperton
143 50.70015801 -2.734380998 Hive Beach, Burton Bradstock
145 50.81626003 -2.771674013 Horn Park
146 50.70154396 -2.737065973 Burton Bradstock snuffboxes

Final day at The Natural History Museum … and one more Jurassic snuff-box

June 17th, 2016

1 Chandler snuff-box cutLondon, England — My last day in London was spent working on GSA abstracts and examining one last ferruginous oncoid (“snuff-box”) from the Jurassic (Bajocian) of southern England. Bob Chandler donated to the cause a large discoidal snuff-box. We cut it (cross-section through the center shown above) and revealed its intricate internal structure.

2 Chandler snuff-box nucleusThe typical limestone nucleus is smaller than I expected, but it still shows typical features such as bioerosion.

3 Snuff-box horn 061716This specimen has beautifully-developed “horns” around the periphery. They are made of laminae not connected to the central cortex. Paul Taylor suggested that they form when the snuff-box is no long being moved about. Nice specimen. Cassidy Jester (’17) will have much to figure out in her Independent Study focused on these objects.

I’ve had a great and productive time on this expedition to England. Thank you again to my amigos Tim Palmer and Paul Taylor, as well as John Whicher, Bob Chandler and Consuelo Sendino. Science marches on.

Addendum: This is the way I like my Tube stations — empty! Take me home, District Line to Paddington. Saturday, June 18, 5:08 a.m.

Fulham Broadway tube station at 0508

Research in a paleontological paradise

June 16th, 2016

1 NHM front 061616London, England — If any center of scientific research can be sacred, the Natural History Museum of London is a holy of holies for paleontology. Its deep history, highly skilled researchers and staff, and magnificent architecture makes it a very special place. As I wrote before, it is a secular cathedral of science, particularly life science.

2 NHM cathedral of scienceIt is no accident the design of this building reflects a place of worship. Who do you think the white figure on the raised platform in the center is? He might as well be sitting on the altar.

3 Darwin presidingOf course! A portrait on Darwin’s upper left, not visible here and probably rarely noticed, is of his colleague Alfred Russel Wallace.

4 Darwin's NHM viewThis is Darwin’s view of the main hall and entrance of the museum. Six million visitors per year pass under his gaze.

5 Paul and SEM 061616This morning Paul and I worked with a scanning electron microscope to study particular fossils we had set aside for closer examination. Paul is the best scanning electron microscopist I have met.

6 SEM stageThis is the open stage and chamber of the SEM, with a brachiopod fixed in place by Paul for scanning. It is a complicated apparatus that can move the specimen in almost all directions in a vacuum under the electron beam.

7 Cortex pdt19574The first specimen we worked with was one of the Jurassic snuff-boxes. This is part of Cassidy Jester’s Independent Study project and her continuing research with Tim Palmer and me. Paul and I are mystified by the pattern we see here in the cortex of the snuff-box.

8 Ooid pdt19575These are two ferruginous ooids embedded in the cortex of the snuff-box. They show exactly the same mysterious irregular platy objects. Tim Palmer suggests they may be limonite, which is amorphous (without crystals). We’ll test that idea later with mineralogical and elemental analysis.

9 Jeffrey Thompson at NHM 061616I was delighted to see my friend Jeffrey Thompson in the palaeontology section doing research for his dissertation at the University of Southern California. He made an earlier appearance in this blog when he was just a kid.

10 Oscar Mmari and Jubilate Lema in LondonFor lunch I met my former student and veteran of an Independent Study field trip to Israel Oscar Mmari (on the left) and fellow Wooster graduate Jubilate Lema on the right. Both of these young Tanzanians are now making their way in the world. Oscar starts this fall at Imperial College, and Jubilate is an economist working with an investment firm in Johannesburg, South Africa. We had a delightful meal and walk around the museum neighborhood.

11 Dinner view 061616My long day ended with an excellent dinner with Paul and Patricia Taylor at the Swan Restaurant along the Thames River. This was our view from the table. This will all seem a dream in just two days time.

 

A day at the Natural History Museum in London

June 14th, 2016

1 Drawer of brachiopodsLondon, England — My first full day at The Natural History Museum in London was interesting and inspiring as always, but it did have its tedium. This drawer of Ordovician brachiopods, for example. I scanned each with my handlens in the dim lighting looking for a particular kind of encruster.

2 Drawers of brachiopodsDrawer after drawer. Saw many curious fossils, but not one example of what I was looking for. Not an uncommon experience!

3 Harry photographing 061416One of the best parts of a museum visit is meeting skilled staff. Harry Taylor is a master photographer of fossils. Paul Taylor and I took him a fossil this morning and he immediately created a superb image for our work. In my inexpert photograph above, what looks like a blast furnace behind the camera is his lighting and flash system.

4 Harry Paul photographyHarry and Paul discuss the image on screen.

5 Bryo copyHere is a small version of the final result of Harry’s artistry. The original file is 111 megabytes! This is a brachiopod (Rafinesquina ponderosa) from the Cincinnatian rocks of southern Ohio. It is encrusted with something special I’ll describe in a later post. We’ll use this high-resolution image for detailed mapping of this surface.

6 Emanuela Di Martino SEM 061416Paul and I visited our colleague Emanuela Di Martino to congratulate her on Italy’s recent win in the Euro 2016 football tournament. She is operating the Scanning Electron Microscope (SEM) Paul and I will be using in two days. I’ve sat here for many hours scanning specimens with Paul.

7 Tony Wighton cuttingPaul and I had a bryozoan we wanted to cut in half to study its interior. Tony Wighton immediately sliced it for us.

8 Tony Wighton polishingTony then gave each half a mirror finish, producing spectacular specimens that considerably enhance the value of the collections.

It was a good day at the museum. The rain stopped long enough for us to get fresh hamburgers at the nearby open market for lunch, and then we had drinks at the Victoria & Albert Museum next door. I don’t take any of this for granted!

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