Wooster Geologist in London at the British Museum

June 22nd, 2014

Front BM 062214LONDON, ENGLAND — I arrived late last night in London after a series of delays in my departure from Poland, so I was pleased that today was a Sunday so I could chill a bit before work with Paul Taylor tomorrow. If I can visit one place in London (other than the Natural History Museum, of course) it is always the British Museum (above). As you can see, the weather was spectacular — and the crowds took advantage of it. I thought I’d just highlight a set of exhibits that is very cool, despite the fact that few visitors seem to spend much time with it.

Enlightenment textIt is the “Enlightenment: Discovering the World in the Eighteenth Century” gallery. I think it is well done and highly evocative, at least for scientists. My favorite part is there on the right end: “The Natural World”.

Enlightenment cabinetThe cases are deliberately old-timey to evoke the “cabinets of curiosity” 18th Century polymaths had for their collected treasures. In fact, some of these cabinets themselves date back to that period. Here we see rocks, fossils, plants and animals collected by Enlightenment explorers, philosophers, historians, and just plain rich guys. These were the very specimens that thrilled and puzzled some very great minds — not that we don’t have plenty of mysteries remaining about them.

Mastodon BM 062214This is a mastodon jaw (Mammuthus americanum) collected “near the Ohio River” and given to the museum in 1768. It was called “The Unknown American” and thought to be from some extinct carnivorous elephant-like beast.

Smith fossils BM 062214My favorite set of fossils here was collected and used by the famous William “Strata” Smith (1769-1839)  in his pioneering work on geological correlation and mapping. Fossils like these were crucial to working out the relationships of rock layers (“strata”) and early concepts of Earth history. There is something inexplicably enchanting about seeing objects handled by past luminaries.

Schist sarcophygusOn an unrelated but geological note, I have a complaint about a small number of the displays. This ancient Egyptian sarcophagus is an example. What is the rock type here? I’d say a basalt or maybe a fine-grained granodiorite (like the Rosetta Stone).

Schist closer BM 062214Here’s a closer view of the sarcophagus. The sharpness of the carving shows how fine-grained and massive this rock seems to be. (I know the rules — no scratching the artifacts to test their properties.) But what does the sign say?

Schist signBlack schist? No way. Schist is foliated and flakey and most decidedly not massive and so superbly suited to carving. Maybe someone will correct my notion of “schist”, but right now I’m certain this part of the label is wrong. I’ve seen this fairly often in museum displays: the rock types given don’t always match what appears to be the actual lithologies. Not enough geoarchaeologists to go around, I suppose.

Romano British hed 062214Here’s a cool Romano-British sculpture that did have a proper identification as “limestone”. (And to be fair, most are correctly labeled.) I liked this artifact in particular because you could look closely at the broken bits —

Ooids 062214The rock is made primarily of these little calcitic spheres called ooids. I would not be at all surprised to learn that this is a Portlandian (Upper Jurassic) limestone from southern England.

It was a fun day at one of the world’s finest museums. Tomorrow I begin work at another.

Wooster’s Fossil of the Week: A silicified rhynchonellid brachiopod from the Permian of West Texas

June 22nd, 2014

Rhynchonellid crura Permian Texas 585Sometimes fossils can be more useful when broken than whole. Above is a much-abused rhynchonellid brachiopod from the Road Canyon Formation (Middle Permian, Roadian, about 270 million years old) found in the Glass Mountains of southwestern Texas. It is part of a set of silicified fossils we etched out of a block of limestone in the last century. The shell has been replaced with resistant silica, so it was easy to extract from the limestone matrix with a long bath in hydrochloric acid that dissolved the carbonate but left everything else. The fossils are like delicate little glass husks. We’ve featured them in this blog several times.

Update: Matt Clapham kindly corrected me in the comments, and it is worth repeating in the text: “It’s Stenoscisma. The large spoon-shaped projection is actually called a spondylium, formed from merged dental plates and it’s quite distinctive for the Stenoscismatidae. The crura are broken but still visible in your specimen; they are the little struts parallel to the narrowest part of the spondylium. There are five Stenoscisma species that appear common in the Road Canyon Formation and yours looks most similar to Stenoscisma triquetrum to me (weakly sulcate with ribs that are somewhat subtle but still extend near the beak).” I made a bonehead mistake labeling the spondylium incorreectly, hence the “c”. Here’s to the value of Twitter, blogging, and knowledgeable colleagues!
Rhynchonellid Permian Texas 585Here’s the dorsal side of the specimen for completion. The exterior is in poor shape.

I’d love to identify this specimen to at least the genus level [update: see above and the comments!], but there is not enough detail preserved, at least for my skill set. The Permian brachiopods of West Texas were famously studied by G. Arthur Cooper and Richard E. Grant in the 1960s and 1970s. The numbers of species are overwhelming in this ancient reef system, and almost all of them are preserved in this delicate way.

References:

Cooper, G.A., and Grant, R.E., 1964, New Permian stratigraphic units in Glass Mountains, West Texas. American Association of Petroleum Geologists Bulletin 48: 1581-1588.

Cooper, G.A., and Grant, R.E. 1966. Permian rock units in the Glass Mountains, West Texas, In: Contributions to stratigraphy, 1966: U.S. Geological Survey Bulletin 1244-E: E1-E9.

Cooper, G.A. and Grant, R.E. 1972. Permian brachiopods of West Texas, I. Smithsonian Contributions to Paleobiology 14: 1–228. [and five other volumes]

Olszewski, T.D. and Erwin, D.H. 2009. Change and stability in Permian brachiopod communities from western Texas. Palaios 24: 27-40.

The Triassic limestones at Góra Świętej Anny, Poland

June 18th, 2014

Gora sw. Anny signSOSNOWIEC, POLAND — My friends Michał Zatoń and Tomasz Borszcz took me on a very pleasant day trip to Góra Świętej Anny in southwestern Poland about an hour’s drive northwest from Sosnowiec. This is a place of considerable geological and historical interest. It is an eroded volcanic caldera and the easternmost occurrence of the fine-grained igneous rock basalt in Europe. You would think I’d be able to show you at least a bit of basalt, but we saw only the surrounding Middle Triassic limestone country rock. (Sorry, Dr. Pollock.) We’ll talk about the history later. Now we’ll look at the geology.

Muschelkalk long 061814Here is a great exposure of the Muschelkalk, a Middle Triassic sequence of limestones and dolomites that extends across central and western Europe. This is its best exposure in Poland. The rock appears very massive in this old quarried wall, but it actually has many distinct layers. Michał is standing at the top of stairs that lead down into a massive Nazi amphitheater called a Thingstätte, but more on this later.

Muschelkalk brachs 061814Part of the Muschelkalk unit is dominated by terebratulid brachiopods, many of which are seen on this slab.

Triassic encrinite 061814The topmost Muschelkalk here contains thick beds made primarily of crinoid skeletal debris, a kind of deposit known as an encrinite. We’ve seen encrinites before in this blog.

trace fossil sign 061814You don’t often see informative signs dedicated to the description of a trace fossil type. Rhizocorallium commune is the most common ichnofossil in this part of the Muschelkalk. It is a ropy, loopy tube produced in this case by crustaceans, probably including the decapod shrimp Pemphix.

Rhizocorallium 061814The slabs used to pave the walks and plazas in this area are filled with Rhizocorallium commune traces.

View 061814Finally, this is a view west from Góra Świętej Anny towards the Oder River. It is the highest place around, dominating this fertile valley rich with farms, mines and factories. This will be the reason it is so culturally and historically significant in Silesia.

A new Polish colleague (and cool dinosaur model)

June 17th, 2014

T rex 061714SOSNOWIEC, POLAND — The above full-scale model of Tyrannosaurus rex is one of my favorite dinosaur reconstructions. It sits in front of the Earth Sciences Building at the University of Silesia. Since it is outside the lighting is always dramatic, and the artists paid close attention to even tiny details like the reported coat of downy feathers on its back (see below).

T rex feathers 061714The roughening you see in the upper half of the image represents the feathery covering. We can only imagine what colors were present in the original.

Alina MW 061714Here is a new Polish colleague I met this morning. Alina Chrząstek is a paleontologist at the University of Wroclaw. She is a specialist in invertebrates and trace fossils. A few months ago she sent me photos of rock and fossil specimens she had questions about, and I told her we could meet when I was in Poland. She came today with boxes and bags of specimens, a few of which are shown below.

Erratics collection 061714These are glacial erratics from a moraine in southwestern Poland. They are rocks of a variety of types and ages scraped up by glaciers in the north and deposited in the south. Alina is sorting through what fossils are in them. It is a fun collection because it contains rocks from the Cambrian to the Cenozoic, with all manner of trace and body fossils. They can be quite a challenge to identify because the stratigraphic context is gone.

Half my day was spent writing, so I have nothing else to report. Tomorrow, though, is going to contain a field trip to the Góra Świętej Anny Mountain. (I hope everyone is noticing how hard I work at getting the Polish letters correct!)

Research begins in southern Poland

June 16th, 2014

Gillette 061614SOSNOWIEC, POLAND — On this beautiful day I began research at the University of Silesia with Michał Zatoń and Tomasz Borszcz in this impressive building. (It is reportedly the tallest Earth Science building in the world, although the Chinese are on the case.) Our first project, and the one I will devote most of my remaining Polish time to, is an analysis of fish-bitten echinoid (sea urchin) spines from the Middle Jurassic Matmor Formation of southern Israel (see below).

Spine 173_bittenWe have dozens of these crunched rhabdocidarid spines, which are critical evidence of early predation on regular echinoids. We hope our work will help illuminate the evolution of predator adaptations in the echinoids, and the actions of the hungry fish. More on this later.

Spines arrayed 061614Here we have a simple sorting of the spines in relation to their likely position on the echinoid test (body skeleton). Pretty simple, but it was an easy way for us to discuss spine morphology and function.

Michal office 061614To give you a glimpse of my new surroundings, here is a view of Michał’s office. As with every working paleontologist, there are plenty of specimens, books and papers!

Office view 061614The view from Michał’s office of Sosnowiec.

Silesia dorms 061614This is looking from Michał’s department building towards a series of dormitories for students at the University of Silesia.

Lunch 061614You know at some point I need to show some Polish food. This is today’s lunch. Note the crunchy latke and the pierogis. You pay for this food by its weight on the plate. This scrumptiousness plus a Sprite cost me $4.

Hotel Cumulus 061614This is my hotel in neighboring Będzin.

Hotel area Będzin Castle 061614Będzin Castle, which is a short walk from my hotel. You can expect a history post coming up soon!

 

Wooster’s Fossil of the Week: A geopetal structure in a boring from the Middle Jurassic of Israel

June 15th, 2014

Geopetal Structure 585We have a very simple trace and body fossil combination this week that provides a stratigraphic and structural geologic tool. Above is a bit of scleractinian coral from the Matmor Formation (Middle Jurassic, Callovian) of Makhtesh Gadol in southern Israel. The coral skeleton was originally made of aragonite. It has been since recrystallized into a coarse sparry calcite, so we can no longer see the internal skeletal details of the coral. In the middle of this polished cross-section is an elliptical hole. This is a boring made by a bivalve (the trace fossil Gastrochaenolites). Inside the boring you see a separate elliptical object: a cross-section of a bivalve shell. This could be the bivalve that made the boring or, more likely, a bivalve that later occupied the boring for a living refuge. This, then, is the trace fossil (Gastrochaenolites) and body fossil (the bivalve shell) juxtaposition.

That stratigraphic and structural interest is that the boring and the bivalve shell are partially filled with a yellow sediment. This sediment has gravitationally settled to the bottom of these cavities (at slightly different levels). These holes have thus acted as natural builders’ levels showing is which way was down and which was up at the time of deposition. We can tell without any clues from the recrystallized coral the “way up” before any later structural deformation (or in this case rolling around on the outcrop) changed the orientation of the coral. Pretty cool and simple, eh? The name for this feature is a geopetal structure. There are some faulted and folded sedimentary rock exposures in the world where we search diligently for these little clues to original orientation (see, for example, Klompmaker et al., 2013). Not all geopetal structures have fossil origins (i.e., Mozhen et al., 2010), but most do. A little gift from paleontology to its sister disciplines.

References:

Klompmaker, A.A., Ortiz, J.D. and Wells, N.A. 2013. How to explain a decapod crustacean diversity hotspot in a mid-Cretaceous coral reef. Palaeogeography, Palaeoclimatology, Palaeoecology 374: 256-273.
Mozhen, G., Chuanjiang, W., Guohui, Y., Xueqiang, S., Guohua, Z. and Xin, W. 2010. Features, origin and geological significance of geopetal structures in Carboniferous volcanic rocks in Niudong Block, Santanghu Basin. Marine Origin Petroleum Geology 3: 15.
Wieczorek, J. 1979. Geopetal structures as indicators of top and bottom. Annales de la Societé géologique de Pologne 49: 215-221.

The last presentations of the 2014 Larwood Meeting, including a sober reminder for paleontologists

June 13th, 2014

pdt lecturing 061314SOPOT, POLAND — This morning we had the final set of talks at Larwood 2014. Out of all the presentations, the one that struck me the most was by Paul Taylor and Andrea Waeschenbach entitled “Molecular phylogeny and the adequacy of skeletal characters in cyclostome taxonomy: The alarming case of Diaperorcia purpurascens.” Paul is shown delivering it above. This project represents the best of what these bryozoan conferences are about: the combination of biology and paleontology to further our understanding of the evolution and ecology of this large phylum. It also warned paleontologists to never be complacent about the value of morphology (shape and form) for sorting out systematic and evolutionary relationships.

Diaperoecia purpurascens is a “fixed-walled, tubuliporine” cyclostome bryozoan species common in New Zealand waters today. Molecular sequence data, though, shows it is without a doubt within the “free-walled cerioporine” cyclostome genus Heteropora. You don’t need to know why those terms actually mean to understand that the molecular work has shown that two dissimilar groups share a surprisingly close common ancestor — so close that the systematics are now fully disrupted. When we knew only the morphology of these bryozoans the differences between them were apparent at a high taxonomic level. Now that we have molecular data it is brutally clear that our reliance on shape and form to separate the groups was an illusion. Molecules trump skeletal evidence — and all paleontologists have to work with are the skeletons.
pdt image 2 061314Paul and Andrea did find, though, that in the early colony growth (astogeny) of these bryozoan groups they share a common pattern of tiny pores (pseudopores) on the earliest portion of the colonial skeleton (the protoecium; see above and below). It is this morphological feature, as subtle as it is, that shows the groups share a close common ancestor.
pdt slide 1 061314The lesson is that paleontological systematics are always provisional. We do our best with morphology alone because that’s what we have, but we should be forever haunted by the knowledge that we lack full biological evidence.

Wooster Geologist on the Baltic Coast

June 11th, 2014

HotelBalconyView061114SOPOT, POLAND — Yes, that’s a view from my hotel window. I’ve suddenly found myself in an old resort town on the Baltic coast of Poland near the cities of Gdansk and Gydnia. Another one of those astonishing geographic transformations we can so easily make.

I’m here for the Larwood Meeting, an annual gathering of bryozoologists held in various places around the world. Besides learning more about these complex little colonies (both fossil and recent), I’ll be presenting a summary of the work Steph Bosch (’14), Paul Taylor and I did on the new bryozoans from the Middle Jurassic of southern Israel. After the meeting I travel south by train with Tomasz Borszcz to visit Michal Zaton at the University of Silesia for some joint projects. From there it is on to London for a few days with ace paleontologist Paul Taylor at the Natural History Museum. I’m at the end of a research leave this summer so I have more travel than usual.

For now I’m enjoying an extraordinary day on the Baltic shore before the first meeting event this evening. My next images will be much more prosaic! My posts will be a bit shorter than usual because I have to stand in the shower to get enough wireless signal to connect. (There’s an accident waiting to happen …)

Wooster’s Fossil of the Week: A fragment of an asteroid (the sea star kind) from the Upper Cretaceous of Israel

June 8th, 2014

zichor asteroid aboral 585This is not an important fossil — there is not enough preserved to put a name on it beyond Family Goniasteridae Forbes, 1841 (thanks, Dan Blake) — but it was a fun one to find. It also photographs well. This is a ray fragment of an asteroid (from the group commonly known as the sea stars or starfish) I picked up from the top meter of the Zichor Formation (Coniacian, Upper Cretaceous) in southern Israel (Locality C/W-051) on my field trip there in April 2014. We are looking at the aboral (or top) surface; below is the oral view.
zichor asteroid oral surface 585In this oral perspective you can see a group of tiny, jumbled plates running down the center. This is the ambulacrum, which in life had a row of tube feet extending out for locomotion and grasping prey.
asteroid 2004Above is a sea star held by my son Ted on Long Island, The Bahamas, back in 2004. You can see a bit of resemblance between this modern species and the Cretaceous fossil, mainly the  large knobby ossicles running down the periphery of the rays.

The asteroids have a poor fossil record, at least when compared to other echinoderms like crinoids and echinoids. It appears that all post-Paleozoic asteroids derive from a single ancestral group that squeaked through the Permian extinctions (Gale, 2013). There is a significant debate about the evolution of the asteroids (see Blake and Mah, 2014, for the latest). Unfortunately our little critter is not going to help much in its resolution.

Recently it has been discovered that some living asteroids have microlenses in their ossicles to provide a kind of all-surface photoreception ability. Gorzelak et al. (2014) have found evidence that some Cretaceous asteroids had similar photoreceptors. Maybe our fossil goniasterid fragment could yield this kind of secret property with closer examination.

References:

Blake, D.B. and Mah, C.L. 2014. Comments on “The phylogeny of post-Palaeozoic Asteroidea (Neoasteroidea, Echinodermata)” by AS Gale and perspectives on the systematics of the Asteroidea. Zootaxa 3779: 177-194.

Gale, A.S. 2011. The phylogeny of post-Paleozoic Asteroidea (Neoasteroidea, Echinodermata). Special Papers in Palaeontology 38, 112 pp.

Gale, A.S. 2013. Phylogeny of the Asteroidea, p. 3-14. In: Lawrence, J.M. (ed.), Starfish: Biology and Ecology of the Asteroidea. The Johns Hopkins University Press, Baltimore.

Gorzelak, P., Salamon, M.A., Lach, R., Loba, M. and Ferré, B. 2014. Microlens arrays in the complex visual system of Cretaceous echinoderms. Nature Communications 5, Article 3576, doi:10.1038/ncomms4576.

Loriol, P. de. 1908. Note sur quelques stellérides du Santonien d’Abou-Roach. Bulletin de l’Institut égyptien 2: 169-184.

Mah, C.L. and Blake, D.B. 2012. Global diversity and phylogeny of the Asteroidea (Echinodermata). PLOS ONE 7(4), e35644.

Wooster’s Fossil of the Week: My favorite part of a crinoid (Middle Jurassic of Israel)

June 1st, 2014

Apiocrinites negevensis proximale 585In April of this year I completed my 11th trip to southern Israel for fieldwork in the Mesozoic. My heart warmed every time I saw these robust plates of the crinoid Apiocrinities negevensis, which was reviewed in a previous blog post. They are thick disks of calcite with a heft and symmetry like exotic coins. They are easy to spot in the field because of their size and incised perfect star. They have been a critical part of our paleoecological and systematic studies of the Matmor Formation (Callovian, Middle Jurassic) in the Negev. Lizzie Reinthal (14) and Steph Bosch (14) know them particularly well!
negevensis proximales 1This part of the crinoid is called the proximale. It has a round base that articulates with the columnal below it in the stem, and its top has five facets that hold the basal plates of the calyx. It is thus the topmost columnal, specialized to serve as the integration between the articulated stem below and the complicated head above. The pentastellate (five-armed star, but you probably figured that out) impression is called the areola. In the very center is the open hole of the lumen, which goes from the head all the way down through the stem to the holdfast as an internal fluid-filled cavity.
Composite Miller Apiocrinites arrowedAbove are Miller’s (1821) original illustrations of Apiocrinites rotundus with the proximale shown by the red arrow. Note how thin this piece is compared to the equivalent from Apiocrinites negevensis. The significant thickness of the proximale is one of the distinguishing features of the Negev species.

I saw many more of these beautiful fossils in the field this year. We don’t need any more for our research, but they always indicate that other good fossils are nearby.

References:

Ausich, W.I. and Wilson, M.A. 2012. New Tethyan Apiocrinitidae (Crinoidea; Articulata) from the Jurassic of Israel. Journal of Paleontology 86: 1051-1055.

Miller, J.S. 1821. A natural history of the Crinoidea or lily-shaped animals, with observation on the genera Asterias, Euryale, Comatula, and Marsupites. Bryan & Co, Bristol, 150 pp.

Wilson, M.A., Feldman, H.R. and Krivicich, E.B. 2010. Bioerosion in an equatorial Middle Jurassic coral-sponge reef community (Callovian, Matmor Formation, southern Israel). Palaeogeography, Palaeoclimatology, Palaeoecology 289: 93-101.

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