A dusty but successful start on field work in southern Israel

March 12th, 2012

MITZPE RAMON, ISRAEL–Melissa Torma, our friend Yoav Avni (Geological Survey of Israel), and I just ended a productive first day in the field. The two of them are shown above in classic paleontological poses. They are collecting fossils from Subunit 51 of the Matmor Formation (Middle Jurassic) in Hamakhtesh Hagadol in the northern Negev. We found excellent crinoid stems and calyx plates, brachiopods, corals, sponges, echinoid spines, serpulid worms, clams, and oysters.The day was very windy but seasonably cool.

You might be wondering why the sky in the above photograph is not the usual bright blue for this region? It is because the air is filled with dust blown off the Sahara Desert to the eastern Mediterranean countries (see NASA image below from 2011). This is a common occurrence here in the spring when a storm system is on its way. In the course of a year, every square kilometer in Israel receives 30-60 tons of this dust. The storm will bring rain to northern Israel tomorrow and Wednesday, but it is very unlikely to break the drought here in the southern dessert.

Shown below is a curious fossil Yoav found at our new site in the Matmor Formation we’ve called (creatively) “halfway”. It is a crinoid stem with a pair of skeletal galls, each with several holes. It appears some organisms infected the living crinoid, which then responded by growing skeletal tissue around the offending critters. Eventually the walled-in organisms drilled their way out, leaving the holes. This is what it looks like, anyway. Feel free to speculate!

I’ve placed a slightly different view of the fossil below to show that these are not encrusters but rather echinoderm skeletal material.

We had a great day despite the pervasive dust and wind gusts. It feels so good to get back to a desert again.

Wooster Geologists in southern Israel for Spring Break fieldwork

March 11th, 2012

It’s a low-light, iPad photo, but at least it shows Wooster geology junior Melissa Torma enjoying a fine meal in the Hotel Ramon of Mitzpe Ramon, deep in the Negev of Israel. We arrived here this afternoon after a 22-hour journey from Ohio. The hardest part for me was enduring the 10.5-hour flight and then making a quick transition to driving through heavy Tel Aviv traffic on our southern journey. It all went well, though, and we are safely in our rooms getting ready for our first day of fieldwork tomorrow.

Melissa and I are here to measure sections and collect specimens for her Senior Independent Study project involving the description and paleoecological analysis of a Jurassic brachiopod-crinoid community in the Matmor Formation of Hamakhtesh Hagadol. I’ve collected these crinoids before here, and now Bill Ausich of Ohio State University and I are describing them as a new species of Apiocrinites. Melissa and I want to find more specimens (we hope more complete specimens) of this crinoid and place them in the context of the entire marine community they inhabited. Our partner in this effort is again our friend Yoav Avni of the Geological Survey of Israel.

When we left the USA yesterday there was a series of violent actions between terrorists in Gaza and the Israel Defense Forces. You may hear about rockets from Gaza striking southern Israel, but they are far from us. We see no evidence of the fighting here. We are very safe in the vastness of the Negev Highlands.

Wooster’s Fossil of the Week: An ichthyosaur vertebra (Middle-Late Jurassic of Wyoming)

March 11th, 2012

It’s only half a bone, but the above is one of my favorite fossils. This is a vertebra of an ichthyosaur, identifiable by its figure-8 cross-section. It is from the Sundance Formation (Middle-Late Jurassic) of Natrona County, Wyoming … and is the first ichthyosaur bone I found. There is not a lot to go on with a single bone fragment like this, but luckily for me only one ichthyosaur has been found in the Sundance: Ophthalmosaurus natans (Marsh, 1879). (“Ophthalmosaurus” is sometimes spelled “Opthalmosaurus” in the literature, and the inconsistency maddens me.)

Finding the ichthyosaur bones on June 23, 2008. Image courtesy of my friend Paul D. Taylor at the Natural History Museum.
Ophthalmosaurus reconstruction (along with some nice ammonites) from Wikipedia. Image Creator: Dmitry Bogdanov.

Ichthyosaurs were magnificent animals that were contemporaries of the dinosaurs. Ichthyosaur means “fish-lizard”, but they were neither fish nor lizards but a unique type of marine reptile. Their streamlined bodies are excellent examples of convergent evolution with the unrelated dolphins and sharks.

Ophthalmosaurus is best known for its very large eyes, up to 10 cm in diameter, with protective bones called sclerotic rings. They probably used these eyes to see in deep, murky waters, or they hunted prey at night.
This view of vertebrae cut in half is from the first paper to describe ichthyosaurs: Home (1814). You can see the distinctive figure-8 shape, known professionally as “cupped vertebrae”. The ichthyosaur specimen Home presented was found by the famous Mary Anning and her brother Joseph. Home thought the animal was some kind of odd fish. Home and the Annings had much more than just these vertebrae, but I like the symmetry of their big discovery and my little one.
Sir Everard Home, 1st Baronet FRS, 1756-1832, was a British physician fascinated by anatomy. Besides the ichthyosaur, he is also known for the earliest anatomical work on the platypus.

References:

Home, E. 1814. Some account of the fossil remains of an animal more nearly allied to fishes than any of the other classes of animals. Philosophical Transactions of the Royal Society of London 104: 571–577.

Huene, F. von. 1922. Die Ichthyosaurier des Lias und ihre Zusammenhage: Berlin (Gebr. Bonrntraeger), 114pp.

Maisch, M.W. 2010. Phylogeny, systematics, and origin of the Ichthyosauria – the state of the art. Palaeodiversity 3: 151–214.

Marsh, O.C. 1879. A new order of extinct reptiles (Sauranodontia), from the Jurassic Formation of the Rocky Mountains. American Journal of Science, 3rd series, 17: 85-86.

O’Keefe, F.R., Street, H.P., Cavigelli, J.P., Socha, J.J. and O’Keefe, R.D. 2009. A plesiosaur containing an ichthyosaur embryo as stomach contents from the Sundance Formation of the Bighorn Basin, Wyoming. Journal of Vertebrate Paleontology 29: 1306–1310.

Wooster’s Fossils of the Week: Belemnites (Jurassic of Wyoming)

November 20th, 2011

This week’s fossils are among the most recognizable. They certainly are popular in my paleontology courses because no one has ever misidentified one. Belemnites (from the Greek belemnon, meaning javelin or dart) were squid-like cephalopods that lived in the Jurassic and Cretaceous Periods. You would never guess their original appearance from the fossils above. These are guards or rostra, internal hard parts that look nothing like the external animal. They are often found in large accumulations called “belemnite battlefields” (Doyle and MacDonald, 1993).
The above image shows a remarkable fossil belemnite in the State Museum of Natural History, Stuttgart, Germany (courtesy of User Rai’ke on Wikimedia). It shows their squidy form and ten equal-sized arms studded with little hooks for holding prey. They probably ate small fish and invertebrates.
The guard or rostrum is solid calcite at its distal end with a phragmocone (chambered shell) at the other. This phragmocone is only rarely preserved. The rostrum above is from the Zohar Formation (Jurassic) of the Golan in northern Israel near Neve Atif.

Belemnites have played an important role recently in sorting out Mesozoic climate change. Their solid calcitic rostra are ideal for examining stable isotopes that fluctuated with water temperature. Dera et al. (2011) showed that the Jurassic had significant climate variations based on the isotopes in belemnite fossils.

Belemnites have a long history in folklore. The English called them “thunderbolts” because they thought they were formed by lightning strikes. The Scottish knew them as “botstones” that cured horses of various ailments. The Swedish thought they were “gnome candles”. The Chinese called them “sword stones”. Much more prosaically, the belemnite is the state fossil of Delaware.
An engraving of belemnite rostra by Captain Thomas Brown (1889).

References:

Brown, Captain T. 1889. An atlas of fossil conchology of Great Britain and Ireland. With descriptions of all the species. Swan Sonnenschein & Co.

Dera, G., Brigaud, B., Monna, F., Laffont, R., Pucéat, E., Deconinck, J-F., Pellenard, P., Joachimski, M.M., and Durlet, C. 2011. Climatic ups and downs in a disturbed Jurassic world. Geology 39: 215–218.

Doyle, P. and MacDonald, D.I.M. 1993. Belemnite battlefields. Lethaia 26: 65-80.

Wooster’s Fossils of the Week: barnacle borings (Middle Jurassic of Israel)

August 7th, 2011

Tiny little trace fossils this week in a Jurassic crinoid stem from the Matmor Formation of the Negev Desert. They are borings produced by barnacles, which are sedentary crustaceans more typically found in conical shells of their own making. These barnacles are still around today, so we know quite a bit about their biology. (More on how in a minute.) These acrothoracican barnacles drill into shells head-down and then kick their legs up through the opening to filter seawater for food. They’ve been doing it since the Devonian Period (Seilacher, 1969; Lambers and Boekschoten, 1986).

This particular trace fossil is Rogerella elliptica Codez & Saint-Seine, 1958. It is part of a diverse set of borings in the Matmor Formation (Callovian) of Hamakhtesh Hagadol, Israel, recently described in Wilson et al. (2010).

We know so much about boring barnacles because Charles Darwin himself took an almost obsessive interest in them early in his scientific career. While on his famous voyage in the HMS Beagle, Darwin noticed small holes in a conch shell, and he dug out from one of them a curious little animal shown in the diagram below.


Cryptophialus Darwin, 1854

He called it “Mr. Arthrobalanus” in his zoological notes. He figured out early that it was a barnacle, but he was astonished at how different it was from others of its kind. He later gave it a scientific name (Cryptophialus Darwin, 1854) and took on the problem of barnacle systematics and ecology. Eight years and four volumes later his young son would ask one of his friends, “Where does your father do his barnacles?” The diversity of barnacles played a large role in Darwin’s intellectual development and, consequently, his revolutionary ideas about evolution (Deutsch, 2009).

Burrowing barnacle diagram from an 1876 issue of Popular Science Monthly.

References:

Codez, J. and Saint-Seine, R. de. 1958. Révision des cirripedes acrothoracique fossiles. Bull. Soc. géol. France 7: 699-719.

Darwin, C.R. 1854. Living Cirripedia, The Balanidae, (or sessile cirripedes); the Verrucidae. Vol. 2. London: The Ray Society.

Deutsch, J.S. 2009. Darwin and the cirripedes: Insights and dreadful blunders. Integrative Zoology 4: 316–322.

Lambers, P. and Boekschoten, G.J. 1986. On fossil and recent borings produced by acrothoracic cirripeds. Geologie en Mijnbouw 65: 257–268.

Seilacher, A. 1969. Paleoecology of boring barnacles. American Zoologist 9: 705–719.

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.

Wooster’s Fossil of the Week: Ancient shrimp burrows (Middle Jurassic of Israel)

July 10th, 2011

This week we have a trace fossil, the burrow Thalassinoides. It is represented by one of my favorite images, reproduced above, showing a very large Thalassinoides suevicus in the Zohar Formation (Middle Jurassic, Callovian) of Makhtesh Qatan in the Negev of southern Israel. Holding the scale is Wooster geologist and Independent Study student Allison Mione (’05) during our 2004 Israel expedition. These burrows were originally described as giant desiccation cracks, but I.S. student Kevin Wolfe (’05), Israeli geologist Yoav Avni and I reinterpreted them as burrows in a rocky shore complex (see Wilson et al., 2005).

Thalassinoides is a complex trace fossil that is today made primarily by thalassinidean crustaceans (a type of shrimp; see below). We know a lot about how the burrows are made today by shrimp, and our knowledge is growing about how the ancient systems were excavated, at least in the Mesozoic and later. We have fossil shrimp preserved in Thalassinoides from the Jurassic (Sellwood, 1971) and the Cretaceous (Carvalho et al., 2007).

Pestarella tyrrhena, a modern thalassinidean shrimp. Image from Wikipedia.

Reconstruction of Mecochirus rapax in a Cretaceous Thalassinoides. A) In its burrowing life mode; B) Predominantly horizontal Thalassinoides suevicus burrow systems showing two successive event levels, with Mecochirus in life position. From Carvalho et al. (2007, fig. 3).

The burrow systems in the Zohar Formation of Israel were critical in working out the depositional environment of these carbonate sediments. We could see that first the water was comparatively deep (below wavebase) with worm burrows (Planolites). Then relative sea level dropped and the Thalassinoides burrows cut through the Planolites fabric, showing that the sediment was become stiffer. Finally bivalve borings (Gastrochaenolites) in the same rock indicated that the sediment had cemented into a shallow water hardground. This hardground showed tidal channels cut into its top surface (Wilson et al., 2005).

This work was done with virtually no “body fossils”, meaning evidence of the actual bodies of the organisms living in and on the sediment. Trace fossils, evidence of organism activity, were the only indications of this significant environmental change. This is why the study of trace fossils (ichnology) should be a part of the education of every paleontologist and sedimentologist.

References:

Carvalho, C.N., Viegas, P.A. and Cachao, M. 2007. Thalassinoides and its producer: Populations of Mecochirus buried within their burrow systems, Boca Do Chapim Formation (Lower Cretaceous), Portugal. Palaios 22: 104-109.

Sellwood, B.W. 1971. A Thalassinoides burrow containing the crustacean Glyphaea undressieri (Meyer) from the Bathonian of Oxfordshire. Palaeontology 14: 589-591.

Wilson, M.A., Wolfe, K.R., and Avni, Y. 2005. Development of a Jurassic rocky shore complex (Zohar Formation, Makhtesh Qatan, southern Israel). Isr. J. Earth Sci. 54: 171–178.

A geological and historical tour of the Polish Jura

June 23rd, 2011

SOSNOWIEC, POLAND–A most memorable day traveling through part of the Polish Jura with Michał Zatoń and his delightful family of his wife Aneta and son Tomasz (4 and a half years old). The Polish Jura, also known as the Kraków-Częstochowa Upland, is a long exposure of Upper Jurassic (Oxfordian) limestones in southwestern Poland. We saw a bit of the rock yesterday — a hard white carbonate with a core of lithistid sponge mounds. The area is deeply eroded by karstic processes and so has vertical cliffs, pillars of limestone, sinkholes and caves. Since at least the 14th Century there have been stone fortifications (called “Eagles’ Nests”)  built on these rocks overlooking the deep valleys and access to inner Poland. One of these is the Castle of Pieskowa Skała shown above.

Michał Zatoń showing how the Jurassic limestones are used to effectively lengthen and strengthen the castle walls at Pieskowa Skała. When bedrock is used like this it is called evocatively “living stone”. A similar use of living stone was recorded in this blog two years ago from Jerusalem.

A large karstic pillar called Hercules’ Club near the Castle at Pieskowa Skała. It is juxtaposed with the castle most dramatically when viewed from down in the valley and is included in almost every early drawing or painting of the castle.

Another one of the Eagles’ Nests is Ojców Castle built in the second half of the 14th century by King Kazimierz the Great commemorating the exile and hiding in the area of his father Władysław Lokietek (called “The Elbow-High” because of his stature). The cliffs give this castle (now in ruins) an excellent view of the valley below.

The 14th Century King Władysław Lokietek mentioned above hid from his rivals in this karstic terrain. There is a legend that he took refuge in this particular cave now called “Grota Lokietka”. It is a good excuse to develop the cave into a tourist attraction. We walked through the slippery, dark and cold passages and chambers with a large crowd of enthusiastic Poles examining cave structures and listening to tales of cryptic royalty.

The third castle of the day is not in the Polish Jura, but I’ve included it for completion. It is Będzin Castle in Będzin, a small city next to Sosnowiec and the home of Michał and his family. It too was built in the second half of the 14th Century and obviously took advantage of the local geology, in this case exposures of Triassic limestones. More on the tragic history of Będzin in a later post. We had a very interesting, informative and touching tour of the city center near the end of the day.

I again want to thank my Polish paleontologist host, colleague and friend Michał Zatoń for arranging a wonderful and productive visit. I shall return with Wooster students someday soon. I am certain they will enjoy their visit and work here as much as I have.

A delightful day in the Jurassic of Polish Silesia

June 22nd, 2011

SOSNOWIEC, POLAND–It could not have been a better day for field work: warm with a light, cooling breeze and plenty of leafy green shade. Our team consisted of me and three Polish scientists: Michał Zatoń and Wojciech Krawczyński (I work hard to get those special Polish letters in there!) of the University of Silesia, and PhD student Tomasz Borszcz of the Institute of Oceanology in Sopot, Poland (near the famed city of Gdansk on the Polish Baltic coast). Our goal was to simply see some Jurassic rocks and fossils and talk geology. Mission accomplished.

The top image shows outcrops of remarkable lithistid sponge mounds from the Oxfordian (earliest Upper Jurassic) punching up through the forest cover a few kilometers northeast of Sosnowiec. They formed relatively deep on the Jurassic seafloor and supported an associated brachiopod community.

I was able to visit for the first time one of the localities from which large Middle Jurassic oncoids (cobbles and pebbles covered with the deposits of microbial biofilms) were found and became the basis for a paper co-authored with Michał and Wojciech. In the picture above of a broken cobble you will notice bivalve borings (Gastrochaenolites) penetrating from the outside.

Lunch was in a tavern near the town square of Sławków in the Silesian Highlands. The Polish custom of carving the date of the building on the central roof beam meant we could see right away it was constructed in 1701. (It seems to be preserved in a modern shell of some kind.) I had a typical Silesian meal of rolled beef and dumplings (I think).

A view of the Silesian Highlands from a street in Sławków. This small city is the western terminus of the Broad Gauge Metallurgy Line, a rail system designed “in communist times” to transport iron ore from Ukraine to iron smelters in Poland. The rail gauge in Ukraine and points east is wider than the standard gauge in western Europe.

Our last stop of the day was to a set of deep holes in the middle of a forest. Amateur fossil collectors dug through about two meters of soil and Pleistocene sediment to expose a layer of Callovian (latest Middle Jurassic) rock rich in ammonites, belemnites and other fossils. The three paleontologists, in typical paleontological poses, are from the right Wojciech, Michał and Tomasz.

 

 

Quality time with a Polish microscope

June 21st, 2011

SOSNOWIEC, POLAND–A day in the lab with my colleague Michał Zatoń at the University of Silesia. We sorted through two very different paleontological problems with a microscope and a lot of hand waving. The first task was to come up with a hypothesis about the origin of the strange pitted tubes shown above. They are found on hiatus concretions of the Late Bathonian (Middle Jurassic) exposed in Zarki, Poland. We recently described and analyzed the sclerobionts on and in these concretions (see Zaton et al., 2011), but these tubes remained a mystery. We think now that they are remnants of egg cases laid by gastropods (snails) on the undersurfaces of the concretions, and we’ve started on the manuscript.

The coiled encrusting shell below is of a Devonian microconchid originally collected by the keen amateur Brian Bade in western New York and generously donated to our research. This group has some fascinating similarities and differences from its Polish cousins, so we have started a systematic project to determine if they represent a new genus or not. (Brian will be excited to hear this.)

Michal's office/lab in the Faculty of Earth Sciences, University of Silesia.

Tomorrow we set off for fieldwork in the area so I’ll post pictures of the wonderful Polish countryside!

Reference:

Zatoń, M., Machocka, S., Wilson, M.A., Marynowski, L. and Taylor, P.D. 2011. Origin and paleoecology of Middle Jurassic hiatus concretions from Poland. Facies 57: 275-300.

Wooster’s Fossil of the Week: Coated snails! (Middle Jurassic of France)

June 5th, 2011

In 1988 I had my first visit to France, hosted by my English friend Tim Palmer. We explored Bathonian (Middle Jurassic) limestones in Normandy tracking looking at hardgrounds and other hard substrates. Along the way we stopped in a quarry near the pretty little town of Aubry-en-exmes. There we found thousands of cylindrical white stones. Where broken, we could see they contained some sort of fossil in the center. When I got back to Wooster I cut a few open and polished them down to their centers, revealing the gorgeous snail shells seen above. The shells were originally the mineral aragonite now replaced with coarsely-crystalline calcite.

The snail is known as Bactroptyxis trachaea of the extinct Family Nerineidae in the informal group “Lower Heterobranchia” (which is still around). Cross sections of nerineids like this show their most distinctive feature: elaborate chamber walls inside the whorls of the shell (as seen in a close up below). It was once thought that these complicated structures evolved to strengthen the shell against shell-crushing predators, but now the most common view is that they held special digestive glands to enable them to exploit nutrient-poor organics on carbonate substrates (Barker, 1990).

There is another fossil type here as well: the thick, white calcareous coating of the snails. These are oncolites, a precipitate formed by cyanobacteria. The shells rolled around in a current as the bacteria added layer after layer of calcium carbonate, preserving the shells in such fine detail — and by the thousands.

Reference –

Barker, M.J., 1990. The palaeobiology of nerineacean gastropods. Historical Biology 3: 249-264.

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