A day of geological exploration in the Negev: the En Yorqeam Formation (Upper Cretaceous) at Makhtesh Ramon

July 8th, 2013

12_EnYorqeamView070813MITZPE RAMON, ISRAEL–Our final stop on our geological tour today was close to our temporary home: on the northern rim of Makhtesh Ramon (N 30.62831°, E 34.81759). Exposed here is the En Yorqeam Formation (Upper Cretaceous, Cenomanian), seen above as the less resistant marly unit between two resistant limestones. I did my first presentation on Israeli geology with bored and encrusted oysters from the En Yorqeam, which were also the subjects of a Fossil of the Week post.

We visited this outcrop today because there are some stratigraphic questions about its thickness and distribution. Its rich fossil fauna has also not been described in detail. This would be an ideal Independent Study project someday, especially with one large outcrop so close to our headquarters.

13_Echinoids070813Echinoids are the stars of the fossil fauna in the En Yorqeam. In just ten minutes we picked up over a dozen well preserved specimens. The large ones at the top are Heterodiadema lybicum. I don’t know the identity of the two in the bottom row. I bet some sharp student, though, can come up with the names quickly!

An outcrop Dr. Judge would love (Upper Cretaceous of southern Israel)

July 5th, 2013

WadiHavarimDragFold070513MITZPE RAMON, ISRAEL–Wooster Geologists Oscar Mmari’s Independent Study project on the Late Cretaceous phosphorites in the Negev has become multidimensional. His most interesting section is in Wadi Hawarim, where we returned today with Yoav Avni for additional observations and measurements. We are now doing a bit of structural geology that Dr. Shelley Judge would appreciate. In this view above, the dark resistant unit on the left is the lower silicified portion of the Mishash Formation (Upper Cretaceous). Even though it looks like an igneous intrusion, these are sedimentary beds folded so that they are vertical in attitude. On the right you may be able to make out Oscar standing on Mishash beds that are almost horizontal. How does this make sense?

What happened was faulting on the farthest left in this view above. A normal fault perpendicular to this screen has its upthrown block on the left and downthrown block on the right (where Oscar is standing). The Mishash silicified rocks are part of a drag fold as the blocks moved against each other. It appears that this faulting took place while the rest of the Mishash was still accumulating because debris from the silicified layers was spread over the phosphorites as they developed. There may also have been a shallowing of sealevel indicated by a layer colonized by shrimp who made Thalassinoides burrow systems that became inundated with siliciclastic sediment likely derived from the fault scarp.

OscarWadiHavarim070513In this view into Wadi Havarim, the whitish phosphorite beds of the Mishash Formation are in the center above a dark conglomerate and below the yellowish Ghareb Formation.

OscarAtWork070513Oscar is sitting on Mishash conglomerate taking careful notes on this complex geological scenario. He’s going to need his skills in structural geology, sedimentology, stratigraphy and paleontology for this project!

Phosphate success while Jurassic bryozoans remain elusive

July 4th, 2013

OscarOZsection070413MITZPE RAMON, ISRAEL–Oscar Mmari celebrated on his second outcrop today the completion of his stratigraphic columns for his project on the phosphate-bearing portions of the Mishash Formation in the Negev of southern Israel. It is certainly the least pretty section we’ve worked with because it is in the industrialized mining zone near the eastern outlet of Makhtesh Gadol, but we got the work done. This particular place is at N 30.94072°, E 35.03784° (for those of you following along). Look at this place on Google Earth and you’ll see how extensive the phosphate mines are here. Oscar is not yet done with fieldwork because we will come back to his sections for further observations and collecting.

LizzieStephMatmor070413Later in the afternoon we visited outcrops of the Matmor Formation in the northern part of Makhtesh Gadol. Just above Lizzie Reinthal’s right shoulder above (she’s in the center) the outlet from the makhtesh is visible as a break in the surrounding walls. Steph Bosch on the right is bravely hiding her disappointment because after lots of careful peering at the encrusted undersides of beautiful fossil corals, the four of us failed to come up with a single bryozoan. This is curious in itself. The encrusters are well preserved and diverse. (Olev Vinn and I wrote a paper on the various serpulid and sabellid worm tubes; Cezary Krawczynski and I have a paper on the thecideide brachiopods from here.) Every place we think we will see bryozoans we find instead worm tubes and calcisponges. The few Matmor bryozoans collected on previous field trips have been on echinoderm ossicles and holdfasts. Since echinoderms are common where corals are not, and vice versa, it may be that the bryozoans preferred the same conditions the crinoids and echinoids did. Later on this trip we will thus have a full-court press in the crinoid thickets and echinoid-rich beds.

PrettyCorals070413Still, the corals here are gorgeous. Here are two varieties of typical colonial scleractinians we saw today. The one on the right has all sorts of encrusters in the nooks and crannies between its corallites. The corals here are remarkably well preserved considering that their original aragonitic skeletons have been replaced by calcite. These are a bit of consolation for the missing bryozoans!

A long, hot day with Cretaceous phosphorites in the Negev

July 3rd, 2013

OscarHawarimOutcrop070313MITZPE RAMON, ISRAEL–This was one of Oscar’s big field days. He is shown above at his first exposure of the phosphatic zone of the Mishash Formation (Campanian, Upper Cretaceous) exposed at Wadi Hawarim (N 30.84423°, E 34.75742°). We see here the entire section from the top of a phosphate-cemented conglomerate to the base of the overlying Ghareb Formation (the brown marls at the top of the image). Oscar is working to understand the complicated stratigraphy and origin hypotheses for these phosphorites. You may be able to make out some of the red ribbons we placed while measuring the section.

HawarimMishash070313This is another view of the Mishash phosphorites at Wadi Hawarim, with the Ghareb Formation in the upper left. We have six measured, sampled and described members in just under eight meters of section here. The phosphates are finely disseminated in some of the chalky units and bound up in a layer of nodules at the top.

ParticleDinosaur070313A conglomerate within the phosphate zone of the Mishash has an interesting collection of clasts, including this large chunk of reptile bone, possibly from a dinosaur. (Which is what we always say about large bone bits from the Mesozoic!)

SharkTeeth070313While Oscar and I worked on his measured section, Lizzie and Steph looked for shark teeth in the conglomerate unit. They did very well. Above is a sample of what they found. So Andrew Retzler — any ideas about what kind of sharks are represented by these tiny teeth? It looks like a small tooth in the lower row is Squalicorax kaupi.

RotemAmfertNegevMeeting070313Near the end of the day we went to one of the phosphate mine and enrichment plant owned and operated by Rotem Amfert Negev Ltd. This was a treat for Oscar who has strong interests in the economic geology of mining. We heard an excellent presentation by the chief geologist of the mine about the value of phosphate, the main markets for the their products, and the geological setting of these Negev phosphorites.

PhosphateMine070313Afterwards we visited the active part of the mine, shown above. Since about 2005 the mine has been restoring land as fast as it mines it. On the right is the working face of the mine, the white unit on the floor has most of the phosphate in it and is being ground up by the vehicle slowing moving across it. On the far left are piles of overburden and “interburden” (unusable material between the three phosphate-rich layers) ready to fill in the pit once the phosphorite is removed. We also saw those parts of the area where the original topography and (they hope) cryptobiotic top soil has been restored.

It was a good day, though a long one. Tomorrow we will celebrate the Fourth of July with yet another Negev work day. Maybe we’ll have a special American-themed dinner afterwards.

Field reconnaissance in the northern Negev of Israel

July 1st, 2013

1FoldedPhosphates070113MITZPE RAMON, ISRAEL–This morning Team Israel 2013 met our friend Yoav Avni, a geologist with the Geological Survey of Israel (GSI), and we traveled north to our field localities. We did a survey of the sites so that we could put together an efficient schedule for our work over the next two weeks. We had a four-wheel drive vehicle from the GSI so we could get to places our little Budget rental car could only have nightmares about.

The first locations were for Oscar Mmari’s Cretaceous phosphorite work. The outcrop pictured at the top of this entry is on the east side of Makhtesh Gadol (N 30.93657°, E 035.03312°). We are looking toward the west at an incredibly asymmetric limb of a syncline. In the upper part of the exposure you can see the rocks dipping almost vertically, yet in the foreground they are nearly horizontal. They make an almost 90° bend. The Mishash Formation phosphatic zone is partly exposed as the white rocks along the side of the wadi. The phosphorites here are very thick and chalky.

2MishhashPhosphates070113A second phosphorite exposure for Oscar is in Wadi Havarim (N 30.84269°, E 34.75509°) not too far north of Mitzpe Ramon. The top of the cherty portion of the Mishash Formation is on the left in the middle; the light-colored units above are phosphorites. In the background is Nahal Zin, a deep valley formed by water draining north into the Dead Sea. The base level of the Dead Sea is so low that the wadis leading to it are rapidly downcut.

3OscarPhosphorite070113Here is Oscar getting is first look at the phosphorites at Wadi Havarim. Later this week we will measure at least one section at each locality and take plenty of samples for thin-sectioning and scanning electron microscopy.

4TraceFossil070113Steph Bosch’s hand gives us a scale for a nice set of trace fossils found in the phosphorite at Wadi Havarim. These look like callianassid shrimp burrows to me. We found some preserved as burrow-fills with apparent fecal pellets forming the outer walls. If true then the trace fossil ichnogenus is Ophiomorpha. This is a good indicator of shallow water.

5PhosphateSign070113We also briefly visited two phosphate mining sites east of Makhtesh Gadol. One has this helpful sign outside describing the geology of these deposits. The phosphorites are shown in yellow. Note that they formed in two synclines, both highly asymmetrical (as shown in our top photo).

6PhosphateMinedValleyWe viewed one phosphate mine where virtually the whole valley has been quarried, producing enormous piles of waste materials. Reclaiming mined terrain like this is especially difficult in this arid climate. Oscar will not only be looking at the geology of these phosphate deposits, but also the economics of mining, which now includes remediation and controls on emissions and water pollution.

7MatmorCollectingFirstDay070113After lunch we drove down into the center of Makhtesh Gadol and plotted out future localities for Steph and Lizzie to do their work in the Matmor Formation. (The above site is at N 30.93837°, E 34.97907°.) I’ve been to these sites many times with students, so it was relatively easy to make our plan for collecting crinoids and encrusting bryozoans tomorrow and next week.

8NabateanCistern070113Finally, no fieldwork in Israel is complete without a touch of archaeology. Yoav took us into a Nabatean cistern and showed us the clever engineering (and strategic plastering) necessary to make this hand-cut cavern into a water trapping and storage facility. This cistern is cut into the Menuha Formation, a chalk unit very familiar to Andrew Retzler (’11). This cistern was originally made sometime between 100 BCE and 100 CE. After the nabateans it was used by the Romans, Byzantines and Arabs. It was last used by Israeli pioneers over 60 years ago.

Tomorrow we return to Makhtesh Gadol and work in the hot sunlight filling collecting bags with tiny bits of crinoids and assorted encrusters. We’ve had a very good start.

Wooster’s Fossils of the Week: Mosasaurid teeth from the Cretaceous of Morocco

June 30th, 2013

PrognathodonTeethKhouribgaCretaceousThese impressive teeth are from the mosasaurid Prognathodon and were found in the Upper Cretaceous phosphorites near Khouribga, Morocco. They are not actually a matching set — I just arranged them to look fearsome.

Prognathodon_lutigini_Dmitry_Bogdanov(Prognathodon lutigi from the Upper Cretaceous of Russia. Reconstruction by Dmitry Gogdanov via Wikipedia.)

Prognathodon (the name means “front-jaw tooth”) was a very large mosasaurid, with some specimens up to 12 meters in length. They were cosmopolitan in extent, being found throughout the world in Campanian to Maastrichtian deposits. They lived in deep waters as shown by some specimens with strengthening bony rings around their eye sockets. They were essentially sea-going lizards, and big ones at that.

Note that the teeth are stout and blunt. They were not adapted for tearing flesh but rather crushing hard-shelled prey they found on the seafloor. One skeleton was found with some stomach contents intact, including a sea turtle, a variety of fishes, and an ammonite. This is not the usual diet of other mosasaurid genera which were nektic (swimming) predators.
Louis_DolloPrognathodon was named in 1889 by the famous Belgian paleontologist Louis Antoine Marie Joseph Dollo (1857-1931). Paleontology and History of Life students will immediately recognize that name because of Dollo’s Law: “evolution is not reversible”. (Or its corollary: extinction is forever!) He started his career as an engineer, graduating at the top of his class in 1877 from the École Centrale de Lille. He worked as a mining engineer and, as luck would have it, quickly discovered an extraordinary mass burial of the dinosaur Iguanodon. Studying this genus and other fossil reptiles became his passion. In 1882 he became an assistant naturalist at the Royal Belgian Institute of Natural Sciences in Brussels. One of his many remarkable contributions was to begin to think of fossils as once living organisms in ecological networks. In this sense he essentially founded paleobiology. In 1912 he received the Murchison Medal from the Geological Society of London. Not too shabby for an engineer.

References:

Buffetaut, E. and Bardet, N. 2012. The mosasaurid (Squamata) Prognathodon in the Maastrichtian (Late Cretaceous) of the Cotentin Peninsula (Normandy, northwestern France). Bulletin de la Societe Geologique de France 183: 111-115.

Schulp, A.S., Polcyn, M.J., Mateus, O.,  Jacobs, L.L., Morais, M.L. and Silva Tavares, T. 2006. New mosasaur material from the Maastrichtian of Angola, with notes on the phylogeny, distribution and palaeoecology of the genus Prognathodon. On Maastricht Mosasaurs 45: 57-67.

Wooster’s Fossil of the Week: A sawfish rostral tooth from the Upper Cretaceous of Morocco

June 16th, 2013

Onchopristis_numidus_052013_585More fossil fish teeth this week. This impressive, barbed tooth is from the ancient chondrichthyan sawfish Onchopristis numidus (Haug, 1905). It was found in the Tegana Formation (Cenomanian, Upper Cretaceous) near Kem Kem, Morocco (and is yet another contribution from our alumnus George Chambers).
Onchopristis_numidus_groupThese are all rostral teeth, meaning they are the sideways teeth on each side of the snout (rostrum) of the sawfish. They each have a barb for entangling prey. Like modern sawfish, O. numidus would have lived along the bottom and occasionally thrashed about, wounding smaller fish and crustaceans so that it could catch and eat them.

onchopristis_size_guideOnchopristis numidus was the largest sawfish known, making it a formidable predator.

Onchopristis_diagram

Of course, seeing it against a human profile makes it more real!

Spinosaurus_OnchopristisDespite its size, O. pristis had a famous nemesis: the dinosaur Spinosaurus. Barbed teeth of the sawfish have been found embedded in the jaws of this beast. The above image is from the show Dinosaur Planet, as is this Youtube clip of the two struggling (with one clearly losing).

And yes, Spinosaurus is coming as a future Fossil of the Week!

References:

Martill, D.M. and Ibrahim, N. 2012. Aberrant rostral teeth of the sawfish Onchopristis numidus from the Kem Kem beds (? early Late Cretaceous) of Morocco and a reappraisal of Onchopristis in New Zealand. Journal of African Earth Sciences 64: 71-76.

Slaughter, B.H. and Steiner, M. 1968. Notes on rostral teeth of ganopristine sawfishes, with special reference to Texas material. Journal of Paleontology 42: 233-239.

Slaughter, B.H. and Thurmond, J.T. 1974. A lower Cenomanian (Cretaceous) ichthyofauna from the Bahariya Formation of Egypt. Annals of the Geological Survey of Egypt 4: 25-40.

A visit to the Natural History Museum of Utah

May 29th, 2013

NHMU052913SALT LAKE CITY, UTAH–On the last full day of our Utah trip, we toured the Natural History Museum of Utah in Salt Lake City. It is in a spectacular place against the red rocks of the Wasatch Mountains and looking over the Salt Lake Valley. This museum has only been open since November 2011. Its exhibits are very up-to-date and modern.  (My test for recent accuracy is whether birds are acknowledged as dinosaurs and if Australopithecus sediba is in the human evolution section.) I’d like to just share some images from the museum and encourage anyone in Salt Lake City to visit it.

EoceneLake052913Dr. Judge will be impressed with the attention paid to exhibits on the Green River Formation (Eocene). This tableau is designed to show animals in the water (below) and on the beach (above). Note the stromatolites on the shoreline representing some of the features she and her students have worked on in the Green River Formation.

585_Deinosuchus_hatcheri_052913Utah is extremely rich in Mesozoic vertebrate fossils. Here is an impressive skeleton of Deinosuchus hatcheri from the Cretaceous.

CeratopsianWall052913The dinosaur exhibit is world-class. Here is a wall of ceratopsian dinosaur skulls showing evolutionary relationships.

DinoPelvis1_052913My History of Life students are well trained in sorting out major dinosaur groups by their pelvic bones. They could tell you, for example, if this is an ornithischian or a saurischian dinosaur.

DinoPelvis2_052913And this set is of the other group. Can you see the differences?

dinohead052913It appears this dinosaur had barnacles for eyes!

PaleontologistsBehindGlass052913Here is the classic paleontologists-behind-glass exhibit of a working laboratory. (I wonder why they never put working petrologists on display?)

NHMUview052913The architects knew exactly what they were doing when it came to designing the building to take full advantage of the setting. The Salt Lake Valley is fully visible from every floor.

What a great place to end our little Utah excursion this year. The real Team Utah of Wooster Geology will be back in the state next month.

Wooster’s Fossil of the Week: Sea urchin bites from the Upper Cretaceous of southern Israel

February 10th, 2013

GnathichnusCenomanian020413_585What you see above is a bit of oyster shell with some curious small gouges in it. The oyster is Ilymatogyra (Afrogyra) africana (Lamarck, 1801) from the En Yorqe’am Formation (Cenomanian) exposed in Hamakhtesh Hagadol, southern Israel. The deep scratches are the trace fossil Gnathichnus pentax Bromley, 1975. As you can just make out in the lower center of the image, the grooves are overlapping series of five-pointed stars. That’s what makes this trace so cool — the stars were made by the unique feeding apparatus of a regular echinoid (sea urchin).
Strongylocentrotus_purpuratus_020313_585This is the business end of the modern sea urchin Strongylocentrotus purpuratus (a preserved specimen in Wooster’s collection). You see here in the center the peristome, which is a circle of plates surrounding the mouth, with the sharp five-sided teeth protruding from the echinoid’s Aristotle’s Lantern. These animals slowly graze across hard substrates, using their teeth to scrape the surfaces for algae, fungi and adherent organisms like diatoms. The biting actions of the Aristotle’s Lantern produce the star-shaped incisions we know as the trace fossil Gnathichnus pentax.

I briefly sampled and studied an exposure of the fossiliferous En Yorqe’am Formation in 2003 during my first visit to Israel. The oyster shells in this unit provide one of the few examples of hard substrate communities in the tropics of the Late Cretaceous. The encrusters include ostreid and spondylid bivalves, the cyclostome bryozoan Stomatopora, and the agglutinating foraminiferan Acruliammina. Borings include those of barnacles (Rogerella elliptica) and sponges (Entobia aff. E. megastoma). There is also a sea urchin present (Heterodiadema lybicum) that was almost certainly the maker of the Gnathichnus pentax traces.

References:

Bromley, R.G. 1975. Comparative analysis of fossil and recent echinoid bioerosion. Palaeontology 18: 725-739.

Wilson, M.A. 2003. Paleoecology of a tropical Late Cretaceous (Cenomanian) skeletozoan community in the Negev Desert of southern Israel. Geological Society of America Abstracts with Programs 35(6): 420.

Wooster’s Fossils of the Week: Shark teeth! (Upper Cretaceous of Israel)

December 2nd, 2012

This week’s set of exquisite fossils is presented in honor of Andrew Retzler (’11) who has just had his Senior Independent Study thesis at Wooster published in the journal Cretaceous Research: “Chondrichthyans from the Menuha Formation (Late Cretaceous: Santonian–Early Campanian) of the Makhtesh Ramon region, southern Israel“. The above beauties are a mix of Scapanorhynchus teeth found in the southwestern portion of Makhtesh Ramon during Andrew’s study in the summer of 2010. We were ably assisted by Micah Risacher and Yoav Avni with these collections.

Andrew identified at least eight shark species and two other fish species in the Menuha Formation around Makhtesh Ramon. Most of the teeth are from a soft yellowish chalk with relatively few other fossils (mostly oysters, echinoids, foraminiferans and traces). They show that the Menuha was deposited in a shallow, open-shelf environment on the flanks of the developing Ramon anticline. So, they not only provide new information about Cretaceous sharks in the Middle East, they help sort out a complex stratigraphic-structural problem.

Well done, Andrew! (Andrew is currently a graduate student at Idaho State University. He is working on the Late Devonian Alamo Impact Event in Nevada with Dr. Leif Tapanila.)

Tooth of the shark Cretalamna appendiculata. Composite photo by Andrew Retzler.

Scapanorhynchus rapax, another shark species. Composite photo by Andrew Retzler.

An elegant Scapanorhynchus texana tooth.

Looking south at one of the productive exposures of the Menuha Formation (shown as the red dot) at Makhtesh Ramon. This is one of those amazing Google Earth images.

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