Paleoecological Reconstruction of the Menuha Formation (Upper Cretaceous, Santonian), Makhtesh Ramon Region, Southern Israel (Senior Independent Study Thesis by Andrew Retzler)

April 11th, 2011

A typical Menuha Formation outcrop south of the Makhtesh Ramon structure.

Editor’s note: Senior Independent Study (I.S.) is a year-long program at The College of Wooster in which each student completes a research project and thesis with a faculty mentor.  We particularly enjoy I.S. in the Geology Department because there are so many cool things to do for both the faculty advisor and the student.  We are now posting abstracts of each study as they become available.  The following was written by Andrew Retzler, a senior geology major from Wooster, Ohio.  Here is a link to Andrew’s final PowerPoint presentation on this project as a movie file (which can be paused at any point). You can see earlier blog posts from his field work by clicking the Israel tag to the right. Andrew also created a Wikipedia page on the Menuha Formation.

It all began with an 11-hour flight from NYC to Tel Aviv, Israel with Dr. Wilson and fellow geology senior Micah Risacher. The airport process required for international travel of this sort was an adventure in itself. Thorough baggage checks, stern looks from security personnel, and a bombardment of questions dealing with our reasons for travelling were all offset by a seemingly endless and free movie selection on the flight! Eventually, we reached our arid destination of Mitzpe Ramon, the city that would serve as our basecamp for the next two weeks.

One of the reasons behind our trip was to scour the Menuha Formation outcrops throughout the Makhtesh Ramon region (shown above). We were hoping to collect and analyze various fossils in order to reconstruct an environment that once flourished during the Cretaceous. This process also involved taking detailed measurements and notes on each outcrop to create stratigraphic columns of each locality. This would become the basis of my thesis. Of course, none of this could have been possible without the help of our all-knowing field guide, Yoav Avni, and our shark specialist, Stuart Chubb, from the Birkbeck College of London.

Although my thesis has a strong focus on the shark and other fish teeth collected from the Menuha Formation, it also incorporates oysters, trace fossils, and several benthic/planktic foraminiferans. At least ten different species were represented in the isolated teeth: Cretalamna appendiculata, Cretoxyrhina mantelli, Squalicorax falcatus?, Squalicorax kaupi, Scapanorhynchus rapax, Scapanorhynchus raphiodon?, Carcharias samhammeri, Carcharias holmdelensis, and two other fish (Hadrodus priscus and Micropycnodon kansasensis?). Many of these fish were thought to occupy outer shallow marine realms, where the continental shelf begins transitioning into the slope. A few of the sharks are also known for being top Cretaceous predators, four or more meters in length, whose diets included plesiosaurs, mosasaurs, and ichthyodectids.

Cretalamna appendiculata tooth, a shark often considered to be an ecological generalist.

Scapanorhynchus rapax tooth. Related to the extant Goblin Shark, S. rapax had the ability to protrude its mouth in order to capture prey.

Cretoxyrhina mantelli tooth. Considered a superpredator of the Cretaceous seas, this shark could reach 5-6 meters in size.

Squalicorax kaupi tooth. The Squalicorax genus is the only group to exhibit serrated dentition, like so, in the Late Cretaceous.

Hadrodus priscus pharyngeal teeth. These teeth would have been found near the back of the throat arranged in a comb-like structure to help crush exoskeletons.

LEFT: The extended left valve of a Pycnodonte vesicularis. RIGHT: Planktic, biserial foraminiferan test (possibly Heterohelix sp.) that has been replaced by silica.

The Menuha Formation consists mainly of white and yellow/brown, glauconitic chalks that were often marly or conglomeratic. This chalk comprised a variety of phosphatic peloids, microteeth, irregular echinoid spines, and benthic/planktic foraminiferans that clearly represent a shallow marine environment.

Irregular echinoid spine recovered from the partially dissolved Menuha chalk.

Microtooth from the Menuha chalk.

Correlating the paleontology with their lithological context, a shallow marine outer continental shelf/middle continental slope environment is suggested as the paleoenvironment of the Menuha Formation. This environment would have also flourished with a variety of small to medium-sized fish, squid, and larger vertebrates (plesiosaurs and mosasaurs) in order to sustain such a shark population. Unlike the deep environment that has often been suggested, my thesis provides strong evidence towards a shallow marine environment during the early formation of the Makhtesh Ramon structure. My work also marks the first identification of the fish teeth within the Menuha Formation, beginning my contributions to the scientific world.

A Paleoenvironmental Analysis of the Zichor Formation in the Cretaceous of Southern Israel (Senior Independent Study Thesis by Micah Risacher)

April 11th, 2011

Editor’s note: Senior Independent Study (I.S.) is a year-long program at The College of Wooster in which each student completes a research project and thesis with a faculty mentor.  We particularly enjoy I.S. in the Geology Department because there are so many cool things to do for both the faculty advisor and the student.  We are now posting abstracts of each study as they become available.  The following was written by Micah Risacher, a senior geology major from Columbus, Ohio.  Here is a link to Micah’s final PowerPoint presentation on this project as a movie file (which can be paused at any point). You can see earlier blog posts from Micah’s field work by clicking the Israel tag to the right.

In the summer of 2011 Wooster geologists Mark Wilson, Andrew Retzler, and I went to the Negev Desert in southern Israel.  We were met by a colleague from England, Stewart Chubb as well as our guide and host Yoav Avni of the Geological Survey of Israel.  The small town of Mitzpe Ramon on the edge of the Makhtesh Ramon (Figure 1) would serve as our home for the next two weeks as we explored the Ramon structure.

Figure 1. A look into the Makhtesh Ramon structure.

My research includes the Zichor Formation which can be found throughout the Makhtesh Ramon structure.  However I focused on three separate locations known as the northern, southern, and western locations.  Each location had different features exposed, the southern location (Figure 2) exposed the Zichor very well, yet it was quite hard to get at it.

Figure 2. Southern section with the Zichor section labeled.

The purpose of my I.S. was to determine the paleoenvironment of this particular formation (Zichor) using the paleontology, sedimentology, and stratigraphy seen in the field/lab.  I found many well preserved echinoids (not destroyed by churning waters), Thalassinoides trace fossils, high mud content and shell fragments in the lithology, as well as several minor regression/transgression cycles.  All of these point to a primarily shallow marine environment that would slightly deepen once or twice before shallowing again.

The echinoids (Figure 3) found were so well preserved that they could be identified down to the species level and greatly helped to correlate this assemblage with others like it around the world during that time.  This process both helps to verify my results as well as put my sites in perspective with similar ones around the world.  Hopefully, this study will go a ways into settling the current dispute as to whether or not this region was a shallow or deep sea environment during the Late Cretaceous.

Figure 3. The most prevalent echinoids Hemiaster batnensis and Rachiosoma delamarri respectively; scale bars=1cm.

Bioerosion on oysters across the Cretaceous-Paleogene Boundary in Alabama and Mississippi (USA) (Senior Independent Study Thesis by Megan Innis)

April 8th, 2011

This is my research team at a road-cut locality in Mississippi. (Photo courtesy of George Phillips.)

Editor’s note: Senior Independent Study (I.S.) is a year-long program at The College of Wooster in which each student completes a research project and thesis with a faculty mentor.  We particularly enjoy I.S. in the Geology Department because there are so many cool things to do for both the faculty advisor and the student.  We are now posting abstracts of each study as they become available.  The following was written by Megan Innis, a senior geology major from Whitmore Lake, Michigan. Here is a link to Megan’s final PowerPoint presentation as a movie file (which can be paused at any point). You can see earlier blog posts from Megan’s field work by clicking the Alabama and Mississippi tags to the right.

During the summer of 2010, I traveled to Alabama and Mississippi with my research team including Dr. Mark Wilson, Dr. Paul Taylor, and Caroline Sogot.  Our trip was about ten days and included fieldwork and research. The purpose of our research was to collect fossils from below and above the Cretaceous-Paleogene (K/Pg) boundary to try and understand the Cretaceous mass extinction from a microfaunal level.

I chose to focus my thesis on oysters and the sclerobionts associated with these calcareous hard substrates.  Although my study was focused on oysters, I also collected a wide variety of other specimens including nautiloids, ammonites, belemnites, corals, sharks teeth, and bryozoans.

The oyster species present in each system.

When I got back to school in August, I identified all of my oyster species (three total) and began to identify and collect data for the sclerobionts. The oysters from the Cretaceous included Exogyra costata and Pycnodonte convexa and the oysters from the Paleogene included Exogyra costata, Pycnodonte convexa, and Pycnodonte pulaskiensis.

Sample specimens that I collected in Alabama and Mississippi. The oysters in yellow boxes and circles are the oyster species that were used in my study.

I identified nine sclerobionts including Entobia borings; Gastrochaenolites borings; Oichnus borings; Talpina borings; serpulids; encrusting oysters; encrusting foraminiferans; Stomatopora bryozoans; and “Berenicia” bryozoans.  My research showed:

1) Bioerosion of oyster hard substrates was common in the Late Cretaceous and Paleogene and sclerobionts were abundant before and after the extinction.

2) Entobia sponge borings appear to increase in abundance across the K/Pg boundary and become more common in the Paleogene.

3) Gastrochaenolites borings, made by bivalves, and serpulids were more prevalent in the Late Cretaceous, suggesting boring bivalves and serpulids were significantly reduced after the extinction.

4) Encrusting oysters and foraminiferans were more common in the Late Cretaceous, but also relatively abundant on Pycnodonte pulaskiensis in the Paleogene.

5) Encrusting bryozoans were more common in the Late Cretaceous and absent in the Paleogene, suggesting bryozoans were severely affected by the extinction.

6) Talpina borings were only found on Pycnodonte pulaskiensis in the Paleogene, but no significant data was collected elsewhere.

To my knowledge, this is the first study of bioerosion on oysters across the K/Pg boundary.

Back to granite on Cima Dome

March 17th, 2011

A granite exposure near Teutonia Peak on Cima Dome. Note our jackets and hands in pockets!

ZZYZX, CALIFORNIA–Our last stop of the rapidly-cooling day was on the huge Cima Dome east of Zzyzx in the Mojave National Preserve. The dome is so large (about 70 square miles) that it is impossible to detect when you are actually on it, but easily visible from miles away. It apparently is the eroded root of a granitic intrusion formed during subduction in the Jurassic to Cretaceous. The alkali granite exposed here is very similar to that of the Granite Mountains we saw yesterday.

Potassium feldspar crystals in the coarse alkali granite of Cima Dome.

The soil of Cima Dome is derived almost entirely from the underlying alkali granite.

Wooster’s Fossil of the Week: A chewed-up leaf (Upper Cretaceous of Kansas)

February 6th, 2011

This week’s fossil is a departure from our usual set of marine invertebrate animals. Above is a leaf of Viburnum lesquereuxii from the Dakota Formation of Ellsworth County, Kansas. The rocks enclosing it are from the Upper Cretaceous Cenomanian Stage, roughly 93-99 million years old. The leaf is preserved as a carbonized film in excellent detail.

What is cool about this particular leaf is that it has damage from insects that fed on the softer tissues between the veins. These feeding trace fossils are distinguished by smooth edges around the circular holes where the plant grew to seal off the torn cells. The leaf-eating insects may have been beetles or some kind of caterpillars. Viburnum is a common and diverse group of plants today, and they still experience significant insect herbivory, as shown below.

Beetles chewing holes in a modern Viburnum (

Viburnum is a flowering plant, an angiosperm. This group appeared in the earliest Cretaceous (about 140 million years ago) and started a rapid rise to dominance just about the time this fossil leaf and its insect pests were alive. This little ecological vignette gives us an insight into the early days of our modern flora.

Wooster’s Fossil of the Week: A most unlikely clam — rudists from the Upper Cretaceous of the Oman Mountains

January 23rd, 2011

This week’s fossil was collected on a memorable trip in 2000 to the United Arab Emirates and Oman with my friend Paul Taylor, an invertebrate paleontologist at the Natural History Museum in London. We were there to study hard substrate faunas (sclerobionts) in an Upper Cretaceous (Maastrichtian) unit known as the Qahlah (pronounced “coke-lah”) Formation. We traveled along the border between these two countries in an old Toyota Landrover plotting out the distribution and characteristics of the Qahlah and its fossils. If you want a pdf of the resulting paper (and I’m sure you do), just click here: Wilson & Taylor (2001).

One of the most interesting fossil types common in the Late Jurassic through the Cretaceous is the rudist clam. The image above is one of our Qahlah specimens known as Vaccinites vesiculosus. There are two conical rudists growing together here, with the one on the left still retaining most of its upper valve.

Rudist clams are an example of just how far evolution can go with a basic body plan. They are heterodont clams sharing a common ancestry with the typical modern Mercenaria we so love to eat (and dissect). Starting in the Jurassic, the left valve began to elongate into a cone and the right valve became a cap-like cover. They attached to each other and formed reef-like masses throughout the warm, shallow tropical seas of the Cretaceous. They were so successful that they appear to have competitively excluded most of the coral reefs. Corals had the last gurgly laugh, though, because the end-Cretaceous extinction completely wiped out the rudists, allowing the later rise of modern coral reefs.

A typical heterodont clam is in the upper left of this diagram; the rest are rudist clams. In the lower right is a drawing of the type of rudist photographed above. Diagram from Schumann & Steuber (1997; Kleine Senckenbergreihe 24: 117-122).

When I see our rudist clam specimen I’m reminded not only of its complex evolutionary heritage, but also of our own desert odyssey with grim musket-bearing Omani tribesmen, endless sand dunes stretching west, and delicious banquets of lamb and dates.

Thoroughly bored at GSA: A Wooster Geologist Faculty Talk

October 31st, 2010

DENVER, COLORADO — How I very much enjoy those few minutes AFTER giving a presentation, especially a Geological Society of America talk. That sense of renewed life, the rush of completing a task which was months in preparation, and the step back into the inviting shadows of the lecture room. I’ll just repeat my first and last slides below, and then link to the abstract. You will, I hope, see the joke in my blog post title!

Wooster celebrates National Fossil Day

October 13th, 2010

Crinoid holdfasts and bryozoans on a cobble from the Ordovician of northern Kentucky.

WOOSTER, OHIO–Today we are celebrating the first annual National Fossil Day (or at least I am!). Be sure to check out that link from the National Park Service — it contains the official National Fossil Day song! My recognition of this special day is to post some photographs of nice fossil specimens from the Wooster collections. You can find larger versions of these photos — and hundreds more — on my Wikimedia page. Here’s to fossils: beautiful messengers from the distant past.

Shark teeth (Scapanorhynchus) from the Upper Cretaceous of southern Israel. These were collected by Andrew Retzler ('11).

Rudist bivalves from the Upper Cretaceous of the Omani Mountains.

Tentaculitids from the Devonian of Maryland.

Thecideide brachiopods, cyclostome bryozoans and serpulids encrusting a bivalve shell from Zalas Quarry (Jurassic: Callovian-Oxfordian) in southern Poland.

Fossil leaf (Viburnum lesquereuxii) with insect damage; Dakota Sandstone (Cretaceous) of Ellsworth County, Kansas.

Visiting a subduction zone in New Zealand

September 29th, 2010

CHRISTCHURCH, NEW ZEALAND–Wooster geology student Andrew Collins has once again visited a fascinating geological locality in New Zealand. He is certainly getting his semester’s worth of adventures, from earthquakes to glaciers. Please visit his blog and see additional photos and descriptions of his trips.

Kaikoura Canyon and associated peninsula and mountains. From:

This time Andrew came about as close to the trench of a subduction zone as is possible without getting wet. He journeyed to Kaikoura on the South Island north of his university base at Christchurch. This town is at the base of a peninsula and squeezed between mountains and the coast. Just a few hundred meters offshore is a deep trough (Kaikoura Canyon) marking a trench where part of the Pacific Plate is being subducted beneath New Zealand, producing volcanoes. The trough also forms an oceanic upwelling system that nourishes phytoplankton which in turn are the primary producers for a diverse and abundant community of organisms culminating with seals and whales. Geologists love to visit active places like this — but we don’t buy real estate there!

Andrew noted the uplifted limestones along the peninsula. These are Late Cretaceous in age, adding to the Cretaceous theme in this year’s blog entries. (Click “Cretaceous” in the tag cloud to the right and see.)

Upifted Upper Cretaceous limestones along the Kaikoura coast, New Zealand. Photo by Andrew Collins.

Tectonic fabric exposed in Upper Cretaceous limestones along the Kaikoura coast, New Zealand. Photo by Andrew Collins.

The Southern Alps, surf and a gravelly beach near Kaikoura, New Zealand. Note the low beach ridges formed by storm waves. Photo by Andrew Collins.

Fossils on the Meuse-Argonne Battlefield

August 16th, 2010

Cretaceous oysters in marly sediment near Baulny, northeastern France.

VIENNE LE CHATEAU, FRANCE–To my delight, while exploring the Meuse-Argonne area this morning, I found an exposure of marly Cretaceous sediments very near where my Grandfather’s tank brigade assembled for an attack at dawn on October 4, 1918. The sediment is poorly consolidated and saturated with water, as expected. Mud again — the same mud that must have been an annoyance and danger to those nervous tank crews that October morning.

The Cretaceous marl in a roadside outcrop near Baulny, France (N49.25672°, E5.01696°).

Some of the fossils from today cleaned up in the hotel room. (They must hate it when I do this.)

The fossils are small oysters, and they are there by the thousands. The only other species I saw were serpulid worm tubes attached to their upper valves. When found in place the oysters are articulated (both valves still in place). The facies is very similar to that of the Paleocene Clayton Formation we saw earlier this summer in Mississippi.

Could Rolland Snuffer, an 18-year-old corporal from Kansas, have imagined that 92 years later one of his grandsons would be collecting fossils in this war-ravaged place? I think he would have been very pleased. His experiences here must have been horrendous. He was the gunner/commander of a two-man FT-17 Renault tank in a unit which took heavy casualties during this action.

Corporal Rolland Snuffer was in Company C of the 345th Tank Battalion attached to the First Division. North is at the top. Map courtesy of Brad Posey.

The village of Fléville today (from N49.30578°, E4.96945°). The 345th Tank Battalion captured this town on October 4, 1918, but the infantry did not follow because of German fire from the west bank of the Aire River.

The village of Exermont then and now.

Corporal Rolland Snuffer in an undated family photograph.

There were over 117,000 American casualties, including 26,000 dead, in the Meuse-Argonne battle, with about the same number for the Germans and another 70,000 French dead and wounded. This was the most costly battle ever fought by Americans. Our losses were far less than those suffered by our European cousins, but we still shared with them the profound effects of this war on a generation. It is hard to imagine this peaceful French countryside convulsed by war, but then it happened again 22 years later. That must have been a bitter pill for the veteran Doughboys to swallow after they survived the War to End All Wars.

A book on the battle I highly recommend: To Conquer Hell by Edward G. Lengel (2008, Henry Holt and Company).

« Prev - Next »