Wooster Geologists at the Center of the World

Mark Wilson May 30, 2011 11:44 pm

Our visit to Jerusalem was to meet geologists at the Geological Survey of Israel main complex in the western part of the city. Those discussions went very well and we met new people and learned much. Will and I also took the opportunity to spend a few hours in the Old City. Here are some of the sites. The view above is of the Old City from Mount Scopus.

When we say that Jerusalem is the “Center of the World“, we are following a medieval tradition illustrated by this European manuscript page reproduced as a tiled image at the City Hall.

The Geological Survey of Israel headquarters have a very unassuming (and secure) entrance. This is an old World War II British military base that was on the outskirts of the city but is now surrounded by an Ultra-Orthodox Jewish community. It is a wise move not to advertise the very secular activities going on in there!

Our main walking route from the Survey to the Old City was Jaffa Street, which leads directly to Jaffa Gate. This is looking northwest. There is a new tram system being tested, thus the tracks in the road and lack of cars.

Will in the Old City market on our way to the Church of the Holy Sepulchre.

Outer courtyard of the Church of the Holy Sepulchre. All those people going in and out of that one doorway. Jerusalem now receives a record three million visitors a year.

Turns out the Center of the World is actually within the Church of the Holy Sepulchre … and its exact spot has been marked!

There are very few places in the Church of the Holy Sepulchre where you can see the original bedrock of the area. This is a famous crack in the rock below what is supposed to be the crucifixion site and above what is known as Adam’s Grave. Note the strain gauge across the joint. There are geological concerns about the stability of the bedrock and monumental structures built on top of it. I can’t imagine how the Israeli authorities got religious sanction to install that instrument!

Crepuscular rays descending from the dome of the Church of the Holy Sepulchre. The top of the Holy Sepulchre structure is at the bottom of the image.

Finally, we visited the Western Wall revered in Judaism. Above it (and not visible in this image) are the Islamic holy sites in Jerusalem: the Al Aqsa Mosque and the Dome of the Rock. We thus visited in the space of a few hours sacred spaces of the three Abrahamic religions. Center of the World indeed.

 

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Wooster Geologists return to the Dead Sea

Mark Wilson May 30, 2011 3:09 pm

MITZPE RAMON, ISRAEL–Today Will and I went to Jerusalem for meetings at the Geological Survey of Israel headquarters. Much more on that later. On the way Yoav drove us along the west coast of the Dead Sea. Will got a chance to dip his hand in the warm and heavy water, and we talked about salt, shorelines and sinkholes.

These are halite (salt) deposits on the Dead Sea shore near Will’s feet above. Halite encrusts all that this water touches, from rocks and sediment to abandoned tires.

This slope above the highway on the west shore of the Dead Sea shows ancient shorelines from roughly 26,000 to 14,000 years ago. The sea then was salty but only about half the current salinity. Shorelines fluctuated but generally fell during this 12,000 year interval.

A serious environmental problem along the western shore is the development of huge sinkholes. These are forming because the Dead Sea is losing water rapidly (it drops about a meter per year) and freshwater is now finding thick salt deposits underground. The water dissolves the salts, forming caverns that eventually collapse and make the pits above. Often the pits then fill with water, making small ponds that have their own flora and fauna.

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Mishash, b’gosh

Mark Wilson May 29, 2011 1:55 pm

MITZPE RAMON, ISRAEL–Today Will and I drove south, east and north to meet Dr. Yael Edelmen-Furstenburg of the Geological Survey of Israel. She gave us a most excellent tour of the Mishash (pronounced ME-shawsh) Formation (Campanian, Upper Cretaceous) in the Wadi Ashosh region (shown above) near Zuqim and Tsofar in the Negev Desert. We talked much about the fossil fauna, particularly the trace fossils in soft and hard substrates. There could be many future Wooster Independent Study projects in this formation, especially here where it is so diverse.

As seen above, much of the Mishash Formation consists of bands of chert. The folds are syndepositional (formed at the time of deposition) as part of the Syrian Arc deformation. This makes for some very interesting local stratigraphy and depositonal patterns.

The Mishash Formation has exquisite fossil shell beds, often silicified (replaced with silica). Above you can see gastropods and bivalves.

An old Cretaceous friend, the ammonite Baculites, is used to sort out the biostratigraphy of the Mishash. They are identified by the style of ribs they have on the outside of the conch.

Like everywhere else in the Negev Desert, shade is a bonus. We always appreciate the acacia trees, even if their shade is not so complete. Will is standing here next to the Geological Survey of Israel vehicle. Shlomo, an old friend and the driver, gave us quite the off-road adventure. Many people pay for such tours!

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Incidents of Travel in Southern Israel

Mark Wilson May 29, 2011 11:23 am

Flat tire at N30.54352°, E35.14007°.

Near miss (if we had been eating lunch here, say, 15 years ago).

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A wall of Cretaceous ammonites

Mark Wilson May 28, 2011 3:11 pm

MITZPE RAMON, ISRAEL–On our way back from Eilat this afternoon, Will and I took a short hike to see the “Ammonite Wall” on the southern outside beds of Makhtesh Ramon. It is an impressive tilted array of large ammonites in the Tamar Formation (Cenomanian). Current thoughts are that this represents a massive death assemblage. The ammonite conchs, which all seem to be of the same species, washed into an embayment and were buried. This is not uncommon as ammonite conchs probably filled with gases after death and floated great distances. They are all preserved as internal molds, with a few, such as the one below, showing their suture patterns.

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A visit to a dying reef system

Mark Wilson May 28, 2011 11:17 am

Fringing coral reef seen from the top of the Underwater Marine Observatory tower near Eilat, Israel.

EILAT, ISRAEL–When I first visited the Underwater Observatory Marine Park outside Eilat on the Red Sea coast near the Egyptian border, I was enchanted. An elegant steel and glass tower was built into a reef so that you can descend well below sea level and look out at a living, natural reef. I’ve brought students to this Observatory ever since to enjoy the beauty of a reef close-up without having to get wet. It is also a splendid place to see living analogues of the many organisms we are studying as fossils in the Jurassic and Cretaceous.

Closer view of the reef in the first image. Almost all the corals are dead.

Alas, the Eilat coral reefs are dying quickly. I see a significant difference in the health of the reefs in the last eight years. Most of the framework corals are completely dead, leaving gray aragonite skeletons to be sparsely inhabited by sponges, feather worms and the inevitable algae. The park tries gamely to keep up appearances at the observatory windows, but it is clear that the dwindling diversity of fish is now the primary attraction, not the corals themselves.

Will Cary looking out one of the underwater windows into the coral reef.

Coral reefs are dying all over the world, but their rate of disappearance in the Red Sea is unusually high. There are many causes, my biologist friends tell me, most related to the narrow nature of the Gulf of Eilat here. Many ships pass through daily, water-loving tourists are abundant, and wastes inevitably drain from the cities of Eilat and Aqaba into the sea. There is also a problem of sand being added to hotel beaches which gets redistributed onto living reef.

The coral reefs viewed from below. The framework is mostly dead coral skeleton.

Fifty years ago there were about 10 square kilometers of living coral reef in this area. Now it is less than 2.5 square kilometers, and much of this remaining reef is so stressed that no new corals are recruited. Very sad.

In the future I may be showing my students a few living corals preserved in the aquaria of the Underwater Observatory Marine Park, and then looking out at what happens to an ecosystem when the reefs die.

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A rare late May rain in the Negev

Mark Wilson May 28, 2011 10:25 am

MITZPE RAMON, ISRAEL–The only other time I’ve seen rain in southern Israel was with Elyssa Krivicich on our March 2008 trip. By May the rains are done in this part of the world. Nevertheless, it rained last night and then sprinkled on us as we drove south to Eilat this morning. The temperature has also dropped a good 6°C, which suits us just fine.

This is the 400th post on the Wooster Geologists blog! It is also near our two-year anniversary. It appears from our statistics (which I do not fully understand) that we have had 21,793 visitors and 163,072 pageviews. I’m not sure if those are unique visitors or what a “pageview” is, but I know we’ve had enough feedback to make this project much fun.

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Cobbling together a Late Cretaceous story

Mark Wilson May 27, 2011 10:08 am

MITZPE RAMON, ISRAEL–This morning Will and I finished our work with the Zihor/Menuha boundary cobbles. We drove to the southern side of Makhtesh Ramon (pictured above) to see the same units we examined 25 kilometers to the north in Wadi Aqrav yesterday. The scenery was spectacular — and the day so hot that the wind felt like a hair-dryer in the face.

Will standing on the very top of the Zihor Formation where it is overlain by the Menuha chalks. This picture was deliberately posed to give his parents a bit of a thrill.

The Zihor/Menuha cobbles in the southern sections. They look very much like those we studied in Wadi Aqrav. They certainly are more numerous here and easy to measure. Some have borings by bivalves (Gastrochaenolites) and worms (Trypanites). We found no encrusters here, but we did find oyster shell fragments.

A difference between these southern exposures and those to the north is that the Zihor Formation top surface here is very well exposed. We can see that it was probably lithified during the erosion that created the disconformity and the cobble lag. It is undulating and well polished. Note that it is also on the edge of oblivion.

The Zihor/Menuha boundary is very distinctive because of the erosional differences, so faults through it show up well. What kind of fault is this? (It is not a trick of perspective because the fault plane has eroded back a bit.)

This is the kind of shade we had in the field today — when we were lucky! It was 40°C by 1:00 p.m. Will is pressed up against an outcrop of the Menuha Formation, by the way, showing a sequence of carbonate nodules that may help explain the origin of the boundary cobbles.

 

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The Ora Formation: A future student project?

Mark Wilson May 27, 2011 9:34 am

MITZPE RAMON, ISRAEL–I’ve always enjoyed seeing the Ora Formation, which is exposed only in Makhtesh Ramon and to the south. It is early Late Turonian in age, so it is part of the Upper Cretaceous and about 90 million years old. It has an astonishing range of depositional units, many of which Will and I saw today on our way to our localities. The Ora Formation has been very well studied by Israeli paleontologists and stratigraphers. Their work can now be expanded with more paleoecological analysis and some of the insights we’ve gained from new ideas about Calcite and Aragonite Sea alternations. Maybe another Wooster Independent Study project or two in the future?

A carbonate hardground in the Ora Formation. The holes were drilled by lithophagid bivalves, producing a trace fossil called Gastrochaenolites. These borings are very densely packed, which is more typical for the Jurassic than the Cretaceous.

A unit composed of almost entirely oyster valves in the Ora Formation. It is above what is called locally the “Vroman Bank”. The shells are like large cornflakes. We didn’t get a chance to look in detail, but I’d love to see what kind of sclerobionts are preserved on these oysters.

Will is sitting in an unusual diapiric structure in the Ora Formation. This is a dissected “mud volcano“, or at least what would have been a mud volcano but for the resistant capping rock. Soupy mud was forced out from underneath the overlying limestones forming an inverted cone in cross-section. The limestones dip into the structure because they were forced down by the accumulating mud. The criss-cross lines in the mud are planes of gypsum that intruded the sediments later. Note the blocks of limestone in the “throat” of the structure — this means the limestones were lithified during the event.

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Makhteshim Country: A Future UNESCO Geopark?

Mark Wilson May 26, 2011 2:30 pm

Yoav Avni and Will Cary hiking down the wadi that exits Makhtesh Gadol. In the background is the wall of the makhtesh. It is made of diverse Cretaceous units.

MITZPE RAMON–Our colleague Yoav Avni of the Geological Survey of Israel is part of a movement to declare the Negev Desert around the three major makhteshim a Geopark cataloged by the United Nations Educational, Scientific and Cultural Organization (UNESCO). A Geopark is defined by UNESCO as “A territory encompassing one or more sites of scientific importance, not only for geological reasons but also by virtue of its archaeological, ecological or cultural value.” Yoav’s dream is that scientists and the general public from around the world will someday visit the makhteshim to tour the unique geological features with an infrastructure in place much like that of a US National Park. The ecological and cultural heritage of this region will be as important as the geology.

Modified from Google Maps.

I played a small role in this process when I wrote a letter to the Israeli government in 2005 (at Yoav’s request) explaining the geological value of Makhtesh Gadol and opposing further expansion of a sand quarry in the northern part of the makhtesh. This added a seed of international scientific interest to the discussion that continues to grow.

Now when we describe geological phenomena and fossils in the makhteshim, we are thinking about the ways we can explain these things to the public through nature trails, museum exhibits and popular press articles. It is exciting to be on the ground floor of such an endeavor.

There is plenty of opposition to this Geopark, of course. On one side are industries and government officials who want to squeeze every bit of economic usefulness from the land; on the other are extreme preservationists who wish to close off large tracts to all human entry. Somehow Yoav and his colleagues will have to find a way to make the future Geopark economically viable and yet with all the protections necessary to preserve its natural assets. This will be a slow process but maybe I will someday be posting blogs from the Makhteshim Country Geopark.

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