Saturday, October 20, 2018

Threading the Gap Between the High Atlas and the Anti-Atlas in Morocco - Erfoud to Ouarzazate

This may have been the most scenic section of a trip full of scenic drives. I'll let the reader decide.

Map of Morocco showing our course to the west-southwest between the Anti-Atlas on the south and the High Atlas Mountains to the north. Destination Ouarzazate.

Leaving Erfoud, we encountered numerous man-made mounds along the roadside. These are access shafts to an underground irrigation system called a ketthara in Morocco (kanat in some other Arab countries). These mounds mark where vertical shafts have been dug to intersect a shallow and sloping water table. The system has been in use since about 1000 BCE Before Common Era) and was devised originally in Persia. The wells here are now abandoned having been affected by over-pumping when tourist infrastructure caused too many wells to be drilled, thus lowering the water table.

We were admiring the ketthara and taking pictures when a man appeared, seemingly out of nowhere in the desert, with jewelry to sell.

Some in our group were interested in this unexpected appearance and the man did quite well from our 20 minute stop.

In the Anti-Atlas, this interesting unconformity was seen, with flat-lying (and relatively young) sedimentary rocks overlying deformed early Paleozoic sediments. This outcrop is along R702 highway west out of Erfoud.

This is a view of a small fossil quarry on the flank of the Anti-Atlas. The small roads cut across the bedding planes in the tilted rocks but the wider areas are where mining occurred along the bedding planes. Much larger quarries are more industrialized and those shown here are likely from the earliest phases of fossil quarrying.

The normally dry wadis were full of run-off from the recent rains. This large wadi was issuing from the Anti-Atlas in the background.

Water running across the highway is a rare enough event that locals in this village came out just to watch vehicles drive through it.

The following six photographs were taken from the coach as we drove through small villages on our way to Ouarzazate. I share them with you to show normal everyday scenes in the hinterland of Morocco's Sahara country. I normally do not even attempt to take photos from a moving coach. However, the scenes we passed were so compelling that I gave it a try and it didn't turn out too bad. A preferred kind of "drive-by shooting."

This may be the village of Touroug.

Woman carrying the mornings harvest.

Goat herder watching the coach go by.

Small, tilted mountain range in the distance.

Folded sedimentary rocks of the Anti-Atlas. These beds of limestone have been put at an angle but within that angle, they are planar. When streams carve depressions in tilted planes, the "curvy" pattern develops. I've not had too much luck in trying to explain the origin of this interesting pattern in the rocks but one way I try is to have people imagine different colored "layers" of construction paper. If you look at that stack from the side and tilt the stack, you'll see different colored layers. But if you cut a curved, V-shaped piece out of the stack you would see each individual color appear as a swirl. So I ask you dear reader, "Help me explain this!"

There are many police stops on the roads in Morocco. They check if drivers licenses and vehicle registrations are current, and if the vehicles are safe. To many Americans, these can make it seem as if it a place is a police state. Actually, scenes like these are commonly seen in many of my world travels. The tourist coaches were always waved right on through.

The next set of photos are from near the town of Tenehir. We are now on Highway N10. The scenery was fantastic here.

Looking southeast over the oasis toward the southern face of the Atlas Mountains.

In many Moroccan villages, the old adobe heart is being abandoned for newer, cinder-block homes. The older town centers are left as ruins. Note the fruit-filled date palm on the left.

Another view of Tenehir in the passing clouds.

What a day! Puffy clouds, blue sky, an uplifted mountain front, a well watered and lush valley, and an adobe village in exotic Morocco.

The local vendors at the viewpoint obviously have experience letting their camel stick its head inside of coaches.

A close-up of the wadi wall reveals an obvious angular unconformity where more recent, uncemented gravel from the mountains overlies deformed and tilted red sediments.

This was definitely a southwestern-equivalent landscape!

The red sediment forming the partially covered apron in the distant mesa is likely Triassic-age deposits laid down as Africa began its eastward drift away from North America, around 220 million years ago. The red sediment collected in the growing rift. The mesa is capped by white limestone that signals incursion of the nascent Atlantic Ocean by about 205 million years ago. Later uplift of the Atlas range greatly deformed and partially eroded these sediments off of the mountains top.

Our destination in Tenehir was the Dades Gorges.

As we entered the gorge, it was evident that very large forces were at work to uplift the Atlas Mountains in the Alpine orogeny, the same mountain building event that created the Alps in southern Europe.

The Dades River has carved a 1,000-foot deep gorge in the Jurassic limestone. The walls shows evidence of faulting where blocks of crust had been jostled about in the uplift.

Once out of the gorge, we continued west along the base of the mountains and the Dades River valley. In the distance lies the Triassic and Jurassic couplet of rocks that formed broad colorful mesas.

This is the town of Boumaine Dades along the river of the same name.

At a rest stop along the way, there was a rock formation with a trail leading to the top. Young people came up here to drinks Cokes and flirt. There is never alcohol involved in public gatherings in Morocco - all of the street side cafes are where men go to drink tea and coffee. The highway followed an obvious deposit of conglomerate laid down by the Dades River. It has since been dissected and rests now about 100 feet above the valley floor. These are blocks of the conglomerate that have broken away from the main pedestal. The age of the conglomerate is likely Miocene or Pliocene, or about 15 to 5 million years old.

Fabrics for sale hanging on a wall.

Highway art - old tires have been cut into shapes resembling tea pots and colorfully painted.

The next four photos are a series of skyscapes seen along the drive near Talat.

Scenes like this just welcome the traveler to stand in awe.

The clouds slowly became thicker though the afternoon...

...until they dominated the sky.

Great light captured by the passing clouds.

This building is a kasbah, which is an Arabic word for fortress. Many kasbahs have been abandoned now and are in ruins along this stretch of highway. But a few have been restored to their former glory. This area is sometimes referred to as the road of a thousand kasbahs. This particular one is called Amerhidil.

Our group interacted with some local boys while making the stop. Our local guide, Seddik is on the right and could interpret for our group.

Handing out school supplies was something that brought our two groups together and a smile to the faces of the locals.

The highway continued to follow the conglomerate deposit, which was underlain by sediments that appeared to be valley fill, when the Dades River became blocked downstream from here.

Eventually, the river cut down down significantly into these sand, clay and mud deposits.

Just before entering Ouarzazate, we passed one of the world's largest solar energy projects, Masen (Moroccan Agency for Sustainable Energy). Morocco presently gets 97% of its energy needs from fossil fuels but has a goal of getting 52% from renewables by 2030.

As I said at the start of this posting, this was a red-letter day for scenery!

Wednesday, October 17, 2018

Fossils and Sand Dunes in Eastern Morocco

The Erfoud area in the Sahara Desert offers some excellent geology-themed items of interest. This is the heart of Morocco's fossil country, for which the country is world renown. The Mergouza sand dunes are a mere 30 miles away and our sunset camel ride was fantastic.

Our explorations began with a morning tour of a fossil processing center, which is really just another one of the area's many fossil shops. Quarries are located all around this part of the country but Erfoud is the source area and economic center of the fossil industry. It sounds strange to say "fossil industry" but fossils are worth $40 million per year to the country (2009 data).

These fossils are known as Orthoceras (Orthoceras sp.) from the Latin for "straight horn." They are nautiloids related to modern day squid and octopus. This is a slab that has been horizontally cut and ready to be made into a large floor tile or coffee table.

This is a coiled nautilus known as an ammonite. It appeared to me that some soft body remains might be preserved at the opening of the shell. If so, this would be a spectacular example of very detailed preservation.

More ammonites. The fossils in this part of Morocco range in age from Cambrian to Devonian (about 550 to 360 million years).

Saudi Aramco Magazine ran this feature article on Morocco's trilobite economy.

In the American Southeast, we rarely find the calyx (head) of crinoids but in Morocco they are wonderfully preserved. These animals were attached to the sea floor and swayed back and forth with the currents. As food drifted by, the feathery tops filtered the food and ingested it downward. Crinoids are related to sea stars and sea urchins.

These are some of the best preserved trilobites I've ever seen. See this New York Times article about Erfoud's place in Morocco's fossil industry.

Next on to Rissani where I saw that the date crop is almost ready for picking. The dates are delicious.

Rissani is located at the junction of a north/south travel corridor and an east/west corridor. In ancient times it was a very important stop along the caravan routes from Mecca to the Maghreb. These are the ruins of a once thriving city near Rissani during the heyday of the camel caravans.

A colorful display located outside a shop in Rissani.

A vendor in Rissani.

The rain had been falling for a few weeks in the Sahara and the Atlas Mountains and we got to experience the desert during a very wet phase.

The rains also cleared away the typical Old World haze that seems to prevail all over Europe and North Africa. We had spectacular skies that seemed to stretch forever into the distance!

Ventifacts (rocks shaped by the long-term buffeting of blowing sand) were commonly seen on the desert floor.

A far-off rain squall creates shafts of sunlight in the Sahara.

These are views I am very familiar with in western North America - an isolated thunderstorm in the distance.

Finally, the Mergouza dunes came into view. These are located about 30 miles southeast of Erfoud.

Close-up of the dunes near sunset.

Note the ephemeral stream running at the base of the dunes. In the Old World, it his common to have trees growing in dune fields.

These dunes are very popular with travelers and many people spend the night in these tented compounds. Our group enjoyed an outdoor dinner in one such compound, complete with Bedouin music and a fantastic view of the Milky Way.

This was our camel driver who took us on the easiest, smoothest cameral ride I have ever enjoyed.

The sand was cool and moist to the touch having been protected by cloud most of the day.

Each grain of sand is composed of pure white quartz grains, eroded from granite or sandstone. Each grain has a thin coating of iron oxide on its surface to give it the red color.

What a romantic view! I thought of all the caravans that traversed the Sahara through the millennia.

For the real hearty geologists out there, be sure to check out a short geologic history of Morocco here taken from Deposits Magazine.