Germany 2021
Germany … my beautiful Germany. When I first came to Germany in September 1988 I had left behind a stifling hot, sun-baked southern California, so when I landed in Frankfurt an drove a rented car to Bremen I was absolutely astonished at the luscious green that surrounded me, the quaint and compact towns, and the patchwork landscape of agricultural fields and wooded areas. Well, I have relived this feeling again over a period of two weeks, and have to repeat once again that Germany and its people are the best of the best in Europe!
Of course I have always felt at home in Frankfurt, in the house of my dear friends Chrissy and Gustav Kobberger. Through them I have built over the years a great network of friends, starting with their daughter Anna (my travel companion to New Zealand), their son Phillip, their good friends Frank and Andrea Feuerriegel and their daughter Alisa, Oma Inge Kobberger (Gustav’s mom), Klaus Kobberger (Gustav’s brother) and his wife Sieglinde and daughter Katrin, Gabi and Dieter (although I didn’t see them this time), Kerstin Buckley and her dog Grace (new friends who I am looking forward to cementing a friendship with), my Georgia travel companions Zsuzsa and Raimond, and all the other friends whose name I am forgetting at this time.
Three days after landing, Chrissy, Zsuzsa, Raimond and I headed for Georgia, but I have already told you about that, so I will regain the thread of my narrative after we returned from Georgia. Gustav picked me up from the airport and we celebrated our meeting with a cold beer. Hmm, it was good. That evening we went for Apfelwein (hard cider with very little carbonation) and Handkäse mit Musik (cheese shaped into a small loaf by hand and then steeped in vinegar and cumin—the “music” comes for the rest of the afternoon, as the guests form a veritable symphony with their flatulence). We have done those many times at Hochstadt, but this time the event was quite special because Kerstin joined us. I was … well … very much impressed by her and hope to see her more often to build a nice friendship.
The following day we had to run a lot of errands, because Gustav was throwing me a birthday party and there were drinks and grill meats to gather. But before we got started I took Leo, Chrissy’s cockapoodle for a short walk to buy Brötchens at the bakery and to figure out where our future walks were going to be. I followed every grassy path I could find, trying to find the perfect spot for him to do number 2. Nada! No place seemed right, so after a while I stopped thinking about it, just as he squatted in the middle of the sidewalk to do his thing. Arghh! I didn’t have a plastic bag with me, but I always carry napkins so I braced myself for the nasty task, leaned down to reach for the smelly pile, and my cell phone slid from by shirt pocket, did a perfect summersault and landed square on la Scheisse! Why do these things happen to me?
The party, the following day, was a great success. Gustav grilled enough steaks and bratwurst to feed an army, and the visitors regaled us with delicious salads and bread. Phillip baked me a cheese cake, and Raimond—who is a professional baker—baked me a chocolate-whipped cream torte. Fortunately the 20 or so guests had sharp appetites and very little was left of the cakes. I got all sort of cool presents, among which was a generous amount for me to buy a new pair of pants (I left one of the two I owned back in Georgia), and an invitation to dine on a calf shank in an old restaurant in Sachsenhousen.
The following day Chrissy took me to Hanau to buy a new SIM card for my cell phone (so now I have a German cell phone number) and to shop for a new pair of pants. It was a very successful trip and I ended with underwear, socks, and two pairs of pants! I love sales with deep discounts. By the way, Hanau’s claim to fame is that it was the city of the Brothers Jacob and Wilhelm Grimm, who thought themselves first and foremost as philologists, but who are remembered today as the collectors of all sorts of fairy tales, such as Aschenputtel (Cinderella), Kleine Rotkäppchen (Little Red Riding Hood), and Schneewittchen (Snow White). To celebrate its most famous sons, the city has placed cute little statues around the city representing these tales. I did notice that Kleine Rotkäppchen was bringing in her basket a bottle of Schnapps to her dear ol’ granny.
Other delightful activities included many walks with Leo, or rather I should restate it as many delightful walks with Christine and Andrea, together with their respective dogs, a very nice invitation to lunch with Oma Inge—who is getting up in years but can still offer a good table and entertain us with the stories of her many travels—, and a visit to Katrina’s new apartment, where Phillip amazed us with his culinary abilities preparing a very nice Thai dinner. We later played Frantik, which is a bit like Uno but where there is a greater opportunity to do damage to the other players. It was a fun evening.
Klaus Kobberger is the ultimate serious businessman, and he works long hours to make sure the fortunes of the Kobberger family are in good standing. The core of the business is the Kobberger Parfumerie, which was established over a 100 years ago my Uropa Gustav, and passed unto the hands of Opa Gustav for nearly 50 years. Klaus took over after Opa Gustav passed away, 30 years ago, and will easily will stay at the helm for another 13 years, until the current lease on the building expires. OK, it was not my intention to go into the details, but you get the idea that he is very dedicated to his work. So he needs a little fun in his life. Half of it is going riding every morning with his wife Sieglinde. Each of them have their own horses, and like good pet owners feel it is their responsibility to exercise them every day—if I were a horse of a dog I would definitely like to live in Germany than everywhere else; here people are super-nice to animals.
The other way in which Klaus decided to have fun was in buying a hunting area all for himself (a Jagdgebiet in which he leases the rights and obligations of being the only hunter in an area of a good 10 square kilometers). Now, the Jagdgebiet has farms within its borders, and a town, so my good Klaus is more like the Duke of the place, rather than its owner. So once a week he dons his hunter’s outfit and goes shoots a deer or a wild. I thought this was all too weird for such a cool guy, so I had been asking for him to take me to his Jagdgebiet for years, and now finally came the time. I expected to see him, gun on the ready, walking through the German forest ready to shoot at anything that moved. I was going to be disappointed.
Klaus picked me up around 5 pm, and driving way too fast soon covered the 30 km to the Vogelsberg, where his Jagdgebiet is located. First thing we did was stop at the town, so he could say hello to his hunting warden, who keeps an eye on things for him, and to show me the cluttered room where the pieces are skinned and placed in cold storage. The butcher across the road is the one who prepares the roasts, ribs, stakes, and sausages. Off we were then to the hunting grounds, and the first thing I learned is that hunting in the woods is a no, no, as these are the places of shelter for the animals and their youngsters. You hunt in the open agricultural fields, or at the edge between the fields and the thin strips of in-between forest that are so distinctive of German agriculture. We really should adopt that strategy, instead of having the fields run against each other, because it promotes a more diverse ecosystem and lots of biological control for agricultural pests. Then you have to take the wind into account. You have to wait downwind from where you expect the animals to be, which means you have to know your area pretty well so you have a nice large field, with many borders in view, upwind from where you plan to wait (in ambush). All around the countryside you see these chairs on 2-meter stilts sitting at the edges of the forest, which normally have a roof and a “blind” so the animals cannot see you. The Duke and his warden must build and maintain them themselves, so I could imagine Klaus building the high stool down at the town, and then bringing it as one piece on top of the truck to install in the best possible place. Klaus tells me he has to shake them before climbing up there, not for fear of critters, but for fear of the ecoterrorists, who from time to time come and take a few screws out to deter the hunter.
Hunting here is Germany is regarded by most as a wildlife managing strategy, so the farmers are happy that the wild population of plant predators (i.e., deer, pigs, hares) are kept under control, as well as those who pray on chickens and rabbits, such as foxes and badgers. The hunter is very much aware of his social responsibility, both to farmers and the wildlife, and tries to make sure that he has a clear shot before he takes it, and that if a wounded animal bolts it is followed and put out of its misery. As Duke of the place, farmers can ask Klaus for payment of lost crops if a herd of wild pigs wreaks havoc among the corn plantation (why do Germans plant so much corn if they don’t eat tortillas?), or if deer cut munching trails across the wheat field!
Of course we didn’t shoot anything, but with an experienced eye Klaus saw three does with youngsters and a male, two foxes, the lair of a badger, and any number of hares. “Good”, he declared “the Jagdgebiet is in good shape for this time of the year.” We finished back at town, where we enjoyed a couple of beers chatting with the warden, his young wife, and Opa. Nice people these Jägers!
For years I have been flying into Frankfurt airport, where Gustav or Christine have picked me up a dozen times, and driven to their house in Dörningheim (maybe 10 km east of Frankfurt) parallel to the Main River. About 5 years ago I noticed that in the distance, by the side of the river there was a church steeple and asked Christine what was that. “That is Fechenheim”, she answered. “Well, how come we have never been in Fechenheim”, I inquired, “Have you been to Fechenheim?” The following years I repeated this question to lots of people, and concluded that half of them had never been there, and the other half was probably lying. It became an on-going dream of mine to visit was the little town of Fechenheim. Finally it happened. Chrissy wanted to take Leo for a walk and suggested we went to Fechenheim, which has some nice meadows by the side of the Main. It was a bit of a disappointment because, although a perfectly good little German town, it really doesn’t have much to offer to the world traveler. Until, that is, said traveler meets Jenny. Christine knew this, and she had been looking for her, but at the end we had to come back to town and ask an old timer, Walter, where Jenny was. “Oh, someone told me that she is in the meadow behind the riverside restaurant”, he informed us, so we walked all that way there and, indeed, we found her there, enjoying the sun and the morning breeze. Jenny is a white mare, 20 years old or so, who for years has been taking herself for walks through the town, along the route of the tram, or most often through the meadows. She stops to eat the geraniums while a delighted lady gives her a rub, gets an apple from the local grocer, peacefully waits until the kids out of school finish stroking her, and simply enjoys the day basking under the sun. She used to have her sister with her, as well as a white German Shepherd, but they have since died. Walter, her owner, opens the door of her stall every morning and when she is ready she goes out for her daily walk, returning at dusk to have her dinner and spend the night in her stall. I have taken quite a liking to Jenny, who like me is a free bird who choses her own path. To learn more about Jenny you can google “Jenny Fechenheim Germany”
I have stayed here a little bit too long, so Gustav and Chrissy are having problems doing their normal routines and catering for their guest. Gustav has been working from home, but the other day he had to go to the field to collect some soil samples and he took me along to one of the most interesting geologic sites ever, the Grube Messel (basically the Messel Pit). Today the Grube Messel is a hole in the ground, from which oil shale was mined starting in the 1880’s and until the 1960’s, to distill kerosene out of it by heating it under pressure. The leftovers, which were now enriched in polyaromatic petroleum hydrocarbons (PAHs) as a result of the heating, were then accumulated in a gigantic pile by the side of the mine. Well, it turns out that PAHs are carcinogenic, so my dear Gustav now has the task of evaluating how bad the problem is, and then removing those leftovers to a hazardous substances landfill. It is a huge job because they will have to move a mountain of debris, but that is not the most interesting aspect of the site. The black shales, although very thick, had a limited geographic distribution, and the company mining them concluded that they had been accumulated in a deep lake during the Eocene (56 to 34 million years ago), and by looking further at the geology concluded that this deep, circular lake had been born as a maar during a phreatomagmatic explosion. Now that is not something you see every day, but … wait … there is more to this story. Germany at the time was this warm, sticky place, and the lake was chocked with algae (that is where the petroleum hydrocarbons came from) among which swam crocodiles, otters, turtles, and a few frogs and fish. The frogs attracted some waterfowl, and the surrounding trees were teeming with lemurs, snakes, birds, and insects. There were so many insects! And all of these critters duly died and sank to the bottom of this euxinic lake, where they quickly fossilized among the black, stinking mud that accumulated relentlessly on the bottom of the lake. The unique conditions thus led to the formation of one of the most amazing fossil treasures ever, which have provided us with beautifully preserved fossils of the dawn of the Age of Mammals. Unfortunately the onsite museum is not very good, so I will have to go to the Senckenberg Museum in Frankfurt to see the best fossils on display.
Just like in the case of Fechenheim, in 30 years of coming to Germany nobody had told me that 14.5 million years ago there had been a large meteorite impact in northern Bavaria, where the town of Nördlingen is located. I only heard about the so-called Nördlinger Ries by chance, when I read an article that described the cathedral as being built with “suevite”. Wait a minute … suevite is a meteorite impact breccia … hence Nördlingen had to be close to a meteorite impact site. So I asked Gustav and learned that indeed this was a famous locality in Germany that he had visited in the course of his studies as a young geologist. Would I like to visit it? Yes, of course! So Gustav organized a four day excursion for the two of us. Great! Tom, Chico, and Gustav are some of my oldest friends, and I really enjoy spending time with either of them, even though sometimes we get on each other’s nerves. For example, Gustav thinks that I am slow-poke driver, and to show me what is what he drove in his best German style, pushing 200 km/hr in the Autobahn, while I cringed with panic and a sense of doom.
Once we got to Bavaria/Schwaben, Gustav chose as our center of operations the town of Wörnitzostheim, along the east side of the Reis, because there is there an old guesthouse that he likes. Germans like their comfort, and a restaurant that is gemutlich or comfortable, is sure to attract a faithful clientele. The owner is a pig farmer who has branched into hospitality, and his wife is a wonderful cook (chatting with him I learned that he has 800 pigs and he was sending a few to the butcher that week, so I asked him if he liked pigs’ feet, to which he added laughing that they eat them all the time).
From the excellent museum in Nördlingen I learned that the meteorite (which probably split in two as it entered the atmosphere because there is a second smaller crater parallel to the Reis) impacted at a moderate angle (30⁰ to 40⁰) coming from the northwest, and in creating the crater vaporized itself and the rocks on which it fell, brecciated the rocks in the periphery, and flipped over great hunks of the surficial limestones and landed them upon the breccias. Within a few minutes, the cloud of fragmented and melted rock that had been vaporized started raining down as a thick, dense storm of comminuted rock and shreds of molten rock to form one or more thick layers of suevite. The impact, and the mound of rubble it left behind, considerably modified the geography of the area. For example, before the impact the proto-Main river was a tributary of the proto-Danube, but was forced to change its sense of low to the west, toward the Rhine river.
The cathedral is indeed built of blocks of suevite, and because they were making some repairs I noticed that there were a few pieces lying around asking to be taken. Gustav put his foot down and forbad me from pinching any of them, so I was reduced to collect my own samples from the outcrop, as if I were a low-life geologist. Speaking of outcrop, I mentioned before that Germany is gloriously green, which means that every square meter is covered by rock-covering, annoying vegetation. Curse this temperate rain forest ;( Fortunately, Gustav knew the location of a few quarries, so we had our opportunity to inspect the Buntebreccia (the colorful impact breccia), the giant blocks of jostled limestone, and the very anticipated suevite (I collected several pieces, but of course I don’t have a way of carrying them around, so they are back in Dörningheim waiting for me to do something about them. I want to show them to my Planetary Science and Engineering students, so I will try to smuggle at least one back into the US.
On the night before our departure our host saluted us with great bonhomie and a wide grin. He had a surprise for us: First, there was Leberknödel Suppe (soup of liver dumplings, which is super yummy) and … Schweinefüssen! Madame had outdone herself and had prepared a big pot of pigs’ feet in honor of their first and only Mexican guest! They were delicious, although in retrospect I should have probably asked for some Sauerkraut as a side dish. When the bill came Gustav noticed that the Schweinefüssen were on the house, but he had to pay for his own steak.
On the way back I resolved to learn from Gustav how to drive like a proper German, and to learn how to be a proper German from my friend Klaus.
Monday I was quite looking forward to an outing with my new friend Kerstin and her little dog Grace. Turns out that an hour east of Frankfurt are the Spessart mountains (where I am going to guess the garnet spessartine was first described), and that in these mountains is the small town of Bieber. Kerstin has a cabin there, and she offered to show me around the town and the surrounding valley. She also did some advanced homework and got me a brief summary of the town and its geology; turns out that in addition to some veins where bieberite (a soluble cobalt sulfate) was mined, the main call to fame of this region is the Kupfershiefer horizon, a 30 cm-thick layer of shale that contains recoverable amounts of copper, lead, zinc, and silver. Because the seam is so thin the mining was done in the form of very low galleries, where children would crawl to chip at the rock. The children grew into stunted adults, and the region was kind of famous for the number of hunchbacks and dwarfs found in the valley. The processed metals were transported to the city of Lohr-am-Main, where the availability of silver gave rise to a well-acknowledged mirror industry. We are talking here about the Middle Ages, and the mirror-makers of Lohr rose to the challenge of making large mirrors that were coveted by the aristocracy of central Europe. The Duchess of Lohr, for example, was reputed to have a very large mirror endowed with the ability to see beyond the confines of the valley.
When we got to Bieber I discovered that Kerstin “cabin” is a handsome three-story tower (The Witch’s Tower) right in the middle of town. She happens to be a very handy gal, so the ground floor is occupied by a well-appointed workshop and a large store of wood for the winter, whereas the second and third levels (in Germany they would count as the first and second floors) have a small but very functional kitchen and bathroom, and the living room, respectively. Since I mention the word bathroom, I have to describe to you the German toilet: For some unknown reason Germans have designed their toilet bowls with a small shelf in the back of the bowl, so when you go number 2 there is a nice steaming pile waiting for you to inspect before you flush. Gustav claims that it is so if you have swallowed your wedding gold ring you have a chance to recover it, and Kerstin thinks it is so you can keep an eye on the state of your gastrointestinal health. Now, doesn’t that sound delightful to you?
The forest around Bieber was fabulous, and we had a good time trying to identify the trees as we climbed to the top of the hill, where a small chapel along the ridge marked the boundary between the valley of Lohr and the valley of Bieber. This was a very important place, for if you were to cross this ridge coming from Lohr, you would have as well as disappeared … wait … I have heard this story before … a girl escaping the sentence of death pronounced against her by the Duchess, her stepmother … she gets to a lonely chapel in the woods where she pleads for her life to the warden who is to kill her … her flight into a mysterious valley where she is rescued by a group of dwarf miners … the magic mirror that let’s her stepmother see where she hides … OMG, I am in the very place where Schneewittchen lived so many centuries ago!
After a delightful walk through the forest Kerstin took me to visit Gelnhausen, which has to be one of the cutest towns ever. We strolled through the steep narrow roads, admired the beautiful landscape of the Spessart, and talked freely like a couple of old friends. Delightful!
Anna, Chrissy’s daughter, has Horacio duty today. I have known Anna since she was a baby girl and adore the wonderful young woman she has turned into. She and I took a trip to New Zealand a few years back, rented a camping van, and traveled all over the north and south islands, looking at the landscapes of Middle Earth, climbing volcanoes, hiking through alpine mountains and deep fjords, and basking on the beach. We keep saying we want to do another big trip together, but she is now a working stiff with limited vacation time. Ah, the joys to be young. In any case, she came to pick me up around 9 am, in her scooter and with an extra helmet, with the idea for us to walk through the recreation area of Oberwaldsee to catch up on personal gossip. She is a very good scooter driver, but I am a heavy guy, so I tried not to jiggle too much as I clung for dear life to the back seat of the Roller. Once we got there I was once again amazed at the natural beauty of a patch of forest that has been left between the urban and industrial development of Hanau (in truth, the series of lakes seem to be old quarries of basalt used as construction stone, which upon suspension of operations were reclaimed into a forest area). We spent a couple of hours walking through the area, but soon the pangs of hunger encouraged to move farther into downtown Frankfurt, where she needed to start work at 1 pm (she works at the family business, the Pärfumerie Kobberger). We settled for a Thai restaurant, where Anna had a deep-fried fish and I, looking for something new, got a salted fermented fish in spicy sauce. The waitress cautiously asked if I had tried that dish before, and warned me that it had a sour flavor that was not loved by all. Good thing then that I liked it very much. Maybe our new adventure would be to go to Thailand and ride scooters all over the place.
That same afternoon, after saying goodbye to Anna, I walked to the Senckenberg Museum to see the best fossil specimens from the Grube Messel. They are stunning, having been well preserved by the oil in the shales to an impressive detail. Some insects still retain their iridescent colors, and the feathers of the birds can be separated into fine strands. I really liked the bats, the turtles, and the big python, but my very favorite was the small crocodile. The Senckenberg is the natural history museum, and besides the Messel fossils it has its own specimens of Archeopterix encased in Solenhofen limestone, as well as some very famous specimens of dinosaurs and marine reptiles. A real treat for the paleontology aficionado.
My time in Germany was coming to an end, but Chrissy and I still had time to pay a visit to Raimond, our friend from the Georgia trip, at his bakery. Yes, Raimond is a baker, and he had invited us to have breakfast and then come see how high-production bread and cakes are done. All the equipment is bigger than life, and every day starting at 2 or 3 am the dough is mixed and allowed to rise in the warm moist chamber. The previous night Raimond analyses the sales for the last week to decide how many buns, croissants, and loaves will be produced that day, and the batches follow each other with amazing precision and rapidity. Big in the glass displays of a German bakery are the Tortes, which are the key ingredients in the afternoon Kaffeklatch among friends, so he has to make sure there is an abundance of fruit and berry tartes. Anna joined us for breakfast, as well as Raimond’s daughter and son-in-law. The latter are pregnant, and sometime early next year Raimond will become Opa, a milestone that he is really looking forward to.
Raimond is also an accomplished handy man, and he and his wide have a very comfortable apartment above the shop (they own the whole block), but as he approached age 70 he has decided that the time for retirement is at hand, so he is going to lease the storefront to another baker, close the production side of the bakery, and split the space available between a very nice hobby workshop and a new apartment for him and his wife, so his son and daughter can each have an apartment in the second floor. This is quite common here in Germany, where old large houses are transformed into multi-generation dwellings, with everybody having his or her own space while still being able to enjoy together amenities such as the garden, the grill, or the big family kitchen.
Kerstin came to the rescue that afternoon, and took me to see the Keltenfürst (or Celtic Prince) archaeologic site just outside Frankfurt. It turns out that the Celts lived in Germany sometime in the Neolithic and Bronze Ages, and had rather elaborated forts and burial rites, and at this site an important personage was buried, surrounded by three terracotta statues in a poor state of preservation. From the three the archaeologists reconstructed one, which is now widely known as the Keltenfürst (aka Mickey Mouse on account of the wide flaps on both sides of his headdress). Kerstin, Gracie, and I took a long delightful walk around the fort, and then I went into the museum (the girls had to stay out taking the afternoon sun because Kerstin wasn’t sure if they would admit Gracie the dog inside the museum – but this is Germany, so I am pretty sure they would welcome her with open arms). The museum was very nice, but at the end I got the impression that no one is quite sure who the Celts were. The English and the Scotts regard them as ferocious warriors, the French think of them as druids and ferociously independent Gaul (think Asterix here), the Spanish loosely equate them to the Visigoths I met in Recópolis, and the Germans seem to associate them to the original pastoral people of the land. You want to be proud of your Celtic heritage? By all means, go ahead; half of the world already does.
The following morning Chrissy and I headed south, to Heidelberg, for the purpose of visiting my old friend Klaus Mehl and his wife Yin-Ru. I met Klaus in Bochum in 1988 and 1989, and Yin-Ru ten years later when I went to visit them first in Taiwan and a couple of years later in Beijing, where Klaus was working as an environmental geologist. It was a good thing to see my old friend, who looks exactly as he looked 20 years ago (some people are lucky and seem to never age). Heidelberg is of course a beautiful university city that was largely spared the bombing of World War II because the Americans had decided it was going to be their General Command during the occupation years. Every year it receives millions of tourists, but thanks to Covid it was reasonably empty on this particular day, and we thoroughly enjoyed ourselves walking through it and walking up to the castle. One thing that struck me as a particularly good idea was the Student Jail. As I mentioned, this is a university town, and the students sometimes get out of hand. For example, even to this day there are the odd re-enactments of duels wit sabers or pistols (quite common 200 years ago). Carousing can also get out of hand. In any case, if the malefactors are caught, then they are tried in university court; if found guilty they have to spend a few days in the Student Jail. I totally think we should establish such a system at CSU Stanislaus.
For lunch we stopped at a restaurant in the main drag, which offered Taco Tuesday deals. Chrissy got an enchilada, Yin-Ru a chimichanga, Klaus a burrito, and I a very German Schnitzel. None of this foreign fare for me!
The end of my pleasant sojourn “in Germany” was a week in
the island of Gran Canaria with Gustav, Frank, and Gustav’s work colleague Ralph. Turns
out both Gustav and I worked in Gran Canaria between 1988 and 1990, so the
island has many good memories for us. It is a very interesting volcanic island,
the geology of which I will explain in painful detail to you in the rest of
this blog, but let me preface it by saying that the modern understanding of its
evolution started with the work of a German geologist, Herr Professor Doctor
Hans-Ulrich Schminke, who did his PhD about it in the 1970’s (at Columbia
University, I believe). Hans-Ulrich eventually became a full professor at
Ruhr-Universität Bochum, and among other things had several of his own PhD
students, and guest researchers like me, work on the details of the geology of
Gran Canaria. Gustav worked on the rheomorphic deformation of Ignimbrite D (it
is a real alphabet soup of units out there), and I worked on the feeder dike
complex exposed in the core of the island.
2. Explosive Mogán rhyolitic volcanism (with funny compositions such as comendites and pantellerites. This is when Gustav’s Ignimbrite D was formed (fed by some of my early dikes), and the roof of the magma chamber foundered in to form a first caldera
3. Explosive Fataga phonolitic volcanism and thick phonolite and trachyte lavas. This is when most of my dikes were feeding lavas to the surface, and when the roof of the magma chamber foundered to form a second caldera
4. Formation of a big stratovolcano inside the Fataga caldera, and its catastrophic collapse as one of the flanks became unstable, with giant blocks of the stratovolcano and its underlying older rocks sliding toward the ocean
5. Last gasps of the dying volcano in the form of small basaltic cinder cones of weird compositions (e.g., nephelinites)
Add to this complicated geologic history the fact that in the deep barrancos that cut deeply into the entrails of the island one finds exposed the most amazing series of cone-sheet dikes (that means that each dike looks like the wall of a cone, both curving around and dipping into the magma chamber, and that there are hundreds of these dikes), and you can well understand why we volcanologists consider Gran Canaria a unique geologic wonder.
The story of Ignimbrite D, as one of several rheomorphic ignimbrites is interesting. Gustav believes that the mass of pumice lumps and glass shards did not cool significantly, and that when the ignimbrite landed the pumice and shards were still above the glass-transition temperature, so they agglutinated and basically became a very thick, stiff lava. Under those conditions it was easier for the whole mass to move by shearing along discrete intervals, with distinctive rolling of rock fragments and “kneading” of big pumice “pancakes”, while the thick portions in between simply got stretched as they got caught in the vice of the shearing zones.
It was fun to go to our old stomping grounds! And I wish I
had the chance to bring my students here, so they too could see what a real
volcano looks like.
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