Geological Review – “Alien”

When the movie “Alien” was released in 1979, it quickly terrified audiences worldwide. Its unexpected mix of classic horror and science-fiction elements got at first mixed reviews, however, over the years Alien had come to be regarded as one of the best horror-science-fiction films ever made.”Alien” screenwriters Dan O’Bannon and Ronald Shusett based parts of their script on various older science-fiction movies and tales, like “At the Mountains of Madness”, a science-fiction/horror story published by American author H.P. Lovecraft in 1936. In the story, a team of scientists is hunted and killed by ancient creatures resembling fossil animals. Lovecraft apparently based this part of his story on the real discovery of fossil archaeocyathids in Antarctica made in 1920 by geologist William Thomas Gordon. Archaeocyathids are an extinct group of sponge-like creatures believed to be among the oldest animals ever to live on Earth.

Hans Rudolf Giger, Swiss surrealist artist, architect and industrial designer, was hired to create all forms of the Alien featuring in the film, from the egg to the adult. Giger created various versions of the alien life-cycle, like a gigantic egg nest, replaced in the final movie with an egg silo inside a derelict spaceship. The eggs were directly inspired by female reproductive organs, slightly modified to avoid censorship. The facehugger, a parasite attaching to the head of its victim to incubate an embryo, is based on the bones and muscles of a human hand and male genitalia, its springlike tail was added to emphasize its quick movements. The parasitic life-form was an idea of Ronald Shusett. Shusett suggested that one of the crew members be implanted with an alien parasite to explain how the alien life-form, discovered at first as an egg in a derelict alien spaceship, came on board of the mining spacecraft Nostromo. The parasite bursts from the chest of its victim and soon the crew has to deal with the fast-growing life-form hiding in the air vents of the spaceship. The design of the chestburster and the full-grown xenomorph (alien-shaped thing) is based on Giger’s “Necronom IV“, an artwork created in 1976. The surrealist drawing shows a female figure composed of different parts of insects, parts of vertebrates and even fossils. Giger used the fossils of 300 million-year-old crinoids, commonly called sea lilies, on display in the Aathal dinosaur museum as a source of inspiration.

A petrified crinoid. Similar fossils inspired the creature featured in the successful “Alien” saga.

The earliest known crinoids date back to the Ordovician (some 450 million years ago). Their remains are very common in the fossil record, forming rocks like limestone or dolostone. The skin of echinoderms, including sea cucumbers, sea urchins, crinoids, brittle stars and starfish, is covered with tiny ossicles made of calcium carbonate forming a protective, yet flexible, outer shell. In a similar way, Giger’s Alien is protected by a silicon-based external skeleton. This outer shell is also very useful to contain the acid blood of the creature. Concept artist John Cobb added the acid blood as a defense mechanism, making it impossible to kill the Alien without damage to the crew or the spaceship.

In the sequel “Aliens” a team of space marines enters an Alien hive, the walls resembling Goethite, Grube Eisekaute, Bad Marienberg, Germany.

The life-cycle of the Alien from egg to queen (as introduced in the sequel) resembles the life-cycle of real animals, the Ichneumonidae. The Ichneumonidae is a wasp family preying on insects. An adult female wasp will lay her eggs within a host through a process known as ovipositing. The eggs will grow and develop into larvae, which will feed on their host from the inside-out. Somewhere along the way the host will actually die or be kept in a state very near death until, finally, the little wasp spins a cocoon around and-or within its host, eventually emerging as an adult wasp. A horrified Charles Darwin famously mentions in a letter sent in 1860 to his friend, the botanist Asa Gray, the parasitoid wasp:

» I cannot persuade myself that a beneficent and omnipotent God would have designedly created the Ichneumonidae with the express intention of their feeding within the living bodies of caterpillars… «

In their natural environment, these wasps play important roles in regulating the populations of their insect hosts, and have been used in agricultural crops to control caterpillar pests. Dolichogenidae xenomorph is a parasitoid wasp species named in 2018 after the xenomorph, as “the wasp is also black and shiny like the Alien.”

The graphic representation of the “perfect organism” earned the visual effects team of “Alien” a well-deserved Academy Award.

Geological Observations Revolutionized Renaissance Art

» It is their art to stop at every stone and carry out an investigation at every layer of earth! «

Swiss author Rodolphe Toepffer describing geologists

During the Renaissance, the study of common rocks inspired great artists and revolutionized artistic techniques. Italian artist Leonardo da Vinci was one of the first naturalists to both understand the origin of sedimentary rocks and recognize fossils as petrified remains of former living animals. He used his geological insights to improve his paintings and in doing so inspired an entire generation of artists.

The Alps, ca. 1513, red chalk drawing by Leonardo da Vinci. He was fascinated by mountains and called them the “bones of the earth.”

This approach can be seen in da Vinci´s earliest recognized works, dating to 1473. In “The Hills of Tuscany” or “Landscape with River”, we are apparently standing on the borders of the Apennines, looking down onto a waterfall and the larger valley of the Arno.

The layers of the earth, visible above the waterfall, are depicted in a geologically correct way – thin at the bottom and thick on the top, like the Turbidite sequences found in the Apennines. Together with the lines used to draw the cultivated fields in the Arno valley, the sedimentary layers help to create an three-dimensional effect giving to this landscape a realistic “depth.” This effect is also helped by the waterfall, which is shown flowing away from the observer in a hydrologically correct manner down the slopes of the mountains into the Arno valley.

Leonardo da Vinci’s sketch of an outcrop.
Outcrop with sedimentary layers as spotted in the Apennines.

Leonardo’s technique was soon adopted by other artists. German painter Albrecht Dürer visited Italy twice to study the perspectival paintings of contemporary Italian architects and artists. Traveling back home, he tried to apply this revolutionary method to his own paintings. One of his drawings shows a quarry, maybe somewhere near his hometown of Nürnberg, displaying horizontal layers of sandstone and thinner layers of marl in a manner similar to da Vinci’s. Using the tectonic fractures as vertical construction lines, Dürer tried here to subdivide the picture like da Vinci and create the illusion of depth along the steep cliff.

“The Quarry” by Albrecht Dürer, probably painted in 1495.

Despite never really completely mastering the geometrical rules necessary to create a perfect perspective in a painting, Dürer nevertheless popularized this new technique in Europe. Soon, many other artists followed and began painting realistic landscapes, even studying rocks in order to correctly depict them in their art.


  • ROSENBERG, G.D. (2009): The measure of man and landscape in the Renaissance and Scientific Revolution. In Rosenberg, G.D., ed., The Revolution in Geology from the Renaissance to the Enlightenment: Geological Society of America Memoir 203: 13-40

Pyroclastic Flows of the Athesian Volcanic Group

May 8, 1902, began as a sunny day in Martinique, an island in the Caribbean, with only a column of steam rising above Mount Pelée. When the volcano suddenly exploded.

The first rescuers arrived on the site twelve days after the eruption, accompanied by British, French and American geologists. In the city of St. Pierre, almost all of the buildings had been destroyed and an estimated 20.000-40.000 people killed.

» I looked back and the whole side of the mountain, facing towards the town, seemed to open and topple down on the screaming people. I was burned by stones and ashes …, but I got to the cave «

Havivra Da Ifrile, a girl who survived the destruction of St. Pierre hiding inside a cave near the shore.
Photographs of the city of St. Pierre before and after the eruption of Mount Pelée, the volcano is seen in the background (from LACROIX 1904).

Geologist Edmund Hovey of the American Museum of Natural History, among the first to arrive to the destroyed city, noted that “In many places the limit [of the devastation] passes single trees, one side is dark and burned, the other green as if an eruption never happened.” A lava flow or landslide could not explain the burned trees nor could it explain the sharp boundary between the destroyed and untouched areas.

Two months later, geologists Tempest Anderson and John S. Flett of the Royal Society of London survived a smaller eruption of Mount Pelée.

» The cloud had a spherical form and resembled rounded protuberances amplifying and doubling with terrifying energy. They extended to the sea, in our direction, boiling and changing shape at every moment. It didn’t spread laterally. It didn’t rise up in the atmosphere, but it descended on the sea as a turbulent mass… «

Sequence showing a pyroclastic flow photographed December 1902 by French volcanologist Alfred Lacroix (from LACROIX 1904).
Alfred Lacroix.

For the very first time geologists observed a deadly nueé ardente – an incandescent cloud or glowing avalanche as the phenomenon was first named by French volcanologist Alfred Lacroix in 1904. A nueé ardente, in modern literature referred to as a pyroclastic density current, is a mixture of volcanic material and hot gases. Because its density is greater than air, it sinks downward, flowing like an avalanche along the slopes of a volcano. Pyroclastic flows can originate from the collapse of the eruption column, from a lateral blast or from the partial collapse of a volcano.

Researchers were able to estimate temperatures inside the pyroclastic flow that destroyed St. Pierre based on the observation that bottles melted (glass melts at ~700°C), but copper tubes were not deformed (copper melts at 1.100°C). The geologists, therefore, concluded that temperatures of a pyroclastic flows can range between 700 to 1.000°C. The high temperatures inside a pyroclastic flow also explain why so many people perished in St. Pierre. The heat was so intense that it instantly burnt the outer layers of skin and flesh. As the flesh shrinks due to the loss of water, the inner organs were squeezed out from their cavities. Even those not hit directly by the pyroclastic flow weren’t spared. Inhaling the still 300°C hot gases, their lungs quickly filled with liquid, drowning them.

The photo shows a 200 million-year-old ignimbrite – a name used for lithified deposits of a pyroclastic flow and derived from the Latin word for fire – of the Athesian Volcanic Group. Some of the larger clasts in the photo show an outer rim, indicating that the temperature inside the pyroclastic flow was high enough to alter the mineralogical composition of the rock. The larger rocks are embedded into a matrix of volcanic ash. Pyroclastic flows – a mixture of rocks, overheated gases and vapour – are able to transport even large boulders at a speed of 160km/h. As a result, the impacting mass destroys everything in its path, as happened to the town of St. Pierre.

An exceptional fossil discovered in 1931 in Athesian Volcanic Group deposits – “Tridentinosaurus antiquus by GB Piaz” – The skeletal remains are surrounded by a carbonaceous patina of soft parts, making it the oldest body fossil found in the Southern Alps. It is suggested by some authors, based on the preservation of the fossil, that the animal was killed during a volcanic eruption by a pyroclastic surge.


Leopold von Buch und die Geologie der Alpen

Christian Leopold von Buch wird am 26. April 1774 in Stolpe, Landkreis Uckermark in Brandenburg, geboren. Er studiert gemeinsam mit Alexander von Humboldt an der Bergakademie Freiberg bei Abraham Gottlob Werner, dem Begründer der Geognosie (Gebirgskunde) in Deutschland, sowie an den Universitäten in Halle und Göttingen. Als Werners Schüler war er anfänglich ein Anhänger der Neptunismus-Theorie, wonach alle Gesteine als Ablagerungen aus einer wässrigen Lösung erklärt werden. Diese Erklärung passte zu den Basaltablagerungen Schlesiens, die anscheinend aus grob- und feinkörnigen Sedimenten hervorgegangen waren. Allerdings gab es schon damals Naturkundler die der Plutonismus-Theorie zugetan waren, wonach der Magmatismus und Vulkanismus die treibenden Kräfte hinter der Entstehung der Gesteine und Landschaften der Erde sind.

Im Jahr 1796 beschloss von Buch die Vulkane Europas zu studieren, um diese geologische Kontroverse zu klären. Im selben Jahr startet er daher gemeinsam mit von Humboldt eine Studienreise nach Italien. Die damaligen Kriegswirren während der Koalitionskriege halten sie aber zurück, sodass sie zunächst auf den Alpenhauptkamm und Salzkammergut ausweichen. Später besucht von Buch die “vulcanischen Berginseln im Venetianischen” (Tertiärer Vulkanismus in Norditalien) und in 1799 den Vesuv.

Von Buch erkennt hier Widersprüche in der Lehre des Neptunismus. In dem vulkanischen Gestein des Vesuvs kann er nämlich nachweißen, dass das Mineral Leucit direkt aus der geschmolzenen Lava auskristallisiert war. Zuvor hatte man angenommen, dass dieses Mineral aus dem von der Lava aufgenommenen Sedimentgestein stamme.

Nach seiner Italienreise begibt sich von Buch nach Paris, wo er unter anderem auf den berühmten Kristallgrafen René-Just Haüy trifft und es entwickelt sich eine herzliche Freundschaft. Mit dem Schweizer Jean-André Deluc, der den Begriff Geologie geprägt hat, kommt es dagegen zum erbitterten Streit über die Entstehung des Granits. Von Buch erklärt dieses Gestein nämlich noch als ein Sediment, im Gegensatz zu Deluc, der Granit als ein magmatisches Gestein interpretiert. Von 1800 bis 1802 hält sich von Buch in der Schweiz auf, um danach in die französische Auvergne zu reisen. Hier erkennt er, dass der Granit tatsächlich in Basalt übergehen kann. Da er nun wusste das Basalt ein vulkanisches Gestein ist – wie er eigenhändig am Vesuv beobachtet hatte – muss auch Granit ein magmatisches Gestein sein. Wärend der feinkörnige Basalt durch das schnelle Abkühlen des Magmas entsteht, entsteht der grobkörnige Granit durch die langsame Abkühlung, wobei die Kristalle mehr Zeit haben um zu wachsen und größer werden.

In den folgenden Jahren beschäftig sich Leopold von Buch weiter mit der Entstehung des Granits und seiner Bedeutung im Aufbau der Gebirge. Im Jahr 1806 reist er durch Skandinavien und kehrt in 1809 nach München zurück. Im Jahr 1814 hält sich Leopold von Buch für kurze Zeit in London auf. Danach setzt er seine Untersuchungen in den Alpen fort und reist auch zu den Kanarischen Inseln. Der Besuch der Kanaren bestätigte von Buch in seinen Glauben die Gebirgshebung mittels magmatischer Kräfte erklären zu können.

Laut seiner “vulkanischer Erhebungshypothese” entstehen Berge, wenn Gesteine durch lokale magmatische Aktivität, zum Beispiel die Intrusion von Granit, emporgehoben werden. Dabei werden die zunächst horizontal abgelagerten Sedimentschichten verfaltet, zerbrochen und steilgestellt.

„Die Hebung der Gebirge durch Kräfte, welche aus dem Inneren der Erde wirkend, gegen die starre Erdrinde kämpfend, sie zersprengend, Theile derselben emportreibend, deren Gestalt eigentlich begründen, erfolgt in ihrer Hauptlängenrichtung nach der Lage von Spalten, aus welchen die hebenden Gesteine hervorbrechen, während der in den Hauptketten dadurch erzeugte Druck seitlich wirkend eine Menge paralleler Nebenspalten erzeugt und den seitlichen Secundärketten ihr Dasein gibt.“

Im Jahr 1822 führt ihn eine längere Exkursion wieder durch die Alpen und auch nach Südtirol. Vulkanische Gänge, die hier die Sedimentgesteine der Dolomiten durchschlagen, beschreibt von Buch als ein klassisches Beispiel für seine vulkanischer Erhebungshypothese.

Geologischer Schnitt durch die “Tiroler Alpen.” Die Sedimentschichten werden hier durch magmatische Basalt- und Porphyrintrusionen verkippt und verstellt. Zeichnung der amerikanischen Illustratorin Orra White Hitchcock (1796-1863) nach Leopold von Buchs “vulkanischer Erhebungshypothese.”

Von Buch glaubte auch mit seiner Hypothese den symmetrischen Aufbau der Alpen erklären zu können. Die äußeren südlichen und nördlichen Zonen bilden Sedimente, die durch eine Intrusion aus magmatischen Gesteinen aufgefaltet und zur Seite gedrückt worden waren.

Die Alpen, Ausschnitt aus der ersten geologischen Karte Mitteleuropas, 1821. Hellblaue Signatur im Norden und Süden=Alpen-Kalk (Sedimente), Grüne Signatur im Norden und Süden=Sediment-Schiefer, Hellgelbe Signatur am Alpenhauptkamm=Granit-Gneis Formation.

Als er um 1835 schließlich alle Gebirge als “einer großen Kraftäußerung aus dem Erdinneren” entstammend erklärte, entbrannte ein Gelehrtenstreit, beinahe so heftig wie die vorherige Neptunisten-Plutonisten-Kontroverse.

Von Buch leistet Wichtiges auch für andere Zweige der Geologie. Im Jahre 1826 veröffentlicht er eine der ersten geologische Karten von Deutschland. Um 1837-39 prägte er den Begriff “Leitmuschel” um Fossilien mittels denen eine relative Altersdatierung möglich ist zu beschreiben. Als eine seiner bedeutendsten Leistungen gilt seine 1839 in Buchform veröffentlichte wissenschaftliche Definition des Gesteinssystems des Jura. Im Juli 1848 veröffentlichte eine Gruppe von 13 Geologen, Mineralogen und Bergleuten, darunter von Buch und von Humboldt, einen Aufruf zur Gründung einer Deutschen Geologischen Gesellschaft, die im Dezember auch gegründet wurde, mit von Buch als ihr erster Präsident.

Ammoniten als Leitfossilien der Muschekalk-Formation.

Noch bis kurz vor seinem Tode, im Berlin des Jahres 1853, war Leopold von Buch in der Welt unterwegs.


  • HUBMANN, B. (2009): Die großen Geologen. Marix Verlag: 192

Geological Star Trek Review – “Amok Time”

In September 2018 astronomers announced the discovery of an exoplanet with 8.47 times Earth’s mass and twice Earth’s radius in the 40-Eridani star system, distant 17 light-years from our Sun. In the Star Trek universe, the Eridani constellation is mentioned as the star system where the planet Vulcan is located, homeworld of Commander Spock. In the episode “Amok Time”, first aired on September 15, 1967, the Enterprise visits the planet. As it orbits its sun on a very narrow orbit, surface temperatures are higher as on Earth. Also, the atmosphere is very thin, barely breathable, and non-Vulcans have a hard time adapting to the harsh environment. According to Star Trek lore, the desert-planet Vulcan orbits its sun together with the planet T´Khut, a geologically very active lava-planet.

In the movie Star Trek 2, released in 1982, the star 40-Eridani-A is mentioned as Vulcan’s sun. In 1991, Gene Roddenberry, creator of Star Trek, published a short article together with astrophysicists Baliunas, Donahue and Nassiopoulos, arguing that the constellation of Eridani would be the most fitting place for Spock’s homeworld.

The 40-Eridani system is a triple star system, with Eridani-A as primary star accompanied by a red and a white dwarf star, named respectively Eridani-B and Eridiani-C. Only Eridani-A is stable enough to host a hypothetical habitable planet. Eridani-B emits too much dangerous radiation and Eridani-C is prone to flares, sudden eruptions of energy and matter. As Eridani-A is smaller than our Sun, also the habitable zone, where a planet could exist with liquid water, is narrower. Unlike the fictional planet Vulcan, the real exoplanet seems to be a Super-Earth or a small gas giant. According to the published preliminary results, the planet orbits its star in just 39 to 40 Earth days, along the inner limit of the habitable zone.

Famously Commander Spock is the science officer aboard the Enterprise, including some notions on geology.

“Obsession” (1967).

In the episode “The Apple”, Spock immediately notes the lush vegetation of the planet Gamma Trianguli VI. He correctly deduces that soil-nutrients (and therefore geology) plays a role in supporting this peculiar paradise-like world. With his sharp geological eye Spock identifies also hornblende and quartz in a collected rock.

Hornblende, Moos in Passeier, South Tyrol.

Geological Star Trek Review – “The Enemy Within”

During a minerals-gathering mission on planet Alpha 177 by the crew of the Enterprise, a transporter accident creates an evil duplicate of Captain Kirk.

In the episode the malfunction is explained by the interference of a yellow ore, collected on the alien planet’s surface, with the transporter’s circuits. The ore is not identified in the episode, but seems to consist of some alien mineral.

In many episodes of Star Trek the crew of the Enterprise visits mining colonies or is on a mission to search for valuable minerals and crystals. There exists even a geological tricorder, designed for analyzing rock samples and comparing them to the records memorized in the mineralogical database of the federation. By convention, the names of terrestrial minerals end with the suffix “-ite”, the denominations of elements with the suffix “- ium”, “-um”, “-on”, “-gen” or “-ine”. Unfortunately it seems that this nomenclature is not always applied with the necessary scientific scrutiny in the 23th century.

There are around 5,000 to 7,000 minerals known on Earth, but we still know little about the mineralogy of other worlds. Over 300 minerals have been identified in meteorites so far. Meteorites display a mineral composition different to most rocks found on Earth. The most common type are stony meteorites, consisting of silicate minerals like olivine, pyroxene and traces of iron-nickel alloys. Just 1% of meteorites are pure silicate rocks. The smell of some fragments resembles asphalt or solvents, evidence for 4.6 billion years old carbon-compounds preserved inside the rock. 4 to 5% of all space debris is represented by iron meteorites, consisting of an almost pure iron-nickel alloy with eventually embedded small crystals of silicate minerals.

Around 130 minerals were discovered on Mars and 80 to 100 on the Earth’s Moon. Most are also found on Earth, however, as some of those minerals were formed under conditions that don’t exist on Earth, such as low gravity or the complete absence of liquid water, some are indeed unknown, alien minerals.

There are about 15,300 possible ways to combine all known elements, so there may be even more alien minerals out there.

The mineralogy of an exoplanet depends on its chemical composition. By analyzing the light of a star, it is possible to identify the chemical composition of distant star systems. As the star and the planets form from the same accretion disk, knowing the chemical composition of the star can provide also some information on the chemical composition of the planets orbiting the star.

The exoplanet 55 Cancri -e is roughly twice Earth’s radius, but has just eight times its mass. Its specific density is too low if compared to Earth. Earth is composed mostly of iron, oxygen, magnesium and silicon, with some sulfur, nickel, calcium and aluminum added to the mix. Observing the composition of the 55 Cancri-e’s host star, astronomers discovered a high concentration of carbon and oxygen. It’s likely that most minerals on 55 Cancri-e are based on a combination of the two elements, forming minerals with a low specific density. Surprisingly enough, carbon minerals are quite rare on Earth. Just fifty have been identified on Earth, and most are associated with life, forming from decaying organic biomass. It seems that on Earth, life “hijacked” carbon and carbon-minerals formed by pure inorganic processes (like diamonds) are uncommon.

Maria Matilda Ogilvie Gordon and her research in the Dolomites

Maria Matilda Ogilvie Gordon
Maria Matilda Ogilvie Gordon

Scottish Maria Matilda Ogilvie Gordon (1864-1939), or May as she was called, was the oldest daughter of a pastoral family composed of eight children, five boys and three girls. Maria Ogilvie entered Merchant Company Schools’ Ladies College in Edinburgh at the age of nine. Already in these early years, she showed a profound interest in nature. During holidays she enjoyed exploring the landscape of the Scottish Highlands accompanied by her elder brother, the later geologist Sir Francis Ogilvie. Maria Ogilvie aspired to become a musician and at age of eighteen she went to London to study music, becoming a promising pianist. Already in the first year her interests shifted towards the natural world and she went for a career in science.

Studying both in London and Edinburgh she obtained her degree in geology, botany and zoology in 1890. Maria Ogilvie hoped to follow-up their studies in Germany, but in 1891, despite a recommendation even by famous geologist Baron Ferdinand Freiherr von Richthofen (famous for describing the fossil reefs in the Dolomites), she was rejected at the University of Berlin – women were still not permitted to enroll for higher education in England and Germany. She went to Munich, where she was welcomed friendly by paleontologist Karl von Zittel (1839-1904) and zoologist Richard von Hertwig (1850-1927). However, she was not allowed to join male students. Sitting in a separate room she listened through the half-open doors to the lectures.

In July 1891, Richthofen invited her to join a five-week trip to the nearby Dolomites Mountains, visiting the Gröden-Valley. From the very first day, Maria Ogilvie was immensely impressed by the landscape and learned rock climbing to better explore the mountains. Richthofen introduced Maria Ogilvie to alpine geology and they visited the pastures of Stuores in the Gader-Valley. At the time Maria Ogilvie was studying modern corals to become a zoologist, but Richthofen, showing her the beautifully preserved fossil corals found here in outcrops of Triassic sediments, convinced her to try a geological career.

The Stuores pastures with fossil-rich marls.

Richthofen was over sixty years old and therefore he couldn’t provide much support in the field. In later years Maria Ogilvie remembers the challenge and danger of fieldwork, sometimes accompanied by a local rock climber named Josef Kostner:

» When I began my fieldwork, I was not under the eye of any Professor. There was no one to include me in his official round of visits among the young geologists in the field, and to subject my maps and sections to tough criticism on the ground. The lack of supervision at the outset was undoubtedly a serious handicap. «

For two summers she hiked, climbed and studied various areas in the Dolomites and instructed local collectors to carefully record and describe their fossil sites. In 1893 she published “Contributions to the geology of the Wengen and St. Cassian Strata in southern Tyrol”. In the paper she included detailed figures of the landscape, geological maps and stratigraphic charts of the Dolomites, establishing fossil marker horizons and describing the ecology of various fossil corals associations. She described 345 species from the today 1.400 known species of mollusks and corals of the local Wengen- and St. Cassian-Formations. This paper, a summary of her thesis “The geology of the Wengen and Saint Cassian Strata in southern Tyrol”, finally earned her some respect by the scientific community. In 1893 she became the first female doctor of science in the United Kingdom. The same year she returned into the Dolomites to continue with her geological and paleontological research. In 1894 she published the important “Coral in the Dolomites of South Tyrol.” Maria Ogilvie argued that the systematic classification of corals must be based on microscopic examination and characteristics, not as usually done at the time, on superficial similarities.

In 1895 she returned to Aberdeen, where she married a longstanding admirer. Dr. John Gordon respected and encouraged her passion for the Dolomites. He and their four children accompanied Maria Ogilvie on various excursions into the Dolomites. In 1900 she returned to Munich, becoming the first woman to obtain a Ph.D. She helped her old mentor, paleontologist von Zittel, to translate his extensive German research on the “Geschichte der Geologie und Palaeontologie” – “The History of Geology and Palaeontology.”

Maria Ogilvie continued her studies and continued to publish. In 1913 she was preparing another important work about the geology and geomorphology of the Dolomites, to be published in Germany, but in 1914 with the onset of World War I. and the death of her publisher, the finished maps, plates and manuscripts were lost in the general chaos. In 1922 she returned into the Dolomites, where she encountered the young paleontologist Julius Pia, who, during the war, had carried out research in the Dolomites. Together they explored the mountains, searching for fossils.

Geological map of Cortina d’Ampezzo, published by Maria Matilda Ogilvie Gordon in 1934.

Apart from scientific papers, Maria Matilda published also one of the first examples of geological guide books for the Dolomites. To honor her contributions in 2000 a new fossil fern genus, discovered in Triassic sediments, was named Gordonopteris lorigae.


  • WACHTLER, M. & BUREK, C.V. (2007): Maria Matilda Ogilvie Gordon (1864-1939): a Scottish researcher in the Alps. In BUREK, C. V. & HIGGS, B. (eds): The Role of Women in the History of Geology. Geological Society: 305-317

Geological Star Trek Review – “The Devil in the Dark”

The 1967 Star Trek episode “The Devil in the Dark” was written in just three days by screenwriter Gene L. Coon. Despite the rushed production, this first season episode is almost always included in every “best of” list. Trekkies value the story and message, as Kirk finds a peaceful solution to a conflict with an unknown life-form, but also love some remarkable classic scenes and lines, including “Pain! Pain! Pain!” and “I’m a doctor, not a bricklayer!” This episode holds also a special place in many geologist’s hearts as it features a lot of geo-babble.

It is one of the rare episodes starting not on board of the Enterprise, but in the mines of Janus VI. According to federation classification Janus VI is a type-E rocky planet with an iron core, similar in size to Earth but just 1.3 billion years old and apparently without atmosphere or life on the surface. It’s rich in minerals and elements, like gold, uranium, platinum, cerium and the fictional pergium. Mining an extraterrestrial world is still fiction, but science shows that it may be profitable. Asteroids are rich in platinum, iridium, palladium and gold. One hundred tons of rock from an asteroid might today be worth more than 9,000 dollars, compared to just 60 dollars worth the same amount of terrestrial rocks. Estimated 5,000 to ten millions of asteroids can be found near Earth and companies are already dreaming of future prospecting and mining spaceflights. Mining asteroids would not necessarily benefit Earth, as bringing the ore to Earth would be costly, but might benefit nearby colonies, outposts or industrial complexes. In “Devil in the Dark” it is mentioned that “dozen planets depend on you for pergium.” Pergium is somehow needed for common power generators (but apparently outdated, as Chief Engineer Scotty hasn’t seen such a thing in over twenty years), providing energy not only for the colony on Janus VI but other worlds.

The mining colony in the episode was successfully operating for over fifty years but after the miners opened up a new level deep within the planet suddenly a monster started to attack and kill people. The Enterprise sends Kirk, Spock and McCoy for help. Spock during a meeting with the chief engineer Vanderberg, the administrative head of the mine, notes a strange sample in the office:

“It’s a silicon nodule. There are a millions of them are down there. No commercial value.”

“But a geological oddity, to say the least. Pure silicon?”

“A few trace elements. Look, we didn’t call you here so you could collect rocks.”

Later Spock and Kirk are able to injure the supposed monster and recover what seems to be living tissue, however, a close inspection reveals the tissue to be “fibrous asbestos, a mineral.” Asbestos is indeed a silicate mineral, which is found as aggregates of thin fibrous crystals on Earth.

Byssolithe, a type of silicate, forms fibrous crystals.

After this discovery Spock speculates that the supposed monster is an alien life-form, not based on carbon compounds as on Earth, but on silicon. The strange silicon nodules destroyed by the clueless miners are eggs and the creature was just defending her children. After Spock joins with the mind of the creature a peaceful agreement is found between the miners and the alien. The miners will not hurt or kill the creatures and the creatures will allow the miners to use their tunnels to mine the deeper pergium-rich layers of the planet (and so become rich). The Horta, as this alien is named in the series, use a sort of hot acid to melt their tunnels in the solid rocks.

The silicon-based life-form as depicted in Star Trek is surprisingly scientifically accurate. In life as we know it only ten elements play a mayor role. Carbon is one of the most important elements, followed by oxygen, nitrogen, hydrogen, potassium, calcium, magnesium, iron, phosphorus and sulfur. Carbon is common in the universe but relatively rare on Earth. Strangely silicon is quite common in Earth’s rock, but plays only an insignificant role in biological processes. Some microorganisms, like radiolarians and diatoms, use silaffins and silica-hydrogels to build their tiny shells. Siliceous sponges use silicon to support their body by constructing a framework composed of tiny needles of silicon dioxide. However, all those organisms use silicon only to build their skeleton, not in their living tissue or metabolism.

Carbon, despite its relative rarity on Earth, has some important advantages for life on Earth. It can form stable and complex macromolecules within the range of terrestrial temperatures. Living bacteria are found on Earth in 240°F hot springs and on frozen rocks of Antarctica, thriving at -60°F . Atomic bounds between carbon-carbon, carbon-oxygen and carbon-hydrogen atoms are strong and the formed molecules are soluble and stable in water. Water is so important for carbon-based life as it´s a perfect environment for molecules to react with each other, resulting in a life-sustaining metabolism. Silicon, like carbon, can form stable bounds with itself and other elements like carbon, nitrogen, phosphorus, oxygen, sulfur and many metals. Such silanes can form sheets, chains, tubes and even complex three-dimensional frameworks. In theory silanes could be combined to form organelles of a living cell and even reactive molecules sustaining an alternative metabolism.

That said, silicon shows a very strong affinity to oxygen and hydrogen. On Earth the tissue of a silicon-based life-form would slowly react with the oxygen of the air and the hydrogen in the water, corroding and killing the creature. Doctor McCoy even mentions this fact in the episode. However, Spock notes that the creature comes from within the planet, where suitable conditions for silicon-based life might exist.

Silicon-life would need an oxygen-free atmosphere, an environment with no water and an alternative liquid for its metabolism. Possible alternative solvents that may work include liquid methane and ethane, but also sulfuric and hydrocyanic acid.  The acid could explain the (fictional) ability of the Horta to “digest rock” and to “tunnel” so quickly “for nourishment” through the planet. As such compounds are unstable at higher temperatures, the silicon-based life-form would best thrive in a very cold environment.

Could such life really exist? Unfortunately we don’t know for sure and the Horta is never again mentioned in the original series. Maybe this question will be answered by future generations, when humanity encounters life, but not as we know it. How will we react? In “The Devil in the Dark,” the first response was fear and hate, in the end overcome by knowledge and emphaty – a message in the best tradition of Star Trek.

Geology and Alpine-Type Fissures

Swiss professor of philosophy Horace-Bénédict de Saussure (1740-1799) was one of the first naturalists to collect observations and measurements in the field. He did so by traveling the Alps and climbing various mountains, among others the Mont Blanc, with 4.810 meter the highest peak of the Alps. During his ascent, he recorded the physiological reactions of his body to the increased elevation, measured air temperature and described the rocks which compose the mountain. One of De Saussure’s guides onto the peak of Mont Blanc was Jacques Balmat, a local chamois hunter and Strahler. A strahler is a crystal seeker, so named after the Strahlen, the shining quartz crystals. The granite of Mont Blanc is famous for its Alpine-type fissures, hosting sometimes spectacular crystals.

The crystal seeker Jacques Balmat, painting by Henry Lévèque.
Reconstruction of an Alpine fissure in Mont Blanc granite, with quartz, flourite and chlorite crystals.

Most common are gash fractures formed during the Alpine orogenesis some 25 to 15 million years ago. Below 500°C rocks like gneiss, schist and amphibolite tend to react brittle to tectonic deformation. Permeable to circulating fluids, in the open fissures and at temperatures of 600 to 100°C crystals will start to grow.

Kluft – an Alpine-type fissure in the field. from “Mineralklüfte und Strahler der Surselva” by Flurin Maissen (1950). A stiff layer will tend to deform, flattened and stretched to the point that it “necked”, opening a gash fracture between boudins. Thin layers will wrap around this point, partially forming quartz veins. More deformed, the layers will tend to weather more easily.

Almost 80% of the Alpine-type minerals comprise feldspar, chlorite, calcite, and quartz. Typical Alpine-type minerals are actinolite, apatite, dolomite, epidote, flourite, hematite, titanite, rutile and zeolithe – more than 140 minerals are known from Alpine-type fissures found in the Eastern Alps.

Alpine-type fissure in greenschist with a typical mineral paragenesis of adularia , quartz and chlorite.

De Saussure’s son – Nicolas Théodore de Saussure – will in 1792 name the mineral dolomite, giving the Dolomites their modern name.

Auf der Suche nach Erzadern in den Alpen

» Vermittelst seines bei sich habenden Perg Geists das Perg Männlein beschwören, Unnd aus Irrer Anntworth Clüfft und Geng, im Gebürge erfahrn … «

Beschreibung eines gewissen Hanns Aufinnger, der um 1607 behauptetet, mittels eines Wurzelmännchens mit den Berggeistern in Kontakt treten zu können und so Erzadern im Berg aufzuspüren.
Konkordante Erzlager in Paragneise im Bergbau Schneeberg. Anthophyllit, strahlig, braun- beige, überkrustet und verwachsen mit Zinkblende und Bleiglanz.

Im späten Mittelalter und der frühen Neuzeit erlebte der Bergbau in den Alpen eine Blütezeit. Bevor ein Bergwerk aber gegründet werden kann, muss zunächst mal das erzhaltige Gestein gefunden werden. Die damaligen Prospektionsmethoden wurden erstmals durch Georgius Agricola in seinem „De re metallica libri XII“ (1556), eine systematische Darstellung des damaligen Berg- und Hüttenwesens, die er gemeinsam mit dem Bergmann Blasius Weffringer aus Joachimsthal veröffentlichte, besprochen und dargestellt. Diese alte Prospektionsmethode wurde von BREWEL & GSTREIN 1999 als Limonitdiagnostik zusammengefasst.

Der Prospektor sollte auf bestimmte Merkmale im Gelände achten, darunter auch Verfärbungen und Verwitterung von Gesteinen, wie z.B. Limonit (braun-gelblich gefärbtes Eisenoxid und -hydroxid das oft Erzgestein überkrustet, daher der Name Limonitdiagnostik). Zauberhafte Utensilien wie der Bergspiegel, mit denen Sagengestalten wie die Venedigermandln angeblich in den Berg hineinschauen konnten, beruhen vielleicht auf die Fähigkeiten der Prospektoren, aufgrund Verfärbungen oder Strukturen an einer (glatten) Fels- oder Bergwand die Erzadern zu finden.

Bestimmte Pflanzen oder Pflanzenassozationen, die tolerant gegenüber Schwermetallen im Boden sind, können auf Erzgestein im Untergrund hinweisen. Gleiches gilt für Krüppelwuchs, wenn zu hohe Schwermetallkonzentration zu Wachstumsstörungen oder das Absterben von Bäumen führen.

» Schließlich muß man auf die Bäume achten, deren Blätter im Frühling bläulich oder bleifarben sind, deren Zweigspitzen vornehmlich schwärzlich oder sonst unnatürlich gefärbt sind … auch wächst auf einer Linie, in der sich ein Gang erstreckt, ein gewisses Kraut oder eine gewisse Pilzart … dies sind die Hilfsmittel der Natur, durch die Gänge gefunden werden. «

Seit jeher schürfen die Menschen nach den Schätzen der Erde und versprechen sich Reichtum und Glück. Generationen von Knappen und Bergleuten gruben tiefe Stollen in die Berge auf der Suche nach Edelmetallen und Erzgestein. Noch heute prägen Abraumhalden die Hochebenen, die von Erzpflanzen besiedelt werden, wie hier in Ridnaun durch das Alpenleinkraut (Linaria alpina).
Erzflechte (Lecidea silacea) auf erzhöffigen Prasinit.

Verwitterungsresistente Gesteine die Erz enthalten, wie z.B. Dolomit, können als Härtlinge in der Landschaft auffällige Kuppen bilden. Die Stelle, an der eine Erzader an die Oberfläche kommt, nennt der Bergmann Ausbiss oder aufgrund der rostigen Färbung auch Eiserner Hut. Mittels Lesesteinkartierung in Bächen oder in Schutthalden verfolgt man umgelagertes Geröll das letztendlich zum oberflächlichen Ausbiss der Erzadern führt. Ebenso bewog den Bergmann eine bestimmte Ausbildung eines Gesteins oder eine natürliche Auflockerungszone zum Schürfen, die dadurch den Vortrieb in den Berg wesentlich erleichterte.

Vermutlich mittelalterlicher Probeschurf im Bergbaugebiet Röttal, Gemeindegebiet Prettau.

Auffällig braune, rötliche oder grünliche Ausfällungen in Bächen, oder der metallische Geschmack von Quellen zeigen gelöste Metalle im Grundwasser an. In moorigen Bereichen flockt Eisen bevorzugt aus dem Wasser aus, und bildet rötliche Ablagerungen von Rasenerze zwischen der Vegetation.

Manche Beobachtungen können nur zu bestimmten Jahreszeiten gemacht werden. Die Verwitterung und Oxidation von Erzen (z.B. Pyrit) im Untergrund kann zu einer geringen Wärmeentwicklung führen, die an der Oberfläche abstrahlt. An solchen Stellen findet man im Winter kein Eis und auch der Schnee bleibt im Frühjahr nicht so lange liegen.


  • KOFLER, H. (2012): Silber und Blei – Der Bergbau im raum Sterzing im 15. und 16. Jahrhundert. Berenkamp Verlag: 196
  • MAIR, V.; VAVTAR, F.; SCHÖLZHORN, H. & SCHÖLZHORN, D. (2007): Der Blei-Zink-Erzbergbau am Schneeberg, Südtirol. Mitt. Österr. Miner. Ges. Bd. 153: 145-180
  • PALME, R.; GSTREIN, P. & INGENHAEF, F. (2013): Schwazer Silber – Auf den Spuren der Schwazer Silberknappen. Berenkamp Verlag: 128
  • PUNZ, W. et al. (1994): Pflanzenökologische Befunde vom Bergbaugebiet Schneeberg/Monteneve in Passeier (Südtirol/I): 67-81