Field of Science

How Groundhogs Can Change A Landscape


We don’t know how much wood a woodchuck would chuck if he could chuck wood, but we know how much sediment he moves per year…
 
Biogeomorphology, also referred as ecogeomorphology or sometimes as zoogeomorphology, is the study of the links between ecology and geomorphology, or in simple terms between life-forms and landforms. Such interactions range from simple tracks left by an organism in the landscape to the complex cycles of energy and matter transfer (like for the element carbon) between the biosphere and the lithosphere.
The role of animals in the evolution of a landscape is still poorly studied, but one of the most interesting processes modifying a landscape involves digging animals. Read On...

The Origin Of Geological Terms: Feldspar


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“What’s in a name?” asked William Shakespeare in his play Romeo and Juliet. It may also be of interest to explore the origin of some common terms used in geology in an upcoming series, like feldspar, the most common mineral on earth´s surface Read On

Charles Darwin And The Search For Extraterrestrial Life

In August 1881, the journal Science (a short-lived predecessor of the modern journal) published an article based on letters exchanged between two amateur geologists – British Charles R. Darwin and the German Otto Hahn – discussing the possibility of extraterrestrial life. Just some years earlier, Darwin had published On The Origin of Species, arguing that complex life forms evolved very slowly over time from simple ones.
However, Darwin faced a major problem with his theory. At the time, based on erroneous calculations of the cooling rate of earth by physicist Lord Kelvin, the Earth was believed to be just some million years old.
Accordingly, the planet seemed too young to explain the modern complexity and diversity of life. However, if already complex microorganisms existed in space (the existence of which would predate the formation of Earth), and only later they evolved in terrestrial animals, could solve this apparent contradiction. 

Avoiding an hangover the mineralogical way

The name Amethyst for the violet variety of quartz derives from the Greek "amethystos" translating in "the non-intoxicated", as it was believed that the mineral protected its owner from drunkenness. 

There are two explanation for the origin of the name and the supposed medical propriety. According to naturalist Pliny the Elder (23-79 A.D., killed by the erution of Mount Vesuvius) the gemstone resembles the color of diluted wine – and so is no longer intoxicating. Or amethyst cups could have been used to serve water as wine during Roman festivities, even if drinking all night long, there was no danger of hangover the next morning.


How Mount Etna Helped Geologists Understand The Birth Of Volcanoes

Mount Etna is the largest active volcano in Europe. The size, location (Italy is worth visiting for a lot of reason) and constant volcanic activity have made Mount Etna an important destination for early traveling geologists Read On..


Damned Souls and Fiery Oceans - Early Views Of Earth`s Core

"We know more about the stars high above our heads, than about earth just below our feet."
Leonardo da Vinci
 
There is some truth in da Vinci´s words, as for a long time the interior of earth was a mysterious place, supposedly the reign of demons and place of eternal damnation. Italian poet Dante Alighieri (1265-1321) imagined a core of ice, an allegoric image, far away from the sun and divine light where the damned souls are entrapped in eternal ice

German Jesuit Athanasius Kircher (1602–1680) imagined earth´s section in his "Mundus Subterraneus" (1664-1665) as crossed by veins of water and fire. The water would feed springs and rivers, the fire the volcanic mountains – but apart practical observations Kircher´s worldview was influenced also by religious-philosophical considerations, the two opposite elements water and fire united in a perfect creation.
 
Fig.1. from "Mundus Subterraneus", first edition published in 1664-1665.

Leonardo da Vinci´s (1452-1519) approach was more rational, even if inspired by the idea that earth worked a bit like a human body, just blood replaced by water. Water, so da Vinci, eroded, transported and deposited sediments, connecting mountains with the sea. He imagined earth filled by an immense underground ocean, sections of the superficial crust sinking into it would explain the formation of mountains.
 

Fig.2. Leonardo da Vinci´s speculative section of planet earth, from his privates notes (Codex Leicester, 1510).
 
James Hutton (1726-1797) recognized the importance of magmatic rocks on earth. To explain the large quantities of volcanic rocks on earth´s surface and the energy needed to melt rocks, Plutonists proposed a molten interior, even if it is was not clear if molten rocks form most of earth or were to be found in only large magmatic chambers, distributed in the upper layers of earth.
 
Fig.3. Section of earth from Erasmus Darwin´s poetic-naturalistic work (1791), note the "unknown region supposed to consist of Lava kept in semifluid state by heat...[]".

French science-fiction author Jules Gabriel Verne (1828 - 1905) based his novel "A Journey to the Center of the Earth" (1864) on the available science of his time. In his novel Verne uses the hollow conduit of the Icelandic volcano Snæfellsjökull to venture inside earth, an idea supported by the geologic models of volcanoes proposed at the time - a single or a series of magma chamber(s) with conduits connecting them to the surface. Geologists assumed that during an eruption the magma reservoir becomes empty and large voids and caverns were left behind.
 
Fig.4. Geological section, published in the book "Einführung in die Erdbeben- und Vulkankunde Süditaliens" (1914), shows the anatomy of a stratovolcano, with a main conduit, various lateral dikes and a large sill connected to the magma reservoir. 

The Spanish adaptation of Verne´s novel "The Fabulous Journey to the Center of the Earth"/ Where Time Began" (1976) summarizes best the problems geologists faced all this time:

"-Gentleman, the truth is that all our theories are just that, theories. None of us has the least idea of how the earth was really formed. Because the distance between the earths crust and its core is over 6.500 kilometres, and no men has ever descended to a depth of more than 3 miles. So it's obvious, we will never have a glimmer of true knowledge, until we are able to reach a depth of at least a 100 leagues.
 

- What's your opinion Professor Lindenbrook?
 

- Well gentlemen, at one point at least I agree with Professor Christophe, the materials of the geologists are not charts, chalk and chatter, but the earth itself. We should never know the truth, until we are able to make that journey, and see for ourselves."

To be continued...


Bibliography:
 
PARCELL, W.C. (2009): Signs and symbols in Kircher’s Mundus Subterraneus. In Rosenberg, G.D., ed., The Revolution in Geology from the Renaissance to the Enlightenment: Geological Society of America Memoir 203: 63-74

Caves Are Unique (And Spooky) Treasure Chests Of Prehistoric Life

Caves have always fascinated people. Tales of strange or extraordinary large bones found in them may have also inspired legends that referred to caves as gateways to an underground world of fear, perhaps still inhabited by monsters and demons...Read On