The Age of Cryptozoon – In Search of the “Hidden Life”

In the first edition of “On the Origin of Species” (1859) Darwin only briefly addresses the earliest known fossils, or better the lack thereof:

“If the theory [of evolution] be true, it is indisputable that before the lowest Cambrian stratum was deposited, long periods elapsed . . . and the world swarmed with living creatures. [Yet] to the question why we do not find rich fossiliferous deposits belonging to these earliest periods . . . I can give no satisfactory answer.“

The supposed lack of fossils older than 500 to 1.000 million years was not only the result of the “imperfection of the geological column“, as Darwin argued, nor the yet incomplete geological survey of most areas. At the time nobody could really imagine how the earliest organisms on earth – and especially their petrified remains – would look like, so what to search for ?

Vitruvian Geology – Leonardo da Vinci and the Realistic Depiction of the Earth’s Surface

Leonardo da Vinci studied rocks and landscapes not only to improve the realism of his paintings, but also in an attempt to understand how the earth works. Leonardo was obsessed with water, which he considered a vector to erode ancient rocks and to deposit new sedimentary rocks, reshaping so over time the “living” earth. The running water is for earth what blood is for the human body – it flows from the mountains to the sea, then – so Leonardo – in subterranean veins returns to the mountains, a circulatory system like found in humans.

The Harmony of Colors

The first "geological" maps used symbols to characterize single outcrops; later maps introduced shaded areas to display the distribution of specific rock-types, but due the high printing-costs these maps were printed only in black & white, making them hard to read - so let´s put some colors on that map...

A Concise History of Geological Maps: From Outcrop to the first Map

March 23, 1769 marks the birthday of pioneering stratigrapher William Smith, who is also credited with creating the first useful geological map, however like many other great accomplishments also Smith’s idea of depicting the distribution of rocks on a topographic map didn’t materialize out of nowhere.

Pompeii – a Geological Movie-Review : Introducing the Main Character

The new movie “Pompeii” reconstructs one of the most famous volcanic eruptions in history with unprecedented “3D” special effects – but even the best visuals can’t help if the science is wrong – so how geological accurate is the movie ?

Mount Vesuvius as reconstructed in the new film “Pompeii” (from the movie trailer – copyright for it is most likely owned by either the publisher or studio, it is believed that the use of low-resolution images for discussion and education purpose qualifies as fair use under United States copyright law).

The Man who made Mountains

U.S.G.S. engineer Bailey Willis († February 19, 1949) was known for his unorthodox approach to geological questions. Puzzled by the geological structures he discovered in mountain ranges, long before computer-models were available, he constructed a machine to simulate the mountain-forming process.

The Destruction of Pompeii - Still a Mystery of History

It's probably the most famous volcanic eruption of all times - the 79 A.D. eruption of Mount Vesuvius that destroyed the cities of Pompeii and Herculaneum. So may it surprise that the exact date of this event is still unclear. The date of August 24 given in textbooks is based on two letters from the Roman author Pliny the Younger to Tacitus, a historian who had asked his friend for help to reconstruct the death of famous naturalist Pliny the Elder during the eruption. However the original letters didn't survive into modern times and what we know of Pliny's response is based only on medieval transcripts. Already there various versions exist with different dates (ranging from August to November) or even without any reference - this discrepancy can be explained by various transcription errors, almost inevitably considering that the eruption happened almost 17 centuries ago.

Also some archeological evidence suggests a later date for the eruption:

- The famous gypsum-casts show people wearing thicker clothing, unusual for August but appropriate for cooler temperatures of an early autumn. Also in many houses portable stovens - ready for use ? - were noted.

-  The lack of typical summer fruits, but the discovery of fresh autumn fruits, like olives and figs in the shops, suggests a period in late October.

- Large jars, used for fermenting wine, were discovered already sealed. Considering that the grapes mature in early autumn this observation would suggest a date for the eruption at the end of October.

- A coin - a Capricorn Silver Denarius issued by emperor Titus in July - June 79 A.D.- found along the corpse of a woman buried in the ash suggests that the eruption occurred late in summer/early autumn, as the coin would not be in circulation earlier. However the exact identification of the coin (there exist various editions and the inscriptions of the recovered coin is difficult to read) is in dispute.

Fig.1. A Capricorn Silver Denarius (named so after the emblem on one side of the coin, on the other side celebrating the coronation ceremony of Titus to emperor in 79) seemingly similar to the coin discovered in the ruins of Pompeii (image from "A Brief Overview of the Flavian Dynasty", by L. HARSH)

- The remains of garum - a spicy fish sauce - made using the fish species Boops boops (bogue), abounding in the Mediterranean Sea from July to August, could also point to a period of the eruption sometime between late August - September.

Also some geological evidence, like the distribution of ash deposits, suggests a later eruption. The mapped ash layers suggest that during the eruption the wind blow from the east. This wind pattern is unusual for the summer in Naples, but dominant in the rest of the year.

So in the end...

"There are known knowns; there are things we know we know. We also know there are known unknowns; that is to say we know there are some things we do not know. But there are also unknown unknowns – there are things we do not know we don't know.“ 
Donald Rumsfeld, 2002

Bibliography:

STEFANI, G. (2006): Scoperte Campania - La vera data dell´eruzione. ARCHEO 260 - Ottobre: 10-13
ROLANDI, G.; PAONE, A.; LASCIO, M.di & STEFANI, G. (2008): The 79 AD eruption of Somma: The relationship between the date of the eruption and the southeast tephra dispersion. Journal of Volcanological and Geothermal research. Vol. 169(1-2): 87-98