Tuesday, April 14, 2009

Mediterranean Contributions To Sedimentary Geology

The journal Sedimentology January 2009 issue is a tribute to the role of the Mediterranean region in the development of sedimentary geology. It is open access and there are several fascinating papers to read.

The Mediterranean region, source of so much knowledge in the world, is the site of major advances in sedimentary geology. In addition to its economic and cultural richness, the geological and geographic diversity of the region, plus its active geological processes, have long stimulated indigenous scholars, along with attracting talented outsiders such as Steno, Lyell, Walther, Kuenen and Bagnold.....

I liked this depiction of the classical Greek and Roman history of Mediterranean geological thought:

Quite a trail of scholarly thinking about geology! I guess when you see lava erupting and the ground shaking, events that happened quite frequently on the time scale of the classical Greek and Roman periods, someone is bound to have a revelation or two about the workings of the earth. Uplifted shorelines and shell beds also provided fertile ground for geological speculations and discourse and mining for stone and precious metals forced map making and systematic assays of the land around them. There were geological casualties too. Pliny the elder died in the Vesuvius eruption of 79 A.D.

The tradition of inquiry has continued in to modern times. From my own field of study of sedimentary carbonates, the Mediterranean offers some of the best study areas. There are mountain size outcrops, spectacularly exposing shoreline to basin transects. A carbonate sedimentologists dream of examining in detail lateral facies changes. Take a look at this field sketch from 1879 which shows interfingering of shallow and deeper water carbonate facies.

The CD refers to the shallow water dolomite and the CM refers to deeper water muds.

And this section which show parallel bedding which can be traced laterally for long distances.

I was always jealous of the lucky S.O.B's who got to work here. Hey, in the southern Appalachians we had to settle for what little road cuts and a few streams offered us.

I ended up reading quite a few studies on shallow platform carbonates and the link between orbital cycles and sedimentary rhythms. There was Alfred Fischer's unrivaled study of the cyclothems of the Alpine Triassic. These deposits were later evaluated by L. A Hardie, R. Goldhammer and others as a test case of orbitally forced cyclicity. The issue is still not settled as its been tough to link shallow water sedimentary rhythmics to specific orbital cycles due to conflict in radiometric data. The deeper water cycles though have been conclusively shown to be orbitally forced.

And then there was dolomite....

Mixed meteoric marine?.. marine?.....direct precipitate? ....secondary replacement?... hydrothermal?......All models have been applied to explain the dolomites of the Alps. This issue has two papers on the dolomite facies of the Alps and the dolomite problem . Many workers now want to explain the massive dolomite as microbial precipitates. Good luck..

...The debate rages on decade after decade.

Aside from this technical journal, on the popular literature front Walter Alvarez has just published a book on Italian geologists and their many contributions.

A region so geologically active both in thought and process deserves attention like this.


  1. I agree, this is a great issue of Sedimentology ... the Mutti et al. paper nicely lays out how important the Mediterranean has been for turbidites as well.

  2. ya, there is something for everyone in this complex region. The great outcrops and locale no doubt helps!