GSA Today's “Geology Through the Lens” - Matera’s Timeless Geological Legacy

In the February 2025 issue of the Geological Society of America’s publication "GSA Today", I had the distinct honor and privilege of showcasing my photo of the ancient and modern city of Matera with an accompanying description. 

Taken during a recent visit to the Southern Italian regions of Basilicata and Apulia, Matera and environs is heaven on earth for geologists, anthropologists, paleontologists, Classical historians, tourists, hikers, bikers, gastronomes, oenophiles, sociologists and cinephiles. The text that accompanies the photo is a bit verbose (my forte) and condensed, but the editors only allow so many characters.

Located on a karstic plateau of the Tertiary-uplifted Apulian Carbonate Platform of Mesozoic African affinity in the Basilicata region of southern Italy (“instep of the boot”), Gravina di Matera is riddled with thousands of solution caves that, in part, constitute the city of Matera’s Sassi (the “stones”) that is perched on the edge of the gorge.  Many caves have Neolithic documentation, and those of Matera have been continually inhabited since the Paleolithic with quarried Renaissance facades over their entrances.  Following a period of extreme overcrowding, disease, poverty and national shame in the twentieth century, Matera emerged as a 1993 UNESCO World Heritage Site and first-class tourist destination.

In the coming months, I plan to post a detailed account of the geologic evolution of the karstic carbonate platform on which Matera resides. In the meantime, I offer this view of the ancient and modern city taken from the bottom of Gravina di Matera and a few images from the Alta Murgia plateau on which Matera resides.

Located about 10 miles north of Matera on the Apulian Platform (Alta Murgia in Italian), the floor of the abandoned Pontrelli Quarry, from a distance, looks like machined striations created by stone workers. To the surprise of paleontologists, it turned out to be an enormous Late Cretaceous dinosaur tracksite with over 4,000 footprints created by over 200 mid-sized, quadruped dinosaurs belonging to at least five different species. 

The ichnofossils (preserved traces of animal activity and behavior) were created within the shallow-water, peritidal Altamura Limestone formation (Calcare di Altamura in Italian) that was uplifted intermittently throughout the Cenozoic by orogenic events that ultimately formed the foreland of southernmost mainland Italy and the Adriatic Sea.

The discovery is unique in several respects. Fossil dinosaur tracks from Italy are rare, and the location in the Apulian foreland sheds light as to the climate at the time of deposition, which was similar to the Bahamas. In addition, it reveals new information regarding the tectonic evolution of the Western Tethys Ocean (the proto-Eastern Mediterranean). As a result, it is believed that the Apulia and Basilicata regions originated as part of the Adria microplate (and promontory) of North African plate affinity, before rifting, drifting and colliding with proto-Southern Italy.

Located about six miles NNW of the quarry and five miles north of the town of Altamura, Pulo di Altamura is the largest sinkhole (doline in European geological terms) in Alta Murgia. The depression in the landscape formed by karst solutional processes, as did Gravina di Matera (in association with fluvial dissection), that possibly progressed in a subterranean locale to the extent that collapse occurred. Some researchers believe that parts of the Grand Canyon of Arizona may have evolved in this manner in regions of limestone stratigraphy that, over time, facilitated development of a west-flowing Colorado River through the Kaibab Upwarp.

The solutional process occurs when neutral pH rainfall becomes mildly acidic by absorbing atmospheric carbon dioxide and groundwater chemically dissolves and mechanically erodes the calcium carbonate mineralogical component of the uplifted calcareous seafloor platform. Notice that the walls of the sinkhole are peppered with caves, as are those of Gravina di Matera. 

As seen at ancient Matera, many of the karstic caves that developed on rocky ledges of the Alta Murgia were inhabited by an archaic form of Homo neanderthalensis that lived in the region during the Middle-Upper Pleistocene between 170,000 and 130,000 BP. In fact, a deep karst cave near the sinkhole, discovered in 1993 by cave explorers but closed to the public, contains a complete Paleolithic skeleton. It's the most intact ever discovered in Europe that has been accurately dated and contains intact DNA that awaits sequencing.

 

Dubbed Altamura Man and irretrievably embedded in calcareous rock in the form of corroloids (cave 'popcorn'), the skeleton is totally intact and in an excellent state of preservation, having been completely encased and replaced by calcite (the most stable polymorph of calcium carbonate). 

Calcium carbonate precipitates out of saturated solution in the reverse direction of the aforementioned karst chemical reaction, as carbon dioxide degasses back into the cave's atmosphere. The Alta Murgia plateau is peppered with such caves ('grotto' in Italian) that await discovery and exploration. One wonders what paleontological finds will be disclosed in the future, hominins or otherwise. (Image from Wikipedia)

By the way, if you pay a visit to the region, the local cavatelli pasta ('little hollows') is delicious but challenging to roll by hand, as my daughter and the rest of our family discovered in a Matera cooking class at "Cook'n Fun at Mary's". A few glasses of the local wine didn't make things any easier. My forlorn culinary creation is on the top tray.