VOLTERRA ALABASTER

The beautiful walled city of Volterra, an ancient Etruscan town some 45 miles southwest of Florence, is famous for its well-preserved medieval ramparts, museums and archeological sites and atmospheric cobblestone streets.

Since ancient times, Volterra, a key trading center and one of the most important Etruscan towns has been known as the city of alabaster.

The Etruscans mined alabaster in the nearby hills and considered it the stone of the dead. The mineral was used for elaborate funerary urns and caskets that housed the ashes of the departed, prized for its durability, beautiful coloration, natural veining and translucence. When the Romans ascended, alabaster fell out of favour and marble became the preferred sculpting material.

To work alabaster requires an assortment of hand tools, an artistic eye, and a tolerance for vast clouds of dust. An alabastraio begins with a block or chunk of alabaster. If the final product is to be a vase or bowl, the stone is turned on a lathe similar to what is used to make pottery and then shaped with chiselling tools.

Although alabaster and marble may seem similar in appearance when polished, they are very different materials, particularly when it comes to their hardness and mineral content. Alabaster is a fine-grained form of gypsum, a sedimentary rock made from tiny crystals visible only under magnification. The ancient Egyptians preferred alabaster for making their sphinxes or creating burial objects such as cosmetic jars. The purest alabaster is white and a bit translucent; impurities such as iron oxide cause the spidery veins. I like a mix of both, preferably backlit to show the blending of colour.

Alabaster is more graceful in appearance than marble. Marble consists mostly of calcite, formed when limestone underground is changed through extreme pressure or heat. It’s not quite as delicate as alabaster and became the preferred material for master sculptors such as Michelangelo who relied on marble from Carrara for his most famous works.

I had the very great pleasure of travelling to Carrara with Guylaine Rondeau many years ago, making her stop at every single roadcut along the way. More on those wonders later...

Alabaster is the common name applied to a few types of rocks. Translucent and beautiful, alabaster generally includes some calcium in gypsum. Gypsum is a composite of calcium sulphate, a type of sedimentary rock formed millions of years ago in the depths of a shallow sea. Left by time and tide, it evaporated into the creamy (full of lovely chemical impurities) or fully transparent (pure gypsum) stone we see today.

Alabaster is simply beautiful. In the right hands, it can be sculpted to evoke the most wondrous reflections of light and emotion. And it stands the test of time, becoming more beautiful with each passing year... rather like my Auntie Gail. I'm thinking of you as I write this my beautiful one. Happy 70th birthday to my Auntie of Alabaster. xo

PROLYELLICERAS ULRICHI

Prolyelliceras ulrichi (Knechtel, 1947) a fast-moving nektonic carnivore ammonite from Cretaceous lithified, black, carbonaceous limestone outcrops in Peru.

This specimen shows a pathology, a slight deviation to the side of the siphonal of the ammonite. We see Prolyelliceras from the Albian to Middle Albian from five localities in Peru.

Reference: M. M. Knechtel. 1947. Cephalopoda. In: Mesozoic fossils of the Peruvian Andes, Johns Hopkins University Studies in Geology 15:81-139

W. J. Kennedy and H. C. Klinger. 2008. Cretaceous faunas from Zululand and Natal, South Africa. The ammonite subfamily Lyelliceratinae Spath, 1921. African Natural History 4:57-111. The beauty you see here is in the collection of José Juárez Ruiz

FOSSIL INSECTS IN AMBER

PISTA DE BAILE JURÁSICA

This trackway from the Iberian Peninsula is a busy one! The theropod dinosaur tracks (and a few sauropods, too) cover the entire surface. They must have crossed this muddy area en masse sometime back in the Jurassic.

The Iberian Peninsula is the westernmost of the three major southern European peninsulas — the Iberian, Italian, and Balkan. It is bordered on the southeast and east by the Mediterranean Sea, and on the north, west, and southwest by the Atlantic Ocean. The Pyrenees mountains are situated along the northeast edge of the peninsula, where it adjoins the rest of Europe. Its southern tip is very close to the northwest coast of Africa, separated from it by the Strait of Gibraltar and the Mediterranean Sea.

The Iberian Peninsula contains rocks of every geological period from the Ediacaran to the recent, and almost every kind of rock is represented. To date, there are 127 localities of theropod fossil finds ranging from the Callovian-Oxfordian (Middle-Upper Jurassic) to the Maastrichtian (Upper Cretaceous), with most of the localities concentrated in the Kimmeridgian-Tithonian interval and the Barremian and Campanian stages. The stratigraphic distribution is interesting and suggests the existence of ecological and/or taphonomic biases and palaeogeographical events that warrant additional time and attention.

As well as theropods, we also find their plant-eating brethren. This was the part of the world where the last of the hadrosaurs, the 'duck-billed' dinosaurs, lived then disappeared in the Latest Cretaceous K/T extinction event, 65.5 million years ago.

The core of the Iberian Peninsula consists of a Hercynian cratonic block known as the Iberian Massif. On the northeast, this is bounded by the Pyrenean fold belt, and on the southeast, it is bounded by the Baetic System. These twofold chains are part of the Alpine belt. To the west, the peninsula is delimited by the continental boundary formed by the magma-poor opening of the Atlantic Ocean. The Hercynian Foldbelt is mostly buried by Mesozoic and Tertiary cover rocks to the east but nevertheless outcrops through the Sistema Ibérico and the Catalan Mediterranean System. The photo you see here is care of the awesome Pedro Marrecas from Lisbon, Portugal. Hola, Pista de baile jurásica!

Pereda-Suberbiola, Xabier; Canudo, José Ignacio; Company, Julio; Cruzado-Caballero, Penélope; Ruiz-Omenaca, José Ignacio. "Hadrosauroid dinosaurs from the latest Cretaceous of the Iberian Peninsula" Journal of Vertebrate Paleontology 29(3): 946-951, 12 de septiembre de 2009.

Pereda-Suberbiola, Xabier; Canudo, José Ignacio; Cruzado-Caballero, Penélope; Barco, José Luis; López-Martínez, Nieves; Oms, Oriol; Ruíz-Omenaca, José Ignacio. Comptes Rendus Palevol 8(6): 559-572 septiembre de 2009.