STUDENT’S VOICE
5. “Sea flower” limestone, Cenomanian (100.5–93.9 Ma). Compact limestone rich in fragments of rudists, bivalves, and gastropods. Fine calcareous breccia of organic origin. Deposited in a dynamic shallow marine environment with a bioclastic sandy seabed.
6. Limestone with Neithea, Cenomanian (100.5–93.9 Ma). Fetid, compact, light grey limestone with organic fragments and valves of the bivalve Neithea. Deposited in a dynamic shallow marine environment with a bioclastic sandy seabed.
7. Laminated limestone (“Komen shale”). Repeated cycli- cally in the Upper Cretaceous: Cenomanian (100.5–93.9 Ma), Cenomanian-Turonian (94 Ma), and Santonian (86.3–83.6 Ma). Stratified, bituminous, fine-grained limestone with dark grey-black colors and fish and reptile fossils. Deposited in a shallow nearshore marine basin with an anoxic seabed.
8. Limestone with Acteonella, Turonian (93.9–89.8 Ma). Compact, light limestone with fossil fragments and complete Trochactaeon (gastropods with smooth, egg-shaped shells). Deposited in an inner carbonate platform backreef lagoon.
9. Limestone with flint nodules, Turonian-Santonian (93.5–85.3 Ma). Block limestone containing flint nodules used by Homo heidelbergensis (0.4–0.3 Ma) to build stone tools. Deposited in a backreef lagoon with stagnant, poorly oxygen- ated water. No photo.
10. Limestone with Vaccinites, Santonian-Campanian (86.3–72.1 Ma). Light and compact limestone with many frag- ments of organic materials and Vaccinites, a rudist with thick conical or cylindrical shells.
11. Limestone with Keramosphaerina tergestina, Upper Santonian (86.3–83.6 Ma). Fossiliferous, light grey limestone with fragments of organic materials and well-preserved K. tergestina, a large foraminifera (up to 19 cm in diameter). Deposited in a dynamic shallow marine environment with a bioclastic sandy seabed.
12. Laminites of Villaggio del Pescatore, Upper Campanian– Lower Maastrichtian (75–70 Ma). Thick laminated limestone with couplets of mm-thick dark organic rich lamina between thicker carbonate mud lamina. Contains fossils of crocodiles, fish, plants, and dinosaurs, the most famous being “Antonio,” a hadrosauroid (Tethyshadros insularis) found in perfect ana- tomical alignment and now on display nearby at the Civico Museo di Storia Naturale. Deposited in an inner carbonate platform in a brackish water basin with an anoxic bed of carbonate muds.
13. Limestone with stromatolites, Danian (66–61.6 Ma). Fossiliferous, black, bituminous limestone with stromatolites. Deposited in a shallow restricted lagoon, inter and supratidal settings.
14. Limestone with Nummlites. Ilerdian (56–50 Ma). Compact, grey limestone with Nummilites, a large foramin- ifera 1–5 cm in diameter). Deposited in a continental shelf, less coastal than Alveolina.
15. Limestone with Alveolina. Ilerdian (55–50 Ma). Compact, grey limestone with many Alveolina, an elliptic foraminifera. Deposited in a continental shelf, more coastal than Nummilites.
16. Sandstone with vegetation remains, Middle Eocene (47.8–41.2 Ma). Turbidite sediments deposited at the base of the continental shelf.
17. Slivia ossiferous breccia, Pleistocene (0.9–0.8 Ma). Breccia with many mammal groups found. Deposited in an arid steppe-like environment with forests in humid areas.
18. Visogliano breccia, Pleistocene (0.45–0.30 Ma). Remains in the breccia include a tooth and jaw of Homo heidelbergensis and large (deer, horse, bison, rhinoceros, bear, fox, minks) and small (vole, dormouse) mammals. Deposited in a sinkhole.
Further information can be found in the park’s booklet at
http://www.ortobotanicotrieste.it/portfolio/percorso-geopleon- tologico/.
Below the Karst: Grotta Gigante
The carbonates of the Karst support many interesting caves and other hydrological phenomena hidden within the belly of the Karst. With a central cavern measuring 350 by 215 by 430 ft, the aptly named Grotta Gigante claims fame as the second largest cave in the world open to tourists (Fig. 2). The 10 million year old cave was first explored in 1840 by a spelunker hoping to find a water source at its bottom, but, alas, the river that carved the cave had left it 3 million years prior. This elusive “dis- appearing” Timavo River enters the ground near the mountains and exits near the sea, its underground course through the carbonates of the Karst Plateau still largely a mys- tery.
Around two-thirds of
Figure 2. View of Grotta Gigante with its pendula visible on the right (two parallel vertical white lines).
the water in the Timavo stems from infiltration of precipita- tion through the carbonate rocks, to which the Grotta Gigante’s magnificent speleothems testify. The water becomes acidic as it travels through the soil, dissolving carbonate minerals and carrying them in solution; as the water falls into the cave, the carbonates crystallize out. Studies in the cave show that its towering stalagmites, platy in shape due to their formation from the splashing of falling water drops, grow upwards from the ground at about 1 mm every 20 years. The stalactites, which hang from the ceiling, sport a more circular appear- ance as raindrops swirl down and around them. Although the limestone is originally white, the water, carrying iron leached from clay above, adds a red color.
The cave’s size, constant temperature, and relative isolation from outside noise sources make it ideal for certain scientific instruments. It hosts two 330 ft pendula, thought to be the longest in the world, that measure the tiniest movements–frac- tions of a millimeter–of Earth’s crust that result from solar and lunar tides and snow loads.
56 TPG •
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www.aipg.org
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