Preparing for environmental changes by studying the past

THE GEOLOGICAL HERITAGE OF THE GEOPARK HAS RECORDED INFORMATION ON PAST CLIMATES AND ENVIRONMENTS, THE STUDY OF WHICH IS KNOWN AS PALAEOCLIMATOLOGY.

Limestone fossils bear witness to a Givetian environment similar to our modern-day coral reefs. Speleothems such as stalagmites, stalactites, flowstones and draperies form over long periods and provide a record of variations in temperature and humidity. How does the environment react to climate variations ? What does a global warming of 2°C mean for Wallonia ? Are questions that can be answered by studying the climates and environments of the past.

FIG 1 The study of limestone fossils (1A) reveals the similarity of the Givetian environment with modern-day coral barrier reefs (1B).

FIG 2 Core sampling of the « Proserpine » stalagmite. Core sampling is preferred to removal of the stalagmite as it leaves much of the geological heritage in place and has a very limited impact on the appearance of the cave.

FIG 3 Stalagmites in the Cave of Hotton (dated as 9000 years old) and in the « Père Noël » or « Father Christmas » Cave (dated as 13000 years old), both reveal that - around 9000 years ago - the area was subjected to heavy rainfall and flooded on a regular basis. This means that the weather in Belgium can be even wetter than it is nowadays ! A range of analytical methods can be used for dating and for compiling climate charts from the information provided by stalagmites.

FIG 4 Global climate record of the earth deduced from studies of marine sediments, ice and stalagmites. The planet has experienced a succession of mild (Interglacials) and cold (Glacials) periods over the last two million years.