The Cretaceous The Cretaceous period features a particularly interesting climatic episode in the Earth’s geological history. It follows the Jurassic Period, better known as the time the dinosaurs inhabited Earth and spanned the period between 145.5 and 65.5 million years ago. The Cretaceous is the last period of the Mesozoic Era, which ends with a well-known mass extinction event. At the end of th ...[Read More]
Name of proxy Levoglucosan Type of record Biomass burning Paleoenvironment Lake and marine sediments and ice cores Period of time investigated Present to approximately 130,000 years ago How does it work? Levoglucosan is a molecule that is exclusively formed during the combustion of vegetation at low-temperature. It is therefore considered to be a source-specific tracer for biomass burning. During ...[Read More]
Name of proxy Sporomorphs (pollen grains and fern spores) Type of record Biostratigraphy and Geochronology markers, Vegetation dynamics Paleoenvironment Terrestrial environment Period of time investigated Present to 360 million years How does it work? The sporomorphs (pollen grains and fern spores) are cells produced by plants involved in the reproduction. They are microscopic (less than a fifth o ...[Read More]
Ice cores are a favored archive to study past climates, because they provide a number of indications on the history of the climate and of the atmospheric composition. Among these, water stable isotopes are considered as a very reliable temperature proxy. Yet, their interpretation is sometimes more complicated than a simple one-to-one correspondence with local temperature and requires intercomparis ...[Read More]
Name of proxy Fluctuations of mountain glaciers Type of record Geomorphological features Paleoenvironment Continent – High mountain areas Period of time investigated From historical periods (c.a. 300 years ago) to the end of the Pleistocene (up to 200 000 years back in time) How does it work? Mountain – or “alpine” – glaciers are small ice bodies (from 1 to 10 000 km2). Alt ...[Read More]
Name of proxy Varved glacial lake sediments Type of record Sedimentological structures Paleoenvironment Ice marginal lake environments Period of time investigated Last Glacial Termination (LGT, c.21-14 thousands of years (ka)) to present times How do varves work? Proglacial lakes form in front of glaciers and act as sinks for water and sediment flowing from melting ice. Analyses of proglacial lake ...[Read More]
Name of proxy Mg/Ca-SST on planktonic foraminifera shell Type of record Sea Surface Temperature (SST) Paleoenvironment Marine environments Period of time investigated 55 Million years ago to recent times How does it work ? Foraminifera (or Forams) are single-celled organisms varying from less than 1 mm to several cm in size. They are very abundant in the ocean floor (benthic species) or floating a ...[Read More]
Name of proxy Phytane, a compound resulting from the degradation of Chlorophyll-a (Chl a), a green pigment in plants and algae that is involved in photosynthesis Type of record Atmospheric carbon dioxide concentrations Paleoenvironment Marine sediments and oils Period of time investigated Phanerozoic (last 540 million years) How it works Before we can start predicting the potential impact of human ...[Read More]
Name of the proxy: Stable isotope ratios of carbonates in speleothems Type of proxy: Precipitation, atmospheric circulation, CO2 availability in soil, soil productivity Paleoenvironment: Continental environments Period of time investigated: Present day to 10 million years How does it work? Speleothems are inorganic carbonate deposits growing in caves that form from super-saturated cave waters (wit ...[Read More]
Applied mathematics is often seen as an obscure field, which the general public has no hope of ever understanding. In the context of climate science, this is far from the truth. In fact, many mathematical concepts and ideas applied to the study of the climate system stem from intuitive arguments. While their implementation can be very complex, understanding the basic ideas behind them does not req ...[Read More]