Paleoenvironment proxy

LOESS IN TRANSLATION

Dr. Kaja Fenn November 25, 2020

Figure image: Loess profile in North Bulgaria. The Danube River in the distance.

Loess is a mineral, aeolian deposit with a range of definitions in literature, which class it as either a sediment, soil, or rock. Some classic texts suggest that “loess is not just the accumulation of dust” [1], and it must include additional processes such as loessification, calcification, pedogenesis, and in-situ weathering. The definition adopted depends on the scientific background and the qu ...[Read More]

Forams, the sea thermometers of the past!

Mercè Cisneros Bermejo and Cacho Isabel from GRC Geociències Marines, Departament de Dinàmica de la Terra i de l’Oceà, Facultat de Ciències de la Terra, Universitat de Barcelona, Barcelona, Spain November 24, 2017

Figure 1: Planktonic foraminifera Globigerina bulloides specimen (scanning electron microscope picture of Isabel Cacho).

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]

What speleothems can tell about the past climates !

Carole Nehme (University of Rouen) and Michael Deininger (University College Dublin) September 5, 2017

Speleothem laminas used to reproduce past precipitation patterns, soil productivity and its carbon dioxide content. Modified from Tan et al. (2006) and Johnson et al. (2006).

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]

Ostracods, the sentinels of past oceanic circulation

Marie-Béatrice Forel April 28, 2017

Figure 1. Left: Inside view of a dissected male of Cyprideis torosa with soft parts and appendages visible (Photo Dietmar Keyser). Right: Fossil specimen of the species Cytheropteron eximium Alexander, 1933 from the Cenomanian, Late Cretaceous (about 93 Ma) of the Western Interior Basin, USA (Photo MBF). For both photos, scale bar is 100 µm.

Name of the proxy Ostracoda Type of proxy Paleoenvironment proxy Paleoenvironment All types of aquatic environments but here we will focus on marine waters Period of time investigated Phanerozoic How does it work? Ostracoda are crustacean of millimetre size which have inhabited all types of marine environments from the Ordovician to today (e.g. Salas et al. 2007) and colonized continental water bo ...[Read More]