GEOG 1265 Lecture Notes - Lecture 12: Younger Dryas, Palynology, Water Table
20 Feb 2017
School
Department
Course
Professor
Document Summary
Bulk density: mass of a gram of dry sediment: providing information on glacial dynamics. Organic content: allochthonous: material coming from outside of the lake (washing in from the surrounding slopes, autochthonous: organic material that has formed within the lake, c:n ratio: C:n >10= terrestrial sources (trees: greenland ice cores: Oxygen isotopes: o16 is the most common, o18. Cores from o16 and o18 ice can have temperatures measured and temperatures can be estimated for the time period that the ice cores are from. Time period that there was a big jump in pollen counts. End of the younger dryas is when the holocene starts: south mesa lake organic content: Temperature records from arctic ice cap studies match those in. Partly decomposed plant material: decomposition is reduced by high water table (anoxic conditions, acrotelm: Waterlogged section of peat: due to occasional drying, organic matter decomposes 100x faster in the acrotelm than in the catotelm, fens:
