ENVS 2270 Lecture Notes - Lecture 8: Glacial Motion, Dendrochronology, Thermohaline Circulation

• School: University of Guelph
• Department: Environmental Sciences
• Course: ENVS 2270
• Professor: Kim Bolton

Document Summary

(cid:1005)h(cid:1006)(cid:1005)6o (cid:894)(cid:862)(cid:374)o(cid:396)(cid:373)al o(cid:396) (cid:862)light(cid:863) (cid:449)ate(cid:396)(cid:863) i. e. , (cid:373)ost (cid:272)o(cid:373)(cid:373)o(cid:374) t(cid:455)pe(cid:895) Different temperatures lead to different stable isotope ratios (heavy/light ratios) The amount of 18o depends on the temperature. So, we can use isotope ratios to give us temperature information: warmer climate= higher heavy to light ratios (heavy ice, cooler climate= lower heavy to light ratios (lighter ice) Accumulate over time: progressively older sediments buried with increasing depth. Sediments contain: mineral particles, aquatic organisms, pollen. Two types of information: inorganic (mineral, organic (biological) Inorganic marine sediments are delivered by rivers, wind, ice and ocean currents: gives information about source region and atmospheric/ocean circulation, e. g. , desert fine particle transport, wind velocity, aridity, etc. Organic marine sediments: microfossils with hard skeletons. Presence/absence can be used to infer ocean conditions (salinity, temperature) O isotopes can be extracted from caco3 skeletons and used for temperature determinations. Preserved in lakes, estuaries, bogs, etc: highly resistant outer layer, distinct morphology allow for identification, palynology= pollen analysis.