Читать книгу Reconstructing Earth's Climate History - Kristen St. John - Страница 24

Earlier in this chapter, you were introduced to a range of terrestrial and marine archives of past climate change. Here, the Owens Lake sediment core record will serve as an introductory paleoclimate case study; you will describe and interpret the clues that this archive and its proxies can offer us about climate in western North America over the past 800 000 yr.

1 Use your library resources and/or the online supplement to read A Record of Climate Change from Owens Lake Sediment by Kirsten Menking. This is a chapter from the 2000 book The Earth Around Us: Maintaining a Livable Planet, edited by Jill Schneiderman.Then use the space on the next page to:Make a visual representation (i.e. a sketch) of the Owens Lake sediment core. Use different patterns or colors to represent the different layers described in the article, with the oldest at the bottom and the youngest at the top.Adjacent to your sketch, list the types of proxy data (e.g. salt layer, pebbles, ash, microfossils,…) obtained from the different intervals of the core.Next to the list of proxies, give an interpretation of the data with respect to past climatic and/or environmental conditions (e.g. dry, cold, volcanic eruption,…).

2 What are three methods used to determine age within the lake core?

3 What evidence is there that part of the Owens Lake record is missing (i.e. that a hiatus exists)?Workspace for Question 1:Sketch of coreType of data analyzedPaleoclimatic/environmenta interpretation of that data

4 What could cause layers of lake sediment to be missing from the record?

5 What evidence would support the hypothesis that humans impacted the environment in and/or around Owens Lake?

6 Use Owens Lake to explain why a multiproxy approach is valuable in reconstructing past climatic and/or environmental change: