GEOL 102 mid term study (part 6)

Photosynthesis requires_____________.

 

water and carbon dioxide

Some dead plant material escapes from respiration (decomposition) through burial in sediments. If a significant amount of plants or organic matter were buried during a time period in Earth’s history, the atmospheric CO₂ level will _________, while the O₂ level will ______________.

 

decrease; increase

Strong silicate weathering for a long period of time (many million years) would lead to _____________.

 

global cooling

Organic matter formed through photosynthesis would have ________light carbon (¹²C) content compared to the CO₂ that they used for photosynthesis.

higher

In the geological history when the rate of carbon burial increases on continents or beneath the sea, both carbon dioxide in the atmosphere and carbon dioxide dissolved in the ocean would have _________.

 

high ¹³C content (higher δ¹³C)

During the last glacial maximum ~20,000 years ago, the δ¹⁸O values of seawater recorded by foraminifera (small carbonate-secreting organisms) would be ________the δ¹⁸O value of modern seawater.

 

higher than

During Carboniferous and Permian, widespread coal beds were formed through the burial of trees/forests in swamps. This process resulted in significant climate changes marked by __________. 

 

global cooling

At the Paleocene-Eocene boundary (~56 million years ago), global warming resulted in the release of large quantity of methane from methane hydrates (methane hydrate destabilization). The methane release event could be recorded by _________. 

 

a negative δ¹³C excursion

The δ¹⁸O of Antarctic ice sheets is __________ that of the ocean seawater.

 

lower than

Global warming in Earth’s history can be recorded by _________________.

 

negative shifts in δ¹⁸O of marine carbonates