Cenozoic Climate Change: A Continental Collision

According to the text, what has been the general trend of atmospheric CO₂ concentration over the last 50 million years?

• AIt has remained relatively constant.
• BIt has increased by a factor of three.
• CIt has decreased by a factor of three.
• DIt has doubled.

What tectonic event is primarily responsible for the decrease in atmospheric CO₂ concentration over the last 50 million years, as described in the text?

• AThe opening of the Drake Passage.
• BThe collision of the African and European plates.
• CThe formation of the Andes Mountains.
• DThe Alpine collision (in a broad sense).

How does the alteration of calcium-rich minerals in high-altitude reliefs contribute to the decrease in atmospheric CO₂?

• AIt releases CO₂ into the atmosphere.
• BIt increases the rate of volcanic eruptions.
• CIt causes the formation of limestone (CaCO₃), which traps CO₂.
• DIt decreases the temperature of ocean water.

What evidence from the Cretaceous period suggests warmer ocean temperatures compared to today?

• AHigher Mg/Ca ratios in Coccoliths.
• BLower levels of volcanic activity.
• CHigher δ¹⁸O values in Coccolith tests.
• DLower Mg/Ca ratios in Coccoliths and higher δ¹⁸O values in Coccolith tests.

What geological factor contributed to a higher global sea level during the Cretaceous period compared to today?

• ALower volcanic activity at mid-ocean ridges.
• BA lower global average temperature.
• CA higher volume of polar ice.
• DMore intense activity at mid-ocean ridges, leading to a higher ocean floor and thermal expansion of water.