A closeup of a stalagmite. Image courtesy of NOAA.

A West Virginia cave stalagmite has provided the most detailed geological record to date on climate cycles in eastern North America over the past 7,000 years, according to a ScienceDaily article.

Gregory Springer, a geologist from Ohio University and his team examined the trace metal strontium in the stalagmite. The stalagmite was able to preserve climate conditions averaged over periods as brief as a few years.

Through their study of the stalagmite, the team determined that there were 7 major drought periods during the Holocene era, which started about 10,000 years ago.

"This really nails down the idea of solar influence on continental drought," said Springer.

Geologist Gerald Bond suggested that every 1,500 years, weak solar activity caused by fluctuations in the sun's magnetic fields cools the North Atlantic Ocean and creates more icebergs and ice rafting, or the movement of sediment to ocean floors. The data from this study is consistent with the Bond events, which showed the connection between weak solar activity and ice rafting, according to the researchers.

Though modern records show that a cooling North Atlantic Ocean actually increases moisture and precipitation, the historic climate events were different, Springer said. In the past, the tropical regions of the Atlantic Ocean also grew colder, creating a drier climate and prompting the series of droughts, he explained.

The climate record found in the stalagmite suggests that North America could face another major drought in the next 500 to 1,000 years, but according to Springer, global warming could offset the cycle.

"Global warming will leave things like this in the dust. The natural oscillations here are nothing like what we would expect to see with global warming," he said

The findings of this study were posted in the Journal of Geophysical Research Letters.