Soil genesis on the island of Bermuda in the Quaternary: The importance of African dust transport and deposition
Article first published online: 1 SEP 2012
©2012. American Geophysical Union. All Rights Reserved.
Journal of Geophysical Research: Earth Surface (2003–2012)
Volume 117, Issue F3, September 2012
How to Cite
2012), Soil genesis on the island of Bermuda in the Quaternary: The importance of African dust transport and deposition, J. Geophys. Res., 117, F03025, doi:10.1029/2012JF002366., , , , and (
- Issue published online: 1 SEP 2012
- Article first published online: 1 SEP 2012
- Manuscript Accepted: 16 JUL 2012
- Manuscript Revised: 13 JUL 2012
- Manuscript Received: 4 FEB 2012
- African dust;
- volcanic rocks
 The origin of terra rossa, red or reddish-brown, clay-rich soils overlying high-purity carbonate substrates, has intrigued geologists and pedologists for decades. Terra rossa soils can form from accumulation of insoluble residues during dissolution of the host limestones, addition of volcanic ash, or addition of externally derived, long-range-transported (LRT) aeolian particles. We studied soils and paleosols on high-purity, carbonate aeolianites of Quaternary age on Bermuda, where terra rossa origins have been debated for more than a century. Potential soil parent materials on this island include sand-sized fragments of local volcanic bedrock, the LRT, fine-grained (<20μm) component of distal loess from the lower Mississippi River Valley, and LRT dust from Africa. These parent materials can be characterized geochemically using trace elements that are immobile in the soil-forming environment. Results indicate that local volcanic bedrock on Bermuda has Sc-Th-La, Cr-Ta-Nd, and Eu/Eu*, LaN/YbN, GdN/YbNthat can be distinguished from African dust and lower Mississippi River valley loess. Bermuda soils have Sc-Th-La, Cr-Ta-Nd, and Eu/Eu*, LaN/YbN, GdN/YbN that indicate derivation from a combination of LRT dust from Africa and local volcanic bedrock. Our results indicate that soils on islands in a very broad latitudinal belt of the western Atlantic margin have been influenced by African LRT dust inputs over much of the past ∼500 ka.