Transcript Parasols Paleosols Paleosols • The islands of Bermuda are composed of an alternation between carbonate deposits and paleosols • Exposed land above sea level.

Parasols
Paleosols
Paleosols
• The islands of Bermuda are composed of an
alternation between carbonate deposits and
paleosols
• Exposed land above sea level is a lithified dune field
composed of calcareous eolianites.
• Paleosols that are interbedded between datable rocks
provide valuable opportunities for reconstructing
past conditions
Paleosols
• Interglacial periods and high-sea stand resulted in
dune formation
• Glacial periods and low-sea stand resulted in
paleosol formation
• Six eolianite formations ranging from >880 to 85 ka
Paleosols
• Reddish to reddish-brown in color
• Consist of high concentrations of aluminosilicate
clays
• According to Herwitz et al. (1996) most of the red
clays of Bermudan paleosols represent
accumulations of fine-grained airborne dust
originating from distant continental areas
• North American origin possible
• Saharan dust likely
Paleosol soil composition
• Fossil soils are clay-rich (up to 60%)
• Originally thought that paleosols formed due to
dissolution of underlying carbonates and volcanic
material
• Would require 150 meters of limestone to produce 1 cm of
paleosol
Paleosols
• 2 primary groups of minerals compose
mineralogical assemblage of Bermuda peleosols
• Immature soils: carbonates and clay minerals
• Mature soils: kaolinite, nordstrandite, gibbsite,
crandallite
• Paleosols sometimes contain dark lithoclasts of
quartz grains
• Avian transport
• volcanic
Paleosols
• Study by F. Prognon et al. (2011) found that the
parent material of the paleosols is from the
underlying volcanic seamount
• Contradicts earlier studies which hypothesized and
showed that paleosol material was primarily wind
blown
- F. Prognon et al. (2011) found that the mineral
assemblages were similar to volcanic substrate, and
noticeably different from Saharan dust