Blue Hole Drilling Project

• Sediment from the bottom of the Blue Hole, a 125 m deep Pleistocene sinkhole located in the lagoon of Lighthouse Reef Atoll, Belize, consists of undisturbed, annually layered biogenic carbonate muds and silts with intercalated coarser grained storm beds. Sedimentation-rate of layered sections is 2.5 mm/yr on average, and up to 6 m long cores collected during a pilot study span the past 1500 yrs. Oxygen isotopes of laminated sediment in these cores provide a late Holocene climate proxy: a high-resolution d18O time series traces the final Migration Period Pessimum, the Medieval Warm Period, the Little Ice Age, and the subsequent temperature rise. Carbon isotopes (d13C) decrease upcore and potentially show the impacts of the decline of the Maya culture and the Suess Effect. Time series analyses of d18O and d13C reveal 88, 60, 52, and 32 year cyclicities, and suggest solar forcing. Storm event beds are most common during AD 650-850, around AD 1000, during AD 1200-1300, and AD 1450-1550. Major storm beds are rare during the past 500 years BP.

The total Holocene marine sediment sequence in the Blue Hole alone can be expected to cover about 8 kyrs and more than 20 m of annually layered sediment, given the average sedimentation rate of 2.5 mm/yr and the early Holocene marine inundation of the Lighthouse Reef lagoon. Because the Blue Hole probably formed not only during the previous but during several Pleistocene sea-level lowstands, we expect similar, laminated marine sediments of previous Pleistocene sea-level highstands below the Holocene sediment package. We attempt to investigate this late Quaternary record in a core study within the framework of the International Continental Scientific Drilling Program (ICDP).

(Figure ©: U.S. Geological Survey)

See also:

• ICDP-06/08

Central America, Belize, Gulf of Mexico

17° 18' 56'' N, 87° 32' 4'' W (Please scroll down to end of page for more information.)

• not yet determined

• Eberhard Gischler, University of Frankfurt/Main, Institute of Geoscience - Geology
• Eugene A. Shinn, University of South Florida at St. Petersburg, Department of Geological Sciences, College of Marine Science
• Flavio Anselmetti, Swiss Federal Institute of Aquatic Science and Technology (EAWAG), Department of Surface Waters - Research and Management, Sedimentology Section

Belize , BLUE HOLE , Central America , Climate Archive , Climate Change , ICDP-06/08 , Quaternary , Sea Drilling , Sediment

Workshop in preparation

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