© ICDP, the International Continental Scientific Drilling Program, 1996-2020

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Scientific Drilling in Lake Malawi, East African Rift

Africa, Malawi, Tanzania, Mozambique, East African Rift Valley, Lake Malawi

addendum full-proposal: ICDP-2004/16
for the funding-period starting 2004-01-15
by Thomas C. Johnson, Christopher A. Scholz, John William King, Michael Richard Talbot (?), Andrew S. Cohen, Leonard S.N. Kalindekafe, Eric Onyango Odada, Michael B. Dolozi, Manfred Strecker
Abstract
The Lake Malawi Scientific Drilling Project is the most ambitious and complex lake drilling project yet to be undertaken by the ICDP, and ranks among the most logistically challenging drilling projects in the entire history of the ICDP. This addendum proposal request is for $500K of additional funds to offset cost-increases in various operational aspects of the drilling project, and involves no changes in the science components of the program. The science objectives are identical to those proposed in our original proposal submitted in January 2000. We have now completed an extensive array of engineering, planning, and logistical activities, and these are summarized in this proposal. The cost increases we are encountering from various vendors and subcontractors since the submittal of our 2000 budget are on account of 1) inflation, 2) currency exchange rate shifts and the decline of the US dollar since the original submittal, 3) higher than expected costs for the Dynamic Positioning System, and 4) higher insurance costs. Recent developments include: · Completion of major subcontracts to key equipment and service vendors · Delivery of the Dynamic Positioning System to Malawi · Completion of major barge design work · Completion of bottom hole assembly design work · Finalization of the logistics plan · Development of an HSE plan (Health, Safety, Environment Plan) The budget increment will allow us to achieve all the main proposed science objectives over a drilling cruise of 37 days. Without additional funds the cruise duration will be 14 days (day rate = $26.6K), and our science objectives will be reduced to a limited paleoclimate record of a few hundred kyr at best, instead of more than one million years.
Scientific Objectives
  • · Determine if tropical African climate responded to changes in low-latitude precessional insolation (23-19 kyr) or to high-latitude ice volume (100 kyr and 41 kyr) forcing, over the past ~800 kyr. Seismic reflection records from Lakes Malawi and Tanganyika show a pronounced acoustic facies cyclicity, which age models suggest occurred at a 100 kyr (eccentricity) frequency. · Assess the phasing of lake level changes in Lake Malawi in the last half of the Pleistocene. Data covering the past 40 kyr suggest that Malawi responded to Southern Hemisphere insolation forcing during that time. · Determine from the high-resolution Lake Malawi drill core records if high-frequency, climate variations (analogous to Dansgaard-Oeschger or Heinrich events) are superimposed on glacial-interglacial timescale variations in the form of wet/dry cycles. Signals from a 100 kyr, low-resolution condensed section from nearby Lake Tanganyika suggest that lake level has fluctuated in phase with North Atlantic Heinrich Events. This low-resolution record needs to be confirmed and extended in the Lake Malawi drill cores. · Establish how interannual African climate variability has changed in association with longer-term climate variations. For instance: - What are the dominant interannual modes of varia bility (ENSO, NAO)? - How have these modes changed in association with changes in African climate? · Determine the long-term evolution of tropical East African climate; for instance we will assess the postulated shift in the dominant Milankovitch frequency, from the present day 100 kyr dominance to 41 kyr dominance to 21 kyr dominance, as is observed in the marine record. In this region of tropical Africa, do we see a significant change in vegetation as the Earth shifted from a 41-kyr world to a 100-kyr world?
Keywords
Africa, GLAD, GLAD800, ICDP-2004/16, Lake drilling, Lake malawi, MALAWI
Location
Africa, Malawi, Tanzania, Mozambique, East African Rift Valley, Lake Malawi: -10.70575, 34.4377

© ICDP, the International Continental Scientific Drilling Program, 1996-2020

www.icdp-online.org