Related DFG-Projects

[Jovanovska] The role of environment in adaptive radiations: Integrating genetic, fossil, and paleoenvironmental information to infer drivers of diatom evolution in the East African Rift lakes (2020 - ongoing)

[Jovanovska] The role of environment in adaptive radiations: Integrating genetic, fossil, and paleoenvironmental information to infer drivers of diatom evolution in the East African Rift lakes (2023 - ongoing)

[Kadereit] Luminescence- and Alpha-Recoil-Track-Dating of Lake Malawi Sediments (2002 - 2004)

[Sirocko] Grain size analysis of sediments from deep Lake Malawi (2006 - 2007)

[Strecker] Tectonics and climate in a low-latitude rift: rift-shoulder denudation and sedimentation processes in northern Lake Malawi (2004 - 2007)

Description

This proposal requests support for drilling operations in Lake Malawi, in the southern end of the East African Rift Valley. Lake Malawi is one of the world’s largest, deepest (maximum water depth of 700 m), and oldest lakes (2- 7+ ma). It is the largest lake in the southern hemisphere after Lake Tanganyika, and is situated between 9 and 14 S. It is one of the most exciting sites on the continents for paleoclimate studies at that latitude and occupies part of Africa’s Great Rift Valley, the archetypical continental rift system. Key Scientific Questions and Objectives The principal objectives of the proposed drilling program were presented, reviewed and refined at a recent workshop on Scientific Drilling in Lakes Malawi and Tanganyika, held at Club Makakola, Malawi, in October 1999. Funds for the workshop were provided by the U.S. National Science Foundation and by the International Continental Scientific Drilling Program. The top scientific objective of the project is to obtain a continuous, highresolution (annual-decadal) record of past climates in the continental tropics over the past ~800 kyr. Other primary scientific objectives of the drilling program intersect several fields, including extensional basin evolution and neotectonics, evolutionary biology, and the environmental background to human origins. Site Selection and Drilling Strategy Seismic site survey data is in hand for all the proposed drill sites. 1) The top priority site is situated in the central basin, southeast of the deepest part of the lake. It is here that seismic reflection site survey data indicate the best prospects for continuous cores of hemipelagic sediment. Such a depositional setting, in an area with no major stratigraphic hiatuses, offers the best chance to recover a continuous section of high-quality paleoclimate proxy records back through the Bruhnes-Matayama boundary. Thus a core through this site will allow us to construct a detailed chronostratigraphy, and be a basis for correlations between other sites that may contain punctuated paleoclimate records. 2) A site in the southern part of the lake (14S) will allow us to record a southern hemisphere tropical signal, as well as nearshore facies that developed during lake lowstands. 3) We intend to recover a series of cores along a northern basin "offset drilling transect" that will allow us to extend the stratigraphic record far back into the Pliocene or perhaps Miocene. In addition, a northern basin site is most likely to recover a section of finely laminated or varved sediments. Logistical and Engineering Considerations The drilling rig to be used for the project will likely be the GLAD800 lake drilling rig, a new facility recently funded to DOSECC by ICDP. The rig will be mounted on the barge Viphya, a 52 m vessel operated by Malawi Lake Services. Our project will require the installation of a moonpool and dynamic positioning system on the barge, for station keeping during drilling. An RFP will be issued to consider companies suitable for completing the barge modification as well as for barge operation. Drilling equipment mobilization will be completed at the port in Monkey Bay, and at the container facility in Chipoka, both in the southern part of the lake. Project Management Syracuse University will provide oversight of field operations, in conjunction with the investigators from other institutions, and with DOSECC, operator of the GLAD800 drilling rig. An on-site project manager will to report to the PI's, and be in charge of local logistics and day-to-day science operations. Personnel front the University of Rhode Island will oversee the operations of the whole-core logging facility, to be set up at the Senga Bay laboratory. The scientific roles for the PI's and collaborators are presented in section 6.2. Preliminary Operational Budget Total direct costs for field operations are $2.3 million USD. A major capital cost line-item included in this total is $600K for the purchase of a series of barge thrusters and a dynamic positioning system, for barge station keeping. We are investigating a variety of avenues of financing of such a system (including cost-sharing with NSF, ODP), which will be required for many future lake drilling and Ocean Drilling projects, and which could significantly lower the costs of this proposal. Most field operations will be operated through a subcontract to DOSECC, significantly reducing the indirect costs charged to the grant.