A time machine will begin operating March 15 in Hilo, Hawaii. The Hawaii Scientific Drilling Project--a cooperative research project involving the University of Hawaii, University of California, Berkeley, and California Institute of Technology--will travel a million years into the past by boring thousands of feet down into the volcanic island.
Researchers hope to reach a depth of 15,000 feet, almost 3 miles beneath the surface, producing a continuous sequence of samples from now-buried lava flows that formed Mauna Kea volcano, the famed "white mountain" that rises nearly 14,000 feet above sea level on the Big Island of Hawai'i.
The culmination of more than 10 years of scientific review, testing and analysis, the research will literally unearth history--illustrating the planetary processes that produced the Hawaiian Island chain. Drilling will go as deep--and as far back-- as technology and available funding permit.
The project is the largest and most important scientific drilling program funded by the National Science Foundation during the coming decade. In addition to revealing new clues about the origin of Hawaiian volcanism, it promises insights into volcanic hazards, the history of Earth's magnetic field and groundwater movement deep within the volcanoes.
Scientists from the three partner universities will be joined by an international team of earth-science researchers from nearly two dozen universities and research institutes. The team will conduct an exhaustive analysis of the chemical compositions of the rock samples recovered, their magnetic characteristics and their isotopic compositions. Another research team will conduct geophysical tests in the hole and collect samples of deep groundwater from the different geologic formations that are encountered.
The site--an abandoned quarry located near the Hilo airport--was selected because it is halfway between the Mauna Kea and Mauna Loa rift zones, reducing the likelihood of encountering intrusive lavas or hydrothermal alteration of the subsurface rocks. Either condition would produce undesirable characteristics in the samples, making the interpretation of their chemical compositions much more difficult.
Drilling and sample collection will occur over two six-month drilling intervals using a coring system designed and fabricated especially for this project. The first coring effort is expected to begin in mid-March; site preparation and rig mobilization are underway. Program scientists hope to recover cores to a depth of about 8,000 feet during the initial drilling. The second drilling campaign, to begin in about three years, will push for 15,000 feet.
Mauna Kea core smples will be recovered at the site and processed for preliminary analyses and documentation. A portion of the core will be reserved for permanent archive and the balance will be distributed to cooperating scientists for analysis at their home institutions.
Analyses of cores recovered during a preliminary drilling program in 1993 indicate that the rocks at the 15,000-foot depth may be as old as one million years. Relatively low temperatures recorded in the preliminary borehole suggest that the samples have been protected from chemical alteration. Thus, researchers will be able to recover nearly pristine samples of the early eruptive products from when Mauna Kea was even younger than Loihi, the submarine volcano forming off the Big Island of Hawaii, is now.
The primary scientific objective of the project is to learn more about the phenomenon known as mantle plumes, which are jets of very hot, solid rock material that rise through the interior of the earth from a depth of almost 3,000 kilometers. Mantle plumes are believed to be responsible for the volcanism in Hawaii, which occurs in the middle of one of the large tectonic plates that constitute Earth's crust.
Most Earth volcanism occurs at the edges of plates, either at the mid-ocean ridges, where plates split apart, or in the Pacific Ring of Fire and related features, where plates come together. The plume of hot rising rock material under Hawaii melts when it gets within about 100 km of Earth's surface, and this melting produces the magma that is erupted from the volcanoes.
By studying the lavas of the Mauna Kea volcano, scientists hope to learn more about how mantle plumes originate and how magma makes its way up to the surface. Some of the scientists will investigate the magnetism of the lavas. Because the lavas to be drilled vary in age from about 1,000 years at the surface to about a million years at 15,000 feet, the core samples will provide a nearly continuous record of the earth's magnetic field over this time interval. Project data will provide the most detailed record ever assembled of how the magnetic field changed over time.
The University of Hawaii at Hilo will host three national/international workshops and training programs in conjunction with the scientific activities associated with the drilling program.
Funding for the research is being provided by the National Science Foundation (more than $10.5 million over the life of the project for the costs of drilling and related science) and the International Continental Scientific Drilling Program ($1.5 million to help pay for remaining drilling expenses plus in-kind scientific and technical support for the drilling and analytical program).
Water Resources International, a Hawaii-based drilling company, has been contracted to provide the rotary drilling services required by the project. Specialized core-drilling expertise will be provided by Tonto Drilling Services, a Salt Lake City--based company. DOSECC, an incorporated consortium of universities and research institutes formed by the National Science Foundation to assist with scientific drilling activities throughout the United States, is providing overall management of the drilling and coring activities.