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Scientific drilling into the Earth is a way for scientists to probe the Earth's sediments, crust, and upper mantle. In addition to rock samples, drilling technology can unearth samples of connate fluids and of the subsurface biosphere, mostly microbial life, preserved in drilled samples. Scientific drilling is carried out on land by the International Continental Scientific Drilling Program (ICDP) and at sea by the Integrated Ocean Drilling Program (IODP). Scientific drilling on the continents includes drilling down into solid ground as well as drilling from small boats on lakes. Sampling thick glaciers and ice sheets to obtain ice cores is related but will not be described further here.
Like probes sent into outer space, scientific drilling is a technology used to obtain samples from places that people cannot reach. Human beings have descended as deep as 2,212 m (7,257 ft) in Veryovkina Cave, the world's deepest known cave, located in the Caucasus Mountains of the country of Georgia. Gold miners in South Africa regularly go deeper than 3,400 m, but no human has ever descended to greater depths than this below the Earth's solid surface. As depth increases into the Earth, temperature and pressure rise. Temperatures in the crust increase about 15 °C per kilometer, making it impossible for humans to exist at depths greater than several kilometers, even if it was somehow possible to keep shafts open in spite of the tremendous pressure. [1] [ failed verification ]
Scientific drilling is interdisciplinary and international in scope. Individual scientists cannot generally undertake scientific drilling projects alone. Teamwork between scientists, engineers, and administrators is often required for success in planning and in carrying out a drilling project, analyzing the samples, and interpreting and publishing the results in scientific journals.
Scientific drilling is used to address a wide range of problems, which cannot be addressed using rocks exposed on the surface or the seafloor. The Integrated Ocean Drilling Program has a broad set of research objectives, which can be divided into three principal themes:
ICDP focuses on scientific drilling to address the following questions about the history, chemistry, and physics of Earth and the biosphere:
The Kola Superdeep Borehole on the Kola peninsula of Russia reached 12,262 metres (40,230 ft) and is the deepest penetration of the Earth's solid surface. The German Continental Deep Drilling Program at 9.1 kilometres (5.7 mi) has shown the earth crust to be mostly porous. Drillings as deep as 2.1 kilometres (1.3 mi) into the seafloor were achieved at DSDP/ODP/IODP Hole 504B.[ citation needed ] Because the continental crust is about 45 km thick on average, whereas oceanic crust is 6–7 km thick, deep drillings have penetrated only the upper 25-30% of both crusts.
The drillship that has been used for the past 20 and more years, the JOIDES Resolution, drills without a riser. [2] Riser-less drilling uses seawater as its primary drilling fluid, which is pumped down through the drill pipe. This cleans and cools the drill bit and lifts cuttings out of the hole, piling them in a cone around the hole. [3] Japan's new drillship, the Chikyu, uses a riser for drilling. The riser system includes an outer casing that surrounds the drill pipe, to provide return-circulation of drilling fluid for maintaining pressure balance within the borehole. A blowout preventer (BOP) protects the vessel and the environment from any unexpected release of gas and oil. This technology is necessary for drilling several thousand meters into the Earth. [3]
The Kola Superdeep Borehole SG-3 is the deepest human-made hole on Earth, which attained maximum true vertical depth of 12,262 metres in 1989. It is the result of a scientific drilling effort to penetrate as deep as possible into the Earth's crust conducted by the Soviet Union in the Pechengsky District of the Kola Peninsula, near the Russian border with Norway.
The Mohorovičić discontinuity – usually called the Moho discontinuity, Moho boundary, or just Moho – is the boundary between the crust and the mantle of Earth. It is defined by the distinct change in velocity of seismic waves as they pass through changing densities of rock.
The Deep Sea Drilling Project (DSDP) was an ocean drilling project operated from 1968 to 1983. The program was a success, as evidenced by the data and publications that have resulted from it. The data are now hosted by Texas A&M University, although the program was coordinated by the Scripps Institution of Oceanography at the University of California, San Diego. DSDP provided crucial data to support the seafloor spreading hypothesis and helped to prove the theory of plate tectonics. DSDP was the first of three international scientific ocean drilling programs that have operated over more than 40 years. It was followed by the Ocean Drilling Program (ODP) in 1985, the Integrated Ocean Drilling Program in 2004 and the present International Ocean Discovery Program in 2013.
The Ocean Drilling Program (ODP) was a multinational effort to explore and study the composition and structure of the Earth's oceanic basins, running from 1985 to 2004. ODP was the successor to the Deep Sea Drilling Project initiated in 1968 by the United States. ODP was an international effort with contributions of Australia, Germany, France, Japan, the United Kingdom and the ESF Consortium for Ocean Drilling (ECOD) including 12 further countries. The program used the drillship JOIDES Resolution on 110 expeditions (legs) to collect about 2,000 deep sea cores from major geological features located in the ocean basins of the world. Drilling discoveries led to further questions and hypotheses, as well as to new disciplines in earth sciences such as the field of paleoceanography.
The San Andreas Fault Observatory at Depth (SAFOD) was a research project that began in 2002 aimed at collecting geological data about the San Andreas Fault for the purpose of predicting and analyzing future earthquakes. The site consists of a 2.2 km pilot hole and a 3.2 km main hole. Drilling operations ceased in 2007. Located near the town of Parkfield, California, the project installed geophone sensors and GPS clocks in a borehole that cut directly through the fault. This data, along with samples collected during drilling, helped shed new light on geochemical and mechanical properties around the fault zone.
Earth's mantle is a layer of silicate rock between the crust and the outer core. It has a mass of 4.01×1024 kg (8.84×1024 lb) and makes up 67% of the mass of Earth. It has a thickness of 2,900 kilometers (1,800 mi) making up about 46% of Earth's radius and 84% of Earth's volume. It is predominantly solid but, on geologic time scales, it behaves as a viscous fluid, sometimes described as having the consistency of caramel. Partial melting of the mantle at mid-ocean ridges produces oceanic crust, and partial melting of the mantle at subduction zones produces continental crust.
The Integrated Ocean Drilling Program (IODP) was an international marine research program, running from 2003 to 2013. The program used heavy drilling equipment mounted aboard ships to monitor and sample sub-seafloor environments. With this research, the IODP documented environmental change, Earth processes and effects, the biosphere, solid earth cycles, and geodynamics.
The International Continental Scientific Drilling Program is a multinational program to further and fund geosciences in the field of continental scientific drilling. Scientific drilling is a critical tool in understanding of Earth processes and structure. It provides direct insight into Earth processes and critically tests geological models. Results obtained from drilling projects at critical sites can be applied to other areas worldwide. It is, therefore, believed that international cooperation in continental scientific drilling is an essential component for a responsible management strategy for the Earth's natural resources and environment.
The Glomar Challenger was a deep sea research and scientific drilling vessel for oceanography and marine geology studies. The drillship was designed by Global Marine Inc. specifically for a long term contract with the American National Science Foundation and University of California Scripps Institution of Oceanography and built by Levingston Shipbuilding Company in Orange, Texas. Launched on March 23, 1968, the vessel was owned and operated by the Global Marine Inc. corporation. Glomar Challenger was given its name as a tribute to the accomplishments of the oceanographic survey vessel HMS Challenger. Glomar is a truncation of Global Marine.
Chikyū (ちきゅう) is a Japanese scientific drilling ship built for the Integrated Ocean Drilling Program (IODP). The vessel is designed to ultimately drill 7 km beneath the seabed, where the Earth's crust is much thinner, and into the Earth's mantle, deeper than any other hole drilled in the ocean thus far.
The riserless research vessel JOIDES Resolution, often referred to as the JR, is one of the scientific drilling ships used by the International Ocean Discovery Program (IODP), an international, multi-drilling platform research program. JOIDES Resolution was previously the main research ship used during the Ocean Drilling Program (ODP) and was used along with the Japanese drilling vessel Chikyu and other mission-specific drilling platforms throughout the Integrated Ocean Drilling Program. She is the successor of Glomar Challenger.
Travelling to the Earth's center is a popular theme in science fiction. Some subterranean fiction involves traveling to the Earth's center and finding either a Hollow Earth or Earth's molten core. Planetary scientist David J. Stevenson suggested sending a probe to the core as a thought experiment. Humans have drilled over 12 kilometers in the Sakhalin-I project. In terms of depth below the surface, the Kola Superdeep Borehole SG-3 retains the world record at 12,262 metres (40,230 ft) in 1989 and still is the deepest artificial point on Earth.
Boring is drilling a hole, tunnel, or well in the Earth. It is used for various applications in geology, agriculture, hydrology, civil engineering, and mineral exploration. Today, most Earth drilling serves one of the following purposes:
The European Consortium for Ocean Research Drilling (ECORD) is a consortium of 14 European countries and Canada that was formed in 2003 to join the Integrated Ocean Drilling Program (IODP) as a single member. ECORD is now part of the International Ocean Discovery Program, which addresses crucial questions in Earth, Ocean, Environmental and Life sciences based on drill cores, borehole imaging, observatory data, and related geophysical imaging obtained from beneath the ocean floor using specialized ocean-going drilling and research vessels and platforms. As a contributing member of IODP, ECORD is entitled to berths on every IODP expedition.
The German Continental Deep Drilling Programme, abbreviated as the KTB borehole, was a scientific drilling project carried out from 1987 to 1995 near Windischeschenbach, Bavaria. The main super-deep borehole reached a depth of 9,101 m in the Earth's continental crust.
The Deep Carbon Observatory (DCO) is a global research program designed to transform understanding of carbon's role in Earth. DCO is a community of scientists, including biologists, physicists, geoscientists and chemists, whose work crosses several traditional disciplinary lines to develop the new, integrative field of deep carbon science. To complement this research, the DCO's infrastructure includes public engagement and education, online and offline community support, innovative data management, and novel instrumentation development.
The International Ocean Discovery Program (IODP) is an international marine research collaboration dedicated to advancing scientific understanding of the Earth through drilling, coring, and monitoring the subseafloor. The research enabled by IODP samples and data improves scientific understanding of changing climate and ocean conditions, the origins of ancient life, risks posed by geohazards, and the structure and processes of Earth's tectonic plates and uppermost mantle. IODP began in 2013 and builds on the research of four previous scientific ocean drilling programs: Project Mohole, Deep Sea Drilling Project, Ocean Drilling Program, and Integrated Ocean Drilling Program. Together, these programs represent the longest running and most successful international Earth science collaboration.
Beth N. Orcutt is an American oceanographer whose research focuses on the microbial life of the ocean floor. As of 2012, she is a senior research scientist at the Bigelow Laboratory for Ocean Sciences. She is also a senior scientist of the Center for Dark Energy Biosphere Investigations, a Science and Technology Center funded by the National Science Foundation and headquartered at the University of Southern California and part of the Deep Carbon Observatory Deep Life Community. Orcutt has made fundamental contributions to the study of life below the seafloor, particularly in oceanic crust and has worked with the International Scientific Ocean Drilling Program.
The upper mantle of Earth is a very thick layer of rock inside the planet, which begins just beneath the crust and ends at the top of the lower mantle at 670 km (420 mi). Temperatures range from approximately 500 K at the upper boundary with the crust to approximately 1,200 K at the boundary with the lower mantle. Upper mantle material that has come up onto the surface comprises about 55% olivine, 35% pyroxene, and 5 to 10% of calcium oxide and aluminum oxide minerals such as plagioclase, spinel, or garnet, depending upon depth.
The deep biosphere is the part of the biosphere that resides below the first few meters of the surface. It extends down at below 10 kilometers below the continental surface and 21.0 kilometers below the sea surface, at temperatures that may reach beyond 120 °C (248 °F) which is comparable to the maximum temperature where a metabolically active organism has been found. It includes all three domains of life and the genetic diversity rivals that on the surface.