Drilling Tells Tale of Climate ChangeMediterranean bottom currents and the sediment deposits they leave behind offer new insights into global climate change, the opening and closing of ocean circulation gateways, and locations where hydrocarbon deposits may lay buried under the sea. A team of 35 scientists from 14 countries recently returned from an expedition off the southwest coast of Iberia. There the geologists collected core samples of sediments that contain a detailed record of the Mediterranean’s history. The scientists retrieved the samples by drilling into the ocean floor during an eight-week scientific expedition onboard the ship JOIDES Resolution. The group – researchers participating in Integrated Ocean Drilling Program (IODP) – is the first to retrieve sediment samples from deep below the seafloor in this region.
“The recovery of nearly two-and-a-half miles of contourite sediments deposited from deep underwater currents presents a superb opportunity to understand water flow from the Mediterranean Sea to the Atlantic Ocean,” says Jamie Allan, program director at the National Science Foundation (NSF), which co-funds IODP. “Knowledge of this water flow is important for understanding Earth’s climate history in the last five million years.”
The world’s oceans are far from static. Large currents flow at various depths beneath the surface. These currents form a global conveyor belt that transfers heat energy and helps buffer Earth’s climate. Critical gateways in the oceans affect circulation of these major currents. The Strait of Gibraltar is one such gateway. It re-opened less than six million years ago. Today, deep below the surface, there is a powerful cascade of Mediterranean water spilling out through the strait into the Atlantic Ocean. As this water is saltier than the Atlantic – and therefore heavier – it plunges more than 3,300 feet down-slope, scouring the rocky seafloor, carving deep-sea canyons and building up mountains of mud on a little-known submarine landscape.
At four of the seven drill sites, there were major chunks of the geologic record missing from the sediment cores – evidence of a strong current that scoured the seafloor. “We set out to understand how the Strait of Gibraltar acted first as a barrier and then a gateway over the past six million years,” says Javier Hernandez-Molina of the University of Vigo in Spain. “We now have that understanding and a record of a deep, powerful Mediterranean outflow through the Gibraltar gateway.”
The first drill site, located on the west Portuguese margin, provided the most complete marine sediment record of climate change over the past 1.5 million years of Earth history. The sediment cores cover at least four major ice ages, and contain a new marine archive to compare against ice core records from Greenland and Antarctica, among other land-based records.
Proper Water Well InspectionsRoutine water well system inspection is vital to assuring proper operation of the well, prolong its operational expectancy, and monitor the quality of the ground water it supplies, according to the National Ground Water Association (NGWA). In addition, just as important as the inspection itself, are the qualifications of those hired to perform the inspection.
To this end, NGWA’s recently issued Water Well Systems Inspection Best Suggested Practice serves as a guide to contractors, pump installers, well owners, water systems managers and regulators, as well as those who perform and depend upon well inspections.
Water Well Systems Inspection Best Suggested Practice covers items a qualified inspector should perform, including, but not limited to:
- Determining the water well use parameters such as its
purpose, e.g., human consumption, irrigation, industrial; estimated ground
water usage per day; any known water-quality issues.
- Visually inspecting the wellhead to ensure proper
- Visually and physically inspecting the water well system components,
including testing the pump, checking valves, and conducting electrical
- Visually inspecting any other equipment such as pressure tanks,
storage tanks, water heaters, softeners, filtration equipment,
- Documenting for the well owner/manager the system specifications observed, any suggested recommendations for remedial work, and a recommended schedule for future routine inspection, testing, cleaning and rehabilitation.
Hydraulic Fracturing RecommendationsThe National Ground Water Association has issued a series of principles for policymaking aimed at protecting ground water in areas of the United States experiencing increased oil and gas development using hydraulic fracturing.
“The greater use of horizontal wells and the hydraulic fracturing technology has the potential to significantly expand natural gas and oil supplies, and hold down prices,” NGWA states in a new position paper. “However, concomitant with this enhanced production is the increased possibility for ground water contamination and other impacts to drinking water supplies if best practices and proper procedures are not used, and if appropriate regulations are not in place.”
NGWA recommends that policies be put in place and enforced, if they are not already, that promote:
- disclosure of all chemicals used in the oil or gas well hydraulic
fracturing process to the appropriate governmental entity,
- proper construction and regular maintenance of oil or gas production
wells to prevent the migration of natural and injected fluids that could
endanger current or future drinking water sources,
- best management practices or appropriate regulations to address
surface spills and waste management related to hydraulic fracturing,
- development of water supply plans in areas where water is scarce or the potential for water use conflicts exist.
“The need for increasing the nation’s energy supplies exists concurrently with the need to ensure adequate freshwater for drinking, food production, manufacturing and ecosystem support,” the NGWA concludes. ND