Scientists from 10 countries are examining core samples from 35 miles off the coast of New Jersey to look into the Earth’s past in order to help predict its future.
The New Jersey Shallow Shelf Expedition 313 is funded primarily by the Integrated Ocean Drilling Program (IODP) through the European Consortium for Ocean Research Drilling (ECORD), a consortium of 17 European countries formed to participate in IODP. Funding also is provided by the U.S. National Science Foundation, Japan, China, Korea, Australia, India and New Zealand. Additional support for Expedition 313 was provided by the International Continental Scientific Drilling Program.
DOSECC (Drilling, Observation and Sampling of the Earth’s Continental Crust) comes in as the drilling expert. DOSECC is a not-for-profit corporation whose mission is to provide leadership and technical support in subsurface sampling and monitoring technology. Fifty-seven research organizations are members of DOSECC, which is headquartered in Salt Lake City. One of DOSECC’s goals is to design, build and operate drilling systems, but most of the drilling rigs it uses are made by Atlas Copco. Other goals of the company are to facilitate and support cost effective scientific drilling projects; link science and drilling technology; promote technology transfer and education; and represent U.S. interests in the international scientific drilling community.
For this expedition, DOSECC has chosen the Atlas Copco CS4002, mounted on Kayd, a 245-class liftboat that is owned and operated by Montco Offshore Inc. of Galiano, La. The Kayd can work in water depths of 180 feet, and still keep the drill 45 feet above rough seawaters. DOSECC will drill three 2,460-foot holes, using specially designed PQ core barrels, in water about 114 feet deep.
Glaciers Melting FasterKen Miller is the co-principal U.S. investigator for the project, and professor in the Earth and Planetary Sciences Department of Rutgers University. He says that when he started thinking of this study in 1988, the idea of global warming still was new and was debated in the scientific community. Now, everyone agrees that glaciers are melting at a faster pace than ever, and Miller is interested in how that will change the world’s shorelines. Past samples taken from drill sites indicate that sea levels have risen 13 feet over the last 5,000 years. Now, sea levels are rising at an accelerated rate of 1.2 feet per 100 years, and that’s expected to keep increasing.
The expedition will collect cores from sediments deposited some 14 million to 24 million years ago, a time of considerable sea-level fluctuation due to climatic variations. Scientists will analyze these cores to accurately reconstruct global sea-level changes during that period, and to assess the imprint of those changes on the development of the sedimentary sequences off New Jersey. It is thought the shoreline has varied from 71 miles landward and 93 miles seaward from today’s location. The New Jersey project has two goals – to establish a time and magnitude of sea level changes over the past 35 million years, and to better recognize the imprint of sea level changes in shallow waters of all ages and all locations. Scientists will better understand the complex ties between climate, sea levels and earth systems on continental shelves, in particular. Then, they can anticipate future changes that may come as sea levels rise due to glacial melt.
Atlas Copco’s CS4002 is a part of a mission-specific platform that is well suited for recovering core samples from the sand-rich shelf sediments. DOSECC education and outreach manager David Zur says, “The cores will show sedimentation rates and types of material found over millions of years. Any information we can get will tell us more about climate change and sea level change – and that’s important, especially in populated areas such as the northeast United States.” Miller explains, “We’ve done 13 sites on shore, and we weren’t reaching the sensitive intervals that we needed. Reaching the correct depth is critical.” Now, he says reaching the right depth is possible with DOSECC’s expertise and equipment. “The drilling technology is absolutely critical. When they came up with the CS line, it made such a difference.” Miller says he receives samples now that are at least 30 percent better than what he received years ago from core drilling.
Every Millimeter CountsDOSECC is using a casing hanger system, where the drill rod goes through a 65⁄8-inch casing, giving the drill string stability as it reaches its depths through the water and down into the bed of the ocean. CphiD LLC of Draper, Utah, is the mastermind behind the design and construction of the platform. Through several iterations and layouts, a suitable cantilever structure was designed and built specifically for the deck space of the Kayd. Drilling for scientific purposes rather than for obtaining the standard exploration samples is picky work for the drillers. When a small portion of a sample can represent 100 years of time, a good sample is more important than anything. DOSECC operations manager Chris Delahunty notes, “We are most interested in quality and taking our time to do it right. Every millimeter matters.” For the New Jersey Shallow Shelf Expedition 313 project, the coring is done in 10-foot sections. Samples are collected in 2.44-inch butyrate plastic liners specially made for the project. The ends are topped with color-coded caps indicating the orientation of the core.
A recent project in Siberia was one of the most complicated that DOSECC has dealt with, and it earned the corporation lots of attention for its significance in core drilling. The deep drilling system for Arctic operations again was developed by DOSECC, which used an Atlas Copco CS14. On that job, the CS14 drilled from a heated platform in a frozen lake.
Delahunty explains that the team planned ahead for any parts or service by bringing everything they could possibly need with them to Siberia. Marc Clark, a technical service and training specialist with Atlas Copco’s ground engineering division, worked closely with all the people involved at DOSECC to make sure they had the right parts, no matter the scenario. This was unusual since DOSECC usually utilizes Atlas Copco service techs from the customer centers in their region. When needed, DOSECC uses its own organized maintenance program to keep its drills running. Greg Kerr, ground engineering regional manager for Atlas Copco, says, “DOSECC has been a very valuable and long-term customer of Atlas Copco. Their work takes them all over the world, and into some unusual conditions including work off floating barges and frozen lakes so they have been able to provide us with invaluable feedback on our drill rigs.”