Mapping the natural gas pipeline in New Brunswick

Sandra Barr

During the summer of 2000, I was able to take advantage of a unique geological opportunity. Beginning in late June, a lateral gas pipeline was constructed across southern New Brunswick to connect the existing pipeline southwest of Fredericton to the city of Saint John, a cross-country distance of approximately 90 km. The pipelines are being built to distribute Sable Island natural gas through Nova Scotia and New Brunswick and into New England.

I have been doing geological studies in that part of southern New Brunswick for several years, with interesting and unexpected results, such as the recognition of previously unknown belts of volcanic rocks and high-pressure metamorphic rocks representing converging continents and subsequent continent collisions between 620 and 400 million years ago. However, an impediment to my work in the area is the heavily forested and swampy terrain in which rocks outcrops are very scattered. Furthermore, access is surprisingly difficult (given that this area can hardly be termed "remote") due to scarcity of roads or trails. Luckily for me, the lateral pipeline route goes right across the bands of rocks on which I am working, and the pipeline trench, in the short time that it was open, provided a unique opportunity to examine and sample fresh rock exposures in normally hard-to-access areas.

I contacted Maritimes and Northeast Pipeline and they were very co-operative in allowing me to work along the pipeline route. First, I had to take a safety course provided by the company and invest in some equipment (such as a cellular phone, to which I am opposed in principle - after all, who wants or needs to get a phone call when in the middle of concentrating on figuring out where one is or on what kind of rock one is looking at? - but in some cases, you have to let your principles slide a bit). After that I was given free access to the pipeline route, as long as I did not get in the way of heavy equipment - and I had no intention of doing that! On my first visit in late June, nothing was visible but a very roughly cleared line. By mid-July, access roads were drivable, and a swath of trees about 25 m wide had been cut along the "right-of-way". By late July, a very rough ATV trail had been constructed along the right-of-way, and blasting was underway. To my amazement, on my next visit in mid-August, a two-metre deep trench had been dug and blasted along the entire right-of-way, and a good roadway had been built. I was able to drive my Explorer all along the route, even over major rivers on temporary bridges. Rocks were piled beside the trench for me to examine and sample (see photo). Now that is the way to do geology! Exposure was not complete because in some areas the till was too thick and the trench did not reach bedrock. Nevertheless, the section gave me lots of new insights and exposed critical contact zones.

But in some ways, my most amazing visit was my last one, in late October, when I went back to find it all finished - the trench filled in, the cleared right-of-way grassed over, and the roadways and bridges gone. I was impressed by this admirable example of environmental reclamation, and was glad that I had been able to see the rocks in the short time that the opportunity existed.