Miners’ Loop Tour
Discover the theory of the Earth
A popular self-guided tour, the Miners’ Loop is a combined walking/driving tour to four amazing geological sites around Marmora & Lake! Each site provides information about the mining and geological history in the area.
Each site is now equipped with an interactive QR code, which can be scanned using a smart device to watch a short educational video produced by local award-winning filmmakers Laura Forth and James A. Smith.
Scan the QR codes for more information about each site!
Site #1: Millside Park
Sedimentation: Tiny particles of calcium carbonate accumulated at the bottom of an ancient sea. Under its own weight and moderate subterranean heat, the limy mud eventually turned into limestone. Weathering and erosion caused the limestone beds to decay. Water then carried the detritus away.
How much time did this “rock cycle” take? Pioneering geologist James Hutton tried to answer this important question in 1795.
Site #2: Hastings Trail
(Walking Section)
Multiple Rock Cycles: 2 km north of Station Road. Horizontal limestone beds lie on top of vertically inclined crystalline limestone beds (marbles). This geological feature is called an angular unconformity. Two complete cycles of “decay and restoration of the land upon the globe” have occurred here.
How much more time did these geological processes take than that of Site #1? Pioneering geologist James Hutton answered this question in 1795: “We find no vestige of a beginning, no prospect of an end.”
Subterranean Heat: Rising molten granite intruded sedimentary rocks with finger-like structures called “dykes and sills.” Hot aqueous fluids circulated through delaminated rocks and deposited gold along with arsenopyrite in structurally controlled quartz veins.
Geologist James Hutton correctly reasoned, in 1795, that intruding granites such as these must be younger than the sediments and were molten at the time of intrusion. The granites are also recycled rocks.
Site #3: Deloro Mine Site
Contact Alteration: Rising molten gabbro intruded marbles here. A chemical reaction took place at the contact between the marbles and the gabbro, producing a very large deposit of iron ore called magnetite. This important economic mineral deposit was buried under hundreds of feet of limestone and went undetected until the early 1950s when New York-based mining company Bethlehem Steel purchased 1,900 acres of land and began the process of removing more than 120 feet of limestone to uncover the rich iron ore underneath. The site would be mined for more than 20 years creating a huge open pit more than half a mile long and 700 feet deep.
