Overview:
Burnt Head is a rugged coastal headland near Cupids, NL, featuring dramatic cliffs, sea arches, and beautifully exposed bedrock. Among the highlights of this area is a small but striking Z-fold in the layered rocks along the coast. This EarthCache invites you to observe this natural fold and learn how geologists use fold geometry to interpret past tectonic movements.
What is a Z-Fold?:
A Z-fold is a type of asymmetric fold whose limbs and hinge resemble the letter “Z” when viewed in cross-section. The Z-fold at Burnt Head is a striking example of ductile deformation (a permanent change in a rock's shape that occurs in response to stress but without breaking) and shows tight folding in fine-grained sedimentary rocks (metasediments) of the Avalon zone. This fold likely formed hundreds of millions of years ago during regional tectonic compression and metamorphism, when horizontal forces caused originally flat rock layers to bend.
Strike and Dip
Geologiests can use a variety of measurements to help interpret the geological history and stress directions that shaped the landscape here at Burnt Head. To understand the orientation of the rock layers, geologists use two key measurements:
Strike (orientation) refers to the line formed by the intersection of a horizontal plane and an inclined surface. This line is called a strike line, and the direction the line points (in either direction, since a line points in two opposite directions) is the strike angle.
Dip (steepness) is the angle between that horizontal plane and the inclined surface (such as a geological contact between tilted layers) measured perpendicular to the strike line down to the inclined surface.
A useful way to think about strike and dip is to look at the roof of a house. A house’s roof has a ridge along the top, and then sides that slope away from the ridge. The ridge is like a strike line, and the angle that the roof tilts is the dip of the roof.
How to Get There:
- Start at the Burnt Head Trailhead (behind Cupid’s Cathedral House Bed & Breakfast /Anglican Cemetery).
- Follow the marked Burnt Head Trail along the coastal path (~2.7 km loop trail)
- The Z-fold outcrop lies along the rocky shoreline near the posted coordinates.
Hints for Your Visit:
- Look for alternating light and dark beds showing a bend or curve to identify the Z-fold
- Use pacing, smartphone apps, or known-size objects to help estimate height and width of the Z-fold.
- Use the geocaching app's compass feature or other orientation tools (like a GPS) to help you determine "strike" direction.
Safety notes:
- Wear sturdy footwear and take care on uneven ground..
- Stay on marked trails and view the Z-fold from a safe distance or vantage point.
- Be extremely cautious near cliffs and the water’s edge.
- Watch children closely and keep pets on leash near cliffs.
EarthCache Tasks / Logging Requirements:
To claim this EarthCache, please answer the following questions. Send your answers to the cache owner via Message Center or email before logging your find (do not post them in your log).
- The Z-Fold: Estimate its approximate height and width in meters.
- Strike (Orientation): Estimate the strike direction (e.g., N-S, NE-SW) of one limb of the fold.
- Dip (Steepness): Estimate the dip angle (e.g. shallow, moderate, steep).
- Geological Significance: Why might this fold be considered important in Newfoundland’s geological history?
- Photo Proof: Take a photo of yourself or a personal item with the z-fold visble (maybe a foot, hand or even your HAT, it's up to you) and include this photo with your log entry.
Permissions and Stewardship:
- The Burnt Head Trail is maintained by the Cupids Trail Committee. Please respect this beautiful site - observe, learn, and leave only footprints!
References:
- Town of Cupids Trails Committee (Burnt Head Trail Information)
- Newfoundland Geological Survey — Avalon Zone structural geology mapping
- General coastal geomorphology formation resources