Logging requirements
To be able to log your find, review cache description. Then visit the EarthCache location and answer the questions. You can send your answers via the email in my profile or the Message Center. You can then log your find immediately after sending me the answers.
Questions:
1. Observe the granite at Portal Point. Describe the colors, texture and what kind of minerals you notice in the rock ?
2. Look for the signs of glacial activity (striations, polished surfaces, erratics). What features do you observe here?
3. Observe the surrounding landscape. Do you think global warming affects this area? If yes, is it a rapid change?
4. Take a photo of you (face showing is not mandatory) or your gps from the the nearby viewpoint, without revealing the answers.
The picture must include your geocaching name (written on a piece of paper, on your phone / tablet, on your t-shirt, on your body, whatever).
Portal Point has a very special place in my heart. Its the location where I set foot on the Antarticas continent for the first time.
In the 1950`s British explorers made a hut on this place to continue local survey work in this region.
In 1996 this Hut was dismantled and transported to the Falkland Islands Museum. Now on Portal Point only huts foundation on the ground remains.
Portal Point now is a perfect place to observe glaciers, floating icebergs, and the exposed rock beneath your feet. All of these elements tell you a story of this regions past and its continuous change.
Geology of Portal Point
Portal Point primarily consists of granite. Its an igneous rock that was formed deep beneath the Earth's surface millions of years ago. Granite from Portal point is part of a massive rock body: Antarctic Peninsula Batholith.
The exposure of granite at Portal Point is a rare opportunity to study the intrusive magmatic history of the Antarctic Peninsula. By observing these rocks and their glacial features, geologists can better understand the relationship between tectonic activity, glacial cycles, and climate change in this remote region.
Evidence of glacial activity
Portal Point has been shaped by glacial activity over thousands of years. As you explore, look for:
- Glacial striations – Its a parallel scratches on rock surfaces which are left by moving ice.
- Polished rock surfaces – Its a result of glaciers grinding over the granite.
- Erratics – Big boulders transported by glaciers from distant locations.
These features tell you the story of how ice has advanced and retreated, leaving behind the rugged Antarctic landscape we see today.
What is a volcanic rock?
Volcanic rocks can often be identified from afar because they have formed dark gray or brown cliffs or bluffs with traces of banding. The layering results from the succession of volcanic lava flows and periods of ash accumulation. Some volcanic rocks are hard and resistant to weathering, forming near-vertical cliffs. Later faults have titled some of these rocks. In some cases, one can observe black vertical pipes, called dykes, the leftovers of old channels that brought molten magma to the surface.
Happy Caching!