Welcome to the only Volcano in Taoyuan!
You read that right — there is a volcano in Taoyuan! Or shall I say there was a volcano in Taoyuan? You be the judge. I mean some 100,000 years ago it erupted but has since been "sleeping" . . . or has it? Is this a "temporary" sleep so this volcano can be considered to be a dormant volcano? Or is this an "eternal" sleep so this place is actually considered to be an extinct volcano?
This place bears the name Caoling Mountain (草嶺山), so I guess its volcano days are long gone, no? But still standing at 347 meters tall here in Taoyuan and being Taoyuan's only volcano is a feat in itself, especially when it comes to seeing the unique shape along with the unique rocks that can be seen and found here.
With this Earth Cache you will be brought to a unique sight where there was once a volcano but has since transformed itself into a "regular" mountain. You will take a journey into the past and see firsthand what used to be the only volcano in Taoyuan, and as you make your way up to the Posted Coordinates you will still see the remnants of volcanic activity from many, many years ago . . .
|
Geological Uniqueness of Caoling Volcano (Mountain)
Caoling Mountain stand at 347 meters high and is located here behind Cihu in Taoyuan. It is considered to be a cinder cone volcano, which as it names bears, looks like a symmetrically shaped cone. It has one vent or opening at the top from which lava erupted approximately 100,00 years ago. During this time, pyroclastic rocks, or fragments of rocks from inside the volcano, erupted out and fell back down in the form of cinders, which are pieces of brown, black, or red rock that forms from solidified lava. They are usually vitreous, or look glassy, and also have bubble-like cavities called vesicles. These pyroclastic rocks can still be seen and are located at the southern side of the mountain, where you will begin the hike (see Waypoint 01.) Below is a diagram illustrating the basics of a cinder cone volcano:
In addition to having cinders present, Caoling Mountain is also composed of a special kind of basalt known as alkali basalt, with a subcategory of basalt known as as absarokite.
First, basalt in general is a type of extrusive igneous rock, which means it forms after lava leaves the volcano and cools very quickly, thus resulting in basalt. It is usually gray or gray-ish black in color but will turn brown when weathered. The basalt here at Caoling Mountain is unique in that it contains alkali — potassium oxide and sodium oxide, which means it can give rise to alkaline minerals. One las thing of interest is that these alkali basalt rocks have a porphyritic texture to them, meaning you can feel and see two distinct sizes of minerals on the rock — one or more minerals are consistently larger than the rest of the minerals on the rock.
Absarokite is unique in that it has a high content of alkaline metals such as barium and strontium. Also, there are absarokite rocks here at Caoling mountain that contain phlogopite and lherzolite — two ingneous rocks. Phlogopite takes on a more yellow, greenish, or reddish-brown color and lherzolite mostly takes on a green color. Below you can see examples of these kinds of rocks that can be found here at Caoling Mountain:
 |
Logging Requirements:
Caoling Mountain is a forgotten geological gem of Taoyuan. Even though geologists may not agree on exactly how much time should pass to classify a volcano as being dormant or extinct, this mountain — Caoling Mountain —, when compared to the geological time line of the Earth, has erupted more "recently", 100,000 years ago to be exact, and isn't necessarily "extinct", right? What do you think? Is it sleeping or has its volcanic activity days since long been gone? Let us go on a journey to the top of this cinder volcano and find out for ourselves the secrets behind Caoling Mountain!
In order to log a Found It! for this Earth Cache, please go to the Posted Coordinates to complete the following tasks:
1. As you begin your 15-minute hike from Waypoint 1 to the Posted Coordinates, pay attention to cinders near the trailhead. Based on what you have learned about the appearance of cinders, what is odd, or rather what stands out, about the cinders here? How did you come to your conclusion?
2. As you continue your way up to the Posted Coordinate, pay attention to the ascent. Based on what you have learned about cinder cone volcanoes, what defining characteristic of this ascent tells you that Caoling Mountain is in fact a cinder cone volcano? How did you come to your conclusion?
3. As you make your way to the peak, which is right near the point of eruption 100,000 years ago, that final stretch will level out. Estimate the size of the radius of the vent for this cinder cone volcano. What does its size tell you about how powerful of a volcano this was back then? How did you come to your conclusion?
4. Find two rocks here at the Posted Coordinates that appear different in color — one light one and one dark one. Feel them and examine them more closely. Based on what you have learned about alkali basalt and absarokite, would you say that these rocks resemble either of these two kinds of rocks? Why or why not? Also, could you identify any presence of phlogopite and/or lherzolite in those samples? Why or why not? How did you come to your conclusions?
5.Based on all your observations and on-site tasks here at Caoling Mountain, and based on what you have learned about this unique place, would you classify this mountain as being a dormant volcano or an extinct volcano? How did you come to your conclusion?
You may log a Found It! on this cache after you have completed the tasks and emailed me the answers. If there are any issues with your answers, I will contact you. And as a friendly reminder, please do not post any of the answers in your logs. Thank you for visiting this Earth Cache. I hope you enjoy your time here at the only volcano in Taoyuan — Caoling Mountain!