Geological Trail Intro Part 2
in Idaho
Green Creek Complex The Green Creek Complex is an assemblage of metamorphic rocks consisting of granite, granitic gneiss (metamorphosed granite), schist and a few other rock types. Radiometric analysis indicates that the Green Creek granite may be as old as 2.5 billion years (Archean) and is considered to be some of the oldest rock exposed on the continent west of the Mississippi River. This granite has a porphyritic texture, meaning it is composed of crystals of two distinct sizes.The larger crystals are potassium feldspar.
They are embedded in a matrix of smaller crystals consisting of quartz, biotite, and plagioclase feldspar. Feldspars are the most common family of silicate minerals. They are broadly divided into two groups: sodium and calcium bearing feldspars, called plagioclase, and potassium bearing feldspars, called orthoclase, microcline or sanidine, depending on their crystallographic structure.
- States
- Idaho
- Trail type
- National Reserve trail
- Centroid nearest city
- Salt Lake City, UT · 131 mi · ~3.8 hr drive
- Centroid coords
- 42.0892°, -113.6866°
About City Of Rocks National Reserve
This trail is inside City Of Rocks National Reserve, a national reserve managed by the U.S. National Park Service. Conditions, road status, trail closures, and reservation requirements are published on the park's NPS page — check it before driving in, especially in winter or during major weather events.
Official NPS trail page: https://www.nps.gov/places/geological-trail-intro-2.htm
Park homepage: https://www.nps.gov/ciro/index.htm
Plan your hike
Maps + permits: long-distance trails like this often require permits for through-hiking, backcountry camping, or specific sections (especially in National Parks). Check with the maintaining organisation listed above and the relevant land manager before booking travel.
Water + supplies: water sources vary seasonally on most U.S. trails. Carry a filter and consult current trail-condition reports — through-hiker journals (PCT-L, AT Reddit, etc.) and the maintaining organisation publish regular updates.
When to go: hiking seasons vary widely with elevation, latitude, and snowpack. Through-hikers traditionally start the AT in March-April (Springer northbound) and the PCT in late April (Campo northbound). High-elevation western trails (CDT, JMT, Wonderland) generally aren't passable until July.
If you've hiked Geological Trail Intro Part 2 and have current notes (water sources, trail closures, permit changes), tell us at /contact — we update pages as we learn.
Other trails within 50 miles
Geological Interpretive Trail - 1 mile
0 miles from this trail's centroid
Stripe Rock Loop - 3.5 miles
0 miles from this trail's centroid
Geological Trail Intro Part 1
0 miles from this trail's centroid
Geological Trail Intro Part 3
0 miles from this trail's centroid
Creekside Towers Trail - 1.2 miles
2 miles from this trail's centroid
City of Rocks Loop - 6.8 miles
2 miles from this trail's centroid
Sources
Trail data on this page is compiled from OpenStreetMap contributors (ODbL), the maintaining organisation's public-facing materials, and Wikipedia (CC BY-SA where excerpts are quoted). Distance, terminus, and descriptive text for nationally-designated trails are hand-curated from federal land-manager websites and trail-association sources. We do not modify the underlying data; this page presents what is already publicly recorded. To suggest corrections, see our methodology page.