Where is Ferruginous Sandstone with Iron Oxide Concretions found?
Ferruginous Sandstone with Iron Oxide Concretions
Got a photo? Identify rocks instantly with the Rockby app
Open the appFerruginous Sandstone with Iron Oxide Concretions occurs in specific geological environments. Knowing where to look, and in what kind of rock, is the difference between going home empty-handed and finding a great specimen.
Where to find Ferruginous Sandstone with Iron Oxide Concretions
Colorado Plateau, USA
Extensive occurrences in Jurassic and Cretaceous sandstones (e.g., Navajo Sandstone, Entrada Sandstone) where iron oxide concretions, including 'Moqui Marbles' (hematite concretions), are abundant.
Midwestern United States
Various Paleozoic and Mesozoic sedimentary formations contain iron-rich sandstones and concretions, often associated with coal-bearing sequences or ancient river systems.
Western Australia
Significant occurrences in Proterozoic and Phanerozoic sedimentary basins, often associated with lateritic weathering profiles and iron ore deposits.
United Kingdom
Jurassic and Cretaceous sandstones, particularly in areas like Yorkshire and the Isle of Wight, exhibit ironstone concretions and ferruginous sandstones.
Brazil
Various sedimentary basins, particularly those with lateritic soils and ancient fluvial systems, contain iron-rich sandstones and concretions.
Collecting tips
- Look for Reddish-Brown Outcrops. Ferruginous sandstones often stand out due to their distinctive reddish-brown to dark brown coloration, which can be quite striking in arid environments.
- Examine Weathered Surfaces. Concretions are often more resistant to weathering than the surrounding sandstone matrix, causing them to protrude from weathered rock faces or accumulate as lag deposits on slopes.
- Check for Spherical or Ovoid Shapes. The characteristic shapes of concretions are a key identifier. Look for rounded or irregularly shaped nodules within the sandstone.
- Test Hardness. Concretions are typically harder than the surrounding sandstone due to the dense iron oxide cement. A steel knife or geological hammer can be used to test this difference.
- Observe Sedimentary Structures. Look for cross-bedding, ripple marks, or other sedimentary structures within the sandstone, which can provide clues about the depositional environment.
Quick Check
- Color:
- Reddish-brown to dark brown/black
- Luster:
- Dull to earthy (sandstone), dull to sub-metallic (concretions)
- Streak:
- Reddish-brown (hematite) or yellowish-brown (goethite/limonite)
Explore Ferruginous Sandstone with Iron Oxide Concretions
Identify rocks anywhere
Free on iOS, Android, and Web. Photo identification, full database, and your personal collection.