What is a siltstone?
Q: What is a siltstone?
A: A siltstone is a type of mudrock that must be over 50% composed of silt-sized material.
Q: What is silt?
A: Silt is any particle smaller than sand, 1/16th of a millimeter (~0.06 mm), and larger than clay, 1/256th (~0.004 mm) of a millimeter.
Q: How is silt formed?
A: Silt is formed through physical weathering processes such as freezing and thawing, and does not involve any chemical changes in the rock.
Q: What are the biggest contributors to silt?
A: Quartz and feldspar are the biggest contributors to silt.
Q: Where is one of the highest proportions of silt found on Earth?
A: One of the highest proportions of silt found on Earth is in the Himalayas, which get rainfall of up to five to ten meters (16 to 33 feet) per year.
Q: What are the properties of silt?
A: Silt tends to be non-cohesive and non-plastic, but can liquefy easily.
Q: What is a simple field test to judge whether a rock is a siltstone or not?
A: A simple field test to judge whether a rock is a siltstone or not is to put the rock to one's teeth. If the rock feels "gritty" against one's teeth, then it is a siltstone.
