Packstone
Under the Dunham classification (Dunham, 1962) system of limestones, a packstone is defined as a grain-supported carbonate rock that contains 1% or more mud-grade fraction. This definition has been clarified by Lokier and Al Junaibi (2016) as a carbonate-dominated lithology containing carbonate mud (<63 μm) in a fabric supported by a sand grade (63 μm to 2 mm) grain-size fraction and where less than 10% of the volume consists of grains >2 mm.
01The identification of packstone
A study of the adoption and use of carbonate classification systems by Lokier and Al Junaibi (2016) identified three common problems encountered when describing a packstone:
- Failure to identify the fabric as supported by the sand grade grain-size fraction - resulting in misidentification as wackestone.
- Packstones with very small volumes of carbonate mud may be misclassified as grainstone.
- Incorrectly estimating the volume of the component grains >2 mm.
Sources and credits
This article is adapted from the Wikipedia article “Packstone”, written by its contributors and licensed under CC BY-SA 4.0. Fathomly has changed the layout, removed citation markers, navigation and maintenance notices, and adjusted punctuation. This adapted version is shared under the same license. For references, see the original article.
Images, from Wikimedia Commons:
- DunhamPackstone.jpg by NikelsenH, CC BY-SA 4.0
- 4 x2 PPL.jpg by Peneropolid, CC BY-SA 4.0
Fathomly is not affiliated with or endorsed by the Wikimedia Foundation. Spotted a problem? Tell us.