Armored mud ball

The name "pudding balls" was originally given to these structures by geologist Lon D. Cartwright Jr. in 1928. However, because the pebbles that protect them are not spread evenly throughout the clay body, but are found only on the outer surface, the name 'armored mud ball' was proposed in 1940 by geologist Hugh Stevens Bell, and has since been widely adopted. ==Formation==

, Turners Falls, Massachusetts Pre-lithification In the early 20th century, James Gardner hypothesized that these structures formed by the accumulation of fine clay particles as they flowed along a stream, gradually building up concentric rings of sediments by adhesion until their weight eventually stopped them rolling with the current. That view held sway for some 20 years, despite an earlier suggestion in 1875 by Jones and King that those mud balls found on beaches had formed from broken off fragments of clay from adjacent cliffs which had then been rolled by wave action. By 1940 it was generally accepted that their formation was due to rolling of broken off fragments of clay and not to concretion. The particles, typically sand or pebbles, form an "armor" that allows the mud ball to retain its shape during transport. This is especially important for armored mud balls that form in deep-ocean sediment flows known as turbidity currents, where fragments of mud initially eroded from submarine canyons become coated with a sand armor that allows them to travel for tens of kilometers without being destroyed. Armored mud balls formed by wave action in beach environments can sometimes carry an armor of seashell fragments instead of pebbles. Lithification Despite their name, armored mud balls are typically quite fragile and often disintegrate after drying out, making them a rare occurrence in the geologic record. However, if armored mud balls are buried quickly, there is a chance that they may become lithified along with their entombing sediment and get preserved for millions of years. The mud balls themselves are preserved as small chunks of mudstone or siltstone surrounded by a ring of pebbles. == Examples ==

Teichert & Kummel (1972) described armored mud balls from the Kap Stosch area of East Greenland. The examples from the Connecticut River Valley of Western Massachusetts are particularly notable because they are among the most well-preserved and easily accessible lithified armored mud balls in the world. ==See also==