Basin plain

Circumstances

Low-density gravity current deposits and suspension fallout deposits at the center of the sedimentary basin. Sediments formed in the basins where few sedimetns supplied from surrounding circumstances. Floating particles of silt size in the lake water spread out along the temperature boundary layers, and those particles deposit.

Sedimentary facies (Sediments)

Graded mudstone, Bedded mudstone (Rhythmite), Gradded pumice tuff, Diatomaceous mudstone.

Sedimentary facies (Structures)

Characteristic clear parallel foliation with several mm to several cm thick. Foliations are formed by various reasons such as annual variations of sediments and periodical changes of particle supply.

Sedimentary facies (Fossils)

Plant fossils