Search

Summary The term “diamicton” has recently been proposed as a non‐genetic name for any non‐calcareous terrigenous sediment containing a wide variety of grain sizes; the lithified equivalent is a “diamictite.” The present paper deals with the origin and classification of water‐borne diamictons. The latter have been divided by the writer into three groups: Group I. Diamictons with the coarse and fine fractions deposited simultaneously. Group II. Diamictons with the coarse and fine fractions deposited separately. Group III. Diamictons with the fine fraction derived from the coarse fraction by diagenetic alteration in place. Group I diamictons have been divided into the following types: (i) P‐diamictons, in which the fine fraction was deposited from true suspension (the coarser material being transported by suspension, saltation, or traction), (ii) M—diamictons, in which the fine (and coarse) fractions were deposited from mudflows. (iii) K‐diamictons, in which the fine fractions were deposited in the form of d...

A Quaternary diamicton covering an a rea of at least 4 sq k m occurs a round and northwest of Ranau, Sabah. The deposit consists of la rge round boulders of adamel­ lite and cobbles and fragments of sed imentary rock in a muddy matrix. The largest boulder in the deposit measures approximately 20 x 10 x l 0 meters a nd is estimated to weigh DOt less than 4,700,000 kg. Absence of sorting, lack of latera l gradation in size of clasts, the great size of the boulders, and field relationships indica te tha t this is a mudf10w deposit. The mudflow probably originated in the Pinosuk Plateau where rock debris of a s imil a r composition is present. The deposit in Ranau represents the most easterly extension of the mudflow.

A drilling at Sundet on the Southern shore of Lake Siljan (Fig. 1) ended 107.5 m below the surface without reaching the bedrock. Analyses of samples taken at regular intervals have shown the presence between, 72.5 m and 74.5 m of diamicton which covers glacio-fluvial deposits containing ground-water under pressure. In a later drilling at a place located 18 m east of the former a similar diamicton was penetrated between 74 m and 76.5 m before the glacio-fluvial deposits with ground-water were reached. The above data and some additional observations at Sundet form this complementary note to the records presenting the results of the authors' preliminary researches (1970) into the river valley of the Pre-Glacial Dalalven.