Tubulichnium Książkiewicz, 1977

Uchman, Alfred & Wetzel, Andreas, 2024, Sequestrichnia - an ethological category of marine trace fossils recording the collection and stowage of nutritional material within burrows, Comptes Rendus Palevol 23 (22), pp. 325-338 : 328-330

Ichnogenus Tubulichnium Książkiewicz, 1977 ( Fig. 2 )

Tubulichnium is an oblique to horizontal, unbranched, blindending tube showing some internal organization due to slight vertical shift; the margins are densely lined with ellipsoidal muddy pellets. The sequestration of material, which is then stowed in muddy laminae and pelleted fill, is documented by its composition: it contains c. 1.5% Corg and 20% CaCO 3 compared to c. 1.1% Corg and c. 26% CaCO 3 in the host sediment and 0.7% Corg and 12% CaCO 3 in the overlying mud in the studied Upper Cretaceous to Paleogene specimens ( Uchman & Wetzel 2017). These data point to selective enrichment of organic-rich particles in the burrow. Microbial activity during priming may generate CO 2 that lowers alkalinity and fosters the dissolution of carbonate ( van Nugteren et al. 2009). Although no clear spreite is developed, a partly laminated fill exhibiting local truncations ( Fig. 2B, C ) suggests utilization of the stowed material, as in the case of Zoophycos .

TUBULAR OPEN BURROW SYSTEMS

Figures

FIG. 2. — Tubulichnium Książkiewicz, 1977 in turbiditic sand (Inoceramian Beds, Campanian-Paleocene, Magura Nappe, Słopnice, Poland): A, Tubulichnium penetrating down into turbidite sandstone; typical lining with mud pellets. Depression (surrounded by a white stippled line) resulting from sediment collapse after abandonment of the tube inhabited by the producer; B, C, traverse (B) and transverse oblique (C) sections of Tubulichnium. Pelletal laminae occurring at the base of the burrow (white arrows) and also in intermediate position (yellow arrows); local truncation of pellet-rich layers indicating subsequent, perhaps multiple reworking by the producer. Scale bars: 1 cm.