dsc08813 (2)

TABLE 17.1 Sunmumted Charactcrlstlcs, Ichnotaxonomic Composition and Environmental Implicaliumt of Archetypal Continental Ichnofacies. The Sholiilws

Ichnofacies may Occur in High Energy Continental Deposits

Ki

9

X

Ichnofacies C-Tn^isrfefcra

Characteristics

Dominant nesting structures and subordinate feeding structures. Misture ot uwertebrate, vertcbrale, and plant structures. Nests of coprophagan scarabs, nests and cells of bees, wasp nesls, ant nests, coprolites, meniscate burrows, vertebrale footprinls and root structures. Termite nests are rare. Mammalian burrows, commonly produced by rodents, constitute one of the most common vertebrate structures. Associalions show moderale to relatively high ichnodiversity and high abundancc, particularly in maturę paleosoils. The complex tiering slructure records the varying depths of the different groups of producer inseets.

Composition

Copriniapliaera, Monesicliiius, Fontami, Teisseirci, Celliforma, Uruguay, Palmiraichnus, llllipsoidciclinus, Rosellichnus, Cluibntolillies, Attaiclunis, Pnmwniiiclinus, Synterme&khnus, Tacnruiclitiiis

Smyrna

Mermm

Meniscate feeding structures, locomotion structures (bołh track-ways and continuous trails) and cylindrical to irregular vertical burrows. Mixture of invertebrate, vertebrate, and plant Iraces. Invertebrates are mainly detritus-feeders, deposit-feeders or predators. Vertebrałes are predators or herbivorous. Verlebrates traces in this ichnofacies invo!ve mainly bird and mammalian fcracks. Ichnodiversity of structures resulting from inverlebrates is generally Iow though same traces may be abundant. Verlebrale footprints may be diverse and abundant around water bodies. Likewise, some Paleozoic associalions show a high diversity of arthropods traekways.

Predominant hori/ontal to subhorizontal gra/.ing and feeding traces caused by mobile detritus-feeders. Subordinate occurrence of locomotion traces. Generally high to moderate ichnodlversity. Poorly spedalized gra/ing patterns show very rudimentary feeding strategie* and include trails displaying overcrossing, stmpfe meandering trails, and sinusoidal, curved and straight trails. Feeding structures show zig-zag, cirtular geometries or form system3 with morę varying morphologies. Pish trails may albe pres*T»t. Although ichnodiversity may be high, it results from minor v»i*tton* within a few generał and basie behavioral patterns. Sutiacz trails are preclom i nai.it in Paleozoic assoclatlons but tłw Mtnnta    i»-** shows Abundant ini.mri.il orgjiiiisin

«tru)łui<>* tłu ring tłw Maeezetc.

Scoycnin, Taciiicliuiii, Ikaconites, Diplichnitcs, Utnfulozia, Mirandaictmum, Diplopodicliuus, Cruzianu, liusophycus,

Merniin, Gorilia, Flelminthopsis, Cochlicltnus, Hclminthoidichnites, Trepticltnus, Circulichnis, Vagorichnus

Implications

Paleosoils related to ecosystems of herbaceuus communities, varying from dry and cold (i.e. steppes) to humid and warm weather con-ditions (i.e., subtropical saeannas). Dominance of hymenopteran traces sug-gests inereased drynrss, and the presence of termite nests is indicative of higher humid-i ty conditions. łt is present in paleosols formed in different sudimentary cnviron-menls induding alluvial plains, desiccated floodplains, abandoned fltivi.il bars, cre-vasse splays, levees and vegctated eolian deposits, which reflects insect capacity to colonize different substrates.

Sandy to argillaceous sediments of Continental origin deposiłed in Iow energy areas. They include both slightly submerged sediments which are periodically emerged and sub-aerial sediments which are periodically submerged. Intermediate Continental envir-onments betwcen acjuatic and non-aquatic. Typical fluvial-lacustrine transitions. Typical eiwironments include floodplains, ponds, lakę margins, cphemor.il lakes and luimid interdunes.

Permanent subaqueous conditions. Well-oxygenated unconsolidated fine-grained lacustrine substrates of Iow energy. Sedimentation ratę is usually Iow. I inwever, these environments may be periodically affected by turbidity or underflow currenls. Although archetypal associalions to distin-guish shalluw and deep lakes seem ditticull to recognize, local bafhymetric zona (fan can be delecletf.

. IW ERTEBRATE ICHNOLOGY OF CONTINENTAL FRESHWATER ENYIRONMENTS

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