Trace fossils and depositional sequences in a clastic shelf setting, Upper Cretaceous of Utah

1990 ◽  
Vol 64 (5) ◽  
pp. 803-820 ◽  
Author(s):  
Robert W. Frey ◽  
James D. Howard
Keyword(s):  
Upper Cretaceous ◽  
Trace Fossils ◽  
Trace Fossil ◽  
Depositional Sequences ◽  
Mancos Shale ◽  
Fossil Assemblages

In Coal Creek Canyon, Utah, the Spring Canyon Member of the Blackhawk Formation is divisible into four regressive hemicycles of deposition, each representing the downdip part of a nearshore-to-offshore sequence. The first and fourth hemicycles are best developed. Individual bedding units span middle-shoreface to lower-offshore lithofacies, the latter corresponding to a thin intertongue of Mancos Shale.Trace fossil assemblages include ~22 ichnospecies and 17 ichnogenera: Ancorichnus, Aulichnites, Chondrites, Cylindrichnus, Ophiomorpha, Palaeophycus, Phoebichnus, Planolites, Rosselia, Schaubcylindrichnus, Scolicia, Skolithos, Taenidium, Teichichnus, Terebellina, Thalassinoides, and Uchirites. Diversity and abundance of ichnospecies are greater in nearshore than in offshore lithofacies. Distal deposits are typified by obscure bioturbate textures: Cylindrichnus concentricus, Palaeophycus heberti, and Rosselia socialis are prevalent through the remainder of the lithofacies suite. Ophiomorpha irregulaire and Schaubcylindrichnus coronus are most common in middle-shoreface beds and Chondrites ichnosp. in upper-offshore beds; Ophiomorpha nodosa and O. annulata also are common in this part of the sequence.

New ichnofabrics of the Cenomanian–Danian Chalk Group

2020 ◽  
Vol 90 (7) ◽  
pp. 701-712
Author(s):  
Kasper H. Blinkenberg ◽  
Bodil W. Lauridsen ◽  
Dirk Knaust ◽  
Lars Stemmerik
Keyword(s):  
Trace Fossils ◽  
Trace Fossil ◽  
Shelf Area ◽  
Fine Grained ◽  
Fossil Assemblages ◽  
Facies Types ◽  
Body Fossil ◽  
Substrate Hardness ◽  
Nw Europe ◽  
Different Levels

ABSTRACT The Cenomanian–Danian Chalk Group of NW Europe is characterized by distinct trace-fossil assemblages dominated by Thalassinoides isp., Planolites isp., Zoophycos isp., and Chondrites isp., whereas ichnogenera such as Taenidium and Phycosiphon are rare. The trace fossils form a complex tiering arrangement, which reflects burrowing activities of diverse benthic associations that operate at different levels in the sediment column, dynamic sedimentation rates, and changes in substrate hardness during progressive burial, forming intricate ichnofabrics. In the Danish Basin, studies of chalk ichnofabrics have focused mainly on the Maastrichtian. Studies of the shallower, grain-rich Danian chalk have revealed similar trace-fossil assemblages, whereas the ichnology of the fine-grained, deeper-water Danian deposits is poorly known. Based on detailed facies and ichnofabric analysis of a mid-Danian silica-rich, pelagic chalk located in the central, deeper shelf area of the Danish Basin, four facies types, eight ichnotaxa, and two ichnofabrics are recognized. Most conspicuous and abundant are randomly distributed, variously sized meniscate burrows attributed to Bichordites isp. and Taenidium isp., whereas other common chalk trace fossils are rare or absent. This trace-fossil assemblage outlines two new ichnofabrics in the NW European chalk, which are dominated principally by upper-tier traces. The producer of the abundant Bichordites isp. and Taenidium isp. burrows is identified as a sea urchin on the basis of an exceptionally preserved Bichordites isp. trace aligned with an irregular echinoid body fossil. The identified ichnofabrics controlled early silicification and produced a more complex distribution of silica concretions compared with chalk successions elsewhere. This results in volumetrically thick silica concretion-rich units rather than distinctive silica bands as seen in other Upper Cretaceous and Danian chalk units.

Characteristic trace fossils in nearshore to offshore sequences, Upper Cretaceous of east-central Utah

1984 ◽  
Vol 21 (2) ◽  
pp. 200-219 ◽  
Author(s):  
James D. Howard ◽  
Robert W. Frey
Keyword(s):  
North America ◽  
Upper Cretaceous ◽  
Trace Fossils ◽  
Trace Fossil ◽  
Interior Region ◽  
Fossil Species ◽  
East Central ◽  
Book Cliffs ◽  
Marine Facies ◽  
Wasatch Plateau

More than 20 trace fossil species occur in marine facies of the Cretaceous Star Point and Blackhawk formations in the Book Cliffs and Wasatch Plateau provinces of Utah. Major genera include Ancorichnus, Arenicolites, Aulichnites, Chondrites, Conichnus, Cylindrichnus, Medousichnus, Ophiomorpha, Palaeophycus, Planolites, Rosselia, Schaubcylindrichnus, Scolicia, Skolithos, Teichichnus, Teredolites, and Thalassinoides. Newly named taxa include Ancorichnus capronus, Medousichnus loculatus, and Rosselia chonoides.Most trace fossils occur in characteristic, albeit intergradational ichnofacies correlative with major lithofacies of regressive nearshore to offshore sequences. The latter include foreshore, foreshore–shoreface transition, shoreface, and offshore facies. Landward facies are typified by clean, well sorted, well stratified, sparsely burrowed sandstones. Seaward facies, except where interrupted by hummocky bedded sandstones, exhibit successively less pure, less well sorted and stratified, more intensely bioturbated, finer grained sandstones, siltstones, and mudstones.Characteristic ichnofacies and lithofacies in the Cretaceous of east-central Utah should provide potentially useful models for reconstruction of nearshore to offshore sequences elsewhere, especially in the Western Interior Region of North America.

scholarly journals Paleoecologic and Biostratigraphic Significance of Trace Fossils From Shallow- to Marginal-Marine Environments From the Middle Cambrian (Stage 5) of Jordan

2012 ◽  
Vol 86 (6) ◽  
pp. 931-955 ◽  
Author(s):  
Richard Hofmann ◽  
M. Gabriela Mángano ◽  
Olaf Elicki ◽  
Rafie Shinaq
Keyword(s):  
Trace Fossils ◽  
Trace Fossil ◽  
Type Locality ◽  
Early Cambrian ◽  
Marine Environments ◽  
Middle Cambrian ◽  
Fossil Assemblages ◽  
Maximum Flooding Surface

The Hanneh Member (Cambrian Stage 5) of the Burj Formation and the Umm Ishrin Formation of Jordan represent a transgressive-regressive succession that contains twenty-eight ichnotaxa, including vertical burrows (Arenicolitesisp.,Diplocraterionisp.,Gyrolithes polonicus,Rosseliaisp.,Skolithos linearis, escape trace fossils), horizontal simple burrows and trails (Archaeonassa fossulata,Gordia marina,Helminthoidichnites tenuis,Palaeophycus tubularis,Planolites beverleyensis,P. montanus), plug-shaped burrows (Bergaueria sucta), horizontal branched burrows (Asterosomaisp.,Phycodesisp.,Treptichnuscf.T. pedum), bilobate structures (various ichnospecies ofCruzianaandRusophycus), and trackways and scratch marks (Diplichnitesisp.,Dimorphichnuscf.D. obliquus,Monomorphichnusisp.). Eleven trace-fossil assemblages are identified. TheArenicolitesisp. andDiplocraterionisp. assemblages occur in transgressive tidal dunes and bars whereas theRosseliaisp. assemblage characterizes areas between tidal dunes. TheCruziana salomonisassemblage reflects a wide variety of environmental settings including channels within tidal-bar complexes, bottomsets of tidal dunes, and interdune areas. TheGordia marinaassemblage is present between dune patches. TheGyrolithes polonicusassemblage penetrates into firmground mudstone below the maximum flooding surface. TheBergaueria sucta,Archaeonassa fossulata,Rusophycus aegypticusandCruziana problematicaassemblages occur in different subenvironments of the progradational delta.Cruziana salomonisandRusophycus burjensis, originally considered indicative of an early Cambrian age, are actually middle Cambrian in their type locality. Occurrences ofCruziana jordanicaandRusophycus aegypticusprovide evidence that these ichnospecies are of the same age in Jordan and may co-exist in terms of stratigraphic distribution withC. salomonisandR. burjensis.

scholarly journals Characteristic trace fossils from Miocene brackish-water deposits in the Niger Delta, Nigeria

Geologos ◽  
2018 ◽  
Vol 24 (2) ◽  
pp. 111-125 ◽  
Author(s):  
Sunny C. Ezeh ◽  
Wilfred A. Mode ◽  
Berti M. Ozumba
Keyword(s):  
Environmental Conditions ◽  
Brackish Water ◽  
Niger Delta ◽  
Trace Fossils ◽  
Trace Fossil ◽  
Fossil Assemblages

Abstract Miocene deposits in the eastern portion of the Greater Ughelli, Central Swamp and Coastal Swamp depobelts contain well-developed brackish-water trace fossil assemblages. Twelve ichnogenera have been identified, namely: Asterosoma, Bergaueria, Chondrites, Gyrolithes, Thalassinoides, Lockeia, Palaeophycus, ?Conichnus, Planolites, Siphonichnus, Skolithos and Diplocraterion. In addition, common non-descript, passively filled burrows and fugichnia (escape structures) have also been observed. The above-mentioned ichnogenera and associated non-descript structures can be arranged into six distinct and recurring ichnoassociations within the Greater Ughelli, Central Swamp and Coastal Swamp depobelts. Each ichnoassociation is comprised of a group of trace fossils which collectively reflect specific environmental conditions during deposition of these Miocene strata. All trace fossil assemblages illustrate deposition in nearshore, restricted settings. Ichnological and sedimentological criteria which may be utilized to recognise brackish-water deposits are discussed and illustrated in pictures of the cores studied.

Trace fossil assemblages reflecting stressed environments in the Middle Jurassic Carmel Seaway of central Utah

1999 ◽  
Vol 73 (4) ◽  
pp. 711-720 ◽  
Author(s):  
J. M. De Gibert ◽  
A. A. Ekdale
Keyword(s):  
Benthic Community ◽  
Middle Jurassic ◽  
Trace Fossils ◽  
Trace Fossil ◽  
Pore Waters ◽  
Shallow Marine ◽  
Marine Carbonate ◽  
Marine Carbonates ◽  
Low Diversity ◽  
Fossil Assemblages

The shallow-marine Carmel Formation (Middle Jurassic) in central Utah hosts low-diversity trace fossil assemblages, including Arenicolites, Chondrites, Gyrochorte, Lockeia, Planolites, Protovirgularia, Rosselia, Scalarituba, Skolithos, Taenidium, and Teichichnus. Non specialized ichnotaxa with a remarkably small burrow size dominate the assemblages. The amount of bioturbation is lower than expected in comparison with modern shallow-marine carbonate environments. These ichnological features also are significantly different from those of other Jurassic shallow-marine carbonates. The trace fossils represent an environmentally stressed benthic community in a marginal marine, restricted setting, with salinities above normal marine and with depletion of oxygen in pore waters.

scholarly journals Deep-Sea Trace Fossils In The West Crocker Formation, Sabah (Malaysia), And Their Palaeoenvironmental Significance

2021 ◽  
Vol 71 ◽  
pp. 23-46
Author(s):  
Mazlan Madon ◽  
Keyword(s):  
Trace Fossils ◽  
Trace Fossil ◽  
Channel Axis ◽  
The West ◽  
Submarine Fan ◽  
Fine Grained ◽  
Sedimentary Environments ◽  
Fossil Assemblages ◽  
Ophiomorpha Rudis ◽  
Mudstone Facies

In the “flysch” series of the West Crocker Formation (Eocene–Oligocene), Kota Kinabalu, Sabah, trace fossils are fairly common although not ubiquitous. The trace fossils commonly occur as hypichnial semi- or full-reliefs on the sole of thin turbiditic sandstone beds (mainly Bouma Tc division) in the thinly bedded heterolithic sandstone-mudstone facies interpreted as submarine fan lobe deposits. Their presence in mainly the thinly bedded facies of the fan system suggests preferential production and preservation in the fine-grained “distal” parts of the Crocker submarine fan system. Trace fossil assemblages characteristic of the Nereites ichnofacies indicate sedimentary environments mainly in bathyal to abyssal water depths (>2000 m). This ichnofacies is dominated by horizontal grazing, farming and feeding traces, ranging from solitary to branching tubular burrows (Ophiomorpha, Palaeophycus and Planolites) to meandering trails and tunnels (Nereites, Cosmorhaphe, Helminthopsis), as well as the spiriform burrows Spirophycus. Graphoglyptids are the most diagnostic of the Nereites ichnofacies, produced by sediment grazers and farmers (agrichnia) and often displaying intricate networks of mainly horizontal tunnels preserved as hypichnial semi-reliefs. They include the delicate spiral traces of Spirorhaphe, as well as the enigmatic hexagonal network burrow Paleodictyon. Other ichnogenera include Planolites, Thalassinoides and Ophiomorpha which are facies-crossing and not environment specific. Detailed observations of the trace fossil assemblages and the degree of bioturbation enabled different sub-ichnofacies of the Nereites ichnofacies to be distinguished. Ophiomorpha is more common in sandy “proximal” facies and tend to penetrate deeply into pre-existing turbidite beds, its presence suggests a well-oxygenated newly deposited turbidite substrate, probably in the axial region of the fan lobes. Hence, channel axis and proximal fan deposits tend to be dominated by the Ophiomorpha rudis sub-ichnofacies. The Paleodictyon sub-ichnofacies is more typical of the lower energy lobe/fan fringe subenvironments. Proximal but off-axis areas are characterized by a mixture of the Ophiomorpha rudis and Paleodictyon sub-ichnofacies.

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