scholarly journals Sedimentology and ichnology of the mid-Cretaceous succession of Ouled Nail Mounts (Eastern Saharan Atlas, Algeria)

2021 ◽  
Vol 74 (3) ◽  
pp. 209-223
Author(s):  
Mohammed Nadir Naimi ◽  
◽  
Amine Cherif ◽  
Keyword(s):  
Trace Fossils ◽  
Decapod Crustaceans ◽  
Shallow Marine ◽  
Marine Deposits ◽  
Northern Algeria ◽  
Continental Intercalaire ◽  
Lowermost Part ◽  
Maximum Flooding Surface ◽  
Glossifungites Ichnofacies

Shallow marine deposits characterize the upper Albian – lower Cenomanian deposits of Northern Algeria. In Djebel Azzeddine (Ouled Nail Mounts), the corresponding sediments have been subdivided into three distinctive units A to C. The first discovered ammonite fauna from the Bou Saada area allowed the attribution of a part of the mid-Cretaceous post-Continental Intercalaire deposits to the upper Albian. The ammonite-bearing level indicates a maximum flooding surface and could be correlated with similar levels from Northern Algeria. The studied succession is characterized by a low ichnodiversity containing eight ichnotaxa with abundant Thalassinoides, common Skolithos, and rare Gyrolithes, Oichnus, Planolites and cf. Tisoa. This ichnoassemblage is dominated by domichnion, fodinichnion and praedichnion trace fossils, and is attributed to the Skolithos and Glossifungites ichnofacies. These traces are produced mainly by decapod crustaceans, polychaetes and naticid gastropods. The sedimentological and ichnological data suggest shoreface to backshore environments with mixed tide/storm energy, and long subaerial exposures indicated by Lofer cyclothems in the lowermost part and dinosaur footprints in the upper part of the section.

Storm-dominated shallow marine deposits: the Fernie–Kootenay (Jurassic) transition, southern Rocky Mountains

1979 ◽  
Vol 16 (9) ◽  
pp. 1673-1690 ◽  
Author(s):  
Anthony P. Hamblin ◽  
Roger G. Walker
Keyword(s):  
Rocky Mountains ◽  
Tidal Current ◽  
Density Current ◽  
Sedimentary Structure ◽  
Fair Weather ◽  
Shallow Marine ◽  
Southern Rocky Mountains ◽  
Marine Deposits ◽  
Storm Waves ◽  
Lowermost Part

The transition from the Passage Beds of the Fernie into the lowermost part of the Kootenay Formation is exposed in 11 sections in the Crowsnest Pass to Banff area. Six distinct facies can be defined. Facies A (thin bedded turbidites) and facies B (thicker bedded turbidites) both have sole marks indicating north-northwestward flow. Facies C is the most important and consists of interbedded sandstones and shales, with sole marks indicating north-northwestward flow, and "hummocky cross stratification" as the characteristic internal sedimentary structure. It is interpreted to be formed by storm waves in depths below fair-weather wave base. Facies D contains low angle intersecting sets of parallel lamination (beach) and facies E is characterized by trough cross bedding (fluvial). Facies F consists of lenticular sandstones and shales, with coals. The facies occur in the sequence listed and indicate a northward prograding beach complex. Following intense storms, water driven toward the beach surges back seaward, entraining sand and developing into a density current. If deposition from the density current takes place in depths stirred by the storm waves, hummocky cross stratification is formed. In slightly deeper, quieter water the density current deposits a classical turbidite. Thus, the eastward-prograding Kootenay "delta" of previous interpretations now appears to be a northward-prograding beach complex fed by rivers, but with sand transported alongshore by waves. There is no evidence of tidal current activity, and shallow marine deposition is dominated by storms.

scholarly journals Darriwilian shallow-marine deposits from the Sultanate of Oman, a poorly known portion of the Arabian margin of Gondwana

2016 ◽  
Vol 155 (1) ◽  
pp. 59-84 ◽  
Author(s):  
A. P. HEWARD ◽  
G. A. BOOTH ◽  
R. A. FORTEY ◽  
C. G. MILLER ◽  
I. J. SANSOM
Keyword(s):  
Ice Sheets ◽  
Trace Fossils ◽  
Sultanate Of Oman ◽  
Polar Ice ◽  
Sea Levels ◽  
Shallow Marine ◽  
Middle Ordovician ◽  
Marine Deposits ◽  
Polar Ice Sheets ◽  
Made In

AbstractThe Amdeh Formation is a 3.4 km stack of sparsely fossiliferous quartzites and shales which crops out in the Al Hajar mountains near Muscat. Here we describe the uppermost member (Am5) that can be dated biostratigraphically as Darriwilian and which is the outcrop equivalent, and probably the seaward continuation, of the Saih Nihayda Formation in the Ghaba Salt Basin of northern Oman. The outcrops at Wadi Daiqa and Hayl al Quwasim consist of 690 m of quartzitic sandstones, shales and bivalve-rich shell beds. Trace fossils referable to the Cruziana and Skolithos ichnofacies abound. The member comprises storm-dominated shelf, shoreface and delta deposits. A number of new discoveries have been made in the outcrops: fragments of the arandaspid fish Sacabambaspis, ossicles and moulds of the early disparid crinoid Iocrinus, two new genera of conodont, an occurrence of the rare trinucleid trilobite Yinpanolithus, and palynological and sedimentological evidence of more continuous Floian–Darriwilian deposition than is usual in the region. Sea levels during Middle Ordovician time are estimated to have been 50–200 m above present levels and a wide, low-gradient shelf covered much of Arabia. Similar trace fossils and storm-dominated, micro-tidal, sedimentary rocks occur throughout the region. Small changes of sea level, possibly caused by the growth and melting of polar ice sheets, could lead to substantial seaward or landward shifts of facies belts. The Am5 deposits are thick compared to most equivalents in Arabia implying active subsidence and a ready supply of sediment.

scholarly journals Glauconitic deposits at Julegård on the south coast of Bornholm, Denmark dated to the Cambrian

2011 ◽  
Vol 59 ◽  
pp. 1-12
Author(s):  
Lars B. Clemmensen ◽  
Richard G. Bromley ◽  
Paul Martin Holm
Keyword(s):  
Lower Cambrian ◽  
Trace Fossils ◽  
Upper Triassic ◽  
South Coast ◽  
The South ◽  
Shallow Marine ◽  
Marine Deposits

Bioturbated, glauconitic siltstones and sandstones are overlain by presumed Upper Triassic deposits at coastal exposures at Julegård on the south coast of Bornholm. These glauconitic deposits have not previously been dated. A 40Ar-39Ar dating of the glaucony gives an age of 493 ± 2 Ma suggesting the deposits belong to the Lower Cambrian Norretorp Member of the Læså Formation. The shallow marine deposits are strongly bioturbated, but only a single ichnoassociation is represented. The ichnogenus is referable to either Trichophycus Miller and Dyer, 1878 or Teichichnus Seilacher, 1955. Rare examples of Rusophycus Hall, 1852, probably trilobite trace fossils, are also represented.

A new, large acteonid gastropod (Mollusca) from the latest Cretaceous of Antarctica

2002 ◽  
Vol 76 (6) ◽  
pp. 1102-1105 ◽  
Author(s):  
Jeffrey D. Stilwell ◽  
William J. Zinsmeister
Keyword(s):  
Antarctic Peninsula ◽  
First Record ◽  
Shallow Marine ◽  
Marine Deposits ◽  
Island Species ◽  
Southern Half ◽  
Lowermost Part ◽  
Seymour Island

Opisthobranch Gastropods are rare in Mesozoic deposits of Antarctica. The first documented occurrence of opisthobranchs from this continent is from Cretaceous shallow-marine deposits of the James Ross Basin, Antarctic Peninsula, where Wilckens (1910, p. 95–96, pl. 4, fig. 19) described the minute ringiculid Cinulia sp., based on five specimens from two localities on Snow Hill Island. No further work has been done on the Snow Hill Island species. The next mention of Antarctic Cretaceous opisthobranchs was by Zinsmeister et al. (1989, p. 733, fig. 2, p. 734, fig. 3), who cited the occurrence of the ringiculid “Oligoptycha cf. O. concinna Meek and Hayden, 1858,” in the lowermost part of Unit 8 of the López de Bertodano Formation (Maastrichtian) on the southern half of Seymour Island (Fig. 1). We report the first record of Acteonidae from the Mesozoic of Antarctica, Acteon (Tenuiactaeon) antarctihadrum n. sp., discovered in shallowmarine Maastrichtian deposits.

An early Cambrian shallow-marine ichnofauna from the Puncoviscana Formation of northwest Argentina: the interplay between sophisticated feeding behaviors, matgrounds and sea-level changes

2012 ◽  
Vol 86 (1) ◽  
pp. 7-18 ◽  
Author(s):  
Luis A. Buatois ◽  
María Gabriela Mángano
Keyword(s):  
Microbial Mats ◽  
Trace Fossils ◽  
Cambrian Explosion ◽  
Early Cambrian ◽  
Marine Environments ◽  
Sea Level Changes ◽  
Feeding Behaviors ◽  
Shallow Marine ◽  
Northwest Argentina ◽  
Marine Deposits

An early Cambrian ichnofauna consisting of Helminthoidichnites tenuis, Helminthopsis tenuis, Multina isp., Oldhamia alata, and Pilichnus cf. dichotomus is documented from shallow-marine deposits ranging from the upper offshore to the offshore transition in the Puncoviscana Formation of northwest Argentina. Although the ichnogenus Oldhamia is more common in Cambrian deep-marine environments, this occurrence provides further evidence that it is also present in shallow-marine environments. The burrow network Multina (senior synonym of Olenichnus) is preserved at the base of tempestites, representing the activity of post-storm colonizers. A drowning surface separating offshore-transition deposits below from upper-offshore deposits above contains widespread evidence of trace fossils in direct association with matgrounds. The undermat miners Oldhamia alata and Pilichnus cf. P. dichotomus occur on this surface, revealing exploitation of organic matter in the biomat. Low sediment rate during drowning and paucity of bioturbation by sediment bulldozers may have promoted the establishment of the matground. In comparison with the simpler animal-matground interactions characteristic of the Ediacaran, the combination of Cambrian evolutionary innovations and the presence of microbial mats promoted more sophisticated interactions. Complex feeding trace fossils revealing that systematic undermat mining, as displayed by Oldamia alata and Pilichnus cf. dichotomus, is a product of the Cambrian explosion.

scholarly journals Anomuran and brachyuran trackways and resting trace from the Pliocene of Valduggia (Piedmont, NW Italy): environmental, behavioural, and taphonomic implications

2016 ◽  
Vol 3 (1) ◽  
pp. 35
Author(s):  
Giovanni Pasini ◽  
Angela Baldanza ◽  
Lorenzo M. Gallo ◽  
Alessandro Garassino ◽  
Hiroaki Karasawa
Keyword(s):  
Hermit Crab ◽  
Fossil Record ◽  
Mediterranean Area ◽  
Decapod Crustaceans ◽  
Intertidal Environment ◽  
Shallow Marine ◽  
Marine Deposits ◽  
Brachyuran Crabs ◽  
Nw Italy ◽  
First Time

We report a rich ichnofacies including trackways and a resting trace made by indeterminate anomuran and brachyuran crabs, and other organic sedimentary structures produced by invertebrates. This is the first fossil record of crab trackways and resting trace in a shoreface intertidal environment from the Pliocene sediments of Valduggia area (Vercelli, Piedmont, NW Italy). Behavioural and palaeoenvironmental data allow reconstruction of the possible scenario of the upper shoreface surface in this area of the northern paleo-Adriatic Gulf during the Pliocene. The resting trace is tentatively compared to the rehydrating and respiration behaviour of a semiterrestrial (?Ocypodidae) crab, documented for the first time in the fossil record. A single trackway is tentatively assigned to the locomotion of a land hermit crab, the first such fossil record from the paleo-Mediterranean area. Moreover, among other invertebrate burrows, hypichnal <em>Halopoa</em> cf. <em>H. imbricata</em> is reported in shallow marine deposits for the first time. Palaeontological, petrological, sedimentological, taphonomic, and ethological implications are discussed and compared with neoichnological data. This notable discovery enlarges our scant knowledge on the palaeo-ichnology of decapod crustaceans.

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