From Siliciclastic to Bioclastic Deposits in the Gulf of Naples: New Highlights from Offshore Ischia and Procida–Pozzuoli Based on Sedimentological and Seismo-Stratigraphic Data

This study discusses the siliciclastic to bioclastic deposits (in particular, the rhodolith deposits) in the Gulf of Naples based on sedimentological and seismo-stratigraphic data. The selected areas are offshore Ischia Island (offshore Casamicciola, Ischia Channel), where a dense network of sea-bottom samples has been collected, coupled with Sparker Multi-tip seismic lines, and offshore Procida–Pozzuoli (Procida Channel), where sea-bottom samples are available, in addition to Sparker seismic profiles. The basic methods applied in this research include sedimentological analysis, processing sedimentological data, and assessing seismo-stratigraphic criteria and techniques. In the Gulf of Naples, and particularly offshore Ischia, bioclastic sedimentation has been controlled by seafloor topography coupled with the oceanographic setting. Wide seismo-stratigraphic units include the bioclastic deposits in their uppermost part. Offshore Procida–Pozzuoli, siliciclastic deposits appear to prevail, coupled with pyroclastic units, and no significant bioclastic or rhodolith deposits have been outlined based on sedimentological and seismo-stratigraphic data. The occurrence of mixed siliciclastic–carbonate depositional systems is highlighted in this section of the Gulf of Naples based on the obtained results, which can be compared with similar systems recognized in the central Tyrrhenian Sea (Pontine Islands).

New insight on tide-dominated estuary and delta in the Eocene-Miocene Mrayt Group, North-Western Rif, Morocco

The sedimentary deposits of Eocene-Miocene Mrayt Group, North-Western Rif, Morocco has been the subject of controversy by previous authors regarding their depositional environment. Detailed sedimentological study based on petrographic and sedimentary facies analysis, ichnofacies interpretation and paleocurrent measurements, leads to several results and new insights. Petrographic study provided the first evidence of mixed siliciclastic and carbonate sediments and their nomenclature: silty micrites, micritic siltstones, micritic sandstones, sandy micrite, and allochemic sandstones, as well as the nature of the sources and its geological context. Twenty two sedimentary facies that have never been described before are identified, and based on their succession and association a new interpretation of depositional processes and depositional systems are proposed. The paleoenvironments of the Mrayt Group are interpreted as littoral and shallow marine settings: tides- dominated estuary, tides-dominated delta systems and open coast tidal flat, under complex hydrodynamics strongly influenced by river discharge, tidal currents, waves and storms action.Sedimentation occurred in “the Maghrebian basin” under the interplay of: i) tectonics related to the Cenozoic collision of the African and Eurasian continental plates, ii) Cenozoic alternation of warm climate and cooling due to the increasing influence of Antarctica glaciation, iii) sediments supplies induced by rejuvenation of sedimentary sources and iv) sea level fluctuation related to the advance and retreat of ice-sheet on Antarctica.

An Insight to the Sedimentological Developments of Quaternary Detritus Ring Fluvial Network, Altun Kupri Paleolake, NE IRAQ

During the Quaternary, an active basin in the shape of open lake originated along the Lesser Zab river at Altun Kupri area. The radial complex of fluvial deposit morphologically initiated by the coarse detritus material, that were transported by the Lesser Zab river and other surrounded valleys in a shape of delta towards the proximal part of coastal plain and the fine sediment to the distal part of it. The coarse one prograde along the fine gradually resulting in the accumulation of about 60 m thickness of continuous Pleistocene fluvial succession mostly of coarse grained sediments with minor sand, silt and clay intervals and some tongues and bands of calcareous mud. The bulk of basin fill is made of two depositional systems, the western and southwestern side was filled up by progradation delta systems, but the northern side was gradually filled up by fluvial sediment of Lesser Zab channel. The water impounded in this lake because of Awanah anticline as a ridge in front of the lake which is open with output channel that crosses the shallow gorge and the gorge became deeper and deeper gradually till the water drooped from the lake. There are several possibilities that this ring shape depression of Altun Kupri paleolake generated, first: the depression at Altun Kupri is formed as a result of dissolving lenses of Anhydrite and gypsum of the Fat’ha Formation beneath the northern limb of Awanah Anticline after the collapse of the cavity roof. second: the presence of ring shape cliffs of about 50m thick and depression is bounded by 8km in diameter of cross bedded conglomerates and sandstone and the third: the depression of Altun Kupri paleolake can be developed by meteoritic impact, with several sedimentological and structural evidence such as a delta distributary fan, and there was a hanging terrace at a high level along the gorge

Macrofloral and microfloral changes in the Middle Jurassic plant assemblages of the Cianowice 2 borehole (southern Poland)

The flora of the Cianowice 2 borehole (c. 20 km NW of Cracow, Poland), dominated by cycadophytes (mainly bennettitaleans) and conifers, shows high taxonomic diversity relative to the low number of specimens. Twenty species were identified in the 96 determinable plant fragments found in 27 core samples: Cladophlebis sp. (ferns), Pachypteris rhomboidalis (Ettingshausen) Nathorst and Ptilozamites cycadea (Berger) Möller (seed ferns), Anomozamites nilssonii (Phillips) Seward, Nilssoniopteris solitaria (Phillips) Cleal & Rees, Otozamites mimetes Harris, Otozamites parallelus Phillips, Pterophyllum thomasii Harris, Pterophyllum cf. aequale (Brongniart) Nathorst, Ptilophyllum cf. okribense forma ratchiana Doludenko & Svanidze, Ptilophyllum pecten Phillips, Ptilophyllum sirkennethii Watson & Sincock, Cycadolepis sp. (bennettitaleans), Pseudotorellia grojecensis Reymanówna, Pseudotorellia samylinae Nosova & Kiritchkova, Pseudotorellia sp. (Gymnospermae incertae sedis), Bilsdalea dura Harris, Mirovia szaferi Reymanówna, and Brachyphyllum stemonium Kendall (conifers). The floristic composition is supplemented by palynological data. The taxa were connected to five depositional successions distinguished along the core: one, alluvial fans; two, four and five, meandering/anastomosing river depositional systems with fluvial plain deposits; and three, lacustrine/backswamp environment developed on fluvial plain. The composition of the fossil plant assemblage changes with the depositional setting within the same range of taxa, seen mainly in changed combinations of taxa, which are most diverse in the fluvial plain deposits. Some taxa occur in a single depositional succession; some are present in two or three. The sporomorph assemblages of particular depositional environments differ significantly from the composition of the co-occurring macroflora: ferns occur sporadically in the macroflora of each depositional environment but they strongly dominate the sporomorph assemblage. Our proposed reconstruction of the palaeoenvironment is a slight rise descending into a valley with a depositionary basin, with gymnosperms on the slope and ferns at the base. Some species are shared between Cianowice and nearby Middle Jurassic localities in Grojec and Zabierzów, and the majority of taxa are known from the Middle Jurassic, suggesting that the Cianowice deposits are of that age.

Organic and Isotopic Geochemistry of Evaporites and Shales of the Santana Group (Araripe Basin, Brazil): Clues on the Evolution of Depositional Systems and Global Correlation during the Lower Cretaceous

Even being the more studied of the interior basins of Northeast Brazil, the Araripe Basin still lacks research in organic geochemistry designed to support interpretations of depositional systems and conditions of formation. This work aims to investigate the organic behavior of evaporites and shales from the Santana Group (Lower Cretaceous), as well as discuss their role in the evolution of its depositional systems. A total of 23 samples, 17 shales and six evaporites, were collected in outcrops and quarries. Analyses of Total Organic Carbon (TOC), Total Sulfur (TS), Rock Eval pyrolysis, and the δ34S isotope ratio were performed. The TOC results revealed high organic content for seven intervals, of which only five had high TS content. From the Rock Eval pyrolysis, dominance of the Type I kerogen was verified, thus corresponding to the best type of organic matter (mainly algal) for the generation of liquid and gaseous hydrocarbons. The Lower Cretaceous (probably Aptian) response to the progressive evolution in redox conditions is linked to a remarked Oceanic Anoxic Event (OAE-1a). The TOC/TS ratio suggests variable palaeosalinity, indicating most of the shales were formed under brackish waters with saline influence, yet tending to increase the salinity upwards where hypersaline conditions dominate in the Ipubi Formation. The isotope data also suggest the occurrence of marine ingressions in the depositional systems even prior to the well-documented event of the Romualdo Formation.

The qualitative and quantitative classification of modern clastic marginal-marine depositional systems, Trinidad

ABSTRACT Trinidad's modern coastal depositional systems are for the first time documented by (traditional) descriptive and (modern) semiquantitative and quantitative classification methods. The processes controlling the morphology and distribution of these systems are also investigated. Google Earth™ satellite images, together with published basinal processes data (e.g., significant wave height, surface littoral currents, and tidal cyclicity) are used to describe system morphology, map depositional elements, and to determine the processes responsible for system distribution, respectively. Coastal depositional systems along Trinidad's east, south, and west coasts comprise deltas, estuaries, tidal-inlet complexes, strandplains, and tidal flats. Their distribution is controlled by the wave regime, although they are also influenced by tidal and fluvial processes. The wave regime changes from wave-dominated along the open east coast, to mixed-energy wave-dominated along the semi-sheltered south coast, and to mixed-energy tide-dominated along the sheltered west coast. Distribution of depositional systems related to this regime are such that the wave-dominated east coast sees the development of wave-dominated estuaries. The south coast has a series of wave-dominated, tide- and river-influenced deltas. The sheltered west coast is the most morphologically diverse with river- and wave-dominated deltas, strandplains, and tidal flats. The application of semiquantitative and quantitative classification methods on modern systems has showed their competence in classifying mixed-influence systems from their morphology and sedimentary record. Quantitative classification using depositional elements lends an appreciation to the morphological signatures of mixed-influence systems. Quantitative classification for sedimentary sections gives an appreciation of the preservation of mixed-influence physical processes. The combination of both allows the correlation of the impact of physical properties on morphology and sedimentary record (i.e., possible disparities between morphology and processes). The combination of semiquantitative and quantitative methods may also hold the key to unlocking the mixed-processes classification of depositional elements.