Journal of Mediterranean Earth Sciences

Demirina meridionalis Özcan, 1994, Cenomanian larger benthic foraminifera from the Natih Formation of Oman: First record outside the type area and emendation of the genus

André Piuz, Felix Schlagintweit — Tue, 25 Nov 2025 00:00:00 +0000

Demirina meridionalis Özcan, 1994 is the only known species of the larger benthic foraminifera genus Demirina Özcan, 1994. It was described as a nezzazatid (subfamily Coxitinae) from the Cenomanian of SE Turkey (Arabian Plate margin) based on limited and rather poorly preserved material. Several well-preserved specimens of D. meridionalis are found in the Cenomanian Natih Formation (members E to B) of Oman. A close architectural analysis of these fossil shells displays a short single rafter in the marginal chamber part, and beams generally aligned between subsequent chambers, which allows the transfer of Demirina to the order Loftusiida, and the family Spirocyclinidae. Reissella ramonensis Hamaoui, 1963, another little known loftusiid larger benthic foraminifera first described from the Cenomanian of Israel, as well as Spirocyclina atlasica Saint-Marc and Rahhali 1982 first reported from the Cenomanian of Morocco, are shown to differ from Demirina mainly by their test morphology and chamber shape. The Omani material represents the first record of D. meridionalis outside its type area in southeastern Turkey; a paleogeographic restriction to the former Arabian Plate is suggested, and a stratigraphic distribution ranging from the uppermost early to middle Cenomanian is proposed.

Linking sand composition and sequence stratigraphy: insights from the Late Lower Pleistocene to Holocene deposits of the Roman Basin (Latium, central Italy)

Daniel Tentori, Salvatore Milli — Thu, 25 Sep 2025 00:00:00 +0000

Sand petrographic changes record the interplay between allogenic (e.g., eustatic, climatic, tectonic) and autogenic (e.g., transport, hydraulic sorting, post-depositional alteration) processes that also govern sequence-stratigraphic architecture. The consequence is that compositional trends vary within the systems tract that forms the framework of the high- and low-rank depositional sequences constituting the late Quaternary successions of the Roman basin, a basin supplied by the Tiber River throughout the Pleistocene. The relationship between sediment supply and sediment composition is well evidenced in the Late Lower Pleistocene to Holocene deposits of the high-rank Ponte Galeria Sequence (PGS), that supplied by the Tiber River and its tributaries records, during the time, the dramatic change in sediment composition due the introduction into the Roman Basin of pyroclastic and volcaniclastic material derived by the Pleistocene volcanic complexes of the Roman Magmatic Province. Three main petrofacies (A-C) were recognized in the PGS that have a strong correspondence with the lowstand (LST), transgressive (TST), and highstand (HST) system tracts deposits of the PGS. Petrofacies A (feldspatho-litho-quartzose to feldspatho-quartzo-lithic) reflects erosion of carbonate and siliciclastic sources with minimal volcanic input during LST. Petrofacies B (feldspathic to litho-feldspathic/feldspatho-quartzo-lithic) captures the abrupt volcaniclastic pulse and recycling associated with Pleistocene volcanism during TST. Petrofacies C (feldspatho-quartzo-lithic) best records downstream reworking and Tiber river-mouth processes during HST. In particular, in the modern highstand, upstream sands show a siliciclastic lithic signature, whereas downstream sands are enriched in carbonate and volcanic lithics; coastal hydrodynamics partition detritus into two populations, concentrating coarser pyroxenes in higher-energy settings and finer feldspars in lower-energy environments, while outer-shelf/slope deposits are largely biogenic and weakly river-influenced. Overall, compositional changes in correspondence with the key stratigraphic surfaces mark paleogeographic reorganizations and changes in sediment pathways. Because multiple drivers often act at once (e.g., tectonism, volcanism, and local autogenic effects), petrographic analysis should be integrated with facies, texture, and process data to isolate the forcing mechanisms better. These results demonstrate that sedimentary petrography can play an important role in the sequence-stratigraphic interpretation of a sedimentary succession, strengthening links between modern routing systems and the ancient record.

Morpho-acoustic characterization of the insular shelves around Stromboli Island (Aeolian archipelago)

Daniele Casalbore — Thu, 13 Nov 2025 00:00:00 +0000

Stromboli is an insular volcano located in the Southern Tyrrhenian Sea, characterized by a bilateral symmetry with respect to its SW-NE axis. The volcanic flanks perpendicular to this axis are mainly dominated by large and steep-sided depressions associated with large-scale lateral collapses. In contrast, the volcanic flanks parallel to this axis are characterized by the presence of insular shelves in the first 100-200 water depth that interrupt the morphological continuity between the subaerial and submarine slopes. These shelves have been formed by wave erosion during Quaternary sea-level fluctuations. In detail, the SW shelf is relatively narrow and has the outer edge in the depth range of 100-130 m, while the NE shelf is wider and has the outer edge in the depth range of 100-200 m. In addition, narrow shelves with the edge at depths of 100-130 m are recognizable on the SE sector, being limited to the morphological highs bounding the collapse scar. The difference in shelf width around the island can be related to the different ages of the coastal sectors that, in turn, would be reflected in a longer cumulative erosive action of waves. In the SW and SE sectors of Stromboli Island, the outcropping volcanic units are less than 100 ka; the NE shelf, instead, represents the dismantling of the upper part of the older Strombolicchio edifice, which has been dated around 205 ka and whose emerged part is nowadays related to a neck emerging from the sea surface. The depth range of the shelf edge in the SW and SE sectors is compatible with the minimum sea-level reached during the last lowstand, while the deeper shelf edge in the NE shelf can be related to a tectonic tilt or subsidence that affected the Strombolicchio edifice during its evolution. The morpho-acoustic characterization of the shelf has been realized through the integration of multibeam bathymetry, side scan sonar data, seismic reflection profiles, and direct observations through scuba dives. It has enabled us to identify four main seafloor types on the shelf: sandy seafloor, volcanic outcrops, blocky accumulation, and seagrass meadows, whose spatial distribution is discussed in the paper.