The Dhaka and Maya mud volcanoes (MVs), located in the Mud Diapir Province in the Western Alboran Basin along the Moroccan Coasts, were cored during the TTR-17, Leg 1 cruise. Cores were taken on the top of the volcanoes at a water depth of 370 m on the Dhaka MV (core TTR17-MS411G) and at 410 m water depth on the Maya MV (core TTR17-MS419G), respectively. On both mud volcanoes the extruded mud breccia provides the nucleation point for the colonization and development of cold-water corals and associated ecosystems. Two phases of cold-water coral growth are observed: (1) between slightly older than 4175± 62 years BP and around 2230± 59 years BP at Dhaka, and (2) between slightly older than 15583 ± 185 years BP and around 7613 ± 38 years BP at Maya MV. On the top of the Maya MV only a small patch reef and/or isolated corals proliferated, whereas a more extended patch reef colonized the top of the Dhaka MV. At both sites the cold-water coral development was triggered by the availability of a suitable substrate for initial coral settling, provided either as a firm ground or as single clasts. Subsequently coral growth was supported by enhanced nutrient flux possibly related to upwelling and/or strong currents. During the intervals of coral growth planktonic foraminiferal assemblages were dominated by Neogloboquadrina incompta. The decline of coral ecosystems on the mud volcanoes is accompanied at surface by a shift from the N. incompta dominated assemblage to a Globorotalia inflata dominated assemblage, possibly reflecting more oligotrophic conditions. This shift is coeval to the passage from wet to arid conditions at the end of the African Humid Period at Maya MV. It is interpreted as an effect of an early human impact on a fragile environment, which was already stressed by desiccation at the time of the development of complex human society along the Mediterranean coasts, at Dhaka MV.
Cold-water coral (CWC) settlement in northern Norway is strongly related to the outlet-glaciers of the Fennoscandian Ice-sheet, and dating of known CWC structures show clearly post-glacial ages. Two gravity cores (POS391 559/2,277 cm long and POS391 559/3,282 cm long) were recovered on a CWC reef in the area of Lopphavet, northern Norway. Detailed investigations on lithology (sediment structures and composition), micropaleontology (foraminifera and ostracoda) and AMS 14 C dating on the epibenthic foraminifera Discanomalina coronata were performed on the two cores. Phosphorus analyses were performed only on core POS391 559/3. Results indicate that the whole core POS391 559/2 is representative of a CWC reef environment. The base of the core is dated at 10,6007120 cal. yr BP, thus representing one of the oldest ages of a Norwegian coral reef. Core POS391 559/3 documents the passage from a proximal glacier environment characterized by fine silty sediments with intercalation of several dropstone layers to a CWC ecosystem. The transition from the glacial to the interglacial stage is dated as old as 10,7257205 cal. yr BP, whereas the base of the core is dated to an age of 15,3007550 cal. yr BP. Diversity of benthic foraminifera is higher within the CWC, especially in the intervals containing coral framework. Five clusters are identified based on the Bray-Curtis Similarity Term Analyses and the interpretation of data shows that they are related to different ecological settings, e.g., fluctuations of the sea-ice cover; influence of the warmer and more saline Atlantic water masses; transitional to a fully interglacial environment; well oxygenated, nutrient-rich and high current setting being conducive to CWC.Ostracod assemblages show that these crustaceans may be also used to characterize sedimentary facies on CWC reefs.
During the TTR-17 Leg 1 cruise in the West Alboran Basin, gravity cores were acquired from three mud volcanoes (MVs): Dhaka, Carmen and the recently discovered Maya. This paper presents micropaleontological and radiocarbon dating results from the three mud volcanoes, using cores containing mud breccias overlain by and interbedded with hemipelagic sediments. At Dhaka MV, the mud-breccia matrix contains very rare Holocene planktonic foraminifera associated with abundant reworked specimens of mixed Late Cretaceous to Mio-Pliocene age. At Carmen MV, the reworked assemblage is dominated by Miocene to Pliocene foraminifera occurring together with rare Late Cretaceous species while at Maya MV the mud-breccia matrix is characterized by the dominance of Santonian-Maastrichtian forms, with subordinate Tertiary species. Shallow-water benthic foraminifera such as Ammonia spp. and Elphidium spp. are generally rare and randomly distributed, but present at all studied sites. Based on these results, we suggest that the main sediment source of the mud-breccia extruded at Dhaka, Carmen and Maya MVs is possibly the lowermost overpressured olistostromic Unit VI (Aquitanian?-Burdigalian). Differences in the micropaleontological composition of the mud-breccia matrix at different sites are most likely due to differences in the main source layer and in the plumbing systems underneath the MVs. Radiocarbon dating of hemipelagic sediments associated to the mud-breccia allowed to define the age of the latest extrusion activities (>0.27 ka to > 15.6 ka BP), which seem to be episodic, short-lived and recurrent over thousands of years.
Major and minor element distributions and solid phase phosphorus contents were measured in a sediment core from the Cretan Ridge that contains the Holocene S1 sapropel. Micro-XRF ultra-high resolution analysis reveals multiple Mn peaks in the oxidized upper portion of the sapropel, which implies either a non-steadystate upward remobilization of Mn or not constant downward diffusion of bottom water oxygen. Sequential extraction allowed the identification of different phosphorus phases. Detrital phosphorus increases in the sapropel layer, suggesting enhanced delivery from land during sapropel deposition. Higher organic carbon to organic phosphorus ratios in the sapropel indicate enhanced regeneration of phosphorus relative to carbon under low-oxygen conditions. Fourier analysis on the ultra-high resolution XRF data reveals frequencies that are provisionally assigned to millennial to decennial solar cycles. Although these cycles have been reported from several continental and marine archives, they have never been documented from Sapropel S1 in the Eastern Mediterranean.
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