Late glacial to Holocene sea-level changes in the Sea of Marmara: new evidence from high-resolution seismics and core studies     

K��r?ad Kadir Eri?  M. N. ?a?atay  Sena Ak?er  Luca Gasperini  Yosi Mart 《Geo-Marine Letters》2011,31(1):1-18

The late glacial to Holocene sedimentary record of the northern shelf of the Sea of Marmara (SoM) has been documented by detailed seismo-, chrono-, and biostratigraphic analyses using sub-bottom (Chirp) profiles and sediment cores. During MIS 3 and the main part of MIS 2 (60–15 ¹⁴C ka b.p.), disconnection from the Mediterranean and Black seas together with a dry climate resulted in a regression in the SoM, when the Sea was transformed into a brackish lake. The river incisions below 105 m water depth along the northern shelf took place during the last glacial maximum, when the lake level was modulated by stillstands at −98 and −93 m. The post-glacial freshwater transgressive stage of the Marmara ‘Lake’ occurred between 15 and 13.5 ¹⁴C ka b.p., leading to a rise in water level to −85 m by 13.0 ¹⁴C ka b.p., as evidenced by broad wave-cut terraces along the northern shelf. Since 12 ¹⁴C ka b.p., high-frequency sea-level fluctuations have been identified at the SoM entrance to the Strait of İstanbul (SoI). Thus, wave-cut terraces have been recorded at water depths of −76 and −71 m that, according to an age model for core MD04-2750, have ages of 11.5 and 10.5 ¹⁴C ka b.p., respectively. Ancient shoreline at −65 m along the northern shelf presumably formed soon after the Younger Dryas (YD) at ca. 10.1 ¹⁴C ka b.p. Moreover, there is compelling evidence of Holocene outflow from the Sea of Marmara to the Black Sea. At the SoM entrance to the SoI, the existence of bioherms on the reflector surface together with abundant Brizalina spathulata and Protoglobulimina pupoides in a core suggests a return to higher salinities due to strong Mediterranean water incursion into the SoM at ∼8.8 ¹⁴C ka b.p. This finding is consistent with earlier suggestions that, after the YD, the Black Sea was flooded by outflow from the SoM as a result of global sea-level rise.  相似文献   

Mathematical modelling of a potential tsunami associated with a late glacial submarine landslide in the Sea of Marmara     

Mehmet Sinan Özeren  M. Namık Çağatay  Nazmi Postacıoğlu  A. M. Celal Şengör  Naci Görür  Kadir Eriş 《Geo-Marine Letters》2010,30(5):523-539

Potential tsunami waves were modelled on the basis of the morphology and geological setting of a late glacial submarine landslide localized in the north-eastern sector of the Sea of Marmara, using a three-dimensional algorithm with the purpose of assessing the future risk of tsunamogenic landslides in the region. The landslide occurred off the Tuzla Peninsula on the north-eastern slope of the Ç?narc?k Basin, the easternmost of the three deep Marmara basins. The mass movement appears to be related to the Main Marmara Fault that passes below the toe of the failed mass. Observations from earlier manned submersible dives suggest that the initiation of the slide was facilitated by secondary faults associated with the Hercynian orogeny and involved Palaeozoic shales dipping southwards towards the deep basin. Radiocarbon dating of core material, together with the well-dated Marmara sapropel above the chaotically mixed landslide surface, reveal that the latest landslide event occurred about 17 ¹⁴C ka b.p. The uppermost scar of the landslide is found at 250 m and its toe at about 1,200 m below the present sea level. At the time of the slide, the Marmara Sea Basin was lacustrine, with its water level at ?85 m. In plan view the landslide has a distinctively triangular shape and the lateral extent of its toe is about 10 km. Multibeam bathymetric data indicate that the sliding motion probably occurred in two phases: a slower phase affecting the eastern part, characterized by an undulating surface, and a more rapid phase affecting the western part that possibly created tsunami waves. In the seismic sections, older failed slide masses can be clearly identified; these were probably displaced during marine isotopic stage 6 (～127–160 ka b.p.). The front of this buried material is located more than 1.5 km further south of the fault. We used a three-dimensional, Green’s function-based potential theory approach, rather than shallow-water equations commonly used in conventional tsunami simulations. The solution algorithm is based on a source-sink formulation and an integral equation. The results indicate that the maximum height of the tsunami in the Ç?narc?k Basin could have reached about half the average thickness of the sliding mass over a lateral extent of 7 km. Assuming an average thickness of 30 m for the landslide, and considering that the water level at 17 ka b.p. was at about ?85 m, the modelling shows that the maximum wave height generated by the slide would have been about 15–17 m.  相似文献   

Origin of fluorine in mineral waters of Bujanovac valley (Serbia, Europe)     

O. Krunić  S. Parlić  D. Polomčić  M. Jovanović  S. Erić 《Geochemistry International》2013,51(3):205-220

This paper deals with mineral and thermomineral water occurrences of the Bujanovac valley in south eastern part of Serbia related to granitoides of the Bujanovac massif along both the margin and the floor of the valley. In past decades (1966–2010) numerous hydrogeological, hydrogeochemical and geophysical explorations were carried out. One of results of these explorations is the completion of test holes and exploratory—production wells. They provide groundwater for three water bottling factories: “Heba”, “Bivoda”, “Prohor” as well as the “Vrelo Bujanovac Banja Spa Centre” for rehabilitation, treatment, and prevention. All stated consumers use the same mineral water aquifer. The content of fluoride in the majority of examined mineral waters is higher than 4 mg/1, whereby they are singled out as typical fluoride waters. The content of calcium ions in them amounts 80 mg/1, and the values of the saturation index in relation to calcium fluoride (SI) range from 0.4 to 0.7 mg/1, which points to mineral waters saturated in relation to fluorite. However, in the study area, there are mineral water occurrences with the content of fluoride significantly lower than in the majority of analysed waters representing hydrochemical anomalies. These waters occur as hydrochemical anomalies in marl and sandstone wherein Secondary mineral water aquifers, originating from cracked granite of the Bujanovac massif, are formed. When mineral waters from granite (with the increased content of fluoride) reach these secondary aquifers, the content of fluoride ions lowers to about 1 mg/1, which is of great significance from the point of view of mineral water utilisation as table bottled water. In this paper, it is proved that, in addition to the presence of some minerals as basic fluorine bearers, the role of the lithological environment where the natural process of defluoridation occurs is significant, which is confirmed by the revitalization of the A-4 well. The paper deals with mineral water deposits of the Bujanovac valley, and the natural way of lowering of fluorine content in the given waters.  相似文献   

Koolau shield basalt as xenoliths entrained during rejuvenated-stage eruptions: perspectives on magma mixing     

J.?P.?Weinstein  R.?V.?FodorEmail author  G.?R.?Bauer 《Bulletin of Volcanology》2004,66(2):182-199

Rejuvenated-stage tuff cones (Honolulu Volcanics) on Koolau volcano, Oahu, Hawaii, contain xenoliths of Koolau shield basalt. Because Koolau subaerial shield lavas represent a Hawaiian geochemical 'end member', and submarine shield lavas have compositions with some affinities to Mauna Loa and Kilauea, we analyzed 28 xenolithic basalts from Salt Lake and Koko Head cones to determine how these seemingly random samplings of the Koolau profile compare to established Koolau geochemistry. Analyses reveal that 24 are shield tholeiitic basalt—the focus of this study—and 4 are rejuvenated-stage basaltic rocks. The tholeiitic xenoliths represent largely upper Koolau shield lavas, as these samples (8.3 to 5.8 wt% MgO) have, with one exception, overall major- and trace-element compositions that overlap those of Koolau subaerial shield lavas. Secondary processes, however, created some distinctions—namely, enrichments/depletions in K, Ba, Sr, SiO₂, and FeO, and, due to zeolitization (chabazite with attending okenite and apophyllite), elevated CaO. One xenolithic basalt with 8.2 wt% MgO has higher Ti, Zr, Nb, and Sc, and lower Zr/Nb than subaerial lavas, and appears to represent relatively early, deeper shield—thereby reinforcing that the Koolau shield source varied temporally. Olivine, orthopyroxene, and plagioclase are the phenocrysts (clinopyroxene is rare), and their core compositions range widely across the suite—Fo_87.8–72, orthopyroxene Mg#s 85–72, and An_74–60. Several xenolithic basalts have both normally and reversely zoned orthopyroxene and plagioclase with a variety of core compositions (e.g., orthopyroxene-core Mg#s 82, 77, and 72, all in one sample). These compositions and zonations record evidence for wide compositional ranges of replenishment (MgO ~13–8 wt%) and reservoir (MgO ~7 to <5 wt%) magmas mixing in varying proportions; however, extreme MgO lavas (~13 and <5 wt%) are not observed as either subaerial or xenolithic basalt, but are indicated by phenocryst cores of Fo_87.8 and orthopyroxene-Mg# 72. The Koolau magma-mixing history resembles that of Kilauea, and is unlike the 'steady-state' mixing known for Mauna Loa. Finally, these basalt samples show that any xenolithic occurrence of Koolau lava is subject to the zeolitization prevalent in the tuff-cone hosts.Editorial handling: M. Carroll  相似文献   

Spatial and temporal geochemical variability in basin-related volcanism, northern Israel     

Yishai Weinstein   《Journal of African Earth Sciences》2000,30(4):1513

Middle Miocene (17-9 Ma) volcanism in northeast Israel migrated from eastern Lower Galilee (Poria, west of the Sea of Galilee) to the southwest (Yizre'el Valley) in association with the development of an extensional basin in that area. The Yizre'el Valley magmas are highly undersaturated in silica (basanites and nephelinites), while those of Poria are alkali-basaltic. Scarce Middle Miocene basalts from the Golan, further to the east, are also alkali-basaltic. Magmas from Kaukab (southeastern Lower Galilee) show a range of compositions from alkali-basalts to basanites. The patterns defined by ratios versus concentrations of incompatible elements in Kaukab basalts (e.g. versus La), as well as the scatter observed in Sr isotope ratios, are interpreted in terms of binary mixing. It is suggested that the Kaukab magmas were derived from veined lithospheric peridotites, melts of the veins and of the peridotites being the two end-members. Accordingly, alkali-basaltic- and basanite-dominated areas are underlain by vein-poor and vein-rich lithosphere, respectively. It is also suggested that melting during the Middle Miocene mainly occurred in response to extension, and that it followed the propagation of the Yizre'el-Galilee Basin from northeast to southwest.  相似文献   

Preface     

Robert J. Orth  Kenneth L. Heck  Michael P. Weinstein 《Estuaries and Coasts》1984,7(4):273-274

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Validation of daily increment deposition in the otoliths of spot (Leiostomus xanthurus)     

Robert C. Siegfried  Michael P. Weinstein 《Estuaries and Coasts》1989,12(3):180-185

The otoliths of 200 postlarval spot (Leiostomus xanthurus) were marked by immersing the fish for 24 hr in a solution of 0.4 g tetracycline HCl l^?1 of salt water (15 ‰). The resulting time-mark could later be identified under ultraviolet (UV) light with an epifluorescence microscope. Spot were held in the laboratory or in the field for up to 30 d. Two validation methods were employed to document daily increment formation. The total number of increments per otolith, or the number of increments formed after the time-mark, were regressed against days held in an experiment. The hypothesis of one increment per day would result in a regression coefficient not significantly different from 1.0. In the field both the total count method (b=1.05) and the time-mark method (b=0.90) supported a one-increment-per-day hypothesis and were not significantly different from each other (p>0.05). In the laboratory the total count method (b=0.56) and the time-mark method (b=0.36) were significantly different from 1.0 (p<0.05), and thus did not support the one-increment-per-day hypothesis. Failure to resolve a one-increment-per-day deposition rate in the laboratory was primarily attributed to food limitation in the experiments.  相似文献   

Collection efficiency of seine and rotenone samples from tidal creeks,cape fear river,North Carolina     

Michael P. Weinstein  Robert W. Davis 《Estuaries and Coasts》1980,3(2):98-105

Efficiency, defined as the percentage of the total number of individuals captured from a known area of tidal creek (blocked with seines), was studied on six occasions from December 1976 through August 1978. Sampling was conducted at two stations near the Cape Fear River, Southport, North Carolina using either seines or rotenone. For the three most abundant species collected by each method, the range for seine efficiencies (60.6±19.4 to 78.0±9.4%) was generally narrower than that for rotenone (29.6±9.5 to 57.7±14.8%). However, overall species richness was better represented by rotenone, the mean percentage of species captured for all samples was 92.1% versus 70.3% for seines. Consistent patterns in efficiency for individual species with regard to size, age, or water temperature were absent. A comparison of individual collections with that of the sample “universe” trapped between the block nets indicated that a representative sample of the extant nekton community was taken by each method.  相似文献   

The Road Ahead: The Sustainability Transition and Coastal Research     

Michael P. Weinstein 《Estuaries and Coasts》2009,32(6):1044-1053

Although the organizing committee for the 2007 Coastal and Estuarine Research Federation (CERF) Biennial Conference and its international members supported the inclusion of sustainability science as a thematic element of the meeting, a preliminary review of program abstracts, conducted by entering various combinations of key words into the conference search engine, identified only 50 individual abstracts that incorporated one or more of the key words, or 3.8% of the 1,300 papers presented. Moreover, only 25 abstracts (1.9%) made specific reference to the integration of the natural and social sciences in emerging coastal research priorities. In this context, a framework is presented for incorporating the concepts of sustainable development, sustainability science, especially for the urban coast, and human dimensions into the amalgam of future US and international CERF research.  相似文献   

Dietary transfer of fluoranthene from an estuarine oligochaete (Monopylephorus rubroniveus) to grass shrimp (Palaemonetes pugio): Influence of piperonyl butoxide     

Filipowicz AB  Weinstein JE  Sanger DM 《Marine environmental research》2007,63(2):132-145

The objective of this study was to determine the potential for dietary transfer of sediment-associated fluoranthene from tubificid oligochaetes (Monopylephorus rubroniveus) to grass shrimp (Palaemonetes pugio). Grass shrimp, either in the presence or absence of sublethal waterborne concentrations of the metabolic inhibitor, piperonyl butoxide (PBO), were fed fluoranthene-dosed oligochaetes for 5-days. All grass shrimp bioaccumulated fluoranthene; however, bioaccumulation was 3X higher in the presence of PBO. Trophic transfer coefficients (TTCs) were 0.02 and 0.01 in the presence and absence of PBO, respectively. Following the 5-day accumulation period, shrimp in both treatments were allowed to depurate for 3 days. Depuration rates were significantly higher in PBO-exposed shrimp. These results demonstrated that sediment-associated fluoranthene can be transferred through the diet from oligochaetes to grass shrimp, and the presence of PBO enhanced fluoranthene bioaccumulation. However, the comparatively low TTCs suggest that biomagnification of fluoranthene in estuarine food webs is low.  相似文献