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1.
Mahnaz Parvaneh Nejad Shirazi Mohammad Bahrami Hassan Amiri Bakhtiar Omid Bamdad 《Historical Biology》2013,25(4):493-501
The Jahrum Formation act as reservoir rocks in the Zagros Mountains west of Iran. For the study of this formation, a stratigraphic section of Lapoee which is situated north of Shiraz has been examined. Petrographic and stratigraphic results along with field observations show that the Jahrum Formation consists of cream-grey thin-to-medium-bedded limestone so that at the top of the formation, they are locally changed to dolomite. The Jahrum Formation overlies the Sachun Formation. We also found Nubecularids as paleoecology indicators in middle parts of the Jahrum Formation. The presence of Nubecularids in the Lapoee stratigraphic section (i.e. the Jahrum Formation) indicates a lagoon depositional environment. 相似文献
2.
Saurav Dutta Devapriya Chattopadhyay Debarati Chattopadhyay Sambuddha Misra Alexandra V. Turchyn 《Lethaia: An International Journal of Palaeontology and Stratigraphy》2020,53(3):382-395
The Kutch Basin is unique among the western Indian sedimentary basins because of its near-complete sequence of post-Palaeozoic rocks. Due to extensive marine influence, the Oligocene–Early Miocene formations of the basin, namely Maniyara Fort, Khari Nadi and Chhasra, contain numerous shellbeds. Although age assignments of these formations exist based on foraminiferal biostratigraphy, detailed numerical age of the lithounits are yet to be established. We have identified a total of eleven distinct shellbeds (oldest SB 01 to youngest SB11) from this interval primarily containing bivalve fossils. Using 87Sr/86Sr of selected oyster and pectinid shells with pristine shell characteristics, we report the age of four shellbeds. The ages of SB 01, SB 04, SB 06 and SB 10 are 24.37, 17.31, 16.85 and 15.38 Ma, respectively. Our dates suggest a Chattian (24.37 Ma) age for SB 01 from the Bermoti Member, validating the previous biostratigraphical estimates from the Maniyara Fort Formation. The Chhasra Formation, however, shows a younger range of ages (17.31–15.38 Ma) characterized by a transition from the Burdigalian (SB 04–SB 06) to the Langhian (SB 10) stages. These dates have important implications in the study of sequence stratigraphy, Palaeobiogeography and tectonic history of the Kutch Basin. A surface with subaerial exposure is found in SB 08 (between 16.85 and 15.38 Ma) that corresponds to a global eustatic sea-level decrease (Mi2). Our new dates will also help evaluate the response of marine fauna to the closure of the Tethyan seaway around 19 Ma due to the formation of ‘Gomphotherium Landbridge’. The dated shellbeds enable us to identify pre- and post-closure fauna and assess the effect of biogeographical separation on these fauna. These dates have important implications in evaluating the regional geological record of western India in the context of various global events. 相似文献
3.
Tree-ring based December–February precipitation reconstruction in the southern Zagros Mountains,Iran
We developed the first tree-ring width chronology from Quercus brantii Lindel for the period 1796–2015 in the southern Zagros Mountains, Iran, using standard dendrochronological procedures. Climate-growth relationships revealed that DecemberöFebruary precipitation has strong positive effects (r = 0.66; P < 0.01) on the species’ growth while mean temperature during the growing season has strong negative effects. Spatial correlations with Palmer Drought Severity Index (PDSI) and gridded precipitation data revealed that the chronology contains regional climate signals and tree growth variations may represent precipitation fluctuations over large areas of the Middle East. The linear regression model accounts for 44% of the actual DecemberöFebruary precipitation variance. The reconstructed precipitation revealed that over the period 1850–2015 extreme dry years occurred in 1870-71, 1898, 1960 and 1963-64, and extreme wet years occurred in 1851, 1885, 1916 and 1921 in the southern Zagros region. The longest dry period lasted 16 years and occurred from 1958 to 1973. Two-year consecutive wet and dry events showed the highest frequencies and the average length of dry and wet events were 2.9 and 3.6 years over the reconstructed period. Correlations between the long-term reconstructed precipitation and the North Atlantic Oscillation (NAO), Southern Oscillation Index (SOI), and Pacific Decadal Oscillation (PDO) confirmed the effects of teleconnection patterns on precipitation in the southern Zagros region. 相似文献
4.
This study is focused on the sedimentary environments, facies distribution, and sequence stratigraphy of the Coniacian–Santonian
sediments of the Bangestan Palaeo-high in the Bangestan Anticline (Zagros, Iran). These sediments are subdivided into nine
microfacies types belonging to various sedimentary environments, ranging from continental lacustrine to very shallow and relatively
deep-water (hemipelagic to pelagic) marine environments. The lower boundary of the studied sections is characterised by an
unconformity. The lacustrine and very shallow marine sediments at the base of the studied sections are interpreted as a lowstand
system tract. The establishment of an open shelf carbonate platform took place during the transgressive system tract. The
maximum flooding zone of the Early Santonian is an important surface because it extends from the distal to the proximal part
of the depositional environment. 相似文献
5.
The Salton Sea is a hypersaline lake located in southeastern California. Concerns over the ecological impacts of sediment
quality and potential human exposure to dust emissions from exposed lakebed sediments resulting from anticipated shrinking
of shoreline led to a study of pesticide distribution and transport within the Salton Sea Basin, California, in 2001–2002.
Three sampling stations—upriver, river mouth, and offshore—were established along each of the three major rivers that discharge
into the Salton Sea. Large-volume water samples were collected for analysis of pesticides in water and suspended sediments
at the nine sampling stations. Samples of the bottom sediment were also collected at each site for pesticide analysis. Sampling
occurred in October 2001, March–April 2002, and October 2002, coinciding with the regional fall and spring peaks in pesticide
use in the heavily agricultural watershed. Fourteen current-use pesticides were detected in water and the majority of dissolved
concentrations ranged from the limits of detection to 151 ng/l. Diazinon, EPTC and malathion were detected at much higher
concentrations (940–3,830 ng/l) at the New and Alamo River upriver and near-shore stations. Concentrations of carbaryl, dacthal,
diazinon, and EPTC were higher in the two fall sampling periods, whereas concentrations of atrazine, carbofuran, and trifluralin
were higher during the spring, which matched seasonal use patterns of these pesticides. Current-use pesticides were also detected
on suspended and bed sediments in concentrations ranging from detection limits to 106 ng/g. Chlorpyrifos, dacthal, EPTC, trifluralin,
and DDE were the most frequently detected pesticides on sediments from all three rivers. The number of detections and concentrations
of suspended sediment-associated pesticides were often similar for the river upriver and near-shore sites, consistent with
downstream transport of pesticides via suspended sediment. While detectable suspended sediment pesticide concentrations were
more sporadic than detected aqueous concentrations, seasonal trends were similar to those for dissolved concentrations. Generally,
the pesticides detected on suspended sediments were the same as those on the bed sediments, and concentrations were similar,
especially at the Alamo River upriver site. With a few exceptions, pesticides were not detected in suspended or bed sediments
from the off-shore sites. The partitioning of pesticides between water and sediment was not predictable from solely the physical–chemical
properties of individual pesticide compounds, but appear to be a complicated function of the quantity of pesticide applied
in the watershed, residence time of sediments in the water, and compound solubility and hydrophobicity. Sediment concentrations
of most pesticides were found to be 100–1,000 times lower than the low-effects levels determined in human health risk assessment
studies. However, maximum concentrations of chlorpyrifos on suspended sediments were approximately half the low-effects level,
suggesting the need for further sediment characterization of lake sediments proximate to riverine inputs.
Guest editor: S. H. Hurlbert
The Salton Sea Centennial Symposium. Proceedings of a Symposium Celebrating a Century of Symbiosis Among Agriculture, Wildlife
and People, 1905–2005, held in San Diego, California, USA, March 2005 相似文献
6.
Small soda lakes represent one of the most vulnerable ecosystem types due to their high hydrological sensitivity to climate change and anthropogenic interventions. Since diatoms are excellent bioindicators, determining the β-diversity and the structuring dynamics of diatom metacommunities can provide valuable information for conservation planning for soda pans. In this study, two diatom metacommunities were surveyed monthly during a one-year period from distinct regions of the Carpathian basin: the Fert?-Hanság National Park (FH) between 2013 and 2014, and the Danube-Tisza Interfluve (DT) between 2014 and 2015. We explored whether β-diversity of diatom assemblages in the two regions is enhanced by species turnover or nestedness (related to richness differences) and investigated the role of deterministic and stochastic processes in shaping β-diversity patterns. Furthermore, we evaluated the contribution of environmental variables, geographic distance and temporal variation to community structure. High β-diversity (>90%) was revealed for both metacommunities, and was maintained primarily by species turnover. Within the metacommunity of the DT where the natural hydrological cycle of soda pans is not disturbed, diatom communities assembled mainly due to the selection force of environment at a spatiotemporal scale. In the soda pans located in the habitat reconstruction area of the FH, besides species-sorting, significant temporal variation in community structure appeared as a result of water management and periodic water supply. Our results point to the need for a conservation management strategy which maintains the natural hydrological regime of small saline lakes, and therefore their habitat heterogeneity which is of high conservation value. 相似文献
7.
《Marine Micropaleontology》2005,58(1):56-72
The Cape Roberts Project (CRP) recovered a composite Eocene to lower Miocene stratigraphic sequence from the Victoria Land Basin, Antarctica, which includes four new species, described herein, of the biostratigraphically useful fossil marine diatom genus Kisseleviella. Specimens of this extinct genus occur predominantly in neritic sediments, which along with the chain-forming nature and morphological similarity to extant benthic genera (e.g. Cymatosira) suggest that Kisseleviella was tychopelagic. The species of Kisseleviella described here appear to be endemic to the Antarctic region with an ecological preference for nearshore environments. The polythermal, subpolar glacial regime invoked for the late Eocene–early Miocene may have acted as a significant driver of speciation events in Antarctic Kisseleviella. Phylogenetic analysis of fossil genera such as Kisseleviella allows the development of a neritic biostratigraphic zonation. New taxa formally proposed are: Kisseleviella tricoronata, Kisseleviella cicatricata, Kisseleviella gaster and Kisseleviella faballiforma. 相似文献
8.
In Sung Paik Hyun Joo Kim Kyungsik Kim Eun-Kyoung Jeong Hee Cheol Kang Ho Il Lee Kazuhiko Uemura 《Review of Palaeobotany and Palynology》2012
Occurrence, preservation and evidence of plant–insect interactions in the leaf deposits of the early Miocene Geumgwangdong Formation are described, and the taphonomy and palaeoenvironmental implications are interpreted. The Geumgwangdong leaf beds are tuffaceous lacustrine deposits consisting mainly of thin-bedded sediments, including shale. Deposition was dominated through the vertical aggradation of fine-grained sediments by suspension sedimentation, rather than by the fluvial deposition of coarse-grained sediments. The majority of the fossil leaves were preserved by compression rather than merely preserved as impressions. The Geumgwangdong leaf deposits can be characterised as a wind-transported, dysaerobic, deep-water, lake taphofacies with some influence of water-transport. The fossil flora of the Geumgwandong Formation consists of 64 taxa belonging to 27 families and 43 genera. The dominant taxa were Metasequoia, Fagus, Betula, Quercus, Acer, Zelkova, and Leguminosae, which is comparable to the Early Miocene cool–temperate Aniai-type Flora of north-east Japan. The similarity between the lake settings of the Geumgwangdong Formation and the Aniai Coal-bearing Formation might have been a factor in the development of similar plant–fossil assemblages. Although traces of insect damage in the fossil leaves of the Geumgwangdong Formation were commonly observed, more than 90% of the damaged leaves showed a low level of diversity and degree of insect damage (< 10%), which is indicative of a cool–temperate palaeoclimatic condition. Despite latitudinal differences and geographic separation, the development of similar floras in the Geumgwangdong Formation of south-east Korea and the Aniai Coal-bearing Formation of north-east Japan during the early Miocene could have been influenced by the incipient NW–SE sea-floor spreading that resulted in the opening of the East Sea (Sea of Japan), which might have enabled floral migration between the two regions. This study provides useful data for understanding not only the taphonomy and palaeoenviroments of the leaf deposits, but also the spatial development of the flora resulting from palaeogeographic changes driven by tectonic movement during the early Miocene in Far East Asia. 相似文献
9.
Many sedimentary processes can lead to the formation of mixed carbonate–siliciclastic sediments in shallow shelf environments. The Miocene Saint-Florent Basin (Corsica), and in particular the Monte S. Angelo Formation, offers the possibility to analyze coarse mixed sediments produced by erosion of a rocky coast, ephemeral stream input, and shallow-water carbonate production dominated by red algae. The Monte S. Angelo Formation was deposited during the Burdigalian to Langhian interval. During this interval, the island of Corsica experienced increased subsidence related to the development of the Ligurian-Provençal Basin and associated Sardinia-Corsica block rotation. Four main rhodolith-rich subfacies have been recognized: conglomerate with rhodoliths, massive rhodolith rudstone, well-bedded rhodolith rudstone, and rhodolith floatstone. The four facies have been interpreted as having been deposited in different environments of a gravel-dominated, nearshore to offshore prograding wedge. Deep-water melobesioids dominate the red algal assemblage from shoreface to offshore. Shallow-water subfamilies of lithophylloids and mastophoroids occur in only accessory amounts. Poor illumination is believed to be due to terrigenous input by ephemeral streams and wave- and current-resuspension. Resuspension processes are favored by the limited occurrence of seagrasses. Two types of siliciclastic–carbonate mixing processes characterize the investigated rhodolith-rich deposits: (1) punctuated mixing, produced by the re-deposition of terrigenous sediments by debris-flow processes during flooding events onto carbonate sediments together with rhodoliths of the shoreface environments, and (2) in situ mixing, produced by growth of coralline algae on siliciclastic pebbles to form the rhodoliths. 相似文献
10.
11.
Francisco Javier Ruiz-Sánchez Matthijs Freudenthal Samuel Mansino Vicente Daniel Crespo Plinio Montoya 《Pal?ontologische Zeitschrift》2014,88(1):85-98
Apocricetus Freudenthal et al. (Treballs del Museu de Geologia de Barcelona 7: 11–93, 1998) is a medium to large Cricetinae, practically without mesolophids in the m1 and m2, with long third molars; anterior and posterior protolophule are present and the posterior metalophule is reduced or absent. Apocricetus barrierei (Mein and Michaux Comptes Rendus Academie de Sciences de Paris D 270: 2780–2783, 1970) was defined on the basis of three specimens from the French locality Chabrier. Apart from this site, several French and Spanish localities of Early Pliocene age contain remains of this species. Despite this extra material, the species is poorly characterized, and none of the localities contains material of all six dental elements. In this paper, two new assemblages from La Bullana 2B and La Bullana 3 (Cabriel Basin, Spain) are described. The rich assemblage from La Bullana 2B provides a better insight in the metrical and morphological variability of this species. 相似文献
12.
This paper describes the first fossil porcupine remains from Iran. Four upper cheek teeth and two fragmentary lower incisors
present sufficient characters for identification as Hystrix aryanensis, a species previously known from the late Miocene locality of Molayan (Afghanistan) estimated at ca. 7–8 Ma. The dental features
of porcupines are discussed to show their systematic value and highlight evolutionary trends in late Miocene and Pliocene
porcupines. This study also discusses the dispersal history of fossil porcupines in relation to paleobiogeographic provinces
and environmental changes during late Miocene to late Pliocene time. 相似文献
13.
Circulichnis is a puzzling, ring-like trace fossil preserved on bedding planes. It is represented mostly by its type ichnospecies C. montanus, which is characterized by an evenly circular or elliptical course. A new ichnospecies, C. ligusticus, is distinguished based on material from deep-sea Oligocene–Miocene deposits of the Tertiary Piemonte Basin, NW Italy. It shows a winding or irregular course. A new model of Circulichnis is proposed as an exploration burrow produced mostly by the trace makers of Helminthoidichnites, Gordia, or Helminthopsis, as it moved to a different sediment layer to checking its feeding utility. This type of behaviour occurred already by the Ediacaran and is common in marine, mostly deep-sea bedded sediments. The trace makers belong mostly to polychaetes in marine sediments and to oligochaetes in continental sediments. 相似文献
14.
《Marine Micropaleontology》2006,58(2):83-102
A marine Cretaceous succession (Barremian–Albian) of a cored borehole (BGS 81/40), located in the Central North Sea Basin, has been examined with respect to its planktic and benthic foraminiferal content, as well as for calcareous nannofossils. The distribution patterns of foraminifera and calcareous nannofossils allow for a two fold division of the investigated interval. (1) The Barremian–earliest Aptian interval, which reflects a marine, temporary restricted setting. This is indicated by sporadic occurrences of planktic foraminifera with very rare planispiral forms suggesting short-term connections of the Boreal and Tethyan Realms. The benthic foraminiferal assemblages indicate aerobic, sometimes dysaerobic bottom-water conditions. High abundances of nannoconids in the Barremian suggest enhanced stratification and/or warm, oligotrophic surface water. (2) The late Aptian–early Albian interval, which was characterised by an open-oceanic environment with cool and aerobic surface water conditions. Planktic foraminifera are more abundant and diverse than in the lower interval. Trochospiral hedbergellids dominate the foraminiferal assemblages. The episodic occurrences of planispiral, clavate and trochospiral-flattened planktic morphotypes indicate the existence of a seaway between the Boreal and the Tethyan Realms. Aerobic to dysaerobic bottom-water conditions are suggested by the composition of the benthic foraminiferal assemblages. High abundances of cool-water taxa within the calcareous nannofossil assemblages indicate a cooling trend across the latest Aptian and earliest Albian. 相似文献
15.
Capsule?Of 26 species of wintering waterbirds, 18 showed an increase in numbers, five showed a decrease and two showed no change. Aim?To assess long-term trends in the numbers and distribution of the 26 most abundant wintering waterbird species in the Czech Republic. Methods?We used International Waterbird Census data from between 48 and 639 wetland sites which had been counted annually in the Czech Republic from 1966 to 2008. From these data long-term changes in numbers and distributions were determined. Log-linear Poisson regression analysis was used to estimate missing data using trim software. The distribution of each species was described as the ratio of the number of sites occupied by that species to the total number of sites investigated. Results?Increasing trends were found for 18 species, five species were found to be declining, one species was stable and two species were found with uncertain trends. Wintering distributions (the ratio of sites occupied by a given species to the total number of sites counted) increased in 16 species and decreased in two species, broadly correlated with the species changes in numbers. Conclusion?In most species changes in numbers as well as changes in distribution followed the Western Palearctic population trends. Those species which increased were mainly piscivores and included geese, ducks and gulls. Scarcer species also exhibited an increase in numbers. The changes in numbers (both positive and negative) were more frequent among species associated with running water, whereas species which showed uncertain trends were more frequently recorded on standing water, which is more affected by variable weather conditions. 相似文献
16.
This paper presents a review of palaeoenvironmental reconstructions of scleractinian corals from the Oligo–Miocene Qom Formation in northeastern Esfahan, central Iran. A total of nine genera and four species of colonial corals are identified, including Platycoenia iranica, Goniopora sp., Porites sp., Tarbellastraea reussiana, Solenastrea sp., Favites neglecta, Leptoria sp., Hydnophora cf. pulchra, Hydnophora sp., and Madracis (?) sp. These corals, all parts of massive colonies, are indicative of a reefal environment, with the main constituents, including Leptoria and Hydnophora, possessing massive meandroid, massive hydnophoroid and massive mushroom- to dome-shaped hydnophoroid colonies. The corals identified here are generally indicative of the upper photic zone and shallow water depths of less than 20 m. In the reefal environment, these corals built a wave-resistant and rigid carbonate framework in the form of a reef-front zone encapsulated by environmental conditions including low sedimentation rates and high wave energy. The occurrence of Goniopora and Porites with distinct calicles reflects clearer waters in the external part of the reefal environment. 相似文献
17.
The palynological investigation of the early Middle Miocene fluviolacustrine sedimentary rocks interfingering with volcanics of the Galatean Volcanic Province at Pelitçik Basin (Central Turkey) have yielded palynomorphs belonging to 51 spore and pollen taxa. The pollen record is dominated by Ulmus, Pinaceae, Quercus, Carpinus and Carya, and appears to reflect climatic conditions. Two pollen zones were established based on changing abundances of plant taxa. Zone 1 is characterized by dominance of Ulmus and Pinaceae. Zone 2 is differentiated and characterized by a dramatic increase in, and predominance of, Ulmus, Carya, deciduous Quercus, Carpinus, Salix and Pinaceae. Mixed mesophytic forests were widespread in the basin suggesting warm and temperate climate. The decreasing relative percentage of thermophilous taxa, with Engelhardia as the main component, and warm temperate taxa, such as Carya, at the upper part of Zone 2 generally indicates a climatic deterioration, probably related to the Middle Miocene cooling. 相似文献
18.
Olivier Rieppel 《Historical Biology》2013,25(3):313-325
Othenio Abel is widely acclaimed as the founder of paleobiology; of the journal Palaeobiologica and of the Paleobiological Society in Vienna. His National–Socialist sympathies, which he shared with fellow paleobiologist Henry Fairfield Osborn from the American Museum of Natural History, resulted in his forced retirement from the University of Vienna in 1934. Abel secured subsequent employment at the University of Göttingen, later sought help from Nazi officials to create his own institute in Salzburg. A leader amongst German paleontologists, Abel supported efforts of the Deutsche Palaeontologische Gesellschaft to align paleobiology with Nazi ideology (‘National–Socialism is politically applied biology’) to secure more support for the discipline. Abel's paleobiology was neo-Lamarckian in nature, based on a ‘reaction theory’ of adaptation. Abel attempted to unify paleontology with biology under a universal law of nature – the Law of Biological Inertia – that itself was anchored in classical physics. 相似文献
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Tethyan microencrusters and microbial crusts, most of them previously unknown in Japanese Mesozoic biotas, are present in the uppermost Jurassic–lowermost Cretaceous Torinosu Limestone distributed in southwestern Japan. They construct reefal facies together with reef-forming metazoans. Bacinella irregularis and Lithocodium aggregatum are quantitatively most important, while subordinate constituents include Thaumatoporella parvovesiculifera, Koskinobullina socialis , Iberopora bodeuri , Girvanella sp. and Tubiphytes morronensis. They are especially common in the shallow-water reefal facies, but appear micritic in outcrops. Microencrusters and microbial crusts can only be recognized in thin sections, and they grow around the reef building metazoans and form bindstone. Each microencruster exhibits some specific spatial distribution associated with its paleoecology. Similarities with the taxonomic composition of the upper Jurassic Tethyan microencruster association imply that the community extended geographically at least to the Tethyan gateway where the Japanese Island Arc was located. 相似文献