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1.
Plant macrofossils from the basal inorganic sediments at Tom Swamp, north central Massachusetts, contained leaves, seeds, and fruits of arctic-alpine species, nearly all of which occur at present near the summits of Mt. Washington and Mt. Katahdin (New England) and in other alpine and arctic areas northward in eastern North America. Included were the needle-leaves of the dwarf shrub, Harrimanella hypnoides (L.) Coville, which matched comparative modern leaf samples in all anatomical details. The macrofossil assemblage was deposited before 12,830 ± 120 radiocarbon years ago and prior to the expansion of spruce populations in the region. Fossils of H. hypnoides suggest that snow beds were a regular feature of the summer landscape of southern New England during late glacial time. Calculations using the average lapse rate indicate that the mean annual paleotemperature in the Tom Swamp area may have been depressed 8–9 C below present means.  相似文献   

2.
Robert Metz 《Ichnos》2020,27(2):142-151
Abstract

Fluvial deposits of the uppermost Stockton Formation (Late Triassic), Newark Basin, west-central New Jersey have yielded an assemblage of trace fossils. Dominated by burrows, specimens include Cochlichnus anguineus, Helminthoidichnites tenuis, Planolites beverleyensis, Scoyenia gracilis, Spongeliomorpha carlsbergi, Treptichnus bifurcus, Treptichnus pollardi, plant remains, and an undetermined vertebrate trace fossil. The assemblage belongs to the Scoyenia ichnofacies. On the basis of stratification and primary sedimentary structures, the beds are interpreted as deposits in a meandering stream environment. Larval insects, wormlike forms, and arthropods are probably responsible for most of the animal traces in wet or moist channel, floodplain, and point bar sediments subject to subaerial exposure.  相似文献   

3.

A new trace fossil, Lunulichnus tuberosus, is described from fluvial deposits of the Wasatch Formation (early Eocene) at Fossil Butte National Monument, southwestern Wyoming, USA. L. tuberosus are straight, vertical to obliquely oriented, unlined cylindrical burrows with pronounced crescent-shaped wall sculptings. In situ examples of these trace fossils are most commonly preserved as sand-filled casts emanating from the erosional bases of fluvial channel sandstone bodies into underlying floodplain mudstone/siltstone beds. L. tuberosus is interpreted as the dwelling trace of a stream-dwelling decapod crustacean. Excellent preservation of fine detail, particularly their diagnostic crescent-shaped wall sculptings, support the hypothesis that L. tuberosus were excavated in firm substrata subjacent to fluvial erosional surfaces. As such, they are interpreted as constituents of alluvial Glossifungites trace fossil assemblages.  相似文献   

4.
Abstract

Scolicia is one of the most conspicuous trace fossils in lower shoreface deposits of the Miocene Chenque Formation of Patagonia, Argentina. This ichnotaxon consists of horizontal, sinuous or meandering trace fossils with a laminated backfill and two parallel strings located at the base. Abundant body fossils attributed to Brisaster iheringi occur in close association to these trace fossils. The echinoids are very well preserved, and most of the specimens have some areas with their spines attached in life position. In particular, preservation of the subanal tufts of spines, associated to isopores (which are interpreted as being associated to funnel building tube feet), supports the interpretation that these organisms are the producers of Scolicia isp. A shaft connecting the burrow with the sediment-water interface was not observed in vertical sections of the excavations, although on bedding plane surfaces, some small circular tube outlets are recognized. However, the great diversity and abundance of ichnofossils co-occurring in these deposits may preclude adequate identification of vertical structures. These deposits provide an excellent opportunity to integrate trace fossil data, body fossil information and observations from modern analogues in order to perform a morpho-functional analysis of Scolicia.  相似文献   

5.

The green alga Botryococcus is an important component of the phytoplankton in lake sediments from the Rotliegend of Central Europe. The first microscopic fossils from the Saar‐Nahe Basin that can be assigned to this genus are described and illustrated here. Their distribution at various stratigraphic levels shows that the primary production of the lakes was at least partially controlled by these green algae. The frequency of fossils in the sediments is correlated with grain size, which varied with the depositional environment. Their abundance is greater in sediments deposited in shallow water, especially in small lakes and in the littoral environments of larger lakes. Sediments of deep‐water lake bottoms contain only minor amounts of algal remains. The abundance of kerogen originating from phytoplankton and occurrences of Botryococcus fossils are correlated in these lake deposits.  相似文献   

6.
Cesare Ravazzi 《Plant biosystems》2013,147(3-4):751-770
Abstract

Fossil pollen of Aesculus aff. hippocastanum L. in the Leffe Basin (Early Pleistocene). Systematic position and palaeocology. A new pollen analysis has been undertaken in the lacustrine and palustrine deposits of Leffe (Northern Italy), in order to re-evaluate the flora, the vegetation dynamics and the climatic change at the southern margin of the Alps during the lowermost Pleistocene.

The present paper deals with the systematic position and the ecology of a fossil taxon of Aesculus discovered in the Leffe sediments. The taxonomical approach is based on a comparative investigation on the pollen morphology of all the present-living species and the fossil taxon from Leffe. Some diagnostic features of the apertures and the exine ornamentation allowed to distinguish some groups, almost coincident with the sections in which the genus is presently subdivided.

The pollen morphology of the taxa which belong to the sections living in temperate regions and in the subtropical-tropical SE-Asia (section Calothyrsus Koch) notably differ.

Among temperate groups, the Section Aesculus can be characterized by having the biggest projections on the colpus membrane. The fossil pollen from Leffe sediments can be related with this Section. Moreover, a comparison of the Japanese living species (A. turbinata Bl.), with the European one (A. hippocastanum L.), indicates that the fossil pollen grains from Leffe may be related to A. hippocastanum. This supports the hypothesis of a Neogene divergence of a pontic-european group inside the Section Aesculus in agreement with the macrofloral record of the Neogene in Europe. Afterwards the palaecology of the Leffe horse-chestnut is discussed. A comparison between fossil pollen spectra and the analogues in the modern vegetation (Colchide, Mesia, Caucasian region and Allegheny Mountains, U.S.A.) shows good relationships in the floral composition.

Finally, the extinction time of some elements of the Colchic-Hyrcanian flora in Italy during the Quaternary is discussed.  相似文献   

7.
A skull fragment (VM-0) from Orce, Granada, Spain, dated palaeomagnetically at about 1.6 Myr, is thought by some palaeontologist to be hominid, while others maintain it is equid. If hominid, it would be by far the oldest evidence ofHomo in Europe. Immunological studies on residual albumin in this fossil were carried out independently, and with different immunological methods, at the University of California, San Francisco (radioimmunoassay), and at the University of Granada, Spain (enzyme immunoassay). Other fossils attributed to hominids also studied wereVM1960 from Venta Micena, andCV-1 from Cueva Victoria, Murcia, Spain. Undisputed equid and bovid fossils from the same deposits and dated to a similar period as the Orce skull were also analyzed. Our results showed that species-specific albumin can be detected in 1.6 Myr-old hominid, equid and bovid fossils. The albumin from the Orce skull fragment and fromVM-1960 was immunologically closer to human albumin. These findings support the contention that theVM-0 andVM-1960 are hominid and that members of the genusHomo occupied southern Spain 1.6 Myr ago.  相似文献   

8.
Abstract

Bromlichnus bromleyi n.igen. n.isp., a compound trace fossil consisting of two segments representing dwelling and feeding, is described. Owing to a concentric spreite in a bow-shaped burrow, B. bromleyi is interpreted as made by holothurians. In most cases, it is connected to a repichnion. The new ichnotaxon derives from the narrow Pfalzpaint Subbasin of the Solnhofen archipelago (Upper Jurassic, SE Germany), interpreted as a tidal channel connecting two basins. The interrelationships of different behaviours reflected in compound trace fossils allow holistic analysis of the work of individual animals, enabling more accurate interpretation of tracemaker anatomy and function.  相似文献   

9.
Finds of fossil wood with bivalve wood borings (Teredolites clavatus and T. longissimus) occur in various facies and presumed sedimentary settings of the platform, shallow-marine Bohemian Crectaceous Basin. The basin comprises areas with sandy-dominated sediments, with marl and clay-dominated sediments, areas with predominat sandy-marly rocks, and finally areas dominated by calcareous nearshore sediments. Teredolites clavatus is common in fossil wood of sandstones, originating in beach or deltaic settings; marl and clay-dominated rock frequently bear wood fragments densely bored by Teredolites longissimus. When accompanied by evidence of marine environments as body fossils, glauconite or typical trace fossils, most of the wood fragments are bored. The presence/absence of borings in wood fragments can be considered the most reliable and easily useable criterion of distinction of marine settings in sandy sediments of the margin of the Bohemian Cretaceous Basin.  相似文献   

10.
Abstract

This report documents the discovery of repichnia trace fossils Ptychoplasma (P. excelsum and P. vagans) and Dendroidichnites (D. irregulare); the fodichnia traces ?Ctenopholeus (?C. kutcheri) and cubichnia traces Bergaueria (B. hemishperica) from silty limestones of the Cretaceous Bagh Formation. These trace fossils have significant implications for the depositional facies and the paleo-environmental interpretations of the Bagh Formation, which have long been debated. Previously identified traces of Protovirgularia were also found in association with the newly discovered trace fossils, indicating the coexistence of both wedge and cleft-foot bivalves. The western area of the mainland Gujarat is known for its abundance and diversity of trace fossils. The trace fossil bearing Cretaceous rocks in the region occur as thin irregular detached patches and linear outcrops. Previous studies documenting trace fossil assemblages from the Bagh Formation characterised them as a combination of dwelling, feeding and locomotion forms, with the stratigraphic unit becoming less fossiliferous westward. Trace fossils in this formation have been studied and described by many workers in the surrounding areas; however, ichnofossils described in this study are new to the Bagh Formation in this area. These trace fossils were observed on recently exposed outcrops along road cuts associated with new road construction from Khasra to Mogra village around Kadipani in Mainland Gujarat.  相似文献   

11.
Abstract

Three species within the genus Calophyllum collected from middle Miocene Fotan Group sediments in Zhangpu County, Fujian, southeastern China are described in this paper. These fossils include Calophyllum zhangpuensis sp. nov., Calophyllum striatum, and Calophyllum suraikholaensis. The new fossil species C. zhangpuensis sp. nov. is oval, possesses entire leaves with closely spaced parallel secondary veins and has a round, or slightly retuse, apex. These specimens represent the first known fossil records of this relative wide leaf-type form of Calophyllum from China and have a length:width (L:W) ratio less than 3:1. In combination with the known modern geographic distribution and habitats of this wide leaf-type Calophyllum and other plants, data suggest that the middle Miocene Fotan flora is indicative of a warm climate. Thus, based on available fossil data, we speculate that this genus probably originated in India during the Paleocene before spreading from India to Bangladesh and into China, Sumatra, Malaysia, Indonesia, and Java during the Neogene, leading to its modern distribution. At least, the 3 fossil species in this region can explain floristic exchange between India, Fujian, and South China, which is consistent with previous studies; the occurrence of these 3 species indicates that Calophyllum began to diversity in China no later than the Miocene.  相似文献   

12.
Western Kenya is well known for abundant early Miocene hominoid fossils. However, the Wasiriya Beds of Rusinga Island, Kenya, preserve a Pleistocene sedimentary archive with radiocarbon age estimates of >33–45 ka that contains Middle Stone Age artifacts and abundant, well-preserved fossil fauna: a co-occurrence rare in eastern Africa, particularly in the region bounding Lake Victoria. Artifacts and fossils are associated with distal volcanic ash deposits that occur at multiple localities in the Wasiriya Beds, correlated on the basis of geochemical composition as determined by electron probe microanalysis. Sediment lithology and the fossil ungulates suggest a local fluvial system and associated riparian wooded habitat within a predominantly arid grassland setting that differs substantially from the modern environment, where local climate is strongly affected by moisture availability from Lake Victoria. In particular, the presence of oryx (Oryx gazella) and Grevy’s zebra (Equus grevyi) suggest a pre-Last Glacial Maximum expansion of arid grasslands, an environmental reconstruction further supported by the presence of several extinct specialized grazers (Pelorovis antiquus, Megalotragus sp., and a small alcelaphine) that are unknown from Holocene deposits in eastern Africa. The combination of artifacts, a rich fossil fauna, and volcaniclastic sediments makes the Wasiriya Beds a key site for examining the Lake Victoria basin, a biogeographically important area for understanding the diversification and dispersal of Homo sapiens from Africa, whose pre-Last Glacial Maximum history remains poorly understood.  相似文献   

13.
孙海静  罗翠 《古生物学报》2024,63(2):138-153
埃迪卡拉纪—寒武纪之交见证了地球—生命系统不同圈层的重大变革, 是复杂多细胞生物演化的重要转折期。华南是开展相关研究的主要区域之一, 但前人工作主要集中在化石材料丰富的浅水台地相区, 深水区生物组成面貌尚未得到充分认识。本研究对斜坡相区贵州交榜剖面的留茶坡组进行了详细研究, 通过酸蚀和薄片观察发现了丰富的化石材料, 包括: 海绵骨针、软舌螺、可能的原牙形类(? Protohertzina sp.)和织金钉类(? Zhijinites sp.)、球形疑源类、Megathrix longus, 及不同类型的多细胞藻类, 亲缘关系未定的Poratusiramus sp.、球形化石和形态多样的丝状、片状化石等。该化石组合属于寒武纪纽芬兰世幸运期, 其中的骨骼化石以海绵骨针为主。化石组合中既有与浅水区共有分子, 也有深水区特有类群, 丰富了斜坡相区的化石记录, 具有潜在的地层对比和演化意义。  相似文献   

14.
The distinctive trace fossil, Ophiomorpha irregulaire, differs from other ichnospecies of Ophiomorpha in the so-called “meander maze” configuration of its horizontal course, and by the possession of unevenly distributed, elongated, tapering wall-lining pellets. The ichnospecies has been described, without doubt, from only two outcrop localities, both Late Cretaceous in age and both lying within the Cretaceous Western Interior Seaway. Only a single, almost convincing example of the trace fossil has been reported elsewhere, in a Lower Jurassic outcrop in Italy. Apart from this last occurrence, the distribution of O. irregulaire in outcrop suggests that the trace fossil has a restricted time span and geographical range. In contrast, O. irregulaire is identified more commonly in cores, and these occurrences show no clear geographical restrictions and are reported in sediments of Jurassic as well as Cretaceous age. Outcrop exposures of Jurassic and Cretaceous sediments have been extensively studied by ichnologists and if the large, eye-catching O. irregulaire were as common as is suggested by core material, then the trace fossil would not have escaped notice in outcrop.Identification of the trace fossil in core is generally made on the basis of two-dimensional, vertical sections. The characteristic meander maze form cannot be seen in this view, and the identification is thus based almost entirely on the special shape of the lining pellets. As is well known, the identification of large trace fossils in the restricted format of core lacks the security of extensively exposed trace fossils in outcrop. The discrepancy between age and geographic distribution of O. irregulaire in outcrop and core suggests that some misidentification is occurring in core analysis.  相似文献   

15.
Abstract

Tursia flabelliformisigen. et isp. nov. is described from the lower Pleistocene Argille Subappennine Formation near Tursi, southern Italy. The trace fossil occurs in protected sandy shoreface sediments and is associated with abundantBichordites. Tursia is a vertical fan-shaped spreite structure that is interpreted as the feeding trace of a deep infaunal deposit-feeding organism, either bivalve or “worm.”  相似文献   

16.
In contrast to the opinion of Miki (1952 b, p. 349) the genus Hemitrapa Miki (Trapellaceae) is not only found in Asia and America but also in Europe. Wrongly determined fossils of the type „Trapa silesiaca Goeppert”︁ (the original species from Schoßnitz in Poland is under research by M. Lancucka-Srodoniowa, Krakow) belong to the genus Hemitrapa Miki. Some other Bavarian fossils are newly decribed here as Hemitrapa heissigii sp. nov. Hemitrapa fossils grew not only in the Senftenberg area (Menzel 1906), in Silesia (Kräusel 1920) or the Niederlausitz area (Menzel in Gothan & Sapper 1933), at Konin (Raniecka-Bobrowska 1954), but possibly also near Cologne (Kilpper 1969 and Kramer 1974) and at Ponholz (Gregor 1980). Especially in the Middle Miocene Upper Freshwater Molasse of Bavaria the fossil species Hemitrapa heissigii is found in numerous specimens near Eberstetten, Haag a. d. Amper and Rauscheröd (all in southern Bavaria). Hemitrapa heissigii can be used as an index-fossil and signs Uppermost Miocene sediments (Badenian, Samartian). The occurence in Pliocene localities is to be prooved. The whole group around Hemitrapa is considered to be a “late element” (Upper Miocene) in Europe.  相似文献   

17.
Abstract

Pollen analysis of lake sediments on Mt. Vulture in Basilicata (Southern Italy).—A marshy sediment, about 7 meters thick, containing fossil pollen, has been discovered in a little lake of volcanic origin on a slope of Mount Vulture in Lucania at 656 m above sea level.

The sediment shows four distinct layers from the top to the bottom. The deepest layer, from 7 to 5.75 m, consisting of clay containing Betula and Ostrya, indicates a rather arid climate; the next layer, from 5.75 to 3.75 m, made up of mud rich in organic substance and containing pollen of Fagus and Abies, is witness of a damp and warmer climate; the following layer, from 3.75 to 2.25 m, with clay containing Betula, Ulmus, Ostrya and Corylus suggests a return to a more arid climate; lastly, the upper layer, from 2.25 m to the surface, with marshy mud rich in organic substance and pollen of plants with greater water requirements leads us to think of a return to a damper climate.  相似文献   

18.
A sequence of Lower Ordovician (Arenig) turbidites in Co. Wexford, Eire, has yielded one of the earliest diverse ichnofaunas yet recorded from deep water sediments comprising: Chondrites, Glockerichnus, Gordia, Helminthopsis, Lorenzinia, Neonereites, Palaeophycus, Paleodictyon, Planolites, Sublorenzinia, Taenidium, Taphrhelminthopsis, Teichichnus and Tomaculum. This ichnofauna is critical in any analysis of the colonisation of the deep seas by trace fossil‐producing animals.

A world‐wide review shows that the earliest trace fossils are mainly from Late Precambrian shelf sea environments, but many more evolved during very rapid diversification in the pre‐trilobite Lower Cambrian.

There was little increase in diversity in shallow water after the Lower Cambrian but a progressive colonisation of the deep ocean took place and this accelerated during the Ordovician, when the main lineages of deep sea trace fossils were established there. Rosetted, patterned, meandering and simple spiral forms evolved in shallow water in the Upper Precambrian and pre‐trilobite Lower Cambrian and only later migrated into the deep sea, whereas complex, closely programmed, spiral traces may have evolved there.  相似文献   

19.
The increase in trace fossil diversity across the Neoproterozoic-Cambrianboundary often is presented in terms of tabulations of ichnogenera.However, a clearer picture of the increase in diversity andcomplexity can be reached by combining trace fossils into broadgroups defined both on morphology and interpretation. This alsofocuses attention on looking for similarites between Neoproterozoicand Cambrian trace fossils. Siliciclastic sediments of the Neoproterozoicpreserve elongate tubular organisms and structures of probablealgal origin, many of which are very similar to trace fossils.Such enigmatic structures include Palaeopascichnus and Yelovichnus,previously thought to be trace fossils in the form of tightmeanders. A preliminary two or tripartite terminal Neoproterozoic tracefossil zonation can be be recognized. Possibly the earliesttrace fossils are short unbranched forms, probably younger thanabout 560 Ma. Typical Neoproterozoic trace fossils are unbranchedand essentially horizontal forms found associated with diverseassemblages of Ediacaran organisms. In sections younger thanabout 550 Ma a modest increase in trace fossil diversity occurs,including the appearance of rare three-dimensional burrow systems(treptichnids), and traces with a three-lobed lower surfaces.  相似文献   

20.
The first named Ediacaran body fossil, Aspidella Terranovica   总被引:4,自引:1,他引:3  
Aspidella terranovica Billings, 1872 was first described from the late Neoproterozoic Fermeuse Formation (St. John's Group) on the Avalon Peninsula of eastern Newfoundland, approximately 1km stratigraphically above the famous Ediacaran biota at Mistaken Point, and several kilometres below the base of the Cambrian. Aspidella has been reinterpreted perhaps more than any other Precambrian taxon, and has variously been regarded as a fossil mollusc or ‘medusoid’, a gas escape structure, a concretion, or a mechanical suction mark. Our studies indicate that Aspidella includes a wide variety of preservational morphs varying from negative hyporeliefs with a raised rim and ridges radiating from a slit (Aspidella‐type preservation), to flat discs with a central boss and sharp outer ring (Spriggia preservation), to positive hyporeliefs with concentric ornamentation (Ediacaria preservation). Specimens occur in a continuum of sizes, with preservational styles dependent on the size of the specimen and the grain size of the host lithology; the elongation of specimens is tectonic. Aspidella is confirmed as a body fossil from observations of complex radial and concentric ornamentation, mutually deformed borders in clusters of specimens, and occurrence on the same bedding planes as certain distinctive Ediacaran taxa. Aspidella is indistinguishable from, and has priority over, several of the most common genera of late Neoproterozoic discoidal body fossils worldwide. Similar fossils from Australia are interpreted as holdfasts of frond‐like organisms. The density of specimens in the Aspidella beds suggests levels of benthic biomass in the Neoproterozoic that could rival those of modern marine communities. The serial growth forms, PalaeopascichnusIntrites, Neonereites renariusYelovichnus, associated with Aspidella, are interpreted as body fossils of unknown affinities rather than trace fossils. A new, trilobed, Ediacaran body fossil, Triforillonia costellae gen. et sp. nov., is described from the Aspidella beds of the Fermeuse Formation.  相似文献   

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