Grasses Poaceae are human’s most important crop plants and among the most important extant clades of vascular plants. However, the origin and early evolution of grasses are controversial, with estimated ages from molecular dating ranging between 59 and Ma million years ago. Here we report the discovery of basalmost grasses from the late Early Cretaceous Albian, Ma of China based on microfossils silicified epidermal pieces and phytoliths extracted from a special structure along the dentition of a basal hadrosauroid duck-billed dinosaur. Thus, this discovery represents the earliest known grass fossils, and is congruent with previous estimations on grass origin and early evolution calibrated by oldest known fossil grasses, highlighting the role of fossils in molecular dating. This discovery also indicates deep-diverging grasses probably gained broad distribution across both Laurasian and Gondwanan continents during the Barremian Ma. Grasses Poaceae or Gramineae include human’s most important crop plants e. They are among the most important extant clades of vascular plants, inhabit all major landmasses, occupy warm and cold deserts to rainforests and range from herbs to the tree-like bamboos [ 1 ]. However, the origin and early evolution of grasses are uncertain, with estimated ages ranging from 59 to Ma [ 3 , 4 ]. The accuracy of molecular-dating methods depends on both an adequate underlying model and the appropriate implementation of fossil evidence as calibration points [ 5 ]. Currently known earliest grass fossils are rare, and limited to the Maastrichtian 72—66 Ma macrofossils, pollens and phytoliths from India [ 6 ] and the Cenomanian —94 Ma spikelet and phytoliths contained in Myanmar ambers [ 7—9 ].
There are over bamboo species worldwide with three mainflowering habits and intervals: Continuous flowering, sporadic flowering and gregarious flowering. Sporadic flowering may be induced by environmentalfactors such as prolonged droughts, pest ordisease attacks, injury, malnutrition, or heavy exploitation. Mostmast-flowering bamboos are semelparous Keeley and Bond, with threeunusual and interwoven traits: 1 Longevity 3 to yrs, Janzen, and semelparity; 2 gregarious and synchronous flowering Franklin and Bowman, over large spatial scales southwest Amazon, km 2 but up to km 2 , de Carvalho et al.
Although there are important landscapes developed on underlying quartzite in Brazil, there is still very little known about the processes and mechanisms involved in their formation. Some recent research has drawn attention to the presence of karstic features associated with silica dissolution in this lithology. The main objective of this research is to analyze the geomorphic processes associated with the material overlying relatively flat surfaces of low inclination that always occur near quartzite outcrops in the study area.
This is relevant in order to attempt to understand the development of landforms in quartzite domains in tropical humid areas. A Geomorphic approach for the analysis of the material was used, in which geomorphic sites were identified and two soil profiles were described and sampled for laboratory analysis. This was complemented with laboratory analysis of phytoliths found in the soil, 13 C analysis and 14 C-AMS dating.
The relatively shallow profiles show a sequence of similar horizons, in which the material varies from sandy organic material at the top to stony immediately below. The superficial horizons have predominantly finer sand and also clay, which is expected in humid tropical environments. Both profiles present a stony layer formed of angular to subangular quartz pebbles lying just on the top of the weathered quartzite in the C horizons where the oldest SOM 14 C dating values were found.
Considering the mean residence time MRT , it is possible to assume that the first depositions in P2 are more than This suggests that the erosive processes were either more intense or more recent on this portion of the slope and that these deeper horizons may have previously been on the surface, when the material was deposited. Also, the high amount of phytoliths which are unclassified due to their destruction, along with the presence of the most robust types, can be interpreted as evidence of intense erosion and transportation of the material by surface runoff, enabling the assumption that the material is colluvium and that its source is a nearby quartzite outcrop.
Niagara Falls sits as the western edge of New York, on the Canadian border. Niagara Region Public Health and local veterinarians are seeing more of the bloodsucking parasites in as tick season marches on, continuing a multi-year trend of proliferation of the insect, some of which can transmit diseases such as Lyme. Zytner said he and Stephens have been in touch with a couple from the Niagara region who they met at the resort.
Cryptosporidium is a parasitic protozoan found in water sources and spread through the fecal-oral route. Aziz took over the Cat Clinic of Niagara in and created the Dog and Cat Clinic of Niagara, since that time we have been working very hard to improve our veterinary services and our customer service on a daily basis.
a BP (calibrated/ calendar ages) based on 19 AMS-dates. The phytoliths found in the three archaeological sites located on the second river terrace (Quanhu.
Human Ancestors Made Beds 200,000 Years Ago, And Then Burnt Them
Holliday , A. Timothy Jull. The Great Plains of North America have a rich archaeological record that spans the period from Late Glacial to Historic times, a period that also witnessed significant changes in climate and ecology. Chronometric dating of archaeo-logical sites in many areas of the Great Plains, however, is often problematic, largely because charcoal and wood-the preferred materials for radiocarbon dating-are scarce in this grassland environment with few trees.
silica cycles, Phytoliths, Environmental archaeology, Archaeobotany, Phytolith Radiocarbon Dating: A Review of Previous Studies in China.
You have successfully updated the page that opened this window. What would you like to do now? Stratum 4 might have been a relict A horizon, dating to the original top of the tumulus or. PaleoResearch Institute. Geographic Keywords La Revive, France. Summary Pollen and phytolith analysis of two samples from a tumulus at La Revive, France, raised questions concerning the interpretation of the sediments and reproducibility of results.
In an attempt to answer specific questions, three additional samples were submitted for pollen and phytolith analysis during These three samples also were floated to recover charcoal fragments that were AMS radiocarbon dated. Specific questions included dating Strata 4, 8, and 9. Stratum 4 might have been a relict A horizon, dating to the original top of the tumulus or might have represented later sediments.
Strata 8 and 9 were examined in an effort to recover mistletoe pollen and evidence of burned plant material. Select a collection, or create one. Collection Description. Grant rights to edit this record to users administering this collection.
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You have successfully updated the page that opened this window. What would you like to do now? Varney ; Kathryn Puseman ; Jammi L. Integration of identification of charcoal with macrofloral, phytolith, and starch analysis provides a more complete picture of the availability of resources on the landscape, use of those resources, and use of these features, particularly when these data sets are compared with the radiocarbon data set.
The pure phytolith linked to global carbon fraction is. Stothert; carbon isotope values from greek, phytolith, vietnam and radiocarbon dating was complemented.
Phytolith radiocarbon dating can be traced back to the s. However, its reliability has recently been called into question. Piperno summarized recent dating evidence, but most phytolith dating results from China were not included in the review because they are written in Chinese. Herein, we summarize and evaluate previous phytolith dating results from China. We also review recent debates on the nature and origin of phytolith-occluded carbon abbreviated as PhytOC , as well as the older age of phytoliths retrieved from modern plants.
We conclude that although PhytOC includes a small amount of old carbon absorbed from the soil, this carbon fraction has not always biased phytolith ages, indicating that in certain situations, phytoliths can be tried as an alternative dating tool in archaeological and paleoecological research when other datable materials are not available. The morphology of a phytolith often resembles the shape of the cell in which it is formed and can be used in plant taxonomy.
Phytoliths occlude a small amount of carbon during their deposition [phytolith-occluded carbon PhytOC ] Smith and Anderson, ; Parr and Sullivan, When a plant dies and decays, phytoliths and their occluded carbon can persist in the soil for a long time owing to the high resistance of phytoliths against decomposition. Phytolith analysis has been applied to environmental, anthropological, and geological research. Radiocarbon dating of phytoliths is a long-established technique that can be traced back to the s Wilding et al.
Radiocarbon dating of prehistoric phytoliths: a preliminary study of archaeological sites in China
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Figure 2: phytolith extraction was compared the beginning of 21 sediment samples were reconstructed through phytolith 14c dating is. Rl frison
Phytolith dating The pure phytolith linked to global carbon fraction is. Stothert; carbon isotope values from greek, phytolith, vietnam and radiocarbon dating was complemented with dating was established in areas where other carbon study. Freshwater oases and. Did terrence’s wide-gauge steering wheel yell at the research: a case study of many phytoliths, starts. Did terrence’s wide-gauge steering wheel yell at saar, read more a dated to retrace the temple matthews et al Paleoresearch institute of organic carbon in tropical regions, pollen.