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Biostratigraphy - Science topic

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I want to use orbitolinids for the biostratigraphy of a Barremiam/Aptian carbonate platform, to support my chemostratigraphy data. I have used related publications for descriptions and pictures trying to identify the different species, but I would like to have the opinion of an expert to confirm my classification.
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try this new published open access work:
Özcan, E., Yücel, A.O., Erkızan, L.S. et al. Atlas of the Tethyan orthophragmines. Med. Geosc. Rev. 4, 3–213 (2022). https://doi.org/10.1007/s42990-022-00072-1
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Dear all,
I am working on the biostratigraphy of Pleistocene sediments from the high latitude region in south-east Indian ocean sediments. Kindly suggest me any book or articles in which the above-mentioned foraminifera are discussed. The articles on the zonation will more be appreciated.
Thank You
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How can we interpolate the age of marker microfossils according to new time scale.
Eg. if the previous research papers or standard zonation charts has used older timescale then how can we use that particular microfossil in the new time scale.
When we are working with multiple microfossils then we try to follow a single timescale (the most recent one) so this is required.
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With an example: in Agnini et al 2014, the LAD of Discoaster lodoensis was calibrated at 48.37Ma on the 1995 GPTS. It is thus between the bottom of C21n (47.906Ma) and the top of C22n (49.037Ma). On the 2020 GPTS, those chron boundaries are at 47.760 and 48.878Ma respectively. The mapped age of the LAD of Discoaster lodoensis on the 2020 GPTS is thus (by linear interpolation): 47.760 + (48.37-47.906)*(47.906-47.760)/(49.037-48.878) = 48.18606Ma. Note that we normally have a page on the NSB website allowing this kind of conversion but it is currently buggy since we updated the website last month and i m currently busy correcting it to allow this type of conversions again).
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is there a relation between SHE analysis and system tracts, Particularily T-R Cycles
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@ BIO-SEQUENCE STRATIGRAPHIC UTILITY OF SHE DIVERSITY ANALYSIS Wakefield, 2003
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Hi Cretaceous experts!
I'm trying to determinate these orbitolinids from the Lower Cretaceous of Sicily (Southern Italy). I would like to identify the species, but their systematics is rather difficult for me. I suppose they could belong to the genus Paracoskinolina and/or Urgonina and the assemblage seems to suggest a late Aptian/early Albian age. Any suggestions are appreciated and will be helpful.
Best,
Vincenzo
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Hi Vicenzo,
just three remarks from my side:
1. Urgonina = subaxial section of Orbitolinopsis kiliani Silvestri
2. Paracoskinolina cf. reicheli = transverse section f an orbitolinid with pillars and one intercalary beam (right side)..such type of sections can be found among various taxa (e.g. P. reicheli, P. sunnilandensis, D. walnutensis etc.)...without axial sections that show the arrangement of the pillars (aligned or alternating) and the presence/absence of rafters in the marginal zone, generic and specific determination is almost impossible.
3. The presence of Orbitolinopsis kiliani challenges your upper Aptian age.
Hope this helps a little bit...more thin-sections = more specimens = more and better determinations = more and better stratigraphy : - )))
Saluti
Felix
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Dear All,
How many grams (weight) is recommended for Planktonic foraminifera Analysis?. The samples are from Ocean Drilling Cores.
Thank You
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Samples from IODP are usually given in the range of 10cc for foraminifera and 5cc for nannoplankton. I usually use half of the 10cc and save the rest in case of need and/or for eventual nannoplankton analyses. Then I weight the dry sediment before washing and the single fractions after washing. Then you split your fractionto have around 300 specimens and you count the single species relative abundances (and you count the number of splits as well). If you need to have foraminifera x gram of sediments, you consider sediment weight and split numbers.
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Most authors agree that the oldest paraconodonts like Protohertzina derive from the "Anabarites trisulcatus - Protohertzina anabarica Zone". According to the geological time-scale 2016 (Ogg et al. 2016), this would yield a minimum age of about 532.7 Ma. Of course, Protohertzina already occurs at the base of this zone, so my question would be are there any earlier "First Appearance Data of Protohertzina" or other early protoconodonts which are bounded below radiometric age or can be reasonable correlate to an interval below 532.7Ma. Your help would be greatly appreciated.
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First Appearance Data of Protohertzina might be constrained to 545–540 Ma according to SSFs (including Protoherzina and other protocodonts) reported from Ust’-Yudoma Formation, Russia. see the ref below:
Zhu M , Zhuravlev A Y , Wood R A , et al. A deep root for the Cambrian explosion: Implications of new bio- and chemostratigraphy from the Siberian Platform. Geology, 2017, 45(5):459-462.
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I am bit confused about which clustering method to use? I have collected sediment samples from an outcrop from old to young (constrained), my samples are hand picked specimens. I wan to run cluster analysis on the foraminifera and thecamoebians , but not sure which cluster method to use, I am between Ward's and Coniss and 'Euclidean' ?
I knew that (correct me if am wrong) Ward's usually used for clustering lateral samples, but what about coniss? in my case I have vertical section where I collected my samples from bottom to top!
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Dear Majed,
This paper may be of interest to you:
Vavrek MJ. 2016. A comparison of clustering methods for biogeography with fossil datasets. PeerJ 4:e1720 https://doi.org/10.7717/peerj.1720
It concerns biogeographic data but its conclusions are interesting for fossil datasets.
All the best.
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The relationship between the origin of the bedded cherts which have volcanic ash beds from the Gufeng Formation and the onset of the Middle Permian Emeishan large igneous province eruptions.
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There are of course ,as follows:
(1)Zhu Zhi-Yong,Jiang Shao-Yong,Liu Guang-Xin,et al. Precise dating of the Middle Permian: Zircon U–Pb geochronology from volcanic ash beds in the basal Gufeng Formation, Yangtze region, South China[J]. Gondwana Research, 2013, 23: 1599-1606.
(2) Wu Q,Ramezani J,Zhang H, et al. Calibrating the Guadalupian Series (middle Permian) of South China[J]. Palaeogeogr. Palaeoclimatol. Palaeoecol., 2017, 466: 361-372.
However,did the volcanic ash beds souce from the Emeishan large igneous province(ELIP) eruptions and whether the bedded cherts of Gufeng Formation were affected by ELIP?
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I have completed the indirect dating methods like foraminiferal biostratigraphy and nannoplankton stratigraphy of Quaternary marine core sample.For direct dating of 1000 yr - 2.5 Ma marine core samples which method will be suitable?
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According to your summary of the minerals involved, I can only recommend to direct your thoughts to the K-bearing mica and make use of K/Ar or Ar/Ar dating techniques.
Kind regards
H.G.Dill
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I found this ammonite in the Oxfordian Ammonitico Rosso from the Balearic Islands, Spain.
I would like to know the genus and the species if possible. I'm doubting between Phylloceras and Trimarginites.
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Following up with the previous questions, I found these specimens in the Oxfordian Ammonitico Rossos facies from the Balearic Islands, Spain. I would like to get some help identifying the genus and species of these 3 specimens.
I suspect that the second specimen, the one with primary and secondary ribs, could be a Taramelliceras.
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From the sample specimen that I saw like Belemnite for photo 1 & 3 for number 2 is ammonite, to determine the species of ammonite we need to note the shape of the suture on the wall in the form of Ceratite or goniatite.
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I need help identifying this ammonite species. It was found in the Oxfordian Ammonitico Rosso facies from the Balearic Islands, Spain.
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I am not an expert of Oxfordian ammonites, but according to the subcircular section in the very internal towers, then oval and finally subrectangular to subquadratic elevattion , I guess it belongs to Peltoceratoides, probably it's
( Gregoryceras pervinquieri (Spath,1913) )
Good luck
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What is the best method for measuring the age of clastic rocks which has no fossils ? Your advice is highly appreciated.
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As I understood you have clastic rocks. The clastic rocks have mineral constituents derived from more than one source, each mineral gives the age of its source rock " assuming a state or radioactive secular equilibrium exists". So, it is impossible to have a true age dating for clastic rocks by simple method of dating as we do for hard rocks. You will then have mixed ages. You can use 87Sr/86Sr stratigraphy if you have chemically formed sediments such as limestone but since you have clastic sediments you will have minerals with different 87Sr/86Sr ratios. People try to use Thermoluminescence dating (TL dating) for clastics and age of sedimentation but with high uncertainty.
TL dating is the determination, by means of measuring the accumulated radiation dose, of the time elapsed since material containing minerals was either heated (lava, ceramics) or exposed to sunlight (sediments).
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I am looking for a reliable method for dating azoic sediments (conglomerates, sandstones and mudstones). they are triassic-Jurassic red sediments separated by the CAMP.
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Dear Mr. Afenzar: You have to investigate in more detail your red bed sediments and clearly distinguish between cement minerals, which are autochthonous and amenable to radiometric dating given they contain K, U, Th, and Rb such as some micaceous phyllosilicates, cryptomelane or uranyl-bearing supergene minerals. The majority of mineral phases might be of detrital origin which have only some implications on the lithological processes in the provenance area and give you a maximum age of formation which has very little meaning for your problem. Lithostratigraphic correlation with other strata of a defined age of sedimentation is possible but needs a lot of experience because you have to take into consideration lateral facies changes between the two.
I wish you much success
H.G.Dill
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Hi Biostratigraphers!
Just wondering what the view in industry is for displaying *interpreted* biostrat data (biozones, chronostrat etc.) on charts. Some companies prefer a "top defines base" principle where the top of any underlying unit automatically defines the base of the overlying unit. Others prefer a "sample defines base" principle where the base of an overlying unit is drawn down to the sample *immediately above* the sample which defines the top of the underlying unit (if that all makes sense!). Or maybe there are even other alternatives?
I'm guessing there's a mix of preferences but it would be interesting to see what people think and reasons for choosing the method they use.
Thanks!
Mike
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Mike,
It is important I think to honour the sample spacing and therefore follow your sample defines base approach. This means there will be unzoned intervals where there are no studied samples; this is fine as it means if additional samples become available in the gap that the zonal boundaries can be adjusted to fit any new data which may be in the new sample.
There is also another approach whereby regional knowledge allows you to know that a formation boundary, which may fall between biostratigraphic sample points allows you to say that the overlying biozone definitely has to fall above that formational (and associated wireline log) boundary. So to take the top defines base principle in these circumstances is something you may know has to be wrong.
I hope this helps.
Phil
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Dear All,
I'm looking for every reference could be useful. In addition I'm looking for the two following specific references that I cant download
1) Larger foraminiferal biostratigraphy of the upper Cretaceous (Campanian) to Paleogene (Lutetian) sedimentary rocks in the Haymana and Black Sea regions, Turkey Kuniteru Matsumaru. Micropaleontology Volume 62, No. 1 pp. 1-68 - online 07 Jun 2016
2) Larger Foraminifera from the Philippine Archipelago PART 1: Late Cretaceous to Middle Eocene Kuniteru Matsumaru. Micropaleontology Volume 63, No. 2-4 pp. 77-148 - online 31 Dec 2017
Moreover, if someone got an update email of Prof. Kuniteru Matsumaru I will be glad to receive this useful information.
Best
Lorenzo
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Hi Patrick,
nice! Many thanks for you very detailed list of references. I will go through them in order to find more on upper K forams.
Best,
Lorenzo
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I;m facing difficulty in identification of Nummulites, Assilinas, Ranikithalia, Lokhartia, operculina species as working on biostratigraphy and microfacies analysis of Early Eocene Formation from Nothern Himalayas, I needed relevant data,
thanking of anticipation..
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Ghulam:
Kindly see this link for useful insights.
Best
Syed
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It come from dolomitic limestone from South-East of France dated from Kimmeridgian (Late Jurassic) following the geological map. This specimen looks like to an Oppeliidae such as Streblites??
What is your opinion? And I know, it 's very poorly preserved, but it is the best specimen!
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Thanks a lot Luc,
It's a pleasure to have some news of you. Yes I know, It's very damage because this surface (probably a condensed surface) is plenty of belemnites and ammonites, even large specimen of 20 cm. Unfortunately the dolomitization and the bad preservation give us bad material... You which work on the area, did you have some publication on Upper Jurassic of the area of Saint-Vallier du Thiez?
Thanks a lot,
Cheers
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Can someone suggests to me some recent or not very old papers about these topics: 
Biostratigraphy, Bentonite and ammonite Dating methods
Thank you in advance.
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Majed:
Have a look at this link for essential insights about Ammonite biostratigraphy of Cretaceous. How Bentonite is related to this theme remains unclear to me.
Best
Syed
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Ihave a fossil wood, t want to do 13C isotope. So i want  to groove 20 to 50 sampled in the fossil wood about 2 mm wide.
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Use a low speed diamond saw with dual blades and a 2mm spacer. It will cut out a wafer which can be broken into samples. The drill was a good idea too.
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This palynomorph is occur within reworked sediments in Iraqi Kurdistan. I think it is Devonian in age any other suggestion?
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Abdalla:
Specimen documented by Rzger does not match the species: Insculptospora maxima . Have a look at the documented form in this link:
Best
Syed
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I have some Eocene samples characterized by planktonic foraminifera assemblages ( I.e.Clavigerinella colombiana, Clavigerinella akersi,and Pseudoglobigerinella bolivariana), which are better adapted to eutrotrophic cold water environments. At the same time in such samples I find increased abundance of calcareous nannofossil genus Chiasmolithos.
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The sediments are supposedly middle Campanian - Maastrichtian.
picture is 100X magnified of original size.
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Taghi:
Strong affinity is suggested with Globotruncana arca (Cushman) of Late Campanian age. 
Best
Syed
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and where can I have my picked foraminiferas analysed? Also, any idea on the costs?
Thank you for you time.
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Dear Taghi,
 Stable isotope studies you can study in many institute/universities around the world. It wont cost you much. If you have good no. of micro fossil that will be well enough.
mainly use G.rubber, G. bulloide etc.
Hope the following papers will help you for further analysis.  Check the methodological part.
all the best
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I am working in a project which aimed to combine all the vegetation data with paleoenvironment, paleocology and paleoclimatology. Since pollens are vital elements for paleoenvironment reconstructions, we will use them as proxies. Recently, I found LPJ-GUESS software (Lund University, Sweden) and I started to look in its own database and models.
The attached image is the "Biomass" model for Azerbaijan as paleoclimate records. I want to understand how to interpret this image in the language of paleoenvironment.
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Sorry, it is not my speciality
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shell is minute with distinctive sculptures, however without a sharp boundary to distinguish the protoconch and teleconch.
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Luoyang:
You may find this link interesting:
Best
Syed
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Can planktonic/bentonic foraminiferal assist in identifyin shale gas/oil plays
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Well, if you're talking about gas/oil plays in the Devonian-Mississippian black shales, not much.  Conodonts form the biostratigraphic framework for them.
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In comparison, which proxy gives more accurate biostratigraphic data: nannoplankton or planktonic foraminifera?
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Suman:
For Palaeogene, again the  facies is important. One should not loose sight of the fact that calcareous nannofossils being much smaller than planktonic foraminifera, yield far more specimens per unit volume of sample. Also the age of the samples could be determined in minutes by calcareous nannofossils, whereas for planktonic foraminifera it may take hours to days. In marginal marine facies, if the biozonation yielded by these two groups are integrated, a much finer resolution could be obtained (Eocene of Kutch, India). But in Palaeogene Flysch facies of Andaman island, for example, you may not get any trace of these two groups, which are otherwise present in Flysch of other regions, like European Flysch. So depending upon region, tectonics, facies and state of preservation, you may choose either of two or both.
Best
Syed
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Both methodologies have limitations. Name some of them.
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Dear Syed,
I am giving you an up vote on your answer. Best wishes, Paul.
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Are palynomorphs or megafossils better for biostratigraphy?
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Zailiang:
You have a choice when you are working with outcrop sections whether marine or of non-marine facies. You have a choice of only palynofossils when working with exploratory borewell material (well cuttings or cores). In certain marine outcrop sections like Jurassic, ammonites are better as they offer much higher resolution than accompanying calcareous nannofossils.
Best
Syed
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What is the most suitable climate change modelling that can be coupled with biostratigraphy data for future climate change prediction?
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Thanks for the refreshing contribution of Zaiiang, Kenneth and Marcelo. I quiete liked the following Aeon video:
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Specifically, I'm interested in estimating absolute ages for nannofossil events (LADs, FADs, acmes, etc.), potentially using published calibrated ages to constrain certain events. The data is in the form of multiple wells with events associated with particular depths. I'm aware of four main methods: graphic correlation, constrained optimization, RASC, and unitary associations. Are there other methods? Any recommendations for software? Suggestions about the best method for this data set? Thanks in advance-
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You might be interested in the very last contribution of Guex and Galster
"A simple technique to establish sequences of datums and to highlight transgressive–regressive cycles"
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It would obviously take a lot of detailed knowledge of the species involved and its paleoenvironment and its biostratigraphy.
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Dear Paul and others. I think this is not a question of either, or. Species are always both: both are intrinsic to species; it strongly depends on the spatial and temporal scales you are looking at how useful the organism/species is for your stratigraphic or environmental purposes.
We live in a deterministic system where every moment is unique and never exactly repeats any previous moment. Furthermore, organisms interact with, and are part of this environment. Both evolution (by natural selection) and ecology are thus interwoven and two sides of a coin - one does not work without the other. Thus, at every given moment in time you have a unique configuration of life forms. Furthermore, each species has a unique set of parameters with respect to its niche (role in the ecosystem) and period of occurrence. I agree with everybody that both can only be elucidated through detailed, study of the organisms in space and time. Mostly, this is a lot of work.
Interestingly, for short time intervals, it is unlikely to see species getting extinct or new species appearing. All you see is changing (relative) abundances and they reflect the changing environment (Think e.g. of reconstruction changes in the order of millennia and shorter periods; like environmental change over the last 200 yrs). Organisms that appear or disappear from your (local) record in such situations are likely to do so because of a changing local environment and haven't become globally extinct or newly evolved.
With an increasing time window, species turnover (extinction and emergence of species) plays an increasingly important role. For environmental reconstruction this is a complicating issue since it interrupts the continuity of the system. You have to find out the ecology of the newcomers and to find a way to deal the loss of information due to extinction.
Despite these complications, each species has a first appearance, and as such is a marker for a given time interval. This interval may be entirely in the past or continue into the future. As such each species is also a biostratigraphic indicator.
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 The enclosed photographs are from Upper Jurassic - Lower Cretaceous fluvial succession of Gondwana. I am of the opinion of their origin through biogenic activities, however, not very sure. The preservation of the structures is in light to dark gray clayey horizons having abundant leaf impressions of Pteridophytic to Gymnospermus remains. The clay units occur as interbedded horizons with siltstone or, lenicular/poketed occurrence in medium grained sandstone
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Thanks for comments, interesting, approach you shortly.
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First time in our lab we are attempting trace element analysis on speleothems. We are using JLs-1 as standard. For major elements we dissolved 6mg sample in 60 ml (10000 x dilution factor). Though major elements were easily measured, trace elements like U and Th went beyond detection limit. The standard used has 0.0287 ppm of Th. For calibration curve, further dilutions may reduce it to undetectable limits.
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The trace fossil was found in lower - upper Turonian Deban Fulani member of Pindiga Formation, Gongola Basin Upper Benue Trough, Northeastern Nigeria.  
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Hello Hans-Volker,
Are you certain? Ammonoid beaks (lowr jaw-parts) (aptychae) are either divided in two parts (aptychus-type with varous subtypes used for an elaborate parataxonomy) or a single part (anaptycus-type). (good examples are here at researchgate in this publication: https://www.researchgate.net/figure/263301051_fig4_Figure-1-3-D-reconstruction-of-four-ammonoid-jaw-morphotypes-%28viewed-from-the-left
This mold looks like it consists of 4 parts. Even if the upper jaw beak is preserved in ammonites (which happens less often than jin lower jaws due to their different thickness etc.) it has a single point not divided by  a deep fold so the resulting mold would have 3 part and not 4 as in this fossil.
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One of the most problematic age determination of rock units is referred to change in stratigraphic range of some foraminifer taxa as endemic species and facies change in Cretaceous of the Zagros shallow water facies, probably it is assigned to paleobathymetric change. I will appreciate that anyone interpret presence and extinction of shallow water foraminifer and provincialism and Cretaceous sub stage. 
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Taphonomic analyses should be done previously to any paleobiogeographic or paleoecologic interpretation. Stratigraphic ranges are not paleobiologic ranges. That we have are taphoregisters. Vertical range does not correspond actually to temporal distribution of taxa, and preservation may be linked to taphonomic factors related to facies. Taphonomic processes such as necroplanctonic derivation, rejoining, or other biostratinomic displacements can also deeply modify geographic distribution of fossils, and some of the biostratinomic displacement mechanisms may be related to facies.
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I am having doubts regarding the best biozonal scheme to use.
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Thank you Massih for your help!
Best regards
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I am interested in biostratigraphic and taxonomic reports of Triassic dinoflagellate cysts, especially such records that are not easy to come by via libraries and on-line access. If you have any such reports that you can share, or knowledge of where I can get access to them, I'd be greatful.
Clarification: I am NOT looking for records of published Triassic dinocyst taxa. It is accounts of undescribed or obscure forms that I am after!
Cheers/Sofie
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Hi Sofie
Late Triassic Dinoflagellate literature is substantial, I can recall one important publication with which you can start searching/requesting for more:
W.A.S. Sarjeant (1963), Nature, 199, 353-354. Fossil Dinoflagellates from Upper Triassic Sediments.
Also look at : Jafar and Tripathi (2001): Late Triassic palynomorphs from the Andaman-Nicobar Basin, Andaman Sea India. Modern Geology, v. 24, 205-219.
Best. 
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I am looking for a protocol to isolate and mount fossil pollen plates from coastal sediments. I have a little experience working with fresh plant material for pollen analysis.
Thanks!
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Hi Yoannis,
Although I am not palynologist, but am very interested in this subject. I have a procedure for Quaternary pollen and you may have a look to the attached file. Hope this will help you.
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I'm putting together a table of Lower to Middle Cambrian fauna and have been using the Palaeo database/fossil works as a reference. However When it comes to filing in regional Stage data, a lot are referred to this 'Solvan Stage'. I have only found one reference to it (in "Phosphate Deposits of the World" by Cook and Shergold), but no other ones. Can anyone point me in the right direction?
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"Solva“ as a stratigraphic term refers to a lithostratigraphic unit generally referred to as the "Solva Group.“ To my knowledge no chronostratigraphic meaning has ever applied to this so that „Solva Stage“ is invalid. The name Solva is a reference to a rock unit exposed in Solva Harbour, Pembrokeshire, South Wales. The name has been introduced by Henry Hicks in 1881 (Hicks 1881, The classification of the Eozoic and Lower Palaeozoic rocks of the British Isles. Popular Science Review, new series 5). A relatively comprehensive discussion on the stratigraphy and the problems related to this can be found in Rushton (1974, The Cambrian of Wales and England. In: Holland, C.H., ed., Lower Palaeozoic rocks of the world. 2. Cambrian of the British Isles, Norden, and Spitsbergen. Wiley & Sons).
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In the Pennsylvanian of Atlantic Maritime Canada this species has a restricted range. I am wondering if this species is a good index fossil.
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Thank you Sysfrizal for your answer, which does  not  essentially answer the question.However, it is very instructive so I am voting you heads up on your response.
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Beside crystallite growth due to thermal overprint it seems that These crystallites also can be enlarged in different ways. Has anybody an idea?
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For cyanobacteria (phosphate deposit forming cyanobacteria) it is documented that it is their post mortem alteration...same is true for shelly deposits generating phosphatic deposits.....It may be the same phenomenon in case of conodonts added with replacement of calcium carbonate by calcium phosphate. It has also been published (in Nature) that apatite crystallites grow over organic carbon nucleites.  
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To reflect on the limits of the application of actualism in paleoecology, I wonder about the significance of paleontological species that have a wide stratigraphic range.
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One important significance is the autoecology of the species. Most of the time, wide-stratigraphic-range species are opportunistic, eurytherm, euryhaline, etc. That is quite paleoenvironmental information on that. If it has extant relatives, or the species is extant, the application of the actualistic principle is more dependable. In fact, the wide-stratigraphic-range species are the one that are good proxys for paleoecology. The short stratigraphic range species are good for biostratigraphy.
If the taxon really changes or not in the geologic time, is another discussion. If there is no morphological differences, paleontologist will see them as the same species (taxon). But there is no more information available in the fossil record! So, that is what it is.
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Almost all marine sediments and sedimentary rocks are expected to hold some phosphatic fossil elements (Sweet, 1988). Based on some factors (including primary results) in the study area I found that going for conodont dating will be fruitful.
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Thanks Haylay for coming back to my answer. It is quite difficult to find any published material on this topic. I worked in Triassic carbonates in Central Europe and from my experience it seems that bioclastic carbonates are the best material to find conodonts. These bioclastic carbonates are rich in invertebrate shell material, but also vertebrate remains such as teeth, bone fragments (fishes, marine reptiles) and it seems that these clastic layers, often related to storm events, yield the best material like in bone breccias.
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In the core I am studying right now, I divided it based on evidence to zone, sub-zone and know I have trouble to determine which prefix I should use for the division smaller than sub-zone? Is there any standard to use for smaller division?
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I think you should use/apply the concept of acme zone, abundance zone, or peak zone.
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The term "Lazarus Effect" gets used a lot in a theoretical sense, but I would like to find out what sort of durations the "outages" are for Lazarus taxa.
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In carribbean modern sediments, we found two dinoflagellate cyst species thought (up to now) extinct since Pliocene. That is discussed in :
« Organic-walled dinoflagellate cyst distribution in the Gulf of Mexico »
Limoges A., Londeix L., de Vernal A.. Marine Micropaleontology in a forthcoming issue (it has been accepted some weeks ago).