Paleogeography - Science topic

It depends on the history of zircon which in all metamorphic rocks is subject to lithogenic recycling represented by zonation, metamictisation, X structure (see Puppin etc.). The edge over single grain dating in a heavy mineral separate is the knowledge about the host minerals and intergrowth which eases the interpretation of age data.

HGD

please check this articles

thank you

Dear Dr Fadhil,

We have just published a paper about our findings at the Iraqi Geological Journal, which was published last week. FYI and kind regards

Adnan

Hi Diego:

I adressed these issues in very recent papers (i send them in attach):

The way I do this is as follows but I am sure there are other ways if you don't have excel or ArcGIS. First, I make my point data into a .csv using excel, then I import the .csv into ArcGIS as XY data. You can then export the data from ArcGIS as a shapefile. Then you can bring the shapefile into GPlates and assign the plate IDs using a static plates file.

Liu:

You may find these links useful:

Best

Syed

The University of Bern has also a very good laboratory for this technique.

They have experience in coral dating as well. See list of publications: http://scholar.google.ch/scholar?q=ESR+Dating+Bern&hl=de&as_sdt=0&as_vis=1&oi=scholart

Louis,

I would fully endorse your suggestion that you should be involved with this project, although I am not a project member myself. The Kivu region of eastern DRC has now become a critical area to study for understanding the Mesoproterozoic evolution of the greater Congo craton (CBT craton), as, if the Kibaran oceanic suture that Kampunzu and Rumvegeri proposed does exist, it should be in this area rather than in Burundi or Rwanda. Although the Mesozoic-Cainozoic western rift valley intervenes between them, making correlations particularly difficult, I think that the area of NW Burundi and SW Rwanda that you have studied is an important transitional area towards the Kivu Belt.

Note that I believe that there are already problems with correlating stratigraphic units from the better constrained eastern Burundi (Muyinga and Ruyigi) areas to the western parts of Burundi (Cibitoke and Bubanza). This is mainly due to the greater incidence of both granite intrusion and later faulting (Neoproterozoic and Phanerozoic) in the west. I also believe that the current division line between the Kagera and Akanyaru Supergroups (which currently runs along the top of the Muremera quartzite unit in most of eastern Burundi and its equivalents in NW Tanzania) is misplaced and probably should lie more to the west, coinciding more with the major N-S tectonic "accident" or shear/thrust belt associated with the Cene quartzite. This opinion is based on interpretation of regional geophysical surveys as well as mapping in eastern Burundi and NW Tanzania.

Although the bases of the regional geological mapping were completed in the 1960s to 1980s in Burundi, Rwanda and Kagera region of Tanzania, which have been supplemented by the high-quality zircon geochronology of Tack et al 2010 and Fernandez-Alonso et al 2012, there is still more that can be done in terms of relating datable metamorphic and hydrothermal events to the regional structural-stratigraphic context. This will be important to carry the correlations by accurate and reliable absolute age dating techniques from the eastern side of the belt to the western side.

Best wishes,

Dave Evans

Dear Zhou:

looj to this link you may find some thing and good luck:

I"m inclined to be agree with Rusty and Jenses. Plus in the left and base photos we can see two straight lines, as if the core-tool had been...shattered ? Maybe it's just a bad quality material ?

Dear Harald, thank you very much for this valluable information. I am also surching a facility were this examination can be done. So far i have found one comercial laboratory in Boston, USA.

I fully support the opinion of Miroslav Bubik: 4 gavelinellids (or perhaps Anomalinoides) and 2 buliminids (perhaps Siphogenerinoides or alike). These are not agglutintated, just very poorly preserved from recrystallisation and/or corrosion.

Contrary to what I read in some of the reactions, this does not point to reworking (only if you would find this quality in modern deposits). The forams are just very old.  The older the rocks, the more likely the forams become poorly preserved at some point  through deep burial, orogenesis, groundwater flow, outcrop weathering, etc.

Obviously poor preservation is not a necessity: forams can be excellently preserved, particularly  in old shales (little groundwater flow)  that have hardly been buried. Clearly that is not the case here. Note that open/deep marine shales may contain abundant in situ agglutinated taxa, either calcareous or non-calcareous ones. Few of these consist of terrigeneous sand or coarse silt grains though. 

Most probably part of a fish..

If I get your question correctly, i can offer method of disaggregation using Na2SO4 · 10H2O (Glauber's sault or mirabilite). I research the Upper cretaceous foramiferas of Volga refion and I work with different species of marls and chalks. Glauber's sault's method is very successufully. I can send you discription. 

Dear Enrique,

You may also think of contacting Joachim Reitner of the University of Göttingen. He is a specialist of Chaetitids (jreitne@gwdg.de). I attach a paper of him with me.

Hope that you are well and that everything goes well.

Best wishes,

Karl

Follow these links and you can download atlases of paleomaps of India from the Cretaceous to the Neogene.

I am not expert in this field

ram

I'm sorry that I do not have information in this regard

Here is another review on the processes of deltaic system that you may be able to draw some useful information.

I supported the views of Dr. James A Green, USA. It is very difficult to say something on the bases of photographs only. It is true that the rocks samples in Sujit's photographs are not identical bifacial tools or it does not looks like an artifact. It does not show clear man-made flakes scars. These may be broken pieces of rocks of nearby source as these were found along hilly stream in Rajgir, Bihar, India.

I don't know of anything off-hand, but I'm not sure your assumption is correct. Stone tool use would dull the tool, and sharpening necessarily removes relatively thick amounts of material. Even incidental flaking associated with use (ie, the small bits that would pop off when the tool hit something with resistance, due to the stresses applied) would be substantial when considering moisture absorption on archaeological timescales. While glass is sharp and hard it' astonishingly brittle at the edges of glass/stone tools.

I would think that before we could determine if the use affected the dating, we would have to see if this chipping and resharpening affected it. Which is not a hopeless cause--the previously-exposed surfaces need not be completely removed to sharpen a tool--but it would necessitate looking at moisture absorption across the whole tool and mapping out differences, if any.

I know there are types of stone knives that had wooden covers on the hilts, and some very impressive stone daggers that had well-defined hilts. Either would create different exposures between the hilt and the blade, and would be a good test case for an analysis of moisture absorption as it relates to use (as the same stone would be present in both areas, minimizing the natural variation in stone tools).

I could not identify at species level, but Haddonia is present for sure in Middle Miocene (Badenian) deposits. Acervulinids can also be abundant in badenian macroids.

Although I'm not a specialist I would say that they look like teeth and agree with J. Mark Erickson that the specimens in the last plate seem to be jaw fragments. Probably belonging to several fish species.

Good luck with solving the "mistery".

Dear Ahmad,

According to my knoweledge, there are huge references of loess-paleosol published on the methology and techniques, even though I do not indergo researches in this field. 

If you have not an experience on the relevant research,  you can search articles by internet through your institution database and do works as the artclies introduced.   

However, it would be better for you to have an expert guide or to cooporate with someone, whom you can find in an article or an institution in either home or abroad by internet. 

Other more, I have some experiences to share with you.  Finding a good cross-section is one of the most important things. The second procession is to describe and to date the strata. The third one is to find the geoscientific questions and build a purpose. Then design the methodology and technology. You can ask someone to cooperate if you can not access a lab for experiment. 

Carbon isotope is a useful tool to analyze paleoclimate, and it have become a common and important proxy in interpretation of climate. There are many labs in the world which can complete the experiment. I believe you can find a cooperator if  cross-sections you found are good enough!

Hope it is helpful for you to do the work!

Dear Mr. Ibraheem,

there are many reports, papers and short-course manuals dealing with this topic. I suggest to consult these books first:

Darling, T. , 2005. Well Logging and Formation Evaluation. 1 st Edition, Oxford, Elsevier. 336 pp.

Etnyre, L.M. , 1989. Finding Oil and Gas from Well Logs. Kluwer Academic Publishers. 249 pp.

 Serra, O. 1985. Sedimentary environments from wireline logs. Paperback , Schlumberger Limited , London, 211 pp.

I recommend especially the last one for the beginner.

Best regards

H.G.Dill

Dear Mr. Namsrai:

I suggest you consult these papers and books and then you might find a basis for placing a bit more focus on your question:

Diessel, C.F.K., 1992. Coal-bearing depositional systems. Springer, New York, 721 pp.

Diessel, C., Boyd, R., Wadsworth, J., Leckie, D., Chalmers, G., 2000. On balanced and unbalanced accommodation/peat accumulation ratios in the Cretaceous coals from Gates Formation, Western Canada, and their sequence-stratigraphic significance. Intern. Jour. of Coal Geology  43, 143-186.

Dill, H. G., Teschner, M., Wehner, H., 1991. Geochemistry and lithofacies of Permo-Carboniferous carbonaceous rocks from the SW edge of the Bohemian Massif (Germany). A contribution to facies analysis of continental anoxic environments. Intern. Jour. of  Coal Geology 18, 251-291.

Dill, H.G, Wehner, H., 1999. The depositional environment and mineralogical and chemical compositions of high ash brown coal resting on early Tertiary saprock (Schirnding Coal Basin, SE Germany). Intern. Jour.of  Coal Geology 39, 301-328.

Dill, H.G., Pöllmann, H,. 2002.  Chemical composition and mineral matter of paralic and limnic coal types of lignite through anthracite rank. Upper Carboniferous coal in comparison with Mesozoic and Cenozoic coals (Germany). Canadian Society of Petroleum Geologists, Memoir 19, 851-867.

Dill, H.G., Koch, J., Scheeder G., Wehner, H., Strahl, J., 2002. Lithology, palynology and organic geochemistry of  carbonaceous rocks in fluvial-lacustrine series of Tertiary to Quaternary age (Kathmandu Basin, Nepal). Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen 227, 1-38. 

Galloway, W.E., Hobday, D.K., 1996. Terrigenous clastic depositional systems-Applications to fossil fuel and groundwater resources. Springer, Heidelberg, 484 pp.

 

McCabe, P.J., 1984. Depositional environments of coal and coal-bearing strata. In: Rahmani, R.A., Flores, R.M. (eds.), Sedimentology of Coal and Coal-bearing Sequences. Spec. Publ. Inter. Assoc. Sedimentologists 7, 13-42

Miall, A.D., 2000. Principles of sedimentary basin analysis. 3rd. ed., Springer, Berlin, 616 pp

Stach, E., Mackowsky, M.Th., Teichmüller, M., Taylor, G.H., Chandra, D., Teichmüller, R., 1982. Stach´s Textbook of Coal Petrology. Gebr. Borntraeger, Berlin, 535 pp

 

Thomas, L., 2002., Coal Geology. John Wiley & Sons, New York, 384 pp

Best regards

H.G.Dill

I am showing my age, now, but I was actually there in Moscow in 1975!  I have made a pdf from my copy of the conference proceedings and will send you a copy. It was incidentally in Volume 5.

Chris

hi David,

Thanks for your thoughtful answer to my question, which I will give you an up vote on.  However, one has to take into  consideration tectonic framework as well as the flora and climate.

Hello Thierry,

I'm attaching to this a recent article on a possible bear-claw pottery motif among the Pueblo groups of the SW United States. The author makes a good case (at least I think so) for the identification. Bear paws also figure prominently as rock art symbols in the southwestern US and northern Mexico. There are very early colonial references to indigenous bear hunting in the mountains of northwestern Mexico; I can dig out the reference if you are interested.

I'm also attaching a study on the range of the Black Bear in Mexico; maybe that can be of interest also?

Saludos, Michael

Jones:

This link could be helpful:

Best

Syed

The method used in palaeomagnetism was devised by Fisher (1953) (FISHER, R. 1953. Dispersion on a sphere. Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences, 217, 295-305) In general after bedding-tilt correction, the selected directions group in two antipodal normal and reversed clusters on stereographic projections.  Fisher statistics (Fisher, 1953) are used to calculate the mean normal and reversed ChRM directions and their α95 (95% confidence angle).  The outliers and transitional directions positioned more than 45° from the normal and reversed means are then rejected. Should you use a different method to this you would need to be able to justify why, as this method is generally recognised and accepted by the palaeomag community.  Another method by Vandamme (1994) (VANDAMME, D. 1994. A new method to determine paleosecular variation. Physics of the Earth and Planetary Interiors, 85, 131-142.) could also be used to statistically reduce the error. keeping outliers in will often make a palaeomagnetic correlation more difficult to justify.  Hope that helps!

Hi James,

I see what you mean now.

My guess is that they are arrow  heads, and that the larger notch was the site for the knot attaching the head to the arrow, which improved the aerodynamics.  Sounds like an experiment is called for :-)

Hi, have a look at dinoflagellate cyst literature. Although you will not find many cysts in the salt deposits you will find distinct assemblages for both low and high salinity environments just prior to, during and just after the crisis. Here are some references I have in my database to start with:

Santarelli, A. Brinkhuis, H. Hilgen, F. J. Lourens, L. J. Versteegh, G. J. M. and Visscher, H., 1998. Orbital signatures in a Late Miocene dinoflagellate record from Crete (Greece). Marine Micropaleontology 33, 273-297.

Popescu, S. M. Dalesme, F. Jouannic, G. Escarguel, G. Head, M. J. Melinte-Dobrinescu, M. C. Sütő-Szentai, M. Bakrac, K. Clauzon, G. and Suc, J. P., 2009. Galeacysta etrusca complex: dinoflagellate cyst marker of Paratethyan influxes to the Mediterranean sea before and after the peak of the Messinian Salinity Crisis. Palynology 33, 105-134.

Londeix, L. Benzakour, M. Suc, J. P. and Turon, J. L., 2007. Messinian palaeoenvironments and hydrology in Sicily (Italy): The dinoflagellate cyst record. Geobios 40, 233-250.

Louwye, S. de Schepper, S. Laga, P. and Vandenberghe, N., 2007. The Upper Miocene of the southern North Sea Basin (northern Belgium): a palaeoenvironmental and stratigraphical reconstruction using dinoflagellate cysts. Geological Magazine 144, 33-52.

Thanks

I don't know about North America, but glendonites have recently been found in upper Pliensbachian sediments in Northern Germany from the Shandelah core. See Teichert, B.M.A., Luppold, F.W. (2013) Glendonites from an Early Jurassic methane seep – Climate or methane indicators? Palaeogeography, Palaeoclimatology, Palaeoecology, 390, 81-93.

Bonsoir,

avez-vous reçu le gros fichier via Research Gate ?

A toutes fins utiles, je joins des pdf pour voir comment les éléments traces peuvent aider à reconstruire les paléoenvironnements.

Bien à vous,

NT

 The sedimentation rate in modern lake environment may be very diffrent 

Probably around 1 m per 1000 yr, but may reach 2-3-4 m 

I would suggest post-IR IRSL K-feldspar dating: worked fine for the Middle to Late Pleistocene Rhine in The Netherlands. 

More info on the technique can also be found at: https://www.researchgate.net/profile/Jakob_Wallinga

This turreted, robust, strongly noded gastropod is also found to co-occur along with the above bivalves.

From the photograph it appears to be Thalassinoides. The branching pattern however is not clear. Thalassinoides and similar traces are attributed to various crustaceans and hence can occur different environmental settings. There are several publications dealing with this aspect

Its a fossil - all the round polyp-like structures are far too regular to be inorganic. thin section is a very good idea, then target a coral and/or bryozoan specialist for a definitive answer!

Can you upload the image of higher size?

小马哥，这么高大上啊，我是整不了啊！

I salute your dedication to the work, certainly the legacy which has been  left by late Prof. Dr. Antonio de Barros Machado should be maintained. If it losts it will be a great loss to entomologists about evolutionary significance of termites. In future certainly it will provide new directions to the experts in the field of geology and geochemistry and entomology.

Dear Mr. Hassan,

I agree with Dr. Towe, that the anomalies of Ce and Eu play a significant part, particularly Ce which responds to redox changes that are fundamental in the mobilization (organo-metallic complexes), thransort (chelat complex) and concentration of iron. You will find a lot of case studies of  these anomalies, also in papers dealing with a different set of elements or metal deposits. I would like to refer also to the classical studies covering Fe-bearing ochres of the deep sea, BIF and ironstone deposits quoted in Maynard (Geochemistry of Sedimentary Ore Deposits). He listed some of the REE elements. Investigations of the isotopes should not only focus on oxygen but also on carbon which is present in the afore-mentioned carriers of Fe and also in one of the most important Fe host minerals siderite (+ ferroan dolomite), both of which show up in  ironstones too.

Best regards

Harald G. Dill

Dear Bastien,

This is an Eldonia, maybe an E. berbera (Alessandrello and Bracchi, 2003), from the Upper Ordovician of Morocco. This genus is well known from the Burgess Shale Fauna (Cambrian of Canada), the ordovician species from North Africa are the youngest members of this genus... Classification as medusae is not really clear, depending which author you will follow.

In contrast to the not very trustfull trilobite on your picture, the Eldonids and also the Scyphocrinites (Crinoid) are very well preserved specimens.

Best regards

Johannes

Mylroie J E and Carew J I 1995 describe flank margin caves from the Bahamas formed in the saline/freshwater mixing zone--maybe helpful for what you need---paper title is: 'Karst development on carbonate islands/Speleogenesis and Evolution of Karst Aquifers 1. In Unconformities in Carbonate Strata-Their Recognition and the significance of Associated Porosity (eds. D A Budd, A H Saller and P A Harris), pp 55-76. American Association of Petroleum Geologists' Memoir no 63.

As far as I can see Waller (1978) has just  declared a new order Limoida without mentioning Moore 1952.

I know of s couple of sources that have such data.

PaleoMap is one.

PaleoGIS is another

Dear Ayanda,

Martin provided the most important information available to the Tswaing crater. In some field guids, shatter cones in the target rocks of Tswaing are mentioned as additional evidence for shock metamorphism, but these "shatter cones" have never been confirmed.

However, the finding of shocked quartz in rocks of drill cores represents unequivocal evidence for an impact origin of the Tswaing carter. By the way, the formation of coesite and/or stishovite as high pressure polymorphs of quartz requires shock pressures of at least 15-20 GPa (shocked quartz 5 to 10 GPa). The relatively small impact event that formed the Tswaing crater most probably did not provide shock pressure high enough to form stishovite and/or coesite.

Best

Elmar

Hi Devi,

maybe these are not really "paleostrandline" maps, but they could possibly help with their Figs. and references.

Check out the paper by our RG colleague Jan Golonka: https://www.researchgate.net/publication/234000859_Phanerozoic_Paleoenvironment_and_Paleolithofacies_Maps._Cenozoic

Then there is Smith et al. 2004: Atlas of Mesozoic and Cenozoic Coastlines

All-time favourites are of course the paleogeographic maps by Christopher Scotese (http://www.scotese.com/earth.htm), Ron Blakey (http://jan.ucc.nau.edu/~rcb7/index.html), as well as the Ziegler maps, although I am not sure whether maps for South Asia are available from the latter. As far as I know, Gérard Stampfli might also have some paleoglobes in his papers.

Hope this helps, good luck with your work!

Cheers, Martin

Dear Shouxian,

I think these are diagenetic structures, not of mechanical [hailstone] origin. If the pits or pans would be created before the dark mudstone, than the dark mudstone lamins should fill pits horizontally. When you look closer it is evident that the dark mudstone lamins lay parallel to the undulating surface of pits. This observation is also applicable to the next, overlying layers which also follow the undulating surface of the pits. Thus, the whole rock complex were immersed or squeezed giving different thickness of the dark mudstone. Maybe is the similar process as the genesis of the nodular limestones but less expressed.

Together with Antarctica and India, Australia is shown in almost all reconstructions to be attached to SE Gondwana.

Dear Julie,

I am happy to read your answer.Thank you for your interest. Sure. We will discuss things related to paleo-monsoon reconstruction. All the very best for your PhD.

Looks like some kind of coquina. Is it well sorted or is the size of shell fragments quite variable? Are the shells abraded? Is there some kind of preferred orientation? These features are hard to tell from this photo.

Apparently the assemblage is not monospecific - there is some kind of coiled shell and some kind of bivalve. Are the bivalves always preserved as single shells or are there sometimes two shells of an individual preserved together in attachment?

The cause of death might be hard to tell if the assemblage is allochthonous, i.e. if the shells were transported over some distance after the living animals' death and washed together.