Paleoclimatology - Science topic

Yes

How about: humans are the greatest challenge? The idea that a capitalistic economy based on consumerism is the "best"? That we need to have the latest smartphone, buy "fast" fashion, eat meat, follow influencer, follow celebrities...to be humans? Human greed is the greatest challenge to Climate Change. Failure to be capable of being able to cope with less things and enjoy Life for what it is. But we all fear Death, don't we? And we fill this fear with meaningless things. If we were Penguins, we would Live and Die because this is how it is. We would not need more than we need. And we could live in a much better World.

Generally speaking, there are two suitable proxies that indicate the paleotemperature conditions. First the δ¹⁸Ο in the ocean is increased with glaciation(Raymo and Huybers, 2008), hence increased δ¹⁸Ο shows lower temperatures and of course decreased δ¹⁸O shows higher temperatures.

Secondly, Planktonic foraminiferal Mg/Ca, is ideal for the indication of past sea surface temperature(Barker et al.,2005). Higher Μg/Ca shows highter temperatures.

Nobody has an answer, so I'll write some observations. First of all, I would say that the phase analysis of clay minerals is one of the most complicated things that can be devised in mineralogy. Some clay minerals have virtually all the vices a mineral can have. Clay minerals show polytypism (all), often have a slightly or even strongly disordered or turbostratic structure, limited particle size and also display mixed layering too. All this affects not only (semi) quantitative but also qualitative analysis, and without a completely correct phase identification, quantitative analysis is meaningless.

But you can't say that it's not possible at all, it's just extremely complicated and you need to combine more techniques. The results of the Reynold Cup, which was organized by the Clay Minerals Society in the past, also prove that this is realistic.

Stable oxygen isotopes and their variations are measured (using mass spectrometer) by the following equation

δ¹⁸Ο={[(δ¹⁸Ο/δ¹⁶Ο)_sample-(δ¹⁸Ο/δ¹⁶Ο)_standard] /[(δ¹⁸Ο/δ¹⁶Ο)_standard]}*1000

"Fractionation is the process by which one isotope is favored over the other during phase change........" (please read section 2.1 for further understanding )-- Matthew Scott Lachniet 2009.

Kinetic fractionation of oxygen isotopes is more of interest in climate studies.

During kinetic fractionation of oxygen isotopes of water, the heavier isotope is concentrated in the liquid as compared to the gas on evaporation or condensation. Due to their energy states, the lighter isotopes (of water ready to) react faster and move quickly as compared to heavier ones. Hence, water vapor becomes 'enriched' with lighter (δ¹⁶Ο) isotopes and heavier (δ¹⁸Ο) isotopes are left behind in the water. During condensation, water is 'enriched' as the heavier (δ¹⁸Ο) isotopes more quickly condenses.

So, low δ¹⁸Ο values of speleothem represent more rainfall and high δ¹⁸Ο values of speleothem represent less rainfall.

For more understanding of Speleothems and precipitation, please go through Ian Fairchild et al., 2007.

Hello, Dimitrios Koutsos that was a great explanation. I would rather use low δ¹³C values to interpret high vegetation and vice versa.

All the best.

Thank you for your comments. The archeological data favor several out-of-Africa dispersals of Homo sapiens, but the climate and genetic data suggest only one of these was successful. The successful model posits a bottleneck at the time of the Toba eruption followed by population grown and expansions at the beginning of MIS 3.

ممكن اعرف الحقبة التاريخية لهذا العصر الذي اشرت اليه

may this article will help

Hi there !

It's very difficult to find a short answer to such a question. But maybe I don't need to.

I would recommend you to look into the latest IPCC reports. While the new version of the main assessment report is only due in April 2021 (AR6 WGI: https://www.ipcc.ch/report/sixth-assessment-report-working-group-i/ ), there is already available plenty of available resources from the fifth assessment report https://www.ipcc.ch/report/ar5/wg1/ and also from the special report on ocean and cryosphere (especially for the high mountain regions) and on the special report on 1.5° of warming ( https://www.ipcc.ch/sr15/ ).

What I find personally very interesting is how the monsoon systems will react to the impact of climate change. While during the holocene, both the Indian and African monsoon systems have decreased in intensity due to the impact of precession, it is not clear yet how they will evolved in a warmer climate.

I hope this helps, it is a lot to read, but the summary for policy makers can maybe already offer you the answer you're looking for. The complete reports are still very useful though !

Cheers,

Mathieu

You can find all information needed in this paper, all the main equations used and how to chose.

Please check the article. This may help you.

Aie...

Not so easy, Sr is mostly associated to Marine carbonate, thus in lake terrigenious carbonate and not in lake carbonate productivity. By this way Ca/Sr could be used as in lake carbonate productivity.

If you do not have terrigenious carbonate you can try estimate the Sr in silicate during a period oh high terrigenious inputs: flood deposit or late glacial period (all Sr = silicate end member). But if you have different terrigenious sources or terrigenious carbonate for me it is impossible with just these data....

Best regards

Pierre

Dear Dr. Saha,

Tidal rhythmites sensu stricto occurring in what is called the intertidal zone result from periodical physical processes of alternating ebb and flood and first and foremost not affected by salinity variations. The tidal environment can roughly be subdivided into three zones, sub-, intra- and suprtidal. Considering the Ca sulfate system represented by gypsum and anhydrite may provide a different picture for the subtidal (basinal) and supratidal (sabkha) zones, where near the coast in combination with OM (algal growth), carbonate minerals such as huntite and particular clay minerals of the hormite group (palygorskite) a crude rhythmic lamination can be observed . In the latter zone the salinity changes can easily be recognized by the ubiquitous but variable accumulation of halite cubes. It is a function of the lateral facies changes which have a control on the fine-tuning of the salinity and last-but-not least the presence of laminated or rhythmic sedimentary sequences.

H.G.Dill

Hi David,

When you are working on paleoclimatology, there is a requirement for huge datasets, hence you will need robust calculation and efficiency. Moreover, it will also depend upon which datasets one is using. In general, MATLAB and R can work, though R is open source. Here is the link for seeing Datasets and Language used for analysis:

https://www.ncdc.noaa.gov/paleo-search/reports/all?dataTypeId=59&search=true

Cheers

https://www.ncdc.noaa.gov/data-access/paleoclimatology-data/datasets

Dear

I am sharing with you some work that addresses the issue in Senegal and in the Senegal River basin.

Best Regards

You can use the Getdata software, it could precisely get the point (x,y) from the pollen diagram, then use the data to draw another digital diagram.

Thanks for @Alastair Bain McDonald; but still I didnot find the paper. Still waiting! 

Volcanic activity and earthquakes are going to be completely uninfluenced by presence or absence of large ice caps, other than the normal ice loading and unloading effects on local earthquakes in the continental crust (if this is the case) under the ice caps.

Iris:

You may like to have a look at this link:

Best

Syed

Hi Cody,

are you aware of the Paleoclimate Modelling Intercomparison Project which is part of CMIP6? A good reference for this, and yes it does have some useful figures, can be found here:

Kageyama, M., Braconnot, P., Harrison, S. P., Haywood, A. M., Jungclaus, J., Otto-Bliesner, B. L., Peterschmitt, J.-Y., Abe-Ouchi, A., Albani, S., Bartlein, P. J., Brierley, C., Crucifix, M., Dolan, A., Fernandez-Donado, L., Fischer, H., Hopcroft, P. O., Ivanovic, R. F., Lambert, F., Lunt, D. J., Mahowald, N. M., Peltier, W. R., Phipps, S. J., Roche, D. M., Schmidt, G. A., Tarasov, L., Valdes, P. J., Zhang, Q., and Zhou, T.: PMIP4-CMIP6: the contribution of the Paleoclimate Modelling Intercomparison Project to CMIP6, Geosci. Model Dev. Discuss., doi:10.5194/gmd-2016-106, in review, 2016.

If that does not have what you want, it will most definitely have the references of papers that will.

ciao,

Scott.

Melt water pulses MWP 1a, 1b, & 1c were caused by the collapse of ice sheets. The 8,2 ka event was cause by the outflow from glacial lakes caused by the cllapse of a natural dam and was much quicker.

Will the collapse of the Greenland ice sheet produce MWP 2?

Colder ocean water temperatures increase dissolved gases such as oxygen and higher winds during glacial periods (as proven by dust records in ice cores) induce more surface mixing and currents (plus add more nutrients like phosphorus via increased dust loads).  These physical factors will increase dissolved oxygen and promote CO2 outgassing to the atmosphere.  I think they are more a positive feedback on productivity than colder ocean temperatures slowing reaction times.

Dear Phillip, a good question.

I cannot answer it, but I may be able to shed some light on it.

I studied, but never published, my fieldwork in Manchester UK on the Manchester Marls exposed in huge strike temporary exposures on the Eccles-Salford cutting section of the M602 motorway. The strike section was in the thick uppermost Manchester Marls which are dull red monotenous marls (mudstones) devoid of shelly fauna. Instead, careful examination showed them to be playa lake deposits with numerous subaerial emergent surfaces proved by dessication cracks. Of interest was that 20 to 100% of the volume of the desiccated surfaces was bioturbated, but not by truly aquatic invertebrates but by semi-terrestrial to terrestrial invertebrates that had tunnelled and backfilled their chaotic burrows by tiny mudtone chips, with no sign of water deformation. In addition, in spite of days of searching no evidence of pseudomorphs of rock salt were found, indicating that the rock unit was non-marine and freshwater very low salinity. The informal MS name for the unit is the Eccles Mudstone and it was found to extend on top of the normal marine Zechstein Manchester Marls between Stockport and Warrington in temporary exposures and boreholes. On one occasion an large diameter cored water borehole in the Eccles Mudstone contained reptile footprints. I conclude that this was a freshwater lake in a depression vacated by the Zechstein marine incursion and clearly non-saline.

Dear Nilton,

The closure of the Isthmus of Panama around 3.5 Ma had major implications on ocean circulation and global climate. In fact, it initiated the onset of the thermohaline circulation we have today (the ocean conveyor belt), as well as the glaciation on the northern hemisphere during the Pleistocene. El Niño conditions have been found to prevail also prior to the closure, in the early Pliocene.

You may want to see following publications for further information:

Haug GH, Tiedemann R. 1998. Effect of the formation of the Isthmus of Panama on

Atlantic Ocean thermohaline circulation. Nature 393: 673–676.

Haug GH et al. 2005. North Pacific seasonality and the glaciation of North America

2.7 million years ago. Nature 433: 821–825.

Fedorov AV et al. 2010. Tropical cyclones and permanent El Niño in the early Pliocene epoch. Nature 463: 1066-1070. DOI :10.1038/nature08831

Bacon CD et al. 2015. Biological evidence supports an early and complex emergence of the Isthmus of Panama. PNAS 112: 6110–6115, doi: 10.1073/pnas.1423853112

Best regards,

Thomas

You could check for studies on ODP leg 207 Demerara Rise and take it from there.

Dear Tomas,

This is exactly what I was seeking; namely sedimentary records to support the ice core GSSP for the base of the Holocene.

Thank you for your help.

best wishes

David

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. 

Callendar, G. S. ‘The Artificial Production of Carbon Dioxide and Its Influence on Temperature’. Quarterly Journal of the Royal Meteorological Society 64, no. 275 (1938): 223–240. doi:10.1002/qj.49706427503.

Callendar (1938) suggested that increasing CO2 operates by warming the surface not the air since the absorption there is saturated. Warming the surface in the tropics causes evaporation and clouds which limits any heating there. OTOH, in polar regions the rise in surface temperature is amplified by the ice albedo feedback, which operates provided no clouds form.

Look like a Valvulineria to me (e.g. V. glabra, with similar 'fins' in the middle)

http://palaeo-electronica.org/content/images/444/figure28.jpg (specimen 22)

Dear Sumanta: the question you posed is a very complex one! The supercontinent cycle has been operating since at least the Paleoproterozoic or Neoarchean, assembling and disrupting continental masses, creating -and destroying- orogenic belts and ocean basins, volcanic belts, and the like. So it is unquestionable that such tectonic variarions had a strong influence on past climate, just as they have been doing since the Pangea disruption in the Jurassic. The problem is relatively easy to resolve in Mesozoic terrains, a bit more difficult in Paleozoic, and really a hard one in the Precambrian. Conditions for deposition of evaporitic basins were widespread during the Permian, but also in the Devonian and Proterozoic, where large evaporitic basins are found, also aeolian sandstones are frequent in this very dry period, and in older times too. Climate changes so profound as to be unimaginable to us happened when continental blocks collided to form supercontinents. Pangea was covered possibly by a desert three times larger that the actual Sahara, and by an enormous ice cover in its southern parts. The uplift of the Appalachian-Caledonian belt surely had a profound effect in the climate of this supercontinent and global Earth. Before this, in the Neoproterozoic, the uplift of the world-wide Greenvillian system of orogenic belts, which was probably even higher than the Himalaya and longer than the Andes..., due to the assembly of Rodinia, certainly had a marked influence in atmospheric and oceanic circulation, as to eventually lead he planet to the "Snow-ball Earth" global glaciation, just as the uplift of the Andes and Himalaya has done in more recent times, creating large deserts in South America and Central Asia. The problem in older terrains is the large uncertainties in the relative shape, positions and paleolatitudes adquired by land masses, this is relatively easy to solve during the Jurassic, but increasingly difficult to ascertain in older times. With regards, Sebastian.

Im my opinion they are nautiloid cephalopods mostly Arionoceratids

Dear Sumanta, you are asking a complex question for which there might be no exact answer today. While in economic literature the statement about temperature growth in the last 100 years by only anthropogenic influence dominates, physicists are still in doubt; see for example https://www.newscientist.com/article/dn11639-climate-myths-the-cooling-after-1940-shows-co2-does-not-cause-warming/ . There exists also a hypothesis about global cooling, but on much larger time scale; see http://isthereglobalcooling.com/ . The graph about global temperature and CO2 dynamics is the last 450,000 years is attached (from this source). If this graph is correct, we have an interesting observation: warming went faster (about 10,000 years) than cooling (100,000 years). It is unclear whether triggering is caused by some shocks or some mechanism of dynamic equilibrium on the Earth. But is is also clear that we observe anthropogenic contribution to this process for the 1st time.

The problem however is that we cannot wait too long without making actions to combat global warming. Less carbon emissions would indeed work towards speed reduction of this process, but it might happen that other greenhouse gases (like methane) will continue working in its favor while increase of volcanic activity (observed in the last 10 years) will work towards reduction.

As for the rise of ocean level, the effect is still small today, and is caused not so much by ice melting but more by change of water density with temperature and salinity. However, melting of all Antarctic ice will cause a catastrophic rise of the ocean level by 60 meters; see https://nsidc.org/cryosphere/quickfacts/icesheets.html . Melting of Greenland will have much lower effect (6 meters), but here we observe catastrophic melting in the last years.

This is a very substantial question that cannot be answered with a few lines. Large numbers of Quaternarists have spent decades working on this question at a range of spatial and temporal scales and with diffrent types of environments (e.g. terrestrial vs marine vs ice), and every 4 years the community assembles for a conference (International Union for Quaternary Research, or INQUA) to present the latest findings. An example of a recent very successful approach has been the INTIMATE project undertaken in the North Atlantic region and also in Australasia (Australia and NZ), which have developed reconstructions over the past 30,000 years (please see literature) and well beyond that now for the NH INTIMATE project.

At the same time, advances in dating techniques are being developed so that reconstructions in different locations can be compared to the same time scale so that leads or lags can be evaluated with quantified uncertainty, and hence causal mechanisms for change can be assessed and tested. Transfer functions and models are also being employed using different 'sensors'  in different environments and applied to different archives.

I suggest you would gain a lot from reading/skimming an excellent text book such as Lowe, J.J. & Walker, M.J.C. "Reconstructing Quaternary environments", 3rd edition 2015 Routledge.

Hi Nicolas,

You adress here an interesting question, which has not been resolved.

As Christian says, in the astronomical solutions, the amplitude of the eccentricity paces the amplitude of the precession. During eccentricity minimums (each 2.4 Myr), the effect of precession is very weak and it is not unlikely to find a dominant obliquity cycle in these intervals (Zeeden et al., 2013 is a nice reference, see also Westerhold et al., 2014).

Another possibility could be short-term cooling within a greenhouse mode. It has been described in a cooling interval of the Early Eocene (Westerhold and Röhl, 2009), or in the Early Aptian just after the OAE-1a (Ghirardi et al., 2014).

Laurin et al. (2015) evoked the role of carbon sequestration in mid- and high latitudes from the Albian to the Campanian. Also an interesting reference.

A last hypothesis evoked is the impact of the summer intertropical insolation gradient, in which spectral analyses show a stronger power in the obliquity band (Bosmans et al., 2015). At moment, it has only be modelled for the Holocene.

References:

Bosmans J.H.C., et al., 2015. Climate of the Past 11, 1335-1346.

Ghirardi J., et al., 2014. Newsletters on Stratigraphy 47/3, 247-262.

Laurin J., et al., 2015. Paleoceanography 30, doi:10.1002/2014PA002736.

Westerhold T., and Röhl U., 2009. Climate of the Past 5, 309-327.

Westerhold T. et al., 2014. Climate of the Past 10, 955-973.

Zeeden C., et al., 2013. Palaeo-3 369, 430-451.

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.

 Dear Daniel,

The limitations of facies analysis in paleoclimatology include the absence of environmentally controlled biota. Flora and fauna could be so adapted  that their presence indicates the environment including climate. Such biota are called facies fossils.Cosmopolitan biota are not so tied, they are "all-weather" types and do not indicate any particular environment.Similarly, there are physical sedimentary structures that are climatically controlled as well as soils, eg, glacial tillite  and boulder-clay for glacial lands; dunes for hot deserts and so on. Absence of these environmental (including climatic) determinants limit facies analysis in palaeoclimatology or any other palaeo studies, since they are the "tell tales" of the environment.

Facies, after all, are the different aspects of the environment that may be existing at a particular time, which also is often the name- bearer.

All the best.

Obianuju P. Umeji

Dear Ms. Rostami,

There are many ways you can approach your topic of interest. You can investigate climate and how it may relate to the selection of crops. That is as climate has changed during the middle and late Holocene in a region, you may want to investigate changes in the emphasis on crops in a region. This is however, complicated by the arrival of new crops and peoples in a region as well. In the American Southwest, palynologists have been able to identify the plant grown in fields. They have identified fields devoted to maize, and other crops. Although this is interesting, I find investigating the impact of climate vs land use much more interesting. I have been modeling surface process (erosion) as they responded to climate input, and changes in what people were doing on the landscape. In southern Italy I have been able to model climate caused cycles of erosion. Comparing these with the cycles of erosion dated in alluvial histories, I have found that there are several erosion cycles not related to climate change. These are instead related to human land use impact. The earliest such event in southern Italy occurred when Neolithic grazing first appeared about 7,000 years ago. The second erosion event occurred when land clearance related to the arrival of Indo-European peoples and forest clearance. In addition, I have been able to model the additional impact of human land use upon climate caused cycles of erosion during the last 2,000 years, and arrive at a relative measure for human impact at different times. 

In Iran it would be a significant contribution to not only investigate past human impact upon the landscape through geomorphology, and palynology (track changes in forest composition as people began forest clearance, and monitor the kinds of crops that appear in the record), but to be able to assess the additional impact of human activity upon natural cycles of erosion. If you can arrive at a model of how people have affected landscape dynamics, you may also be able to use it to test current human impact upon the landscape, and predict future impacts of people upon the landscape given current estimates for global change. 

You can increase the precision of your model by using tree-ring analyses to extend your current climate record into the past so that you can calibrate your model, or test it.

Therefore, by linking past climate, and past agricultural practices, you can examine not only how climate affected what people grew, but also how their agricultural practices may have impacted the landscape in both positive and negative ways.

For example, there is a heated discussion regarding the end of the Roman Empire in the central Mediterranean. Some argue that soil deterioration lead to the end of the Empire, but in southern Italy it seems that despite possible landscape deterioration, the region prospered. In order to draw such conclusions we need the kind of information that might find. Remember that although the present is the key to the past, the past can provide examples of long-term impacts of human land use, and crop use that can be used to assess current practices in agriculture.

I hope that this helps....discuss this with Dariush, and Reza, and Dr Azizi. See what they might suggest.

Thank you very much Andrej. I will read those papers.

Kind regards,

Fernando.

Dear Erhan,

Have a look at these papers.

Kind Regards,

Masoud Ovissi

Testa, G., and S. Lugli. "Gypsum–anhydrite transformations in Messinian evaporites of central Tuscany (Italy)." Sedimentary Geology 130.3 (2000): 249-268.

Azimi, Ghazal, and Vladimiros G. Papangelakis. "Mechanism and kinetics of gypsum–anhydrite transformation in aqueous electrolyte solutions." Hydrometallurgy 108.1 (2011): 122-129.

Ossorio, M., et al. "The gypsum–anhydrite paradox revisited." Chemical Geology 386 (2014): 16-21.

Here's a good link: "Forced and Internal Twentieth-Century SST Trends in the North Atlantic", by Mingfang Ting et al., 2008:  http://journals.ametsoc.org/doi/abs/10.1175/2008JCLI2561.1 .  Their conclusion is that the AMO is an internal mode of variability, not forced by global factors such as anthropogenic warming or solar variability. 

Otherwise, the wikipedia article (https://en.wikipedia.org/wiki/Atlantic_multidecadal_oscillation) is a good place to start and has plenty of further references.

You seem to have everything in that long account, but very jumbled! Yes it was a greenhouse period. Sea levels had lowered after the CRETACEOUS maximum in the Turonian. There was a tsunami, but do not believe every 'wild' statement about its size. There is an erosion surface in Texas, and some erosion, but not that excessive. The plankton was most badly affected, possibly by ocean acidification event that lasted only a few thousands of years. In some of the lowermost Paleocene in Texas the foraminifera, post-impact were actually quite large and do not show dwarfism. See account in my 2014 paper in the Gulf Coast Transactions.

Dear Prof. Stigter, Thank you very much! 

You could read one or more text books. "Paleoclimatology" by Raymond S. Bradley is a good one for a general understanding of paleoclimatology. You should also be clear what time-scales and objectives you are going to focus on, and choose to read the specific books or papers in your field.

The Urbino summer school in Italy has an extremely good reputation, and all of the details (including course content and logistics) are on their website: http://www.urbinossp.it/

I don't know of others, but I hope that is helpful.

You can put them in clean aluminum foil. Then it is possible to transfer the pack in boxes or bags, and send them to the lab.

Dear Markus,

by frequency-related properties do you mean frequency signals embedded into the reconstruction records you study? 

In that sense, the most critical parameter is time resolution, which forces you to observe a precise frequency range. After the identification of precise signals, each related to a frequency, you can isolate and link them to some property.  May be I'm not catching your question properly, so sorry in advance.

Let me know,

Kind regards,

Gianna

Additional references that will be helpful:

Coxall, H.K., Wilson, P.A., Pälike, H., Lear, C.H., and Backman, J., 2005, Rapid stepwise onset of Antarctic glaciation and deeper calcite compensation in the Pacifi c Ocean: Nature, v. 433, p. 53–57, doi: 10.1038/nature03135.

Coxall, H. K., and P. A. Wilson (2011), Early Oligocene glaciation and productivity in the eastern equatorial Pacific: Insights into global carbon cycling, Paleoceanography, 26, PA2221, doi:10.1029/2010PA002021.

Lear, C.H. et al., 2008, Cooling and ice growth across the Eocene-Oligocene transition: Geology, v. 36(3), p. 251-254.

The genus Pupoides has 44 species, of which only one P.  albilabris C. B. Adams, 1841, is found in Canada.  Four species are found in the United States,  two of which are probably fossil, being  washed out of Pleistocene deposits (Hubricht, 1985, Fieldiana, Zoology Series #24.  The rest are distributed across Africa, Asia, South America and Australia. In North America.  In the USA, they are a species of bar ground, roadsides, old quarries and waste ground, usually on a calcareous substrate in humid climates.

Hi,

sepiolite or attapulgite (special clay minerals) could be indicative of sebkha-type environments.

Hello Reza, there are several papers by Odile Peyron and others using fossil pollen as a proxy to reconstruct seasonality in the Mediterranean that may be of interest.  This paper by Combourieu-Nebout and coauthors discusses several other proxy data that support the climate interpretation of changing seasonality from a marine sediment core (http://dx.doi.org/10.5194/cp-9-2023-2013).  While I understand you are working in a wetland, it may be worthwhile to read the paper to see which proxies might be of use.  The challenge with pollen is that you need a good modern data set and this may not be available for the region in which you are working.

Milner et al. also look at shifts in precipitation in Greece (http://geology.geoscienceworld.org/content/40/10/919.abstract) which might also give you some direction.

You should first look at the possibility of horsts and graben in the area.  These are widespread along the shores of the Laptev Sea and between Greenland and Baffin Island,\and can produce similar features.

Generally ice mean Quaternary formations the best way to identifiy layers is the tapport So18 / So16 by  i think S/Na that show marine or continental water.

You can refer to Materials and Methods section in article entitled : Recovery of temperature records from slow-growing corals by fine scale sampling of skeletons by Anne L. Cohen1 and Simon R. Thorrold (2007), GEOPHYSICAL RESEARCH LETTERS, VOL. 34

link: http://onlinelibrary.wiley.com/doi/10.1029/2007GL030967/pdf

Regards

Massih

You can also look at

Popov, Rögl, Rozanov, Steininger, Schcerba and Kovac Eds. 2004, Lithological-Paleogeographic maps of Paratethys. 10 maps Late Eocene to Pliocene, Courier Forsch. Inst. Senckenberg. They deal with

Eastern Europe.

We have ground ice content (intrasedimental + ice wedge + buried ice) for Canadian Arctic, Yukon, Nunavik and Alaska. Have a look at the papers + scientific report on my profile.

PS: several papers to come (09-2015) with tota ground ice for the Canadian Pmf conference.

Jeremy Caves has been doing some work with stable isotopes in precipitation and HYSPLIT modeling. The main findings were that precipitation in Southern Tibet receivs a large contribution of monsoonal moisture, while Northern Tibet receives more from the westerlies with a mixing zone in the middle. No papers yet, but see the following abstract:

Also paleoclimate records from Central Asia suggest this may be a long-lived climatic regime, evident throughout the Cenozoic. See:

Caves, J.K., Sjostrom, D.J., Mix, H.T., Winnick, M.J., and Chamberlain, C.P., 2014, Aridification of Central Asia and uplift of the Altai and Hangay Mountains, Mongolia: Stable isotope evidence: American Journal of Science , v. 314 , p. 1171–1201, doi: 10.2475/08.2014.01.

Hi Peter:

Try this publication in the USGS Library. I think you will find what you are looking for in Figure 1.

Past, Present, and Future Sea Level Rise and Effects on Coasts Under Changing Global Climate (Chapter C of Sand Resources, Regional Geology, and Coastal Processes of the Chandeleur Islands Coastal System: an Evaluation of the Breton National Wildlife Refuge). Scientific Investigations report 2009-5252.

Thanks.

Dear Peta,

You could find a answer in the paper of Kwiecien et al. (2008) entitled: ``ESTIMATED RESERVOIR AGES OF THE BLACK SEA SINCE THE LAST GLACIAL`` RADIOCARBON, Vol 50, Nr 1, 2008, p 99–118.

小马哥，这么高大上啊，我是整不了啊！

The PETM can influence the organic material in this boundary and  its quite common in iran at the Top of Pabdeh Formation ,where its also responsible for oil generations in certain oil fields

This is an interesting question, one suggestion I have relates to a method for deriving air density based on the terminal impact velocity of raindrops (density 1), although several process-related assumptions are necessary.  I learned of this method from Dave Pyle (Oxford) in discussion for use with soft pyroclastic ash and possibly impact ejecta, and there are now a few papers applied to the Archaean, see Som et al (Nature 484, 359-362) Air density 2.7 billion years ago limited to less than twice modern levels by fossil raindrop imprints. If splash textures related to terminal velocities of fall-back impact spherules could also be established, it might then be possible to extract more precise estimates based on heavier particles (density >>1), but I am not sure such rock surfaces exist for the Precambrian.  In the ~end Cretaceous Chicxulub global ejecta, potential atmospheric interactions are complex, but may hint at a separate method for future extraction of chemical evidence for oxygen in Precambrian impact ejecta/spherule beds. An on line PhD thesis by Tamara Goldin (university of Arizona, 2008) sets the scene for atmospheric interactions from Chicxulub ejecta, and Precambrian impact spherule beds have been reviewed by Johnson and Melosh (2012, Nature 485, 75-77) and Glass and Simonson (2013) Distal impact ejecta layers (Springer). 

In order to be able to confirm the identification some higher magnification images are needed that show the venation of the foliage.

CaCO₃ precipitation decreases the carbonate alkalinity (HCO₃^-+2*CO₃^2-) and not the CO₃^2- alone. Precipitation of CaCO₃ however increases the partial pressure of CO₂ in the sea (Ca²⁺+HCO₃^-=CaCO_3(s)+CO_2(aq)+H₂O) that may l escape to the atmosphere and taken up by the phytoplankton population both leading to increase in the ¹³C/¹²C of seawater DIC (dissolved inorganic carbon) and no significant change in the ¹⁸O/¹⁶O ratio, as indicated by Julie in the answer above. In epeiric sea the situation is more complicated because also changes in the alkalinity input from the nearby land masses may shift the carbon balance of the sea. 

Hope that it helped,

Boaz

Hi,

Please find attached the geological map of India, published by the Geological Survey of India.

Thanx !

I'll do it definitely.

Dear Gareth,

You might find this book helpful. Sarah E. Metcalfe and David J. Nash (2012) Quaternary Environmental Change in the Tropics

My co-authors and I provide a partial review of the impact of changing glacial winds on the Agulhas Retroflexion during the LGM in this paper. We discuss the impact of variation in regional winds on marine production and coastal currents off West Africa. The results should help you to hypothesize changes you may see in the Indian coastal currents for comparison with your study.

You can also review the chapter from my dissertation work on the California Current during the LGM for comparison. Primary production can be enhanced by several processes in addition to the Fe hypothesis noted in the prior answer. For example, increased offshore Ekman transport, or increased Ekman pumping via enhanced wind stress curl will increase the nutrient flux to the surface ocean, thereby potentially increasing primary and by inference secondary production.

D Nof, V Zharkov, J Ortiz, N Paldor, W Arruda, E Chassignet, The arrested Agulhas    retroflection, Journal of Marine Research 69 (4-6), 4-6, 2011

J Ortiz, A Mix, S Hostetler, M Kashgarian, The California Current of the last glacial maximum: Reconstruction at 42 N based on multiple proxies, Paleoceanography, 12, 191-206, 1997

Ashleigh Costelloe is working in the population dynamics of foraminifera in the Caroni Swamp, Trinidad.  As an adjunct to her work, I took a couple of push cores to examine and, below about 3 cm, found. . .  nothing.  Even the organic walled foraminifera had disappeared, never mind the  calcareous ones.  The same thing has been found in northern South America (see Debenay, J.-P., Guiral, D., Parra, M., 2004. Behaviour and taphonomic loss in foraminiferal assemblages of mangrove swamps of French Guiana. Marine Geology 208, 295-314).