Paleoclimatology

Paleoclimatology

  • Joseph Daniel Ortiz added an answer:
    What was the fate of coastal currents (West India Coastal Current, East India Coastal Current) along the Indian coasts, during the glacial period?

    I'm trying to reconstruct the productivity changes in the southeastern Arabian Sea, during the last glacial period. The foraminiferal proxies suggest an increased glacial productivity in this region. I want to understand the physical forcing, responsible for high surface primary productivity in this region during the last glacial period.

    Joseph Daniel Ortiz · Kent State University

    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

  • Xianghui Li added an answer:
    What age are the bivalves?

    Bivlaves occur as very thinned coquina blanket in the Mesozoic strata in southern Tibet (Tethyan Himalaya). Quite abundant by single taxon. What species or genus in what age? T, J, or K? or in epoch?

    Xianghui Li · Chengdu University of Technology

    谢谢阴老师的鉴定!

  • Jooly Jaiswal added an answer:
    What are the main points during Speleothem sampling?

    Can somebody tell me the proper site for speleothem sampling?

    I am little bit confused whether is taken from the location where it is equilibrium with external atmosphere or deep from the cave where humidity is near about 100. Some one told me the sample collected near from the cave entrance are most significant for the climatic study because it records the diurnal variation of the atmosphere. but here the kinetic fractionation also goverened the precipitation process please tell me the exact things.

    Jooly Jaiswal · Wadia Institute of Himalayan Geology

    Thank you so much Mr. Silviu Costantin for your answer. Now I am understand the point of consideration during the speleothem sampling.

  • Sharon Kanfoush added an answer:
    What is the magnitude of global dimming?
    To what extent does global dimming counteract global warming, and where could I find data on the amount of global dimming through time? Also, what is the current status of the debate about whether global dimming versus natural SST cyclicity (e.g. AMO) played a role in the 1980s drought and famine in the Sahel?
    Sharon Kanfoush · Utica College

    Many thanks, Arturo.

  • Brent Wilson added an answer:
    Is anyone aware of any research on carbonate budget within mangroves (both fossil and modern?
    I am wondering if mangrove environments have ever been considered in global carbonate budget calculations? How are these systems affected by climate/drainage change?
    Brent Wilson · The University of the West Indies, Trinidad and Tobago

    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). 

  • Brahim Damnati asked a question:
    After sampling of tree rings, where we can put the samples before isotopic analysis?

    Tree rings?

  • Mahjoor A. Lone added an answer:
    Where can I find hIgh-resolution paleoclimatic data for the Roman period of 3rd century AD for Iberia (references needed)?

    We observe a dramatic drop in export of fish products of the Iberian Atlantic coast in the middle of the 3 cent. AD. We discuss presently cooling, Mega-ENSO, catastrophic event (tsunami), pirates, political or economic crisis in the western outskirts of the Roman Empire. Who can contribute? We need high-resolution data in terms of years or decades. Thanks in advance, Klaus

    Mahjoor A. Lone · National Geophysical Research Institute

    Dear Klaus

    I have generated Indian summer monsoon (ISM) variability data using Indian speleothems (Not yet published) and have encountered an adverse decline in ISM activity. This is actually an extended dry event of around 3000 years during Roman Warm Period (RWP). Since it is understood that RWP was warmer in most of the Europe and North Atlantic, I am currently working to crack this discrepancy. Once published, i will send you a copy.

    Regards

    Mahjoor

  • P. Divakar Naidu added an answer:
    What's the evolution history for ice sheets in polar regions during the Holocene?

    As I know, palaeoclimatologists use benthic foraminifera oxygen isotope to reconstruct the ice volume. However, this contains both Arctic and Antarctica information. Shall we separate the signal? Thanks.

    P. Divakar Naidu · National Institute of Oceanography

    I agree with K.G. Miller that from 5 ka onwards ice sheets in both polar regions are stable.

  • Valenti Turu added an answer:
    Could I use isotope ratios of precipitation and lake water to quantitatively calculate past water balance?

    I have reconstructed the isotope ratios of precipitation and lake water, and I have the reconstructed temperature record.

    Could I use these to quantitatively calculate the water balance in the past?

    Could some palaeolimnologists give some suggestions? Thanks.

    Valenti Turu · Marcel Chevalier Earth Sciences Foundation

    Yes, you are right. May be I did not explain correctly, sorry. A nice paper about C/N ratio possibilities is maybe Wilson et al (2005); Quaternary Science Reviews, 24, 2015-2029.

    Best regards

  • Bhupendra Pratap Singh added an answer:
    What is the difference between insolation and solar irradiance?

    In paleoclimate research, there always talking about the forcing factors, such as insolation and solar irradiance. However, I could not make it clear the difference between them. I have some knowledge about the latter one, which indicate the activity of the sun, such as sunspot, and could be measured by 10Be and 14C.

    Could you shared some of your opinions on this? Thanks.

    Bhupendra Pratap Singh · Shri Mata Vaishno Devi University

    Irradiance is the rate of energy that is being delivered to a surface area at any given time. Its units are Watts per square meter. That means that for any given surface area A, there exists a specific amount of power P that is being delivered to that area in photonic form. The equation is shown below:

    Irradiance = Power / Area

    Insolation is the total amount of energy that has been collected on a surface area within a given time. While the irradiance denotes the instantaneous rate in which power is delivered to a surface, the insolation denotes the cumulative sum of all the energy striking the surface for a specified time interval. This interval must be specified in order to make sense, and the typical unit of time measurement is the hour. Since energy is equal to the rate of power P being delivered for a specified time T, the resultant insolation equation is as follows:

    Insolation = Power * Time / Area

  • Florian Mittermayr added an answer:
    What is incongruent dolomite dissolution?

    Can some body tell me about the the inciongruent deolomite dissolution in speleology?

    Florian Mittermayr · Graz University of Technology

    Take a look at the book Geochemistry, Groundwater and Pollution from Appelo and Postma. They describe dedolomitization very well in natural environments. 

    In our studies we investigated dedolomitization in highly alkaline solutions and in concrete. Maybe you will find some more information there.

  • Mingda Wang added an answer:
    Is anyone familiar with the early Holocene climate situation in western TP?

    Hi everyone, I read the paper below, the author mentioned there is a wetter condition in western TP from terrace study. It explains about the effects of the Indian Monsoon. However, I am wondering if there is another explanation. If the temperature is higher in Early Holocene. and indeed the situation. More melting water flow into the lake, causes the lake level to rise. Hence, this is different from the monsoon explanation. What's your thinking. Plz share with me. Thanks.

    Mingda Wang · Chinese Academy of Sciences

    Thanks Prof. Ren. Thanks for sharing your published paper. Yes, the climate configuration is heterogeneous, and proxies may tell different stories. For TP, where the human's influence could be neglect,  no matter pollen evidence or other lines of climate reconstruction tell us a drier Late Holocene.

  • Mingda Wang added an answer:
    How the Asian speleologists record the abrupt events in N Atlantic?

    Abrupt events, such as YD and H1, etc, have been recorded in cave deposits (Wang et al.,2001 and so many papers). However, could you tell me the mechanism behind it? What is the bridge for the signal transmit? The atmosphere or the ocean current (THC).

    Mingda Wang · Chinese Academy of Sciences

    Thanks, Dr.Naidu.

    Could you share some references to support the idea? Thanks. By the way, could you give some specific details about the atmospheric transmission? For example, westerlies or others? Thanks.

  • John F Mejia added an answer:
    How to decide whether the distribution is unimodal or bimodal in grain size distribution?
    In the given examples, I am not able to decide whether the distribution is uni-modal or bi-modal. I think it is in between uni- or bimodal, but do not know if this kind of class exists or not.

    Can anyone please suggest something so that I can easily understand in which case i should say uni-modal or bimodal distribution?
    John F Mejia · Desert Research Institute

    Hi, note that kurtosis and skewness parameter help discriminate bimodality. I use the aproach outlined in freeman and dale (2012; http://psych.nyu.edu/freemanlab/pubs/2012_BRM.pdf) to locate simple (monomodal) elongated shapes using edge map PDFs. 

  • Xianghui Li added an answer:
    How can I interpret palaeoclimate with carbon and oxygen stable isotope data?
    I have VPDB data for stable C and O.
    Xianghui Li · Chengdu University of Technology

    I generally agree with Alberti and Hosseini. A key depends on materials. That means it is important for environments the calcite carbonates form. By C-O isotope values, paleoclimatic Interpretations may be quite different for carbontate from neritic, (semi-) pelagic, lake, swamp, paleosol. There are many published papers to refer.

  • Valery Pipin added an answer:
    What are the origins of DeVries (~200 year) and Gleissberg (~83 year) solar cycles?
    I am trying to find information on DeVries (~200 year) and Gleissberg (~83 year) solar cycles. What is their origin? Are these manifestations of the 11 year sunspot cycle or some other mechanism? A pointer to any publications much appreciated.
    Valery Pipin · Russian Academy of Sciences

    There several  physical processes which can result to  the Gleissberg variations of the   sunspot cycle. One of  the first proposed mechanism  is related with the beating of two fundamental modes with close periods, see the recent paper by Feynmann & Ruzmaikin JGR 2014.  Another mechanism  is related with the nonlinear interaction of the differential rotation and the solar dynamo (Tobias, 1996,1997), Pipin (1999), Kueker Ruediger, Arlt (1999). Currently it is unclear how strong such interaction could be on the Sun.  The direct numerical simulation support the idea that both the Reynolds and the Maxwell stresses are essential to reproduce the solar angular velocity profile. The third possibility for the Gliessberg cycle variations is related with the stochastic excitation. In this case  the typical periods of the long-term variations are related to the typical times on the nonlinear re-establishment  of the basic state of the dynamo which is perturbed by stochastic fluctuations. Those stochastic fluctuations of the dynamo governing parameters are naturally appeared  in the the stellar convection zones (Pipin, Sokoloff, Usoskin 2012).

  • Zbyszek Remin added an answer:
    Does anyone have knowledge on the Hailstone Impression - looking for new examples?

    I want to ask if anyone knows any structures from the fossil record that could be considered as hailstone impression. We have already published some from the Neoproterozoic/Cambrian transition and simply looking for other examples. They could tell a lot about the early atmosphere it dynamics and climate zone distribution.
    Thanks for any respond.

    Zbyszek

    Zbyszek Remin · University of Warsaw

    Jose and Kenneth, 

    Thank you for those information. I was simply unaware of them. If you will have any other, just let me know.

    Best

  • Claude Hillaire-Marcel added an answer:
    How can I interpret driving factors of a paleoclimate record's long-term trend?

     For example, when we need to distinguish which one is the dominant driving factors for a late Cenozoic record, tectonic activity or global cooling, what is the judgement criteria

    Claude Hillaire-Marcel · Université du Québec à Montréal

    The answer depends on the nature and time resolution of the time series you are looking at. A good example: Miller and others's review of sea-level changes (Science 310, Nov. 25, 2005). I attach a figure from this paper.

  • Hans-Jürgen Gawlick added an answer:
    Does anyone knows if data on OAE1a were published for the Paris Basin?
    I'm looking for data about the characterisation of the Oceanic Anoxic Event 1a (Lower Cretaceous, Aptian) in the Paris Basin (France), or at least data about carbon isotope record in this area. Thanks in advance!
    Hans-Jürgen Gawlick · Montanuniversität Leoben

    go to ISI Web of knowledge and search for OAE1 - yu will find a lot

  • Jooly Jaiswal added an answer:
    Why are pillars (speleothem) not supposed to be used as palaeoclimate archives?

    Stalagmites are excellent palaeoclimate archives. To some extent stalagmite is also used. But we do not use columns? Please do not confuse with the large size of pillars, sometimes we get small pillars which can be cut and carried....Please tell me what are the flaws if we use pillars as paleoclimate archive?

    Jooly Jaiswal · Wadia Institute of Himalayan Geology

    Mr. Samuel ya it is the same water coming but it is coming from the point source and there is not any lateral seeping involved in the stalagmite formation. I think it is clear from Mr Constantin. I want to thank Mr Constantin for the explanation.

  • Attila Demény added an answer:
    What is the method for water isotope analysis of speleothem fluid inclusions?
    I want to separate fluid inclusion which are trapped in speleothem.
    Attila Demény · Hungarian Academy of Sciences
    Here are some additional and related papers where you can read about the different methods and applications.

    http://www.sciencedirect.com/science/article/pii/S1040618212003709

    http://onlinelibrary.wiley.com/doi/10.1002/rcm.3473/abstract

    http://link.springer.com/article/10.1007/s00710-014-0333-7

    If you can't have access, please drop me an e-mail (demeny@geochem.hu),
    Attila Demeny
  • Himadri Basu added an answer:
    If Fe2O3 and CaO concentration is relatively higher in continental sediment than PAAS value, which climate occurred in the source area?
    Other major oxide values are within limit of PAAS value.
    Himadri Basu · Atomic Minerals Directorate for Exploration and Research
    Higher Fe2O3 is undoubtedly due to oxidizing environment. For CaO, you need to see its source - detrital feldspar or calcite cement. Calcite cement is generally characteristic of warm and arid climate.
  • Michael Clark added an answer:
    Do you have paleoclimate data on Europe between 90,000 BP and 50,000 BP?
    I’m looking for data set or publications on paleoclimate (temperature, precipitation, vegetation distribution) in Europe between 90,000 BP and 50,000 BP
    Michael Clark · New Mexico State University
    Paleo climate information can be gotten from the
    wall chart : A correlated History of the Earth.

    The temperatures are long term averages.

    The chart is useful for comparing lots of inter-related things.
  • Martin Schobben added an answer:
    What is the relation between continental weathering and primary productivity in the ocean on a global scale?
    I constructed a simple 1- box model similar to a sulfur-sulfate model given in: Adams et al 2010 Volcanic triggering of a biogeochemical cascade during Oceanic Anoxic Event 2 Nature Geosci v3 p. 201-204. To extend on this box-model I want to link the microbial sulfate reduction (MSR) to the weathering flux. I considered this as I thought that weathering would enhance primary productivity by nutrient supply, this in turn would increase organic carbon remineralization by MSR. Would a connection between these two parameters make sense? If so, what would a function be that could capture this?
    Martin Schobben · Museum für Naturkunde - Leibniz Institute for Research on Evolution and Biodiversity
    Thanks for your contribution. It would certianly be helpfull to check this with proxy data. However I was wondering if I could express this relation between weathering/ flux to the ocean with primary productivtiy in a simplistic way, so that I can fit this in a box model.
  • Bing Song added an answer:
    How are the high resolution paleoclimatic changes deduced from marine sediments/ foraminifera?
    I intend to address the timing of abrupt climatic changes like glacial terminations. Can someone answer what is the best temporal resolution that can be achieved using foraminifera or other associated proxies from marine sediment cores. Can we get decadal or multi-decadal resolution?
    Bing Song · East China Normal University
    I suggestion that you can test the chemscial elements change trend by XRF scaner machine. The equipment is very good, which is very quikly and high resoultion. 1 m core sample only spend about 3 hours will be completed the test and the data interval for 1 mm. If there are some abrupt climatic changes show by chemsical elements, you can decied do any other proxy analysis.
  • John Jones asked a question:
    Percentages of architectural elements in corals (Montastraea)
    Does anyone know where I can find quantitative values for the percentages of septa, theca, costa, Exodissepiment, and Endodissepiment architectural structures in various corals (or just Montastraea) Thank you very much. John Paul Jones
  • Ines Galović added an answer:
    What is the abundance of diatoms in a diatomite deposition?
    Want to know when we can tell the sediment is a diatomite deposition.
    Ines Galović · Hrvatski geološki institut
    Andy, the perfect artical for you about diatomite is: D’Elia, C.F., Nelson, D.M. & Boynton, W.R. (1983): Chesapeake Bay nutrient plankton dynamics: 3.The annual cycle of dissolved silicon. Geoch. Cosmoch. Acta 47, 1945-1955.
  • Morgane Philippe asked a question:
    Is it possible to identify annual layers in ice cores from the ratio Sulfate/Sodium?
    As mirabilite is formed at the sea ice surface during the winter, there is a depletion in the ratio Sulfate/Sodium in the aerosols that deposit on an ice core site. Can we use the summer peaks of this ratio to identify annual layers or is it not reliable?
  • Zoltán Kern added an answer:
    Can anyone provide isotopic data (bulk carbonate, snow, rain, lake water) from the Himalayas or the Tibet plateau?
    We are working on a high altitude lake from the Himalaya region and looking for the potential proxies for climate changes.

    I am searching for the isotopic data from the high altitude region, especially from the Himalayas and Tibetan Plateau. I have searched in some literature, but couldn't get success.

    So, please suggest me something, so that I can compare our results with other modern climatic conditions of these regions.
    Zoltán Kern · Hungarian Academy of Sciences
    Hi!

    You also might find useful two recent papers from TellusB
    here ar ethe links:

    http://www.tellusb.net/index.php/tellusb/article/view/22567

    http://www.tellusb.net/index.php/tellusb/article/view/21043

    good luck!

About Paleoclimatology

Paleoclimatology (palaeoclimatology) is the study of changes in climate taken on the scale of the entire history of Earth.

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