- Christopher C. Sorlien added an answer:4Can you provide information about erosion of huge ice stream/piedmont glacier troughs?
S. Davis, me, et al 2014 AGU abstract proposed that a 400 km-long, 50 km-wide pre-30 Ma buried erosional and rift trough in Ross Sea could have last been eroded by ice, and this ice could have been from the earliest (33 Ma) East and/or West Antarctic Ice sheet. This was very controversial among our co-authors, and we allowed other possibilities, such as River erosion after rifting ceased, assuming restoring differential subsidence removes the huge reverse gradients of the major unconformity along the trough axes.
Related to this:
Question 1: Is large (Piedmont) glacial or ice stream erosion like River erosion, where the ice can cut down on the order of 1 km in 1 or 2 million years if out of equilibrium in one direction (while the bed would instead aggrade if out of equilibrium in the other direction. I know that cold-based ice streams/glaciers are frozen to their beds and do not erode.
Question 2: Do you know of examples of 50 km-wide and >500 m deep troughs known to be deeply eroded by ice in a couple of million years or less? I’m thinking Northern Hemisphere like Greenland, because ice had not been there for tens of millions of years. Laurentian Trough on the shelf of Atlantic Canada may be one example, but I have not been able to find papers or seismic reflection data that show the base of the sub-bottom trough (we have figures of the sea floor trough, which is 50 km-wide but only a couple of hundred meters deep.
I am being a bit lazy; I have an abstract deadline on this in a week and just have not had time to focus on looking into the literature because I have had to spend my time on the Ross Sea interpretation and other projects.
(Davis et al is a student abstract; is my project).
Thank you. this is useful. But, I suspect that most Norwegian fjords do not have the large scale of what I am studying: 50 km-wide eroded trough (hundreds of km-long). We are making progress on our paleotopography/bathymetry, but it is likely that the Ross Sea pre-30 Ma erosion had to cut to about 2 km below paleo-sea level (generally less, but in middle of the 2 closed basins, maybe 2 km).
If you have any references on such large troughs, please post them.
- Wolfram Meier-Augenstein added an answer:5Can someone recommend an IRMS use methodology ?Stable isotope analysis
What instrumental methodology (IRMS or Laser CRDS) is best suited will depend on your application. Laser CRDS systems are less expensive than IRMS systems but are limited to analysis of CO2 (13C; 18O) and water (2H; 18O). IRMS systems can be coupled to gas chromatographs (2H, 13C, 15N, 18O), HPLC (13C only), elemental analyzer (13C, 15N, 34S) and high temperature conversion elemental analyzer (2H, 18O).
For a comprehensive guide to IRMS methodology have a look at this guide:
forensic-isotopes.org/assets/IRMS Guide Finalv3.1_Web.pdfFollowing
- Carmen Fraticelli added an answer:7Can anyone help me with Cenozoic European paleomaps that are or can be geo-referenced?
I need European maps for the Cenozoic that can be used in GIS to plot fossil data.
Actually, what you need is a plate model first. Fossil data should be plotted (in GIS) on present day maps. Then you reconstruct them back to a specific time period (Cenozoic is too broad). The second overlay is the depositional environments followed by the paleotopography/bathymetry. You can, in this way, also test the validity of the paleoenviromental maps.Following
- Natalia S Duxbury added an answer:9Does anyone have data about weight ice content (ice wedges, massive ice bodies and segregation ice) and bulk density in Arctic permafrost deposits?
Papers, references, databases? Quaternary deposits of Beringia region (from Taymir to Alaska) are interest for me....
Articles by V. E. Romanovsky and me on this ResGate, also D. Nicolsky and other members of the V. E. Romanovsky's group at the UAF, Alaska.Following
- Selvaraj Kandasamy added an answer:3Does anyone know how the westerlies affect the central Tibetan Plateau where the precipitation dominated by Indian Summer Monsoon?
There are a lot of literatures suggest that the westerlies could take precipitation into the central Tibetan Plateau and far more eastern areas during the cold period. Do anyone give some evidence?
Please check the paper on Holocene moisture evolution in arid central Asia and its out of phase relationship with Asian monsoon history by Chen, F.H. et al. published in the year 2008. They discussed the influence of Westerlies in arid China during the Holocene, though they are not entertained any discussion of the Westerlies on the Tibet, in particular.Following
- Antonio Fernando Menezes Freire added an answer:5How can I estimate paleotemperatures based on oxygen isotopes of dolomite cement? Could someone point me to a good reference?
How can I estimate paleotemperatures based on oxygen isotopes of dolomite cement? Could someone point me to a good reference?
- Richard Stern added an answer:4Where can I find estimated Global Sea-level history data sets for the past 140,000 years?
I want to plot global sea level changes for the past 140,000 to determine trends in marine taxa radiations in the oceans. I have been unable to find data sets from NOAA.
Not sure if you are looking for an already completed dataset for global changes, or trying to compile it from regional sources....at any rate, here are a few references mostly from the circumpolar world with "sea-level" in the title. Cheers, Richard
Moore, G. W.
1960 Recent Eustatic Sea-Level Fluctuations Recorded by Arctic Beach Ridges. In U.S. Geological Survey Research, 1960, pp. B355-357. U.S. Geological Survey Professional Paper 400, U.S. Geological Survey, Washington, D.C.
Hume, James D.
1965 Sea-level Changes During the Last 2000 Years at Point Barrow, Alaska. Science 150:1165-1166.
Kind, N. V.
1973 Late Quaternary Climatic Changes, Sea-level Fluctuations and Glacial Events of the Old and New World: Geochronology According to Isotopic Data. In The Bering Land Bridge and Its Role for the History of Holarctic Faunas in the Late Cenozoic (Abstracts), Academy of Sciences of U.S.S.R., Far-Eastern Scientific Center, Khabarovsk.
McManus, Dean A. and Joe S. Creager
1984 Sea-Level Data for Parts of the Bering-Chukchi Shelves of Beringia from 19,000 to 10,000 14C Yr B.P. Quaternary Research 21:317-325.
Shennan, I., M. J. Tooley, M. J. Davis and A. Haggart
1983 Analysis and Interpretation of Holocene Sea-Level Data. Nature 302:404-410.
Searle, D. J. and P. J. Woods
1986 Detailed Documentation of a Holocene Sea-Level Record in the Perth Region, Southwestern Australia. Quaternary Research 26(1):299-308.
Shugar, Dan H., Iam J. Walker, Olav B. Lian, Jordan B.R. Eamer, Christina Neudorf, Duncan McLaren and Daryl Fedje
2014 Post-glacial Sea-level Change Along the Pacific Coast of North America. Quaternary Science Reviews 97(2014):170-192.Following
- P.J. Mudie added an answer:6What age correction is needed for mollusc C-14 dates from Black and Marmara Sea lacustrine phases?
High resolution dating of events in the Black and Marmara Seas during non-marine phases requires appropriate correction of C-14 ages because shells are not in equilibrium with global values of ca. 400 yr. Proposed values range from 0 (fully mixed, in equilibrium with atmosphere, no correction needed) to 1000 yrs (benthos contain old bottom water or river transported carbon). Peat (grows in equilbrium with atmosphere) compared to in-situ shell from the same sample indicates a reservoir correction of ca. 850 yrs is needed for shells. Which correction value is correct for A) Black Sea? B) Marmara Sea with overflow water.
Thanks for all your answers. In Marmara Sea we have new cores with lacustrine sediment containing shells next to tephra layers dated by wood. These may provide a more accurate reservoir correction value for the late Pleistocene interval.Following
- Sidney Ash added an answer:13Could any Palaeobotanist help me to identify the ancient plants?
The picture was taken from a piece of core in the late Triassic Ordos basin. Could any Palaeobotanist please help me to identify the ancient plants and list its implications for paleoclimate : in the late Triassic Ordos Basin, central China. It deposited in deltaic or lacustrine environment. I want to know its Latin name and implications for paleoclimate. Thanks a lot!
I agree with Han, we need a better picture.Following
- Zhitong Yu added an answer:1Can a modeler help me test my hypothesis using a model (such as GCM) to modified topography ?
I infer that there probably existed a passage between the Tibetan Plateau and the Qinling Mountains during the Late Miocene based a lot of tectonic and climatic records. Development of the passage was mainly controlled by the eastward expansion of the Tibetan Plateau, which constrained rainfall transported by the Asian summer monsoon to flow into interior China. I need a modeler help me to test this hypothesis? Please contact me for specific information
- Jamal Munshi added an answer:7What is the 1-sigma and 2-sigma error in radiocarbon dating?What is 1-sigma and 2-sigma error in the radiocarbon dating and how to decide which error range we should use for the data set?
I think we should stick to probability based confidence intervals such as the commonly used 95% CI. This is what I have done in my paper on radiocarbon dating which I believe is available on Researchgate and if not it may also be found at
- Massih Afghah added an answer:3Is there any hard evidence concerning the thickness of the Precambrian troposphere?
Simply, I’m looking for papers that gives me knowledge about any models or assumption concerning the thickness of troposphere of Early Atmosphere, e.i. during the Neo-, Meso- and PaleoProterozoic?
Thanks in advance, Zbyszek
I think the attached paper is useful for your question
- Fadhil A. Lawa added an answer:1Can anyone suggest how the ecological functioning of PETM and Early Eocene climatic optimum can add value to E & P of hydrocarbon?
Distinguished Colleague, am working on the ECOLOGICAL FUNCTIONING OF ZOO AND PHYTOPLANKTON COMMUNITIES ACROSS THE PALEOCENE-EOCENE HYPER THERMAL EVENTS. Can anyone suggest how this can add value to petroleum exploration and production?
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 fieldsFollowing
- Chris Gueymard added an answer:6What 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.
Insolation is a vague colloquial term, not a scientific quantity--at least not anymore
The terms to use are either irradiance (W/m2) or irradiation for accumulated energy over time (MJ/m2 or kWh.m2)Following
- S. K. Shah added an answer:6Where can I get a detailed map of the Triassic of India?
Does anyone know of detailed geologic maps of India? Thanks in advance...
Visit the website of Geological Survey of India and ask for maps of north west Himalaya and Gondwana rocksFollowing
- Boaz Lazar added an answer:2Does anyone know "Increased carbonate production and burial in epeiric seas，decreasing the [CO32-],leading to the positive d18O excursions ?
It is about stable isotope geochemistry
CaCO3 precipitation decreases the carbonate alkalinity (HCO3-+2*CO32-) and not the CO32- alone. Precipitation of CaCO3 however increases the partial pressure of CO2 in the sea (Ca2++HCO3-=CaCO3(s)+CO2(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,
- P. K. Gautam added an answer:4Can anyone provide me with the tropical solar irradiance during Bølling-Allerød period?
I am interested in understanding the solar irradiance of Tropics during Bølling-Allerød period. I am not able to get the data/curve for the said period.
I'll do it definitely.Following
- James Blinkhorn added an answer:2What was the nature/variability of Middle/Upper Pleistocene environments in the Senegal River Valley?
I'm interested in patterns of Palaeoenvironmental variability in the Senegal Valley during the Middle and Upper Pleistocene, particularly in the lower valley after the confluence with the Faleme River. However, I am having trouble finding modern sources of information, and many older sources are not available on-line. Can anyone help direct me to available/key resources that document patterns of environmental variability in the Senegal Valley?
Thanks for the links - terrestrial proxies are pretty rare in this part of the world it seems!
- Gustavo Hinestrosa added an answer:3What 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.
I would also suggest to search for articles on the Eastern Australia Current or the Southern Equatorial Current that circulate offshore Queensland, Australia. Whilst it is a very different region, there is some work on the evolution of these currents since the LGM and this might give you some useful insight (hopefully) on what was going on in India during the last glaciation. Good luck.Following
- Michelle Mckeown added an answer:4What are the key uncertainties and knowledge gaps in palaeoclimatology in South America and ENSO activity?
I'm a current masters student and wanted to see if people are aware of knowledge gaps in ENSO activity in South America and/or palaeoclimatology reconstruction needed. I've looked in a lot of literature and seems to be a lot of modelling for ENSO activity not actual proxy evidence, is this true?
You might find this book helpful. Sarah E. Metcalfe and David J. Nash (2012) Quaternary Environmental Change in the Tropics
- Stéphane Bersac added an answer:3Does 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!
Thanks a lot for these info!Following
- Xianghui Li added an answer:6What 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?
- Jooly Jaiswal added an answer:8What 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.
Thank you so much Mr. Silviu Costantin for your answer. Now I am understand the point of consideration during the speleothem sampling.Following
- Sharon Kanfoush added an answer:6What 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?
Many thanks, Arturo.Following
- Stephanie Larmagnat added an answer:6Is 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?
Many thanks for your answers and for the recommended readings. The work on mangroves is on hold for the moment (in French Guiana actually) but my interest is still there!Following
- Brahim Damnati asked a question:OpenAfter sampling of tree rings, where we can put the samples before isotopic analysis?
- Mahjoor A. Lone added an answer:6Where 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
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.
- P. Divakar Naidu added an answer:4What'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.
I agree with K.G. Miller that from 5 ka onwards ice sheets in both polar regions are stable.Following
- Valenti Turu added an answer:10Could 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.
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.
Paleoclimatology (palaeoclimatology) is the study of changes in climate taken on the scale of the entire history of Earth.