Laguna Paco Cocha, Peru

A while ago, I summarized an interesting article from the Venezuelan Andes. In that case, they concluded that the glaciers did not exist in the MWP. The post is worth re-reading in the context of Quelccaya. The authors used the continuous deposition of sediments in a proglacial lake to yield evidence of the discontinuous movements of the glacier.

Given that Thompson’s PNAS article is so inadequate as a survey of relevant information, one can only wish that a similar study had been done at one of the Quelccaya proglacial lakes. If one had, you’d think that even Thompson would have thought to mention or that one of the PNAS referees would have asked about it.

But, hey, it’s Thompson so you never know what fundamental information he leaves out. I googled Paco Cocha, the name of one of the proglacial lakes and, needless to say, there was an almost precisely identical study to the one in the Venezuelan Andes, Abbott et al 2003 . It was even done by geologists at Ohio State – Thompson’s own university. You’d think that Thompson would give them a mercy citation – but this is the Team.

Abbott et al concluded that "glaciers were probably absent from the watershed between 10.0 and 4.8 thousand years BP – which raises interesting questions about the 50,000 year old moss. The authors conclude that glaciation has been present in the area since 4800 BP. but with "significant fluctuations."

Multiproxy analyses of Laguna Paco Cocha (13″‚⟵4S, 71″‚⟵2W) include studies of sedimentology, geochemistry, physical properties, magnetic susceptibility, and stable isotopes. The age model for the core was produced by linear interpolation between 11 calibrated AMS radiocarbon dates on individual macrofossils (Table 1) (Stuiver et al., 1998). Fig. 4 shows the results from the analysis of organic matter content (LOI at 500″‚⠃), bulk density, magnetic susceptibility, cellulose-inferred N18Olw, and mass accumulation rates of organic and mineral matter. The abrupt shift to glacial values at 4.8 ka B.P. for all parameters is highlighted by a dashed black line.

This includes decreased organic matter values from ~15 to 65 wt%, higher dry bulk density from 60.5 g/cc to ~0.9 g/cc, higher magnetic susceptibility from 65 to ~10 SI, and an abrupt N18Olw decrease of 3x. We interpret the results of the analyses presented in Fig. 4 to show that glaciers in the Paco Cocha watershed retreated rapidly beginning prior to ~12.7 ka B.P. and were gone from the watershed by 10.0 ka B.P., as indicated by the dashed gray line (Mark et al., 1999). Although glaciers were probably absent from the watershed between 10.0 and 4.8 ka B.P., the lake remained at the overflowing stage during this period, as suggested by analyses of organic matter, sediment density, and magnetic susceptibility. If the lake had desiccated during this period we would expect oxidation of organic matter leading to low values which we do not see. Additionally, cellulose-inferred N18Olw values remained 6310x suggesting that the lake did not become a closed basin during this period. Increased mineral and decreased organic matter accumulation rates after 4.8 ka B.P. also support the return of glacial ice to the watershed at this time and the lack of ice in the drainage basin during the early and middle Holocene. After glaciers returned to the watershed at 4.8 ka B.P. they have been present until today, but analyses of organic matter, sediment density, and magnetic susceptibility in addition to changing accumulation rates suggest significant fluctuations during this period. Cores from Laguna Llacho Kkota, which is located to the south (15″‚⟰7S, 69″‚⟰8W), show the onset of wetter conditions at 3.4 ka B.P.

Fig. 4. Sediment-core analyses from Laguna Paco Cocha including organic matter, dry bulk density, magnetic susceptibility, cellulose-inferred N18Olw (thick line is the three-point running average), and mass accumulation rates of organic and mineral matter. The dashed horizontal gray line indicates the retreat of glaciers to at least the neoglacial limit by 10.0 ka B.P., and the horizontal dashed black line shows the return of glaciers to the watershed at 4.8 ka B.P. The vertical dashed lines on the graph of inferred N18Olw provide a framework to interpret the status of the watershed based on the modern calibration samples shown in Fig. 3. The cellulose-inferred N18Olw values were corrected for a systematic o¡set arising from methodological di¡erences between the University of Waterloo and University of Minnesota laboratories (Beuning et al., 2002).

Reference: Abbott et al 2003, Holocene paleohydrology and glacial history of the central Andes using multiproxy lake sediment studies, Palaeogeography, Palaeoclimatology, Palaeoecology 194 (2003) 123-138. url


  1. Lee
    Posted Aug 22, 2006 at 10:15 PM | Permalink

    Let me point out that unless I’m misinterpreting the contours – which I’m still having a hard time seeing on the map – that Paco Cocha is in a relatively smallish valley, below a finger of the Quelcayya ice cap that extends out a flat-top ridge above the lake – see the “some geologists” thread Steve posted earlier for the map.

    This means that a retreat of the ice cap sufficient to remove just that ridge-top finger of the ice cap would remove glaciers from the Paco Cocha watershed. Ice from most of the ice cap would not be in the Paco Cocha wttershed. So the absense of glaciers from teh Paco Cocha watershed only tells us about that finger of the ice cap, and is not indicative of whether the entire ice cap ws there or not.

  2. James Lane
    Posted Aug 22, 2006 at 11:18 PM | Permalink

    Lee, you are clutching at straws. You do realise that the geologists who wrote the paper have actually been there?

  3. Dave Dardinger
    Posted Aug 22, 2006 at 11:19 PM | Permalink

    Lee, now you’re making me wonder if you can read maps. It’s clear from the map with the green ice, that this lake has basically a straight shot all the way to the peak of the icecap. IOW, even if the last remains of the ice cap were melting it’d still send some of the melt water to the Paca Cocha lake.

    I would like to know what the date of the moraine below the lake is. I assume it must be older than 15k or the lake would have been beneath ice when some of the data show is supposed to have occurred.

  4. Lee
    Posted Aug 22, 2006 at 11:44 PM | Permalink

    James, sure, and they talk about their data for the watershed. I’m simply trying to understand how much of the ice cap is in the watershed.

    Dave, I’m looking at the map in the “some geologists” thread, because that is the one where I can best see the contours, at least until I get a printout. For some reason, the contours are nto showing well on my monitor.

    Paco Cocha is in a small valley more-or-less parallel and next to the valley with the active glacier. Continuing around that same direction ther is another small valley comong off the nose of that ridge, with a stream dropping into the Huancane valley, and on the other side, yet another valley with a stream that curves around in front of that ridge and into the Huancane valley. That means for any of those vallesy to be ‘glacier free” the cap only neds to retreat enough to move out of that watershed. If that extension of the ice cap ice cap retreated to near the present active glacier, it would, it appears, be out of all three of those watersheds, including the one feeding the Paco Cocha lake, and would still leave a lot of ice cap.

  5. James Lane
    Posted Aug 23, 2006 at 12:26 AM | Permalink


    Goodman et al date the moraine downslope of the lake at 12,800 – 14,280BP (calibrated). 14,800BP is within the uncertainty, and where the record of Abbott et al (above) begins.

    My guess would be that the lake was actually created by the moraine.

  6. Steve McIntyre
    Posted Aug 23, 2006 at 6:23 AM | Permalink

    I’m sure that the meaning of the authors (and the most plausible interpretation of their findings) is that no “glaciers in the watershed” means that there was no Quelccaya ice cap prior to 5000 BP.

    This would be consistent with the growth of Distichia at relatively high elevations in the prior period. It is not consistent with the idea that the 50000 year old plants have been continuously covered by glaciers until the recent glacier recession.

    If (1) the Quelccaya ice cap completely disappeared for some thousands of years in the Holocene; (2) 50,000 year old plants are being exposed by the recession of the present-day glacier, there must be some sort of mechanism by which the 50,000 plant deposit was preserved during the previous glacier recession and some sequence of deposition and erosion which led to its present-day exposure. I’m obviously not in a position to say what the sequence was, but that there was such a sequence seems beyond any reasonable dispute for the 50,000 year old plant.

    Personally I think that it’s plausible that a similar sequence applied to the 5,000 year old plant deposit, in view of the 2700 and 2200-year old plant deposits at high altitude.

    Where I started with this was to demonstrate that the stratigraphy of glacial sediments is highly complicated and that it is impossible to draw any conclusions without a careful exposition of the sratigraphy and careful integration of all available materials. At this point, any person interested in the topic would get a better understanding at CA than from reading Thompson’s absurd PNAS paper.

  7. Dave Dardinger
    Posted Aug 23, 2006 at 8:12 AM | Permalink

    re: #4 Lee,

    I find the best graph is the one in the “Quelccaya Plant Deposits Again” thread with the ice cap in green. (That’s the second graph) You can just see the Paco Cocha lake on the Left center edge. The valley it’s in is quite clear and appears to rise to at least the 5400 meter level. Above that it’s iffy as the indentation in the 5600 level could head toward any of several surrounding valleys. But clearly if the ice cap retreated that far there wouldn’t be much of it left. Probably one photo would be sufficient to let us see just how the spines between the valleys / watersheds are arranged.

  8. Steve Sadlov
    Posted Aug 23, 2006 at 8:14 AM | Permalink

    (sarc)Got to keep the geologists, and especially, the stratigraphers, the heck away from “Climate Science” – they ask too many boring and dry questions, slow us down, and keep us from moving on! >:| (/sarc)

  9. Steve McIntyre
    Posted Aug 23, 2006 at 8:19 AM | Permalink

    Note that 4 samples are described from the Lago Paco Cocha valley in Goodman et al, which I summarized in the previous thread:

    Goodman et al report four samples associated with site 13 (altitude 5180 m), all of which are upvalley from Lago Paco Cocha “modern ice margin above Laguna Paco Cocha” (not all of which are reported in Mark et al 2002). There appears to be an outlet glacier in this valley as well. The samples are said to come from a “time when QIC was smaller than present” – although it remains unclear whether “present” in this context means 1977 or 1997 (when the more recent geological visit took place.) The oldest sample, said to be “basal peat beneath modern glacier” was dated 2670 – C14; 2760 calibrated. A second sample, “upper peat beneath modern glacier” was dated 1950 C14; 1880 calibrated. A third sample, “upper peat beneath modern glacier” was dated 1625 C14; 1520 calibrated. A fourth sample, “upper peat beneath modern glacier” was dated 1395 C14; 1290 calibrated. In all cases, the table states that the the peat was created at a “time when QIC was smaller than present”.

    A couple of these samples were not mentioned in Mark et al.

  10. Steve McIntyre
    Posted Aug 23, 2006 at 8:28 AM | Permalink

    Looking at the Venezuelan graphic and the Lago Paco Cocha graphic, my impression is that the mag susceptibility graphic is perhaps the least blurred. Mag maps are used all the time by geologists in mapping rock formations and very handy; so it doesn’t surprise me that mag measurements in sediment cores might provide a useful proxy of glacial activity.

    The onset of the Neoglacial period, a prominent NH feature, is quite marked in the mag susceptibility.

    Thompson’s recent paper discusses the onset of glaciation ~5000 years ago – as though this were his own discovery without mentioning that the Neoglacial was a term of art a generation ago. But, hey, Porter and Denton 1967 weren’t on the Team – so why would Thompson cite them?

  11. Steve Sadlov
    Posted Aug 23, 2006 at 1:35 PM | Permalink

    Back when I had my Upper Division Grav/Mag course, I initially found mag techniques frustrating, but later, I definitely came to appreciate them. Once I saw the SQUID in one of the labs, I was hooked!

  12. Lee
    Posted Aug 23, 2006 at 2:04 PM | Permalink

    re 6:

    Steve, the authors are analyzing data from water runing into and out of the lake, so ‘ice in the watershed” must refer specifically toice ocntributing to the water flow at Paco Cocha. That is what their data is measuring.

  13. Lee
    Posted Aug 23, 2006 at 3:13 PM | Permalink

    We seem to have a problem here.

    The Lago Paco Cocha in the Abbott et al paper Steve cites here is located at 13 54 S 71 52 W.

    The Quelcayya ice cap is at 13 55 S 70 50 W. This is a full degree of longitude away. I was just looking at the glacier on Google Earth, and noticed this location discrepancy.

    I suspected that Abbott et al might have made a typo (although that location appears in the text and the graphic, so it would have to have been a repeated transcription of a typo), and they might actually mean 13 55 S 70 52 W, but that is way down in the huancane valley below the outlet glacier, and is clearly not the L Paco Cocha in the high valley just below the Quelccaya ice cap.

    Unless there is serious problem with the stated location for the Abbott et al paper, it appears that we are looking at two different L Paco Cocha, which happen to share nearly the same latitude and are about a degree of longitude apart. I cant confirm that, as of yet, because Google Earth and Google Map have only a very low resolution image of the Abbott et al location, so I cant see if there is a cirque lake there.

  14. Lee
    Posted Aug 23, 2006 at 4:07 PM | Permalink

    The wrong lake?!

  15. Steve Sadlov
    Posted Aug 23, 2006 at 4:21 PM | Permalink

    Might seem like a silly question regarding a 2003 paper, but were they using GPS and if so, was it any good? Also, Lee, which specific point on the glacier / ice cap has the coordinates you listed?

  16. Lee
    Posted Aug 23, 2006 at 4:29 PM | Permalink

    Sadlov, I picked a point near the center of the ice cap, that gave round number coordinates.

    Its about 100km between the Abbott et al location and ANY point on the ice cap. Its a different mountain, several mountains away.

  17. Lee
    Posted Aug 23, 2006 at 4:38 PM | Permalink

    another point – the graph in the Abbott paper for Paco Cocha lists the headwall elevation as 5580 m, but the ice cap at Quelccaya is at about 5100 m.

  18. Steve Sadlov
    Posted Aug 23, 2006 at 5:11 PM | Permalink

    RE: #16 & 17 – I’ll anxiously await Steve M’s follow up to this.

  19. James Lane
    Posted Aug 23, 2006 at 5:34 PM | Permalink

    It’s almost certainly a typo. Abbott’s Fig 1 clearly shows the location of the lake, in the same position as in Mark et al. There is no doubt it’s Quelccaya.

    Not sure about the “headwall” reference. In mountaineering terms the headwall usually refers to the rock immediately below the summit. The NOAA gives the summit altitude of 5760m, so most likely the 5580m given by Abbott is the altitude of the actual (rock) summit below the ice. (The summit has been cored, so this would be known.)

  20. Steve McIntyre
    Posted Aug 23, 2006 at 5:59 PM | Permalink

    James Lane’s observation is correct. Additionally, Abbott et al includes the authors of Mark et al. Finally if you consult the sample numbers posted up here and compare it to the sample numbers shown in the radiocarbon date table for the Paco Cocha in Abbott et al, you will notice that the sample AA-27032 occurs in both Mark et al Abbott et al for Paco Cocha, both with the same age. So Lee, for your hypothesis to hold and for there not to be a misprint, in addition to being two Lago Paco Cochas at the same latitude separated by exactly one degree of longitude, the two Lagos would have been studied by the same geologists and even have a sample with the same identification AA-27032 with the same age in each case. While this may seem like an acceptable possibility for climate scientists, most geologists (and myself) would be inclined to think that there is a typo for the longitude in Abbott et al.

  21. Steve McIntyre
    Posted Aug 23, 2006 at 6:03 PM | Permalink

    BTW one thing that I noticed in the radiocarbon scale for Lago Paco Cocha is that the youngest radiocarbon date in the lake is 1450 BC. Given that the lake has obviously been in existence for the last millennium – indeed since the glacier has been receding, sedimentation rates must surely have been significant in the past 150 years and, given some of the caveats about radiocarbon dates for peat, I wonder if the error bars on these radiocarbon dates are really very reliable. Where are the more recent radiocarbon dates?

  22. Steve McIntyre
    Posted Aug 23, 2006 at 6:14 PM | Permalink

    Reid, John B., Jesse L. Reynolds, Nathan T. Connolly, Shari L. Getz, Pratigya J. Polissar, Lawrence J. Winship, 1998. Carbon isotopes in aquatic plants, Long Valley caldera, California as records of past hydrothermal and magmatic activity. Geophysical Research Letters, 25(15):2853-2856.

    ABSTRACT. Hot and cold springs contribute “dead” (14C free) dissolved inorganic carbon (DIC) to the Owens River and Hot Creek. Headwaters aquatic plants have modern 14C, but live plants downstream of the intracaldera springs are depleted in 14C, (as low as 19% modern, with apparent ages up to 13.3 kyrs). In an abandoned meander of the upper Owens River, preserved streambed plants are buried by 600 year old Inyo Craters pumice. Apparent 14C ages of these plants exceed true ages by ~1100 years indicating that they also incorporated dead DIC as they grew. The preserved plants are downstream of Big Springs, whose elevated dead DIC may represent magmatic CO2. The buried plants incorporated ~10% dead carbon, although modern plants here have ~50% dead carbon, suggesting that more magmatic CO2 is now entering the upper Owens River than at the time of the Inyo Craters eruptions 600 years ago.

  23. Steve Sadlov
    Posted Aug 23, 2006 at 7:28 PM | Permalink

    RE: #22 – That is certainly an interesting area (and how ironic, ever so close to those White Mountain Bristlecone sites!). Although it does not get the media attention Yellowstone gets, the Long Valley caldera is plenty big. The last time it went off, I seem to recall, dated at about 700K YBP, the Bishop Tuff ended up spanning from the California coast all the way to about western Nebraska. I digress … while the volcanism and geothermal activity is a bit more extensional in nature versus the subduction induced Andes, nonetheless, some of the issues are similar. The main point is obviously the magmatic CO2 and dead carbon issue. Again, fascinating!

  24. Howard
    Posted Aug 23, 2006 at 7:54 PM | Permalink

    RE: #22 Is it possible that this “reservoir effect” and false aging also possible in plants fed by ancient meltwaters from a receding glacier?

  25. JMS
    Posted Aug 23, 2006 at 9:12 PM | Permalink

    Well, I am going to argue this. Laguna and Lago are different. The lat/long are different. Steve, you are referring to the wrong lake.

  26. JMS
    Posted Aug 23, 2006 at 9:23 PM | Permalink

    Steve, what the heck does volcanic activity in the Owens Valley have to do with lake sediments at Laguna Paco Cocha in the Andes? You are really reaching for it here, why don’t you just give up? It is quite clear that Thompson is not lying, look at the picture which you posted of the 5200bp find. Right next to the ice cap!

    If you keep arguing this line of evidence you will look like the fool the scientific community thinks you are.

  27. jae
    Posted Aug 23, 2006 at 9:36 PM | Permalink

    I just hope that everyone here understands that JMS, Bloom, and Dano are ON ASSIGNMENT. Hate to sound like a complete conspiracy nut, but I’ve been through this many times in connection with chemical regulations. Their JOB is to discredit this site. Period. They add nothing. They simply try to discredit the site. And that is their JOB. Don’t know yet about gbalella/muirgeo and Lee; maybe they are sincere. But I will bet you that the others are here just to discredit this blog.

  28. James Lane
    Posted Aug 23, 2006 at 9:36 PM | Permalink


    Well, I am going to argue this. Laguna and Lago are different. The lat/long are different. Steve, you are referring to the wrong lake.

    Well there goes any credibility you might have had. Fool, indeed.

  29. Steve McIntyre
    Posted Aug 23, 2006 at 9:49 PM | Permalink

    #26. OK, JMS. Start arguing sith sample AA-27032.

    #22. Rodbell et al in a discussion of radiocarbon dates in proglacial lakes in Ecuador observed substantial differences between readings bounded by well-dated tephra. He postulated re-cycling of “dead C” from old peat – which was the purpose of the reference to dead C in California, JMS. I really wonder at the absence of young radiocarbon dates in these glacial sediments and whether the effect observed by Rodbell et al in similar lakes in Ecuador might not be in play here.

  30. JMS
    Posted Aug 23, 2006 at 10:47 PM | Permalink

    Steve, you are a tool.

  31. Dave Dardinger
    Posted Aug 23, 2006 at 10:54 PM | Permalink

    re: #27

    jae, well I don’t know. I know I consider myself as “on assignment” to protect Steve and others from such as you list. But I get nothing other than my own satisfaction for doing so. I don’t think even Steve M particularly likes me since I play a game of “tit for two tats.” I’m willing to give people the benefit of the doubt the first time, but when they continue being obnoxious I start making snide remarks back. After a bit this looks like I’m just as bad as they are, but in fact I’m the mild-mannered one.

    Still, this is more or less what you mean, the trolls want to get Steve in particular, and any others they can mad at them so that they can poison the well and make browsers think this place is just full of flame wars. The trouble is that if Steve starts agressively eliminating the trolls, despite their worthlessness, the charge of “censorship” is what the claim becomes. Still, those who stick around a while both learn who’s honest and who isn’t and that there’s a ton of important things discussed here. Things that Dano, et. al. won’t or can’t engage on.

  32. JMS
    Posted Aug 23, 2006 at 11:07 PM | Permalink

    Steve, why don’t you post a link to your much vaunted sample…

    And Steve, give me a break. The volcanic processes in the Owens Valley of California are much different from the geologic process at work in the neighborhood of Quelccaya.

    Jae, I do not have a job trying to discredit this site, I just do it as a hobby. Since I have a real job, I cannot read all of the papers (nor afford them…) which are cited. However, I do try and tell the truth as I see it. It is true, I don’t try and add anything, I try and remove falsehoods.

    James, the words Laguna and Lago are different, although they can refer to similar geologic formations. If a different word is used to name a feature at a different lat/long it is most likely a different feature. Period.

    And Steve, study the volcanology of the Owens Valley and the Eastern Sierra before you say that the article you cited has anything to do with this argument. This whole discussion is ridiculous from a scientific viewpoint and until you can back up your argument (I have been tempted to email Thompson about the location of the finds, I’m sure he has it, why haven’t you done so?) with some decent facts shut up. You obviously don’t know anything more about this subject than I do, and I know only a little bit. You won on the centering issue and sort of won on the BCP issue (more info is needed on the specific samples and how to exclude them) but you are out of your league on this stuff. I don’t care how many mining reports you have read, you don’t have a clue about the biological processes in action here.

  33. Wm. L. Hyde
    Posted Aug 24, 2006 at 1:03 AM | Permalink

    Please! ‘Laguna’, ‘lago’. Get a life! I’m so tired of you people disrupting this site with your know-nothing rants. Either contribute positively or get off. And show some respect!Please!….theoldhogger

  34. James Lane
    Posted Aug 24, 2006 at 1:06 AM | Permalink


    James, the words Laguna and Lago are different, although they can refer to similar geologic formations. If a different word is used to name a feature at a different lat/long it is most likely a different feature. Period.

    Lago means “lake”. Laguna means “lagoon”. In Spanish speaking countries, the words are often used interchangably, e.g. from wikipedia:

    “In Mexico often the use of “laguna”, which lagoon translates to, is used to describe a lake, such as Laguna Catemaco”.

    The Paco Cocha discussed by Abbott et al is clearly the one at Quelccaya as indicated on the map, Figure 1 in Abbott et al.*

    Stop wasting everybody’s time and go away.

  35. muirgeo
    Posted Aug 24, 2006 at 2:04 AM | Permalink

    Re 27

    And that is their JOB. Don’t know yet about gbalella/muirgeo and Lee; maybe they are sincere. But I will bet you that the others are here just to discredit this blog.

    Comment by jae “¢’‚¬?

    Count me in with the other conspiracy guys. I’m definitely out to discredit this site in favor of the truth. Now if I happen to be wrong and MWP wood starts popping out from underneath glaciers my position will certainly change. I have an open mind that way. But for now I’d say the IPCC has about as much chance of being wrong as Darwin.

  36. John A
    Posted Aug 24, 2006 at 2:18 AM | Permalink


    I’m definitely out to discredit this site in favor of the truth.

    Well you’re doing a fine job of making Steve McIntyre look credible, in my opinion.

  37. Steve McIntyre
    Posted Aug 24, 2006 at 6:32 AM | Permalink

    I already gave the references to the two citations of sample AA27032 – one in Abbott et al 2003 and one in Mark et al 2002. I’ve even posted the Mark et al table on this site; Abbott et al 2003 is online. I’d appreciate it if both Lee and JMS and would check the citation of sample AA-27032 and withdraw their comments.

  38. jae
    Posted Aug 24, 2006 at 8:15 AM | Permalink

    You will note that none of the hired guns for the “environmental” organizations have countered my statement in 27.

  39. Howard
    Posted Aug 24, 2006 at 10:43 AM | Permalink

    #29 Steve M: This new point you have brought up seems to have struck a nerve. The analogies I can think of are salting of a mine and cross-contamination of an aquifer. It seems that before any of the carbon dating and plant sampling can be used to draw real conclusions, at a minimum a reconstruction of the geologic history, the evolution of paleo surfaces, the age of the water sources and the changing depositional environments must be made to put the grab sampling results in context.

  40. Steve Sadlov
    Posted Aug 24, 2006 at 11:33 AM | Permalink

    Typically, JMS the muck thrower and muirgeo/gballela the bomber, have completely failed to understand (or do understand and seek to slime) the main point of this thread. The point is not the mechanism by which dead carbon is generated, the point is, dead carbon can cause a dating error in plants that take it up. But truthfully, you both do know that. Therefore, I must conclude your goal is to slime. You know, the more I observe the key slimers who come here, the more they remind me of slimers known from a reading of history, who tended to accompany vile totalitarian movements in their early days. And I am not kidding when I write this. I write this explicitly and forcefully. I do meant it with all my heart.

  41. Lee
    Posted Aug 24, 2006 at 11:33 AM | Permalink


    I’m not going to ‘withdraw’ my comments. There *is* a major error or mismatch in the stated location. BTW, it is not ‘exactly’ 1 degree of longitude – it is one degree and a few minutes from teh Paco Cocha at Quelccaya, and if I correct the longitude by exactly one degree, it puts the lake at the bottom of the huancane valley, acccording to Google Earth.

    The sample ID is strong support for it being the same lake, and thus a major error in stated location – strong enough to convince me that it almost certainly is the same lake. You’re making arguments on this – why dont you email the author and ask, just to be sure?.

    BTW, you also asked ‘where are the recent dates’ from Paco Cocha. The table shows the depth of the sample in the sediment, and the most recent sample is not at the surface – so I propose that the most recent sediments are at the surface, and were not sampled or tested.

    I’m off to be productive – if I can put together the time, I plan to post in the next couple days with what I think all this evidence is telling us about the history of Quelcayya and environs.

  42. Lee
    Posted Aug 24, 2006 at 11:35 AM | Permalink


    “2. Never attribute ulterior motives to another participant.”

  43. Steve Sadlov
    Posted Aug 24, 2006 at 11:38 AM | Permalink

    RE: #40 – dang, the dangers of editing. Rewrote the sentence but forgot to change the verb tense – “meant” s/b “mean” …

  44. JMS
    Posted Aug 24, 2006 at 11:56 AM | Permalink

    James, I looked at the map and Laguna Paco Cocha is clearly west of the ice cap. Lago Paco Cocha is a pro-glacial lake right at the edge of the ice cap. The lat/long Abbot refers to is about 1 degree west of the ice cap.

    I don’t know where you are from, but in the neck of the woods I grew up in you can camp at several places named “Mosquito Lake”. There is only one “Sam Mack Meadows”, though.

  45. Steve McIntyre
    Posted Aug 24, 2006 at 12:04 PM | Permalink

    #44. JMS – look, I’ve been in exploration business in Canada and know all about Deer Lake, etc. Care to explain how sample AA27032 got taken from two “different” lakes. Didn’t think so – you’ve resisted all invitations so far. Abbott et al and Mark et are discussing the same lake/laguna.

  46. Lee
    Posted Aug 24, 2006 at 12:11 PM | Permalink

    Steve, there is either a major error in location, and the sample number is correct, and its the same lake –

    Or the location is correct and there is an error in the sample number, in which case its a different lake.

    Why dont you email the authors and find out?

  47. Ken Fritsch
    Posted Aug 24, 2006 at 7:48 PM | Permalink

    Steve M, I continue to applaud your efforts to cover in more detail some of the evidence that the NAS committee overlooked in its seemingly hasty effort to support AGW while at the same time downgrading the efforts of the temperature reconstructions beyond 400 years ago. I have learned much from the published articles that you have presented, your comments on them and the discussion of them in the comments — to the extent that they have remained on topic.

    While your efforts to avoid the implication of censoring of opposing views should be commended, I am not a little distracted by the noise levels that I find come from (a) personal debates that frequently do not add to the knowledge base of the specific topic at hand, (b) posters who seem to come to the discussion with the intent of having their feelings hurt or to uncover evidence of a bias towards them and/or people with their points of view, (c ) posters who raise to the bait of these posters and thus contribute to wasted space (ad hominem ad infinitum), (d) posters who merely seem to want to let skeptics and agnostics know at every opportunity that the circumstantial case is closed on AGW and only fools would question what they surmise to be an overwhelming and proven consensus from the climate scientists, (e) those who make their personal cases against AGW with little or no evidence to back it up and (f) those who seem to want to show that they can turn your efforts as a critic of some sometimes sloppy and vague climate science publishing back on you.

    How does one separate the noise in these discussions to obtain a more comprehensible thread on the subject at hand — or should that be the reader’s obligation? A recent example of a noise level that ended, I thought, constructively was the reaction of a poster to your criticisms of the NAS HS committee report for not presenting all the evidence (outside the realm of multi-proxy surface temperature reconstructions) for past climates being as warm as the last decade of the 20th century (which I very much suspected simply from their haste to show that natural temperatures fluctuations could not entirely explain the recent warming). You were more than willing to discuss your views on the Thompson paper not as an expert in the field but simply to show the lack of detail on Thompson’s part and to perhaps elicit more detailed information, but the poster appeared to me to be more intent on showing that your criticisms of NAS were unwarranted and then proceeded to pick at your analyses Thompson’s paper and the ice cap and glacier definition.

    I must say that I learned from this exchange, but thought it to be rather inefficient because of what I judged to be the ulterior motives of the criticizing poster getting in the way of clearly explaining the effect his criticism would have on the any final conclusions drawn from the discussion.

    I do see two separate directions from which the original threads tend to evolve: (1) the more technical discussion that usually starts the initial discussion and (2) the noise that evolves from the sources that I listed above but not limited to them. At what point the noise (to which I have contributed) of an individual post actually becomes an off topic subject would be a matter of someone’s subjective evaluation. I would hope that the noise level does not discourage potential contributors with information to add to the knowledge base, but if it was shown that it did would it be possible to at least allow the poster to determine whether they considered their postshould be categorized Off Topic of Subject X and posted under that category? I would also think that a post to be considered on topic should contain some discussion of an included link and not just a link or series of links by themselves.

    As an AGW skeptic, I continue to look for probabilities of the evidence for and against, how much and, in general, clear arguments for and against. I think blogs like yours are good sources for this information and provide a means for point and counter point evidence that published papers do not provide. The personal touch in blogs is an added attraction, but there are times when I think some of the content needs to be compartmentalized.

  48. James Lane
    Posted Aug 24, 2006 at 11:59 PM | Permalink


    Steve, there is either a major error in location, and the sample number is correct, and its the same lake –

    Or the location is correct and there is an error in the sample number, in which case its a different lake.

    You forgot the bit about the “lakes” having the SAME NAME.

  49. Steve McIntyre
    Posted Aug 25, 2006 at 3:18 AM | Permalink

    I’ve changed the title of this post from “Lago Paco Cocha” to “Laguna Paco Cocha”, which is the term used in the articles. I never attributed any significance to a supposed distinction between lago and laguna; in the Venezuelan article, they called the little proglacial lakes “lago”. However, for good order’s sake, I’ve changed the title here and made simialr edits to the post Quelccaya Plant Deposits Again.

  50. James Lane
    Posted Aug 25, 2006 at 4:01 AM | Permalink

    Amusingly, paco translates to “alpaca” and cocha translates to “ox-bow lake”.

    So, both “lago” and “laguna” are redundant. It’s a bit like saying “Lake Alpaca Lake”. Abbott et al use both Lago and Laguna in the space of a few lines.

  51. Lee
    Posted Aug 25, 2006 at 8:47 AM | Permalink

    James, you forget the part where I already said I find the sample number to be nearly completely convincing, but point out that there still appears to be a major error of some kind, and ask Steve here to simply email the authors and find out for sure.

    Ken, let me ask you: If Thompson had published a paper where they get the location of a sample wrong by a bit over a degree of longitude, and someone pointed that out, and there was a discussion similar to this one as to whether the location was wrong or the sample was actually taken from a differnt place – would that be noise?

    Actually, I rather suspect taht if this had been Thomspon, there would be a dozen or more posts consisting of nothing more than berating of Thompson, and it would be perfecly acceptable to this board.

  52. Ken Fritsch
    Posted Aug 25, 2006 at 11:00 AM | Permalink

    Ken, let me ask you: If Thompson had published a paper where they get the location of a sample wrong by a bit over a degree of longitude, and someone pointed that out, and there was a discussion similar to this one as to whether the location was wrong or the sample was actually taken from a differnt place – would that be noise?

    I do not consider your longitude “find” to be noise — in fact you should be commended for your attention to detail. Steve M’s attention to detail got us to an identical sample ID for both finds at lakes with the same name and that appears to have answered the question you posed to a goodly but not complete finality. The mistake that you found in your referenced example would appear to confirm that peer reviewed literature in general is not infallible and I think that goes along with what many here have stated in the past. Of course, when one can get that mistake quickly corrected the discussion can continue in a timely manner — unlike the cases with Mann’s HS papers and some others who have published temperature reconstructions. (I found that the article in question refers to “Lago” in the caption to a paragraph and then immediately writes about “Laguna” in that paragraph. Evidently detective work is contagious.)

    Some climate articles can be vague and incomplete in detail without showing any obvious mistakes and I think that is to what Steve M is referring in the Thompson article. Wegman made the same observation about Mann’s papers (besides pointing to his statistical mistakes).

    It is when the discussion veers off into other issues that are not critical to the discussion or to drawing conclusions from the discussion that, in my mind, unnecessary levels of noise are created. Sometimes when this noise enters into a reply it can obscure a valid point being made that might be critical to the original discussion and I found that to be the case of my comprehension (could be my problem) of your original replies to Steve M on the Quelccaya terrain. I kept asking myself and looking for the point you were making that was critical to the discussion and waiting for you to put it into clear form.

  53. Steve McIntyre
    Posted Dec 22, 2006 at 2:55 PM | Permalink

    The diagram shown in this post was also shown in Thompson’s Day Two AGU presentation discussed here in which Thompson said that this merely showed the “approach” of the glaciers, whereas Rodbell said that they were “probably absent from the watershed between 10.0 and 4.8 ka”.

    I suspect that we’re going to be hearing more discussion (post-Hansen) about warmest in 12,000 years (PAchauri in NAirobi) and so evidence from the tropics in the Holocene Optimum is going to be in play. This is rather an interesting proxy, especially when combined with peat moss from this period.

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