Talk:Heinrich event

From Wikipedia, the free encyclopedia
Jump to: navigation, search
Good article Heinrich event has been listed as one of the Natural sciences good articles under the good article criteria. If you can improve it further, please do so. If it no longer meets these criteria, you can reassess it.
WikiProject Geology (Rated GA-class, Mid-importance)
WikiProject icon Heinrich event is part of WikiProject Geology, an attempt at creating a standardized, informative, comprehensive and easy-to-use geology resource. If you would like to participate, you can choose to edit this article, or visit the project page for more information.
 GA  This article has been rated as GA-Class on the project's quality scale.
 Mid  This article has been rated as Mid-importance on the project's importance scale.
 

Changes[edit]

I've made some changes, some of which undo some of Wetmans changes (sorry). As far as I can tell, HE's are very specific things as far as the glacios are concerned, and there are 6 of them. They aren't the same as D-O events and they aren't the same thing as the more recent shorter cycles. Also I'm a bit unclear in which way H3 and H6 are different but I think its not just in terms of their sources. William M. Connolley 21:06, 23 September 2005 (UTC).

I've added some external links, so that a reader who finds the present article insufficient and inconclusive may read some recent science on the subject. --Wetman 00:01, 24 September 2005 (UTC)


Hemming (2004) reports that there is little published evidence for Heinrich events in previous glacial periods, though Stokes may beg to differ in the 2005 edition of Global and Planetary Change. Moved the italicized addition here. Anyone want to render this obscure hint relevant? --Wetman 17:12, 7 November 2005 (UTC)

No idea. Was intending to try to find out... might be [1] William M. Connolley 17:54, 7 November 2005 (UTC). Oh, and if it *is* that then we should leave it out: its still in press. Unless we're into really topical science, we shouldn't be including stuff within a year of publication really. William M. Connolley 17:56, 7 November 2005 (UTC).
BTW, Heinrich events are related to, but not the same as, Dansgaard-Oeschger events is, I agree, unsatisfactory. I shall try to improve that. William M. Connolley 17:50, 7 November 2005 (UTC).
Hodell et al, Palaeoceanography vol 23(PA4218)December 2008 provide detailed evidence of Heinrich events (detected using Si/Sr ratios and other XRF-based proxies) in previous glacials going back to at least 640 ka in the North Atlantic (Site IODP U1308). Interestingly, there is "a pronounced change" in the "composition and frequency of IRD" at this time, which is approximately coincident with the change from a 41 kyr (orbital obliquity) to a 100 kyr (probably orbital eccentricity) dominated climate regime. The absolute size of the ice sheets developed at this time may have played a role in these changes, but the authors point out that more sites need to be studied at this level of resolution. Orbitalforam (talk) 12:21, 7 January 2009 (UTC)
Incidentally, studies such as Hodell's indicate that this remark in the article is incorrect: "Heinrich events are observed during the last glacial period; the low resolution of the sedimentary record before this point makes it impossible to deduce whether they occurred during other glacial periods in the Earth's history". Hemming, in Reviews of Geophysics,42, RG1005, doi:10.1029/2003RG000128, 2004 also discusses evidence of Heinrich events prior to the last glacial (ie before about 130 kyr BP).Orbitalforam (talk) 15:27, 31 March 2010 (UTC)

Popularized explanation[edit]

It would be nice to add popular-science-like explanation into introduction part of the article, here and for Dansgaard-Oeschger event as well. Readers would appreciate it. 02:21, 17 November 2005 (UTC)

Hemming 2004[edit]

Where have the ages for the Heinrich events been taken from? They don't appear in the article.

The dates are sourced in the table. I can't remember if Hemming states them explicitly or if I had to read them off a graph. William M. Connolley 15:46, 21 December 2005 (UTC).

August 2006[edit]

There is an easy answer to Conolley's question. The mineral assemblage of H1,2,4,5 ist different from H3 and H6. The latters are characterized by higher amounts of the clay mineral smectite (weathering product of volcanic rock) and volcanic glass shards. All this points to a stronger supply of ice from the Norwegian-Greenland Sea area. Whereas H1,2,4, and 5 have mineral assemblages of the Laurentian region.[User: Hartmut Heinrich, 10 Aug 2006]

Richard Alley's estimate on the volume of ice discharged during a H event (370 km³) seems by far too small. New investigations (satellite gravimetry) report an annual loss from Greenland of about 230 km³ due to the present climate warming. Are we "enjoying" a H event? :-)[User: H Heinrich, 11 Aug 2006]

Good spot H. The actual figure is 370 000 000 000 km³… Verisimilus T 18:58, 7 May 2007 (UTC)

Coiuld use some clarification[edit]

This phrase is confusing. Perhaps it makes sense if you already know something about Heinrich events, but why wouldn't H3 and H6 be "different"? If they were the same, wouldn't they have the same name?

Six such events, labelled H1-H6, have been identified. There is some evidence that H3 and H6 are different.

Some context would help readers understand just how much the volume of water below is; is there something to which we can compare it?

the volume of freshwater discharged by a typical Heinrich event as 370 km3

Also, what's a "glacial"? An ice age? Clarifying that, and linking to an appropriate Wikipedia article, would help.

Most importantly, what characterizes a Heinrich events? Anything beyond lots of icebergs and fresh water? —The preceding unsigned comment was added by 66.92.53.49 (talkcontribs) .

I added a link to the "last glacial" which is hard to name as it has different names in different part of the world - see the link in this very sentence. I also added a sentence on the possible sources of the water discharge. I believe that otherwise the definition in the article is well done. Friendly Neighbour 10:51, 19 September 2006 (UTC)

Failed GA Nomination[edit]

This is a good article but it has some issues which will take a while to fix.

- Article needs a lot more references. I don't mean as in more references being used but as the facts currently in the article need to be sourced.

-I could not understand the lead section. I think it needs a complete rewrite to make it understandable to those who know little about the topic. It also needs to be made into two or three paragraphs.

- The section heading "H3 & 6 - Heinrich events?" needs to be changed. Usually questions are not put as section headings and according to the Manual of Style the word "and" should be written out.

- There are a few one sentence paragraphs which need to merged or cut.

- In the External Forces section several words are in bold. I could not figure out why.

- In the internal Forces section, the word not is in itallics.

I hope someone will resubmit this article. It is close! --Banana 02:26, 26 May 2007 (UTC)

Hi, many thanks for your review and constructive feedback!
I've had a look at the article and made a few changes, and will continue to make more.
However, I'd quite like to keep the bolding of the different explanations, as I think it makes reading clearer, especially to a skim-reader. It seems to be legit with the MOS - see this page, which admittedly uses bulleted points.
And whilst I've removed the italics from "not", I think this makes reading a little easier, too, emphasising the difference. Do I have to get rid of it?
Thanks, Verisimilus T 10:34, 26 May 2007 (UTC)
Though I avoid the jury process and don't care whether this good article is a "Good Article" or not, I have some suggestions to make this fine presentation more user-friendly. Nordic Sea is an unfamiliar term: is the Norwegian Sea intended? Hartmut Heinrich: introduce him, as formerly, as soon as the reader is asking "Why 'Heinrich'"? "Density-driven circulation": identify it as identical to the thermohaline circulation. The specialized vocabulary always needs to be given an unobtrusive phrase in apposition at its first appearance: alkenone, speleothem, aren't in the usual reader's vocabulary: what if the reader is asking "What's a lithic?" Most of the bulleted items can be expanded, not to be so gnomic: ask "why is this so?" at each instance. Writing out Thorium-230 is friendlier. --Wetman 11:06, 26 May 2007 (UTC)

Review[edit]

This is a well written, well sourced and comprehensive article. The only issue, that I have with it, is the lead section. It should provide a summary of the article and not to introduce any data that are not mentioned in the main text. For instance, the second paragraph should be moved to a different section as it defines the volume of fresh water. Some information in the third paragraph is also not mentioned in the main text. In addition the main text lacks any definition of Heinrich events themselves, it is only present in the lead. I hope that the lead section can be rewritten quickly so I can promote the article to GA status. Ruslik 10:41, 21 June 2007 (UTC)

Thanks for your thoughts. I'll take a proper look at re-structuring the article when I'm feeling a little better! Verisimilus T 11:21, 21 June 2007 (UTC)
I've moved some bits of the lede into the article. I feel that the first two paragraphs of the Diagnosis section now give a suitable explanation of what a H event is, but am open to your thoughts. Thanks again for your review, hope you find this okay! Verisimilus T 14:26, 24 June 2007 (UTC)
The lead is OK now. However I don't see any definition like: "Heinrich events are defined as periods during the last glacial period when vast amounts of ice in the form of icebergs were dumped into the North Atlantic." or smth like this. In addition it may be useful to move the "Timing" section to the beginning of the article and to start it with this definition. The current position of the "Timing" section seems a bit odd. It'd be better to define the events, then provide their timings and then discuss diagnostics etc. Ruslik 18:07, 25 June 2007 (UTC)
Since there is no answer I agree that the article has failed GA. Ruslik 11:33, 28 June 2007 (UTC)
Sorry, been a bit busy. Will fix presently - is it alright if I get in touch with you once I've done it and you reconsider it for GA then? Cheers. Verisimilus T 11:44, 28 June 2007 (UTC)
Please also add some inline citations. Quite important in a GA. Anonymous DissidentTalk 11:46, 28 June 2007 (UTC)
There are several inline citations already present in the article. See WP:CITE#Harvard_referencing.
Unfortunatly, I have already removed it from the list of candidates. However it you do the job and renominate it I will review this article again. Ruslik 11:59, 28 June 2007 (UTC)
Thanks! Verisimilus T 12:32, 28 June 2007 (UTC)
...and now Verisimilus sees the difference between this and the peer review process, with which V. is familiar. --Wetman 18:12, 28 June 2007 (UTC)
Face-smile.svgVerisimilus T 18:25, 28 June 2007 (UTC)

Review (2)[edit]

Since my suggestions from the previous review (see above) have been taken into account, now I think that the article passes GA. Ruslik 08:58, 29 June 2007 (UTC)

Hooray! Thanks for taking the time to review this article and provide feedback. Verisimilus T 13:08, 29 June 2007 (UTC)

Serious fact error in estimated water volume[edit]

In the second paragraph of the "Diagnosis of Heinrich events", it is stated that "Alley & MacAyeal (1994) estimate the volume of fresh water added to the North Atlantic over each 500 year event at around 3.7±1.2×10¹¹ km³ — a huge influx of cold, fresh water that would have had global effects." This is totally wrong, in several ways. The cited numbers "3.7±1.2×10¹¹" refers to IRD (ice-rafted debris), not water. And it is given in cubic meters (m³), NOT cubic kilometers (km³). Quote from Alley & MacAyeal (1994): "Assuming that IRD has a density of 2700 kg m³, the m [mass] we estimate corresponds to an IRD volume of 3.7±1.2×10¹¹ m³". Actually, 3.7±1.2×10¹¹ km³ of water is almost 300 times the total global ocean volume (ca 1.3×109km³, http://en.wikipedia.org/wiki/Ocean), a freshwater contribution that indeed would have global effects.

I suggest that the sentence in question is replaced by this: During Heinrich events, huge volumes of fresh water flow into the ocean. For Heinrich event 4, the fresh water flux has been estimated to 0.29±0.05 Sverdrup (http://en.wikipedia.org/wiki/Sverdrup) with a duration of 250±150 years (Roche et al., 2004), equivalent to a fresh water volume of about 2.3 million km³.


References:

Alley, R.B.; MacAyeal, D.R. (1994). "Ice-rafted debris associated with binge/purge oscillations of the Laurentide Ice Sheet". Paleoceanography 9 (4): 503-512. DOI:10.1029/94PA01008.

Roche, D., Paillard, D., Cortijo, E. (2004). "Duration and iceberg volume of Heinrich event 4 from isotope modelling study, Nature 432: 379–382. Cutnell, J. D., and Johnson, K. W.(1995). Physics, 3rd Edition. New York: Wiley: p315. 129.177.53.72 12:18, 27 September 2007 (UTC)

I think you are right here, I actually did not check the numbers, when I reviewed it. Ruslik 12:41, 27 September 2007 (UTC)

GA Sweeps Review: Pass[edit]

As part of the WikiProject Good Articles, we're doing sweeps to go over all of the current GAs and see if they still meet the GA criteria. I'm specifically going over all of the "Meteorology and atmospheric sciences" articles. I believe the article currently meets the criteria and should remain listed as a Good article. I have made several minor corrections throughout the article. Altogether the article is well-written and is still in great shape after its passing in 2007. Continue to improve the article making sure all new information is properly sourced and neutral. It would also be beneficial to go through the article and update all of the access dates of the inline citations and fix any dead links. If you have any questions, let me know on my talk page and I'll get back to you as soon as I can. I have added an article history to reflect this review. Happy editing! --Nehrams2020 (talk) 21:43, 24 April 2008 (UTC)

Disputed parts[edit]

140.254.57.59 left this comment in the article:

"Ice provenance: Icebergs in H1, H2, H4, and H5 appear to have flowed along the Hudson Strait; H3 and H6 icebergs appear to have flowed across it (just WRONG: read literature before write this crap again, ok? Kirkby and Andrews, 1999)."

Acdx (talk) 01:48, 23 July 2010 (UTC)

Some questions[edit]

I read this article because I had just watched a TV programme in which Clive Finlayson argued that the Neanderthals went extinct because they could not cope with the rapid climate fluctuations during the Heinrich events, which changed Europe from forest to tundra. The article did not help answer what I would like to know about Heinrich events. What were their effects on ecosystems and is Finlayson right? He makes the same point in a Scientific American article at http://www.scientificamerican.com/article.cfm?id=the-mysterious-downfall.

What was the reduction in temperature in each Heinrich event, and how does it compare with earlier ice ages. I find the Heinrich event chart unhelpful. The lines do not appear to me to have any clear relation to the H events and do not have a temperature parameter. There is a much clearer chart, Vostok Petit data, in the Quaternary glaciation article, http://en.wikipedia.org/wiki/File:Vostok_Petit_data.svg, which shows H2, H5 and H6 clearly, and that H2 was the most extreme (as the TV programme says but the Heinrich article does not) and also suggests that there were similar fluctuations between 130,000 and 180,000 years ago, although the Heinrich article says that there is no data for earlier periods. I would suggest replacing the confusing Heinrich events chart with the informative Vostok one.

How do the Heinrich events relate to the Older and Oldest Dryas? The date for H1 appears to be similar to the Oldest Dryas.

This is outside my field, so excuse me if I am making unfair criticisms through ignorance. Dudley Miles 00:58, 30 July 2011 (UTC) http://triksgretz.blogspot.com/ — Preceding unsigned comment added by Budi354 (talkcontribs) 09:55, 26 December 2011 (UTC)

The graphs are shown on different timescales[edit]

This is a comment to the plot in the article. Heinrich events are shown on a GISP2 timescale while Greenland icecore data are shown on a NGRIP/GRIP timescale. This places the Heinrich events wrong with respect to the Greenland icecore record. The Anarctic icecore data are also shown on a different time scale. Please put all the curves on a synchronous timescale and inform which timescale has been used. 192.38.112.134 (talk) 11:35, 10 June 2013 (UTC)