From: PO2::"QUATERNARY@MORGAN.UCS.MUN.CA" "Research in Quaternary Science" 14-APR-1996 12:55:55.09 To: Multiple recipients of list QUATERNARY CC: Subj: Re: 1000 year cycle in Holocene >Dear Quaternary friends, >Mr.Wei Minjian,a PH.D student here found four peaks and three troughs in the >Holocene series of North China Loess, when he was examining the ferrous oxide >and palynoflora of the black loam deposits intercalated in the Loess. When >correlated with the data of C14 dating,they appear as four 1000-year cycles. > >Does anybody know similar phenomena in other part of the world ? comments or >suggestions on this puzzle will be very much appreciated. I find a similar (but weak) periodicity in the Holocene diatom record of Lake Victoria, East Africa, though I have no idea what it means. I'll be submitting that record soon for publication, so I'm sorry I can't give you a formal reference for it yet. Also, I believe the delta C-14 residual series has a perdiodicity of slightly less than 1000 years; I think it's closer to 900, actually. Do you have anything in print on China loess periodicities you could share with the rest of us? Regards; Curt Stager. > From: PO4::"QUATERNARY@MORGAN.UCS.MUN.CA" "Research in Quaternary Science" 15-APR-1996 09:35:23.76 To: Multiple recipients of list QUATERNARY CC: Subj: Re: 1000 year cycle in Holocene There was a recent short article in Science News describing rapid climate changes during the Holocene (Science News, March 2, 1996, Vol 149, p. 140-141). Here are a few notes from that article: Suzanne O'Brien (Univ. New Hampshire) was reported to have identified 4 Holocene climatic coolings in the Greenland Ice core record (reported in Dec 22, 1995 Science). These cycles had approximate periods of 2,600 years. Gerard Bond (of Lamont-Doherty) supposedly has identified several Holocene Heinrich-like sediment layers in North Atlantic cores with ages at 1,050, 3050, 3,950, 5,650, and 8,050 years ago (reported at Dec 1995 AGU meeting). These layers are interp'd to represent colder times when more extensive sea ice carried Icelandic volcanic debris farther southward. Bond speculated that either oceanic circulation changes (analogous to El Nino events, but bigger and longer) may cause rapid climate cycles in the absence of a large northern hemisphere ice sheet. The other possibility mentioned in the Science News article were solar variations. Hope this helps. -- Steve Roof sroof@hampshire.edu School of Natural Science, Hampshire College Amherst, MA 01002 (413) 582-5667; FAX (413) 582-5448 From: PO4::"weiler@ers.unr.edu" "James Lyons-Weiler" 15-APR-1996 12:06:51.90 To: Multiple recipients of list QUATERNARY CC: Subj: Re: 1000 year cycle in Holocene On Sun, 14 Apr 1996, yuan dao xian wrote: > Dear Quaternary friends, > Mr.Wei Minjian,a PH.D student here found four peaks and three troughs in the > Holocene series of North China Loess, when he was examining the ferrous oxide > and palynoflora of the black loam deposits intercalated in the Loess. When > correlated with the data of C14 dating,they appear as four 1000-year cycles. > > Does anybody know similar phenomena in other part of the world ? comments or > suggestions on this puzzle will be very much appreciated. > Sincereely yours, > Yuan Daoxian > In our work with Holocene lake sediments from lowland Amazonia, we have seen apparently regional, synchronous changes in both pollen spectra as well as sediment chemistry (paleolimnology). My master's thesis at the Ohio State University contains the details. Also, Mo:rner's 1992 conjecture that there were past Mega-ENSO and paleo Super-ENSO (El Nin~o Southern Oscillations seems to provide a possible mechanism. However, the time scale is a tad more fine than 1,000 year cycles, and the causal interpretation is made difficult by multiple causes (tectony vs. climate shifts). Morever, the periods are less than regular. David Raup once advised me to steer clear of seeking statistical support for cycles in paleo records, with or without mechanism, given his experience with how people received the cyclic mass extinction arguments. I'd hate to cite him out of context. If he's online, maybe he could provide us with some further insight? J L-W. _________________________________________________________________ JAMES LYONS-WEILER PH: (702) 359-6391 ECOLOGY, EVOLUTION AND FAX: (702) 784-4583 CONSERVATION BIOLOGY/186 eMAIL: weiler@grass.ers.unr.edu 1000 VALLEY ROAD THE UNIVERSITY OF NEVADA, RENO RENO, NEVADA 89512-0013 _________________________________________________________________ From: PO4::"QUATERNARY@MORGAN.UCS.MUN.CA" "Research in Quaternary Science" 20-APR-1996 02:15:15.16 To: Multiple recipients of list QUATERNARY CC: Subj: 1000 year cycle in Holocene Dear Quaternary Friends, On behalf of Mr.Wei Minjian,many thanks for Linda Heusser,Curt Stager, Stein-Erik, Steve Roof, James Lyons-Weiler,and Alessandro M.Michetti for the very interesting and helpful discussions on the 1000 year cycle in the Holocene. It seems that this phenomena can be found at different parts of the world including North America,East Africa,Arabian Sea,North China,Norway, Northwest England and South America with various proxies,i.e,diatom,loess, Pollen,chemical contents,stalagmite,sand dunes,and etc.,although it origin needs to be explored. I have printed out and mailed to Mr.Wei all your informations and asked him to provide more data about his findings. He is working in the Institute of Hydrogeology at Zhengding,north China. I will put his data on the LIST as soon as I get it. Again thank you very much! Yuan Daoxian