Re: [SWR] icicles and stal WHOOPS, here is the message.
Penny Boston pbos...@nmt.edu wrote: This ripple pattern is observed only on icicles (and stalactites?) that are growing via deposition on the exterior surfaces. Soda-straws and helictites are fed from internal canals (water-drop diameter in straws; capillary size in helictites), and can't be expected to show effects that develop in an external film. Helictites are typically irregularly crooked (thought to be the result of crystal-growth forces), and are not made of regularly-spaced annular rings. In helictites, the nearest thing I have seen to that is the rare beaded pattern in which some aragonite helictites are composed of a string of repeating growths of conical clumps of diverging crystals (e.g., in Silent Splendor and Breezeway Cave at Manitou, Colorado). As far as I know, the mechanism that causes beaded helictites has never been explained, so I can't rule out that development of their structure may involve subtle chemical effects. In general, however, helictites and stalactites are often found together, sharing the same water source, and whether a helictite or stalactite grows from a given point seems to depend on whether the source flow is enough to form a hanging drop at the tip (which will make the resulting form a stalactite). ?Donald Dear All, I strongly suspect that there is a combination of physical factors involved in the production of the ridges, namely fluid flow regime (i.e. laminar vs turbulent flow at a very tiny scale) and the effect of subtle wind velocities coupled with issues of surface tension and capillarity. Once the standing ripple pattern is begun it is probably self-reinforcing because of enhanced precipitation on the ridges and less in the valleys. I have seen this same ridged pattern not only in icicles and stals of the calcite variety but also in soft sediment features of fine particles held together with microbial biofilm, microbe bodies, and mineralized micro crystals. So I think it is much less dependent on the materials and hence chemistry than it is on the physics. However, any additive that would have an effect on the physical properties, e.g. surface tension and wettability, capillarity, or the like is likely to have an effect like salt. Cheers, Penny Very persuasive remarks. --Donald ___ SWR mailing list s...@caver.net http://lists.caver.net/cgi-bin/mailman/listinfo/swr ___ This list is provided free as a courtesy of CAVERNET
texascavers Digest 27 Nov 2013 04:20:58 -0000 Issue 1890
texascavers Digest 27 Nov 2013 04:20:58 - Issue 1890 Topics (messages 23104 through 23106): The current weather related to Texas caves 23104 by: David Tienkengs 23105 by: dirtdoc.comcast.net Re: [SWR] Tienkengs 23106 by: dirtdoc.comcast.net Administrivia: To subscribe to the digest, e-mail: texascavers-digest-subscr...@texascavers.com To unsubscribe from the digest, e-mail: texascavers-digest-unsubscr...@texascavers.com To post to the list, e-mail: texascavers@texascavers.com -- ---BeginMessage--- I was thinking that this cold weather is a fine time to go down in places like Kiwi Sink and look for some warm blowing air.Right ? Would newly opened cracks in Kiwi Sink blow warm air this week ? David Locklear Ref: http://answers.yahoo.com/question/index?qid=20110326191631AAHFotV ---End Message--- ---BeginMessage--- Tienkengs National Geographic - Mystery Caves Of Guangxi http://www.youtube.com/watch?v=wiYn-DeQjL8 A production of the National Geographic Channel in conjunction with Chinese television CCTV-9 I have been asked to provide some clarification for the US caving community about the use of the term tiankeng. As many of you know, I have been leading karst-focused tours for geologists and cavers and have first-hand knowledge of Chinese karst since 1993. The cavers staring in the film have clearly had a wonderful time in a spectacular area courtesy of National Geographic. The film does a good job of explaining the area to the general public, and conveying the wonder and excitement of exploring the karst of SW China. This is a spectacular and interesting film. It is also contains some unnecessary (in my opinion) exaggeration and self-promotion from National Geographic. Anyone in the caving community who has been to the spectacular karst areas of China recognizes the hyperbole. National Geographic seems either to have done a poor research job (unlikely) or made a deliberate decision to add additional mystery and danger to some of the most spectacular karst on Earth. These are clearly world-class caves. Cave scientists have understood how these huge pits are created for over a hundred years. First described from the Dinaric Karst, known in China since 1992, explored in China by the Cave Research Expedition in 1993 (that was before the Funny Word tienkeng had been coined), and explored extensively in China by the Hong Meigui Cave Exploration Society (Erin Lynch) since 2001, the British Cave Research Foundation , and others. These large limestone pits have been found all over the world. Simply, they are unusually large collapse dolines. They become large when there is a good-sized underground river to keep extracting the breakdown blocks that fall underground. In this part of China there is stratigraphically over 7 miles (total thickness) of soluble limestone, high topographic relief, and it rains a whole lot to produce the groundwater that dissolves the limestone. Fracture traces in the limestone likely relate to the specific location of these pits, just as they do for millions of other cave passages around the world. The public perception and misunderstanding about tienkengs has been caused by prominent Chinese geologist who arbitrarily made up the word tienkeng (Sky Hole or Heavenly Pit) for exceptionally large collapse dolines. He defined them as collapse dolines that are more than 100 wide and deep. This is a completely arbitrary term. It is just like using the word skyscraper for tall buildings and megabuilding for the very tallest one. Then you can claim that you city has the only megabuilding in the world. It has allowed the Chinese to make a Big Deal out of the fact that they do, indeed, have a lot (more than 50) impressively gigantic collapse dolines in their country. There are numerous references to these large pits in China that have been written over the last 20 years, some accurate, some with included hyperbole. Here is where to start: Tiankengs: Definition and Description, 2006, Zhu Xuewen and Tony Waltham http://www.speleogenesis.info/directory/karstbase/pdf/seka_pdf9541.pdf This is a summary paper that concludes: The concept of tiankeng karst has been considered within China as a term to describe an extremely mature type of karst landscape that has matured beyond normal fengcong karst with high relief. The term could be used to describe the Leye karst in Guangxi, China, and perhaps the Nakanai karst in New Britain, Papua New Guinea, both of which are distinguished by unusually large numbers of tiankengs. However, some mature karst terrains contain just a few tiankengs, notably just two in each of the karsts of Xingwen, Croatia and Mexico, and these question the applicability of the term. Tiankeng karst may be purely descriptive of the Leye and Nakanai terrains, but the
[SWR] Tienkengs
Tienkengs National Geographic - Mystery Caves Of Guangxi http://www.youtube.com/watch?v=wiYn-DeQjL8 A production of the National Geographic Channel in conjunction with Chinese television CCTV-9 I have been asked to provide some clarification for the US caving community about the use of the term tiankeng. As many of you know, I have been leading karst-focused tours for geologists and cavers and have first-hand knowledge of Chinese karst since 1993. The cavers staring in the film have clearly had a wonderful time in a spectacular area courtesy of National Geographic. The film does a good job of explaining the area to the general public, and conveying the wonder and excitement of exploring the karst of SW China. This is a spectacular and interesting film. It is also contains some unnecessary (in my opinion) exaggeration and self-promotion from National Geographic. Anyone in the caving community who has been to the spectacular karst areas of China recognizes the hyperbole. National Geographic seems either to have done a poor research job (unlikely) or made a deliberate decision to add additional mystery and danger to some of the most spectacular karst on Earth. These are clearly world-class caves. Cave scientists have understood how these huge pits are created for over a hundred years. First described from the Dinaric Karst, known in China since 1992, explored in China by the Cave Research Expedition in 1993 (that was before the Funny Word tienkeng had been coined), and explored extensively in China by the Hong Meigui Cave Exploration Society (Erin Lynch) since 2001, the British Cave Research Foundation , and others. These large limestone pits have been found all over the world. Simply, they are unusually large collapse dolines. They become large when there is a good-sized underground river to keep extracting the breakdown blocks that fall underground. In this part of China there is stratigraphically over 7 miles (total thickness) of soluble limestone, high topographic relief, and it rains a whole lot to produce the groundwater that dissolves the limestone. Fracture traces in the limestone likely relate to the specific location of these pits, just as they do for millions of other cave passages around the world. The public perception and misunderstanding about tienkengs has been caused by prominent Chinese geologist who arbitrarily made up the word tienkeng (Sky Hole or Heavenly Pit) for exceptionally large collapse dolines. He defined them as collapse dolines that are more than 100 wide and deep. This is a completely arbitrary term. It is just like using the word skyscraper for tall buildings and megabuilding for the very tallest one. Then you can claim that you city has the only megabuilding in the world. It has allowed the Chinese to make a Big Deal out of the fact that they do, indeed, have a lot (more than 50) impressively gigantic collapse dolines in their country. There are numerous references to these large pits in China that have been written over the last 20 years, some accurate, some with included hyperbole. Here is where to start: Tiankengs: Definition and Description, 2006, Zhu Xuewen and Tony Waltham http://www.speleogenesis.info/directory/karstbase/pdf/seka_pdf9541.pdf This is a summary paper that concludes: The concept of tiankeng karst has been considered within China as a term to describe an extremely mature type of karst landscape that has matured beyond normal fengcong karst with high relief. The term could be used to describe the Leye karst in Guangxi, China, and perhaps the Nakanai karst in New Britain, Papua New Guinea, both of which are distinguished by unusually large numbers of tiankengs. However, some mature karst terrains contain just a few tiankengs, notably just two in each of the karsts of Xingwen, Croatia and Mexico, and these question the applicability of the term. Tiankeng karst may be purely descriptive of the Leye and Nakanai terrains, but the term has not yet been shown to have any geomorphological status with reference to karst evolution. Also: For a list of 33 tienkengs known to exist outside China in 2004 (including El Sotano and Golindrinas in Mexico: www.speleogenesis.info/directory/karstbase/pdf/seka_pdf9540.pdf Special Issue: Tiankengs Transactions of the British Cave Research Association: Cave and Karst Science: V. 32, n. 23 (in one volume). Descriptions of the giant collapse dolines in China and the Wulong Karst World Heritage site. Intro: http://www.speleogenesis.info/pdf/SG9/SG9_artId3289.pdf The Mother Of All collapse Dolines is Xiaozhai, close to the Yangtzee River, just south of the first of the Three Gorges. Down-cutting by the Yangtze has created the great relief found in the area. Xiaozhai is 662 meters deep (measured by the Chinese to obtain maximum depth) and has a trail (with many steps) to the bottom, where a diversion tunnel for
Re: [SWR] Tienkengs
dirt...@comcast.net wrote: Tienkengs=20 National Geographic - Mystery Caves Of Guangxi=20 http://www.youtube.com/watch?v=3DwiYn-DeQjL8=20 A production of the National Geographic Channel in conjunction with Chinese= television CCTV-9=20 I have been asked to provide some clarification for the US caving community= about the use of the term tiankeng. As many of you know, I have been lea= ding karst-focused tours for geologists and cavers and have first-hand know= ledge of Chinese karst since 1993. The cavers staring in the film have clea= rly had a wonderful time in a spectacular area courtesy of National Geograp= hic. The film does a good job of explaining the area to the general public,= and conveying the wonder and excitement of exploring the karst of SW China. This is a spectacular and interesting film. It is also contains some unnece= ssary (in my opinion) exaggeration and self-promotion from National Geograp= hic. Anyone in the caving community who has been to the spectacular karst a= reas of China recognizes the hyperbole. National Geographic seems either to= have done a poor research job (unlikely) or made a deliberate decision to = add additional mystery and danger to some of the most spectacular karst o= n Earth. These are clearly world-class caves.=20 Very informative explanation! Even without having been to the Chinese karst, I could smell the hype. Nothing seemed that unusual about these features other than the exceptional size, and the implication that this was just now being discovered seemed improbable, to say the least, when one of the scenes shows a constructed guardrail overlooking the pit, and in others, trails or roads are clearly visible above. Shame on NGS. --Donald ___ SWR mailing list s...@caver.net http://lists.caver.net/cgi-bin/mailman/listinfo/swr ___ This list is provided free as a courtesy of CAVERNET
Re: [SWR] Tienkengs
Very informative explanation! Even without having been to the Chinese karst, I could smell the hype. Nothing seemed that unusual about these features other than the exceptional size, and the implication that this was just now being discovered seemed improbable, to say the least, when one of the scenes shows a constructed guardrail overlooking the pit, and in others, trails or roads are clearly visible above. Shame on NGS. --Donald x Glad you found that useful, Donald. FYI It appears that Figure 1 of Tiankengs: Definition and Description, 2006, Zhu Xuewen and Tony Waltham http://www.speleogenesis.info/directory/karstbase/pdf/seka_pdf9541.pdf shows EXACTLY the mystery cave in the Leye Karst that this film is all about. (Note that Bandong and Baidong are likely the same when you read the Chinese characters or pronounce then in Mandarin - there are all sorts of problems trying to write Mandrin in English, and then trying to figure out by reading the English translations if the names are really the same in Mandarin). Maoqui Dong is the incipient tienkeng that they first rappelled into. What a true mystery it was for their 2013 expedition! DirtDoc ___ SWR mailing list s...@caver.net http://lists.caver.net/cgi-bin/mailman/listinfo/swr ___ This list is provided free as a courtesy of CAVERNET
