(1) Carbon cycle in epigenic karst processes. A network to investigate carbon cycle in karst was formed covering different ecological conditions of the world. Upward and downward dual CO₂ gradients were found in soil atmosphere in Guilin, China. The global annual Carbon uptake from the atmosphere by karst processes was preliminarily estimated as 6.08 ´ 10⁸ t/a(Yuan,China) or 2.2´ 10⁸ t/a(Yoshimura, Japan) respectively. John Mylroise(USA) estimated a sequestered carbon of 1.1 ´ 10⁷ t/a by CaCO₃ dissolution on world coastal platform.

(2) Deep source CO₂ from karst areas. Typical geothermal springs on Tethys realm with deep source CO₂ emission and tufa deposit were investigated(Tibet of China, Turkey, Italy). Deep source CO₂ emission in the territory of China was distinguished into 3 types: with many calcareous tufa; with few tufa; and CO₂ reservoirs. In Southeast France, deep source CO₂ in karst processes were identified with geochemical, geological, and isotopic approaches. The P_CO2 in Lez Spring, the water source of Montpellier was found as high as 10%. It is considered to be responsible for high HCO₃^- and Ca²⁺ contents, resulting in a very active dissolution of carbonate rocks. Deep CO₂ intrusion into the aquifer was observed in the high Guadalantin Valley, Southern Spain. The over exploitation of the carbonate aquifer had declined its water heads remarkably, and produced a sudden emergence of CO₂ (up to 85% in P _CO2 ) and HCO₃^- rich water.

(3) High resolution paleoenvironment reconstruction with karst records. Results in this direction have been achieved in quite a few countries, including Australia, Belgium, China, Czech, Japan, Mediterranean region, New Zealand, Norway, Poland, S. Africa, Saudi Arabia, UK, and USA. In south China, environmental change in the past 36000 years was reconstructed with a 1.22 m long stalagmite taken from Panlong cave, 37 km south of Guilin. By AMS ¹⁴C dating, stable isotopic and geochemical approaches, the transition from last glaciation to Holocene, and several events of rapid climatic change were identified at a resolution 100-500 year. In Israel, similar results back to 25000BP were got with a speleothem from Soreq Cave. In north China, a late Holocene rapid climatic change was recorded by stable isotopic data in a speleothem from Shihua Cave, Beijing. In New Zealand, seven glacial advances in the last 230 ka were underpinned by 26 U-series datings on speleothem from Aurora Cave. In a late Glacial stalagmite of Southern Belgium, there are successive laminae microsequences forming very regular cycles of 11 years separated by a thick dark-compact lamina. The latter is considered to be corresponding to a period of high water excess(by comparison with modern stalagmite). Hence, the 11-year cycle may reflect a climatic cycle.

2.1 General scientific achievements(including societal benefits)

Major development in all the three objectives of the Project was reflected in the papers and discussions of the Project’s two meetings, and reports from some National Working Groups

2.1.1 Carbon cycle in the epigenetic karst processes

(1) The monitoring sites to study the CO₂ uptake from atmosphere by karst process have been continuing to collect data. In Akiyoshi-dai Plateau, Yamaguchi, SW Japan, 1-2 month time lag of calcium concentration peak in karst water from the relevant soil CO₂ concentration peak was found(Yoshimura). In Guilin monitoring site, Chinese people got the similar results.

In the catchment of Beke Cave, Aggtelek Karst, North Hungary, the monitoring of a karst dissolution system is improved from 15-year occasional observation to continuous recording. It has 18 measuring sites in a pit excavated in a doline to monitor the CO₂ transfer and hydrochemistry changes from atmosphere through pedosphere to hydrosphere (Laszlo Zambo).

(2) A karst denudation map in the scale of 1:8,000,000 is compiled by Elena Trofimova for the 93 basins of Irkutsk region of Russian Siberia. The soluble rock (including carbonate rocks, sulphates and rock salt) of Cambrian totaling 400,000 km², makes 50% of the Irkutsk region. The maximum denudation rate is 52.1 mm/ka, being located in the area between right side of Lena River and NW of Baikal Lake, whereas the denudation rate on the upper reach of Angara River is less, being 5-15mm/ka, and even less than 5mm/ka. The map will be helpful for the estimation of CO₂ uptake by karst process in the region , but raise a new problem how to take into account the mixture of sulfates in carbonate rocks in the estimation.

(3) The behaviors of CO₂ migration on the interfaces between atmosphere, vegetation, soil, rock and water are investigated into depth. In Swabian Alb (SW Germany, Torsten Clemens et al), Yudong Underground stream (Central China, Liu Zaihua et al), seasonal and synchronic variation of CO₂ in soil atmosphere and the calcium content in underlying karst groundwater were identified. Moreover, it is found to be dependent on the vegetation type in the catchment area. Von Eberhard Pechhold(Deutschland) considers that in karst area, the CO₂ in soil air is in a dynamic equilibrium between biological CO₂ production and CO₂ losses in karst processes, and is controlled by convection - induced ventilation in the rock and the overlying soil. W.B.White gives a conceptual model for the distribution and transport of CO₂ in the epikarst zone. Y.Y.Shopov(Bulgaria) investigated the CO₂ contribution from vegetation respiration, soil decomposition, and carbonate rock dissolution by stable isotopic approach.

2.1.2 Deep Source CO₂ in Karst Area

In the past year, the Project got more information about deep source CO₂ in karst.

(1) Do Tuyet reported that there are many geothermal springs in Vietnam along the northwest oriented plate margin zone. The hotest one is at Bang, Le Chuy district, Guang Pinh Province. It is 105° C, with many calcareous tufa, showing CO₂ outgassing. There are also many geothermal springs at the eastern side of Taiwan Island, China. Ching-Nan Liu reported a 20m high tufa cascade near Changchun Temple, along Liwi Hsi River, north of Hualien county. It is outflowing from metamorphosed limestone. On the Tethys realm, Yang Lizheng and Zhang Jiagui made field works on the Tibet Plateau of China. A total of 1370 hot springs were registered, some of the CO₂ emission spots at Gangzhi, Daofu, and Xianshui He active fault zone were investigated. In Kangdin City along, there are more that ten hot springs in a valley 15 km long, with temperature ranging between 23-93° C, and HCO₃^- content as high as 1500ppm, obviously of deep source. S-E Lauritzen(Norway) considered the big glacial karst spring Trollosen in South Spitsbergen is related to deep thermal water. Y.V.Dublyansky (Russia) gives indicators to distinguish hydrothermal and cold-water karst, including morphology, mineralogy, isotopic features, trace elements, temperature and salinity of paleowaters(by fluid inclusions).

(2) Deep source CO₂ from oil-gas field. A.V.Petukhov(Russia) put forward some new ideas of karst processes and carbon cycle in a carbonate rock oil-gas reservoir, which are related to the reduction of sulphates by hydrocarbon under the high pressure of tectonic movement. The reduction of sulphates by hydrocarbon will produce both H₂S and CO₂ , and thus intensify karst processes in the overlying carbonate rock strata. The ideas come from the occurrence of abundant H₂S in many oil-gas fields in the world, and are testified by laboratory experiments.

2.1.3 Paleoclimate Reconstruction with Karst Records

This year the new development of the Project in this direction is characterized by more geographic coverage, more techniques involved, and getting higher resolution.

(1) the use of karst records for paleoclimate reconstruction have been expanded to almost all the continents, i.e, Africa 5, Asia 5, Europe 12, N.America 6, Oceania 4, S.America 2. Results from S.Africa, Tazania, Botswana, Namibia, Morocco, Argentina, and Coastal areas of Spain, Bahamas, and Svalbard, Norway were reported. K.Holmgren(Norway) et al did Uranium-Series dating, stable isotopes and laminae analysis on stalagmites from some caves in Tanzanian coastal region(Amboni Cave, Matumbi Cave, and caves on the coral island Songo-Songo), S.Africa(Ficus Cave, Cold Air Cave in Transvaal), and compared it with previous works on speleothem from Botswana (Lobatse Cave). The ages of the speleothem are ranging between 90ka to the present. The laminae analyses show growth rates varying from 0.5mm/ka in Holocene, to 7mm/ka between 38 and 34ka. So it is expected to get a 1-10 year resolution in paleoclimate reconstruction. In central Namibia Desert, Klaus Heine(Germany) revealed a more humid phase around and after 200-150ka with a speleothem taken from Rossing Mountains. In Morocco, Mohamed Salem Ould Sabar(Mauritania) identified Pleistocene climatic change with fossils taken from karst fissures exposed in quarries. The Anuran Amphibian faunas are considered to be indicators of more humid and warm climate in Middle Pleistocene than present. In Andros Island, Bahamas, J.Lundberg revealed the date of sea level rise at the end of Penultimate Glaciation (131ka) by TIMS dating on a stalagmite recovered from a blue hole 45m below present sea level. In Kapp Ekholm, Svalbard, Norway, Henriette Linge took the advantage of high Uranium content(2-31 ppm) in calcareous algae, and tried to use it as a tool for dating paleo-water table in coastal karst settings through U-Series dating. In southeast Asia, Kazuko Urushibara-Yoshino reconstructed the palaeoclimate of Last Glaciation Maximum,with karst geomorphological records of Java and surrounding area.

(2) More techniques are employed in paleoclimate research with karst sediments. In Romania, TL method was used to date a stalagmite from Wind Cave(59,052± 9600 years), and paleomagnetic method used for sediment of Movile cave which suggested a fluviokarstic deposition during the Brunches Normal Polarity Chron(younger than 770 ka). In Argentina, S.P.Barredo also used paleomagnetic method to study sediments in Cuchillo Cura Cave. In NW Canada, W.D.MacDonald discussed the ideas to use perenial ice in Serendipity Cave of the Crows Nest Pass(with trapped guano of 970 years BP in a depth of 14.3m) as proxy climate indicators.

(3) Higher resolution. From a speleothem of Sihua Cave, Beijing, China, Tan Ming interpreted climate change from 1470 to 1992 AD by its transparent microbanding, and claimed an annual resolution. In Lipu County, S. China, Li Hongchun(U. of S. California) and Lin Yushi, Zhang Meiliang(Karst Dynamics Lab.) worked on a 13cm speleothem taken from Fengyu Cave. By TIMS, Pb210 dating and high resolution stable isotopic analysis, environmental change in the past 600 years was reconstructed, with clear records of Little Ice Age, and the possible deforestation event in late 18^th century.In eastern coast of Mallorca, Spain, caves on 1.4-2.5 m a.s.l are dated back to 83,108, and 124 ka BP, and are considered by Paolo Tuccimei as minor events within stage 5 of the marine oxygen isotope record. In a speleothems from Grotta di Ernesto, NE Italy, climatic events including the Holocene hypsithermal (7,650 to 5,300 years BP), the Medieval Warming, and the Little Ice Age cooling are marked (Silvia Frisia et al). In a speleothem from SW Slovenia, A.Mihevc reported a possibly Younger Dryas hiatus. Yves Perrette finds charcoal burning mark of 14th century in a speleothem taken from Vercors region, France.

2.1.4 Societal Benefits

The results of the Project in the past years made new contributions to IGBP and IHP.

(1) In one of the core Projects of the International Geosphere-Biosphere Program (IGBP): the Past Global Change (PAGES), karst records become not negligible as proxy paleoclimate indicators. In all its three Pole-Equator-Pole Transits: PEP I, North to South America; PEP II, Asia-Australia; PEP III, Europe-Africa, karst records have played more parts in paleoclimate reconstruction, and provided higher resolution records. This is reflected in PAGES NEWS Vol.5 No.1(April,1997) and Vol.5 No.2 (August, 1997).

(2) In an International Workshop "Water, Environment and Society in Times of Climatic Change", July, 1996 in Negev Desert, Israel, sponsored jointly by IHP and some Israeli organizations, the stable isotopic records in a speleothem from Soreq Cave, 60 km inland from Mediterranean coast, provide a detailed insight into the climatic evolution, (rainfall and vegetation pattern) of the late Pleistocene and Holocene (Bar-Matthews et al).

2.2 List of meeting with approximate attendance and number of countries

(1) IGCP 379 Symposium "Karst Processes and the Carbon Cycle" April 26-30, 1997, Lipu, China, including field excursion in the Fengyu Underground Stream Cave System in Lipu, and karst and carbon cycle monitoring site in Guilin. 79 people from 5 countries participated the symposium, 32 people took part in the field excursion. 47 papers were presented in 6 sessions.

(2) The 12th International Congress of Speleology and the 6th Conference on Limestone Hydrology, August 10-17, 1997, La Chaux-de-Fonds, Switzerland. 150 people related to this Project from 27 countries participated relevant sessions in the Conference (Karst Sediments and Paleoclimate; Cave Atmosphere; Epikarst; Dissolution Kinetics and karst hydrogeology). 56 people took part in the relevant excursions: ESJ 3 karst hydrogeology in Swiss Jura; ESC 16, alpine karst in north Italy, classic karst in Slovenia. 98 papers were presented in the sessions mentioned above.

2.3 List of most important Publications (including maps)

1. IGCP 379 Newsletter 1997, 125 pages, the Institute of Karst Geology, Guilin, China.

2. Yuan Daoxian, Sensitivity of karst process to environmental change along the PEP II Transit, Quaternary International, Vol. 37, pp105-113, 1997

3. Yuan Daoxian, the Carbon Cycle in Karst, Zeitschrift fur Geomorphologie, Suppl-Bd.108, pp91-102, July, 1997

4. Yuan Daoxian, Rock desertification in the subtropical karst of South China, Zeitschrift fur Geomorphologie, Suppl-Bd.108, pp81-90, July, 1997

5. Yuan Daoxian, Book review (for M.M.Sweeting, Karst in China, 1995), Zeitschrift fur Geomorphologie, Suppl-Bd.108, pp105-107, July, 1997

6. Klaus Heins, Climate change over the past 135,000 Years in the Namib Desert, Namibia: Proxy data, p67-68, Abstract Book of IGCP 349-404 Symposium in Mauritania, January, 1997

7. Mohamed Salem Ould Sabar, An indicator of paleoenvironments in Deserts Margins: The Anurans., p125, Abstract Book of IGCP 349-404 Symposium in Mauritania, January, 1997

8. Elena Trofimova, Karst denudation in Irkutsk region, Proceedings of the 12th International Congress of Speleology, Vol.1, p391-394, 1997

9. Y.Y. Shopov et al, Influence of the bedrock CO₂ on stable isotope records in cave calcite, Proceedings of the 12th ICS, Vol.1, p65-68,1997

10. Marian Pulina et al, Human Impact on karst environment of Silesian-Cracow region in South Poland, Proceedings of the 12th ICS,Vol.1, p323-326, 1997

11. B.F. Mijatovic, Aspect hydraulique de l’ecoulement karstique et ses consequences sur le fonctionnement du systeme aquifere, Proceedings of 12th ICS, Vol.2, p295-298, 1997

12. W.E. Krawczyk et al, Similarity between the hydrologic system of the Werenskiold Glacier (SW Spitsbergen) and a karst, Proceedings of 12th ICS, Vol.1, p493-496, 1997

13. Zaihua Liu et al, Carbon dioxide in soil and its drive to karst processes: A case study in transitional zone between North and South China, Proceedings of 12th ICS, Vol.1, p300

14. Torsten Clemens et al, the influence of the soil air Pco2 on the chemical composition of karst spring water (Swabian Alb, SW Germany), Proceedings of the 12th ICS, Vol.1, p301-304, 1997

15. Yuan Daoxian, Characteristics of hydrochemical responses to environmental change in a carbonate rock aquifer, Proceedings of 12th ICS, Vol.2, p123,1997

16. Stein-Erik Lauritzen, Groundwater recharge in thermoglacial karst springs, South Spitsbergen, Proceedings of 12th ICS, Vol.2, p320, 1997

17. J.Lundberg, Paleoclimatic reconstruction and timing of sea level rise at the end of the Penultimate Glaciation, from detailed stable isotopic study and TIMS dating of submerged Bahamian speleothem, Proceedings of the 12th ICS, Vol.1, p101-102, 1997

18. V.Labau, E.Gaspar, Speleothem dating using the thermoluminescence method, Proceedings of 12th ICS, Vol.1, p41-43,1997

19. K. Holmgren et al, Speleochronology, stable isotopes and laminae analysis of stalagmites from South Africa, Proceedings of 12th ICS, Vol.1, p55-56, 1997

20. S.P.Barredo, Paleomagnetic study in the Cuchillo Cura System, Neuquen Province, Argentina, Proceedings of 12th ICS, Vol.1, p69-72,1997

21. W.D. MacDonald et al, the isotope systematic of Perennial Cave ice in Northwestern Canada, Proceedings of 12th ICS, Vol.1, p60,1997

22. A.Mihevc, Absolute datings of speleothems and its speleomorphological significance from Divaska Jama and Jazbina Caves, Kras Plateau, Slovenia, Proceedings of 12th ICS, Vol.1, p57-59,1997

23. Five papers of the Project were published as a special part in the Vol.24, Environmental Geology, Proceedings of the 30th International Geological Congress, VSP,the Netherlands, 1997

24. Liu Zaihua et al, stable carbon isotope geochemical and hydrochemical features in the system of carbonate-H₂O-CO₂ and their implications - evidence from several typical karst areas of China. Acta Geologica Sinica, Vol.71,No.3,p.281-287,1997

25. Xu Shenyou, Jiang Zhongchen, A preliminary estimation on the relationship between karst process and source-sink of atmospheric CO₂ in China. Chinese Science Bulletin, Vol.42, No.9, p953-956, 1997

26. Selected papers from the symposium in Lipu, China were published in Carsologica Sinica

27. Liu Zaihua and Dreybrodt, W., Dissolution kinetics of calcium carbonate minerals in H₂O- CO₂ solutions in turbulent flow: the role of the diffusion boundary layer and the slow reaction H₂O+CO_{2 «} H⁺+HCO₃^-, Geochimica et Cosmochimica Acta, Vol. 61, No.14, pp.2879-2889, 1997

28. A book "Global Karst Correlation" published 1998 by the VSP Science Publisher, Netherlands,and the Science Press, Beijing

2.4 Activities involving other IGCP projects or the IUGS

(1) IGCP 404, IGCP 349, IGCP 396

We have close exchange with IGCP 404 "Terrestrial Carbon in the Past 125 Ka" (1996-1999), and IGCP 349 "Desert Margins and Paleomonsoons of the Old World: 135,000 years to the present" (1993-1997). Members of IGCP 379 attended a joint meeting of IGCP 349 and IGCP 404,, held Jan 3-7, 1997 in Noukchott, Mauritania, and 4 days excursion in the Coastal areas of Mauritania. The scientific Programe was "desert margin change in Africa since 135ka: implication for water, carbon and mankind". The meeting was also the first working group meeting of INQUA Commision on Carbon. We have also exchanged information regularly with IGCP396 "Continental shelves in the Quaternary"(1996-2000).

(2) INQUA Commision on Carbon (Prof. Hugues Faure, France). The Commission was established in August, 1995. It is intended to foster scientific cooperation for the study of how the carbon cycle changes during glacial and interglacial oscillations and its role in the Earth System. IGCP 379 has acted as one of its six thematic working groups, and had attended its first meeting in Mauritania, January,1997. IGCP 396 is its another WG. Fruitful and helpful informations from the Commission have reached our Project regularly through Internet.

(3) Karst Commission of IAH (Prof. Heinz Hotzl, Germany)

The Project is initiated and has got continuous support from this Commission. The implementation of this Project has been in many cases in coincidence with its activities. We participated the Commission’s annual meeting on August 15, and August 18, 1997, La Chaux-de-Fonds, and briefed the new development and future works of the Project. The IGCP 379 Newsletter 1997 was distributed to every Commission members.

(4) Cooperation with IGU Karst Commission, and relevant Commissions of International Union of Speleology, including its Commissions of Karst and Climate (S.E. Lauritzen); Physical Chemistry and Hydrogeology(Y.Y. Shopov); Epikarst (Klimchouk); Cave Mineral (C.Hill). During the Conference in Switzerland, we took part in all the working meetings of these Commissions to exchange informations and coordinate future directions and work plans.

(1) IGCP 379 meeting in Las Vegas, USA, September 27-Oct.2, 1998, in conjunction with the 28th Conference of International Association of Hydrogeologists (IAH). Field excursion will be arranged to visit some karst features around Las Vegas.

(2) Joint meeting of IGCP 379 and USA Friends of Karst. It will take place on September 23-25, 1998 at Mammoth Cave, Kentucky, USA, just before the meeting in Las Vegas. The meeting will concentrate on the impact of karst processes on carbon cycle at a variety of scales. Monitoring sites in Mammoth Cave areas will be visited.

(3)IGCP 379 seminar "Karst processes and the carbon cycle", Guilin, China,Oct.5-15, 1998. The objective of the Seminar is to bring together scientists interested in karst processes with those interested in carbon cycle and global change. The Seminar will consist of a series of lectures, discussions, and field demonstrations in Guilin karst Experimental Site and some caves near Guilin (contact Dr. Liu Zaihua, zliu@mailbox.gxnu.edu.cn).

(1) Number of participants included in the Project’s email list increased to 88. They are from 29 countries or regions. The facility provides fast communication for the project.

The Home Page of the Project put into use in early 1997 (http://www.gxnu.edu.cn/KDL), and has got more than 5000 visitors.

(2) IGBP/PAGES. The Project has participated in many activities of PAGES in China, and in other countries.

(3) Connection with other international projects and orgnization with similar direction:

I.CDIAC (CARBON DIOXIDE INFORMATION ANALYSIS CENTER, WORLD CENTER-A FOR ATMOSPHERE TRACE GASES).

CDIAC is sponsored by U.S Department of Energy’s Global Change Research Program. This year we got CDIAC Communications issue No. 23, spring 1997 (10.p) from its home pages. Moreover, we have downloaded "New Maps Series of the Paleovegetation of the World at Intervals since 18,000 ¹⁴C year BP" (compiled by Jonathan Adams) from the Oak Ridge National Laboratory.

II. MOULIS SOUTERRAIN LABORATORY, FRANCE.

We have long contact with this Karst Research Institution. In La Chaux-de-Fonds, August 16, 1997, we met scientists from the laboratory (Dr. A Mangin and others). New directions of the laboratory were briefed, and intentions for cooperation were discussed.

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