IV5 KARST RESEARCH TECHNIQUES
F.W.J.Leaney and A.L.Herczeg
Centre for Groundwater Studies & CSIRO Division of
Water Resources Private Bag No.2, Glen Osmond SA 5064
Sinkholes and other karstic features are a significant component of recharge to many carbonate aquifers in temperate and humid regions throughout the world. Their importance to the water balance of karstic aquifers in semi-arid regions with low topography have received much less attention. This study focuses on an investigation into recharge mechanisms to a lime- stone aquifer in South Australia which is extensively utilised for irrigation. The study area is in a low lying, semi- arid region of South Australia where mean annual rainfall is 500 mm yr-1, potential evapo-transpiration rates are high (up to 2, 000 mm yr-1) and there is no permanent surface water. We use naturally ocurring isotopic and chemical tracers to establish the importance of a number of natural ( sinkholes and swamps) and artificial (boreholes) features in the landscape for point-source recharge to a karst aquifer. Conventional approaches for estimating recharge using bore hydrographs and purposeful tracer studies such as dyes or chemicals are not appropriate in these regions because dispersion in areas of low hydraulic gradients are beyond detection limits on a time scale of weeks to months.
We installed piezometers to the upper part of the limestone aquifer near several types of potential features: 3 sinkholes, 1 swamp and 1 man- made drainage borehole and monitored water level, temperature, major ion chemistry and stable isotopes of water over an 18 month period. We also analysed chlorine-36 from groundwaters for a single sampling from some of the sinkhole sites. The chemical and isotopic composition of waters from all of the point-source features is distinct from that of the regional groundwater and can be used to estimate the importance of point-source recharge to the regional water balance. Recharge from all of the point-source features is detectable only on a local scale and contributes <10% of water to the study area. Only for two of the largest sinkhloes can we detect water movement beyond 500 m from the sinkholes. More typically, recharge occurs only for a few days at a time and only after a threshold of sustained rainfall had been exceeded (i.e., > 2. 5 mm/day for 3 days) .Variations in water level, chemistry and stable isotopes suggests that a significant component of water derived from the sinkholes, is diverted through a small fraction of the aquifer and such movement is heterogeneous.
The stable isotopic composition of waters recharging via sinkholes tend to be enriched in 2H and 18O relative to regional groundwater and local precipitation. This is caused by a small degree of evaporation (<3%) at high humidity(>95%) prior to recharge. Chlorine- 36 from weapons testing is detectable in the groundwaters near to sinkholes and indicates significant recycling of Cl within the respective sub-drainage systems which limits the usefulness of this isotope for recharge studies.
Department of Geography and Oceanography, University College, ADFA, University of New South Wales, Northcott Dr,ACT 2600, Australia Problems encountered in field applications of water tracing dyes include background fluorescence and interference between dyes, where the complexity of hyrological systems, particularly in karst areas, make multiple dye tracing experiments desirable. The fluorescence of water tracing dyes may vary dramatically according to the pH of the water and this property can be used to address these problems. The response of a number of commonly available water tracing dyes to pH is investigated; the distinctive curves provide a means of distinguishing between dyes, and between dyes and background fluorescence due to algae. It is not necessary to reproduce the full pH response curve to utilize these properties. Recommendations are made on the use of pH buffering to improve sensitivity in detecting dyes, and for quantitative laboratory analysis. Buffering to a small number of predetermined pH can be used effectively to distinguish both between dyes which fluoresce at the same wavelength, and between natural and induced fluorescence. It is particularly useful in the case of the green dyes, both for detection when there are high natural backgrounds and because it enables more than one green dye to be used simultaneously. If Rhodamine is used together with, for example, Fluorescein and Pyranine, triple dye tracing experiments can be executed.
Quinlan and Associates, Box 110539, Nashville, Tennessee 37222, USA
Reliable monitoring of groundwater quality in any terrane is difficult. There are many ways in which violation of sound principles of monitoring-network design and good sampling protocol makes it easy to acquire data that are not representative of the water or pollutants within an aquifer. In karst terranes it is especially easy for irrelevant data, which inadvertently misrepre- sent conditions within the aquifer, to be obtained.
The special problems of monitoring groundwater in most karst terranes can be grouped into four major categories of problems that are rarely as significant in other terranes. These categories are the following:
1. Where to monitor for pollutants: The only relevant locations are at springs, cave streams, and wells that have been shown by tracing tests to include drainage from the facility to be monitored rather than at wells to which traces have not been run but which were selected because of their convenient downgradient locations. Wells located on fracture traces and fracture-trace intersec-tions and wells located randomly can be successfully used for monitoring, but only if there is a positive trace from the facility to them. Often successful monitoring can only be done several kilometres away from the facility.
2. Where to monitor for background: The only relevant locations are at springs, cave streams, and wells in fractured rock-in which the waters are geochemically similar to those to be monitored for pollutants but which have been shown by tracing tests not to drain from the facility- rather than at wells selected because of their convenient locations upgradient from the facility site. This, too, may have to be done several kilometres away from the facility.
3. When to monitor: Before, during, and after storms or meltwater events-rather than regularly with weekly,quarterly, semiannual,or annual frequency.
4. How to determine reliably and economically the answers to Problems 1.2.and 3:Reliable monitoring of groundwater on karst terranes can be done,but it is not cheap or easy.
These problems exist because many of the assumptions made for monitoring flow in granular media are not valid for karst terranes. Implicit assumptions made for monitoring in karst terranes with the strategy recommended herein can be stated axiomatically , but they are valid only about 95% of the time.
The monitoring strategy recommended herein is not applicable universally, but it is applicable in most karst aquifers, especially, all those that drain to springs. It is not applicable in terranes that are merely recharge areas of regional aquifers.
Ivanovskiy O.T.1, Samoilova S.B.2
1 Rightbank Geology Prospecting Expedition PGU "Sevukrgeology", Ukraine.
2 Perm University, Russia.
The report is concerned to the application of the biological detection and ranging for mapping of the chalk, carbonate and sulphate karst. The example of Rovno Nuclear Power Station and the cities Dzerzhinsk and Kentauis considered. The high efficiency of the method in resolving problems of the engineering geology of the karst regions of the country is based on the actual results.
The biological detection and ranging method is known for more than 4000years. The old name for the method is dowsing. The introducing of the method in practical geology prospecting working was promoted by the activity of the Communications Institute named after Popov A. S. joint commission on biological detection and ranging effect in the approbation of the method on various geological objects throughout the whole regions of the country.
The biological detection and ranging works were officially recognized due to their low cost and high efficiency.
The biological detection and ranging effect is conditioned by the physical fields complex affection - the magnetic field, the gravitational field and the electrostatic field etc.- on an operator organism.
At the present stage of art the problem of the biological detection and ranging effect origin is not solved. One of the hypothesis of its origin is worth of paying attention .
There are hundreds of billions nuclei in a metastable state in human organism. Moving along the earth surface, an operator crosses the physical field gradients, formed by the nonuniformity of a section. At that time the nerve cells metabolism, the membrane potential etc. are changed due to the external affections. In sum, these signals reach a sufficient power to create at the nerve ganglions level a signal, which comes into the brain, subcortical centres and the cerebral cortex. The human has a high level of the representation of upper extremeties in the brain. By irritating their motoreceptors, without an operator's wish there is a movement of an indicator-unit (dowsing-rod), so called an ideomotion.
Certain methods of an interpreting and operator hand ideomotion reactions allow to locate the bands and other parameters of an object. A metal - or -form indicator-unit is used as an indicator of the human organism ideomotions, the reaction of the indicator-unit represented by its deviation from the balanced state in one or other direction, a rotation around the axis, stopping of a rotation and a sign reversal rotation.
The biological detection and ranging survey is done on the geological section topogeodetic grid, which was preliminary marked out with the instruments and which density is conditioned by the assumed dimensions of searching objects. In mapping the layer of karst spreads, the grid density assumed equal 20×VVVØVVVØVVVÐVV20×VVVØVVVØVVVÐVV10 meters, the detailed objects locating is executed by intermediate tracking of the bands.
The speed of an operator movement on the profiles is 4 km/h. To prevent errors of missing anomalies in each profiles, fourfold observations are done.
The examples of mapping by the biological detection and ranging survey of the chalk, carbonate and sulfate karst followed.
THE BIOLOGICAL DETECTION AND RANGING SURVEY
OF THE MAIN UNIT FOURTH BLOK OF ROVNO NPS
The region of Rovno Nuclear Power Station (NPS) placing has unfavourable engineering and geological conditions, i.e. ,It is a karst region and neotectonic movements occur there. At the depth of 20-25 metres there is the Middle Quaternary non-segmented fluvioglacial and frontal morainic formations, represented by sands, under which stretch sedimentations of glauconitic clays of the Upper Palaeogene Kharkov stage 0.5 m thickness, that uninformaly are deposited by spots on the chalk sedimentations of the upper chalk. The thickness of the chalk strata is 13-15 m. In the mass of the former there are crackings and cavities, filled with sand, sand loam and clays. Under the chalk not everywhere the basalt conglomerates are deposited on the lime cement of the Lower Cenomanian (thickness 0.2 through 0.7 m). Described sedimentations, represented by basalts, stretch on the eruptive rock of the Berestovsky suite of the Upper Proterozoic at the inspected depth of 50 m.
The fourth block site is placed in the zone of the deep-seated Manevichesky tectonic structure, which was traced with deep seismic probing to the depth of 40 km.
Due to the constructing crane falling-down in the special unit of the radioactive waste burial of Rovno NPS, the biological detection and ranging survey on the 1×VVVØVVVØVVVÐVV1 m grid was carried out in 1982, the survey showed the karst cavity at the distance of 15 m from the falling-down. In 48 hours exactly on the fixed place the failure into the karst cavity 7 m diameter and 5 m depth occurred, this failure was registered in the protocol of Kiev department of "Teploelectroproject". Due to this, Rovno NPS fourth block foundation pit, where drilling works that hadn't located karst cavities were done earlier, was inspected by the biological detection and ranging survey on 25×VVVØVVVØVVVÐVV25m grid. The survey on 1×VVVØVVVØVVVÐVV 1 m grid which was being done during 15 days showed 14 karst cavities, tectonic fissuring areas, the data was absolutly confirmed later on by falling-down of drilling instruments into the karst cavities at 5-9m depth.
The results of the palaeostructural analysis, which was executed in a month after the biological detection and ranging survey, absolutely confirmed the presence of all the located tectonic crackings and fracture. Additional measurements of helium and radon emanations, carried out by the Ukrainian Academy of Sciences Institute of Geological Sciences in the bore- holes of the fourth block, match with completely the biological detection and ranging survey data in the tectonic aspect.
Now both on the building site and on the territory of the city Kuznetsovsk, according to the biological detection and ranging survey data, grouting of the located karst cavities is executed, and some of those cavities absorb 200 to 3000 m3 of concrete. The new part of the city was built according to the biological detection and ranging survey data - the architectural plan of the city is changed or buildings are built on concrete slabs.
Teh-Lung Ku1, M.Ivanovich2, and Shangde Luo1
1 Department of Geological Sciences, University of
Southern California, Los Angeles, California 90089-0740,
2 B7 Harwell Laboratory, UK atomic Energy Authority,
Oxfordshire OX11 ORA, UK.
U-series chronologies of the emerged coral limestone terraces on Barbados, West Indies, together with those of the terraces from New Guinea, have formed the basis for most late Pleistocene eustatic models. The so- called "Barbados sea level model" has been challenged in recent years, however. A major issue is whether during oxygen isotope stage 5e, when Rendezvous Hill reef complex on Barbados Island formed , the sea rose above the present position for one relatively brief period of <10,000 yr., or for two or more periods spanning approximately from 140,000 to 115,000 yr. B.P.. Evidence for the latter scenario has not come from initial studies of Barbados but from elsewhere; it is also inconclusive because of the dating uncertainties involved. We have carried out careful redeterminations of U-series ages on a suite of 29 Acropora palmata samples systematically collected from four of the lowest terraces on the island. Diagenetic disturbance may have caused the age spreads at some sampling outcrops. A model for the diagenetic exchange of uranium isotopes in coral samples with those in groundwater explains the anomalous 234U/238U ratios in samples with apparently unaltered mineralogy (aragonite) and trace element (Mg and Sr) chemistry. It shows that age dispersions of 5-10% can be engendered by a U exchange coefficient of the order of 10-6 yr-1. The lower-limit terrace ages, estimated from averaging the multiple measurements, are 81,000±V V VV 2000 yr. (Worthing), 105,000±V V VV 1000 yr. (Ventnor), 120,000±V V VV 2000 yr. (Maxwell), and 117,000±V V VV 3000 yr. ( RendezvousHill). No evidence was found of previously inferred bipartite sea levels centering around 118,000 and 135,000 yr. ago. This study documents the need of dating coral with the high precision/sensitivity mass-spectrometric techniques for future resolution of the temporal relationships among sea level changes, climate oscillation, and astronomical forcing-relationships originally addressed by the Barbados sea level model.
HORI,Nobuyuki1, ARAKAWA,Tatsuhiko1 and MIURA,Hajime2
1Faculty of Integrated Arts & Sciences, Hiroshima University, Hiroshima, Japan
2Dept. of Geography, Faculty of Education, Yamaguchi University, Yamaguchi, Japan
Recently, some dating methods have been suggested as a possibility of estimating age through the analysis of secondary deposits. Speleothems have presented many interesting results on the topic of environmental changes during the Quaternary period. On the other hand, the study of tectonic movements in coral reef areas has been developed by dating fossil corals. However, in the humid tropical or sub-tropical regions, many fossil corals have been recrystallized, and consequently it has been difficult to clarify the age.
Some carbonate speleothems were collected from Nakabaruabuchyagama Cave in Miyako-jima Island, the Ryukyus. The axis of these stalagtites has been curved on their dropping way from the roof of the cave. This fact may suggest the curved axis was caused by tectonic movements.
THE PROLONGED MINIMA AND MAXIMA OF SOLAR ACTIVITY
V.N.Dermendijev1, G.T.Buyukliev1, Y.Y.Shopov2
1 Department of Astronomy and NAO, Bulgaria
2 Faculty of Physics, University of Sofia, Bulgaria
Abstract: We study a new indirect index of solar activity - the Intensity of Luminescence of Cave Flowstone Microzones. This index correlates directly with the solar activity. Using a time series of the index with resolution 4-5 pixels/year we study some of the statistical properties of the solar activity cycle during 28 prolonged minima and 21 prolonged maxima.
1.THE NEW INDEX OF SOLAR ACTIVITY
Proxy data on past solar activity nowadays provide a useful means of approaching the problem of solar magnetic field generation ( Dermendjiev et al., 1990). For this purpose, however, we need time series of data capable of distinguishing individual solar cycles. In this work we study from this point of view 28 prolonged minima of solar activity in the past (until 22000B.C.) using time series of a new indirect index.
The new index was named "Microzonality of Luminescence of Cave Flowstones" (Shopov and Dermendjiev, 1990). For its detection the method of Laser Luminescence Analysis (LLMZA) was developed (Shopov, 1987) . If the growth rate of the flowstone is known (e.g. from the nuclear dating of the sample), the intensity curve of the luminescence, depending on the distance from the flowstone surface, can be transformed into a time series.
In our study we use time series with resolution of 4-5 pixels per year. They make it possible to obtain information on the phase, period and epoch of the minimum, and other data about the properties of the separate 11 year cycles.
2.THE PROLONGED MINIMA AND MAXIMA OF THE LLMZA DATA
We had the possibility of obtaining time series of LLMZA data with time resolution about 5 pixels/year spanning 22000 years. It contains 110000 measurement. We use this long time series of proxy data of solar activity to seek answers to the following questions: 1) Does the 11 year cycle continue during the Maunder, Sporer, and other prolonged minima of the past solar activity? 2) Is the 11 year cycle typical of the epochs of normal activity and prolonged maxima of solar activity? and 3) Is there any correlation between duration of the minima, considered as phase shifts of a very long cycle reflecting possible global stochastic nature of solar activity, and the amplitude change of the subsequent activity?
We determined 28 prolonged minima and 21 prolonged maxima. Among them are the Modern and Medieval maxima, Maunder and Sporer minima, and the other14 prolonged minima and maxima which have been found in 14C time series. We study these peculiar intervals in the past solar activity by means of power spectrum analysis.
The largest period for the Maunder minimum is 5.6 years and for the Sporer minimum 7.6 years. The power spectra for these two epochs differ insignificant but they are rather different in comparison with the power spectra of the Medieval maximum.
The empirical distribution of the periods obtained for the prolonged minima and maxima determined from LLMZA data are shown on Fig.1. As one can deduct from this figure, the solar cycle is shorter during the prolonged minima (mean value T=7.85 years). The distribution of the periods during the prolonged maxima shows a specialfeature. When the solar cycle is longer, the preferred period is 14-15 years. It is interesting to note also that there are no periods of 11-14 years. The very good time resolution of LLMZA data also gives us the possibility of studying the correlation between the duration of the prolonged minima, considered as phase shifts of a very long cycle, and the amplitude change of the subsequent activity maxima. The results obtained from a 12000 years long time series are shown on Fig.2. The correlation coefficient r = 0.422 is positive and statistically significant.
Fig.1 Empirical distrbution of the solar cycle periods
for the prolonged minima and maxima.
The data can be approximated by linear regressions.The problem of the nature of prolonged minima of solar activity is still under discussion. From a modern point of view the prolonged minima are considered as strange attractors (Ruzmaikin, 1985). For large dynamo numbers the solutions of the Lorenz system for the magnetic field are chaotic in time with episodes of very low amplitude. It will be interesting to discover if such a positive correlation exists between episodes of reduced activity and the amplitude of the envelopes of the magnetic field taken from theoretical models of non-linear dynamos.
This work was supported by the Ministry of Culture, Science and Education under Grant No. 1162/88.
Fig.2 Correlation diagram of the duration of the prolonged minima and
amplitude change of the subsequent activity maxima
for the time intervals 1985 AD - 10000 BC.