THE LANZAROTE UNDERGROUND LABORA TORY

Transcription

1 THE LANZAROTE UNDERGROUND LABORA TORY R. Vieira; M. Van Ruymbeke ; J.Fernández; J.Arnoso and C. Toro Instituto de Astronom(a y Geodesia Facultad de Ciencias Hatemátlcas Ciudad Universitaria HADRID Observatolre Royale de Relglque Avenue Clrculalre, Bruxelles ABSTRACT Slnce 1987 and as a past of the research project that I s carrylng out the Lnst l t ut,o de Astronomfa y Geodesia of Hadr I d In Canary Islands, a geodynamlc permanent statlon Is worklng InLanzarote Island, themost northerlyand easter l y of the maln Islands of Canarlan Archlplelago. The statlon has two fundamental objetlves: (a) to test di fferent Instruments developed In the context of the tlde research and to apply them to other ar-ee s of earth research; arid (b ) to Investlgale lhe posslble eorrelat.lons of earth responses to lidal forees and other phenomena, such as crust stucture and t.b t ckne s s, vo l can t sm, qeolhermlc anomalles and heal flow, selsmlclty, mass dlsplaeements Inslde lhe crusl, ocean and almospherlc lides, melereo logleal Influenees, deformallons, ete... In thls paper, we present the Instrumenlatlon worklng In lhe lhree modules o( lhe Lanzarole Geodynamles Slatlon aelually, and lhe maln resulls oblalned so faro 1NTRODUCTION The st.udy of the earth tides has been one of the main investlgation lines of the Instituto de Astronomía y Geodesia (1. A. G.) since 1972, when these lnvestigations started to be carried out. In this 18 years a great effort has be en made, with a total of 21 stations for gravimetrlc tides almost completely 1

2 covering the Iberian Peninsula, moving in an important way fordwards the resolution of the very many problems we outlined at the begining and some others which arose as a consecuence of the running of the investigations (F. Lambas et al., 1981; M. Orejana et al., 1983(a); M. Orejana et al., 1983(b); R. Vieira et al., 1986(a); R. Vieira et al., 1986(b); R. Vieira et al., 1986(c); R. Vieira et al., 1988(a); C.Toro et al., 1988; R. Vieira et al., 1988(b); C. Toro, 1989). The collaboration with the group of scientists of the Consejo Superior de Investigaciones Cientificas dedicated to the study of volcanism in the Canary Islands, in the geodesy speciflc flelds, started in 1984, and as a consequence of this collaboration we are offered the opportunlty to install a laboratory for a permanent geodynamic lnvestlgation in Lanzarote, more exactly at the nort of the island and inside of the volcanic tunnel of the La Corona volcano; a really spectacular tunnel with more than 6 km length fram the volcano to the coast line which continues in the ocean, underwater, for at least two more kilometers. Fr om the very beginning we gave us scientific objetives coherent with our invesligations and so absolutely ciear that we can resume them in t.he following points (R. Vieira et al., 1989(a); R. Víe í ra et al., 1989(b); R. Vieira et al., 1989(c); R. Vleira et al., 1989(d)): 1~ Those objetives related with investigations on gravimetr'ic and clinometric tldes, mainly in those aspect.s in whieh and Is1and wlth the characterlstics of Lanzarote has a greater interest: study of the effects from oceanie origln, correlation of the earth tide with the earth shell thickness (shell in LanzarQ te has a thickness of about 12 km (E. Banda et al., 1981; A.G.Camacho et al.,1990)) possible correlations between tidal parameters and the anomalies with ther mai origin (in Lanzarote there are lmpo rt an t geothermlc anomalies, mainly in the area of the great eruption of the XVIII century, with places where the temperature reaches 600 C at only 14 m depth); temparary variations and possible modulations on amplitude factors and phase af lhe tldal harmonics, validlty or not of the Schwiderskl charts in the area of Canary Islands, etc. 2~ Those aspects of geodynamic interest, consequence of the continuous auscultation with high accuracy instruments not only gravimetric ones but on inclination and deformation in general. These sensors

3 s c s have been developed to register phenomena of a very small magnltude, such as earth tides, and being installed in a place llke Lanzarote, wich can offer us information of a great interest from the volcanic point of view and its associated seismicity offers now a days a moderated activity, but a future potentlal totally unexpected. For this reason, we inted this laboraty to be a place to test instruments developed for different aplications which adapted, in every case, to the conditions of geodynamic activity of the area would provide us with an information about such activity additlonal to the one obtained through the usual methods. Obviously, it is a geodynamic laboratory opened to the international collaboration, as lt can be seen from the instruments installed as a consequen ce of the collaboration with the European Center for Geodynamic and Seismology ( E.C.G.S ) from Luxemburg and the Observatoire Royale de Belgique (O.R. B.). DESCRIPTION OF THE STATION On Figure 1 we can see a sketch of the volcanic tunnel as well as the geodynam í stauon located inside the tunnel. We must really differenciate three modules in t.his laboratory. The matn module í, Figure IIa ), the one located in t he interior of the tunnel, at around 1 km from the coastal line and at about S km, from the volcano t.hat gives origin t.o the tunnel. In t.his module are most of t.he sensors presently installed which can be seen In Table 1 (FernAndez et al., 1990(a)). Another observational module is placed in the intersection of the tunnel with the ocean, Figure l(b), where a lake of incredible transparence is formed. This lake being directly connected with the ocean shows the corresponding tides, although as it ls normal, with the difference originated by the form, dimensions and oceanic connection of the tunnel; we ha ve installed sensors in t.his module to continuosly regist.er t.he sea level as well as the air temperature, presure and humidlt.y. Finnally, the t h í rd module, Figure 1 (e), is locat.ed in the so named Casa de los Volcanes, a cult.ural, sclentific and turistic center that the Cabi ldo de Lanzarote í finish1ng to make in the existing bulldlngs in the place known as Jameos del Agua in the lake area. In this third module 1s located the central computer, which is d1rectly linked with t.he observat.ional modules and allows to collect all t.he information registered in such modules. We have foreseen the connect1on via telephonlc modem between this comput.er and another one located in the offices of the I.A.G. in Madrid. 3

4 1NSTRUHENTS On Table 1 we relat.e the maln characterlcs of the instruments working in t.he geodynamic station. A data acquisition system designed in cooperation with the company Geonlca S. A. (Fernández et al., 1989) allows a data collection, for the 16 sensors connected, every second; provlding arate every ten minutes, and this is the datum which goes to the memory system. RESULTS Apart from the results, periodically or continuosly made in the laboratory and near surroundings, of t empe ra t ure and high accuracy measurements from wich we are informing in a different work published as well in this volume (J. Fernández et al., 1990(b)), the main results obtained up to the moment are resumed in the following sections: 1 ) Gravimeters: The analysis of the series of more than 3 years (R. Vieira et al., 1988(d); R. Vieira et al., 1988(e); R. Vieira et al., 1989(b )) obtained with the LaCoste Romberg no 434 gravimeter wi th a feedback system incorporated (M.V. Ruymbeke, 1985) are shown on Table 2. We must point out the high quality of these resul ts ref lected by the low ra te of quadra tic errors In diurnal and semi-diurnal bands. The strong oceanic effect observed in semi-diurnal frecuencies must be lately studied, as the station offers peculiaritles that make it very interesting (C. Toro, 1989). We can advance as an hypothesis that the laboratory located in the ground gained to the ocean in the eruption of the La Corona volcano, which we suppose ocurred two o three thousand years ago (T. Bravo, 1964; F. Macau, 1965), 1s floating, or even better, sustained over a sea of lavas of a very low density and that the ocean itself enters beneath thls laval surface, known in volcanologlcal terms as "malpaís", up till 1t reaches the old coastal llne located at more than 3 km in the direction of the volcano ltself, Figure 2. Because of the tidal effect, the sea level suffers variations of more than one and a half meters; the se level flucluations are as well verifled under this sur f'ace of lavas giving place to several phenomena such as the strong oceanic effect observed In the analysis of the gravimetric records. Likewise we have observed lhat the sea level osclllations registered in lhe mareograph located In the module number two of the laboratory, with periods between the range of 10 to 12 minutes whose cause we are investigating, are perfectly reglstered in both, the gravlmeters and the lnstruments lnstalled in the laboratory, and very speclally in the two components of 4

5 the long base clinometers (WT 1 and WT 2) and in the three components of the vertical pendulum. In agreement with this hypothesis the thermal variations of the semi-diurnal frecuencies and the humidi ty variations registered in the Cueva would be as well related wi th these phreatic level fluctuations induced by the oceanic tide. 2 0 ) A vertical pendulum of 6 m length was installed in the station in This pendulum allows to register not only tilts in the directions north/south and east/west but the vertical deflections; afterwards, on February 1990, two cllnometers of a long base, of 24.3 and 12 meters, were installed (M. Van Ruymbeke et al., 1990) to measure tllts between lts ends which were oriented according to the tunnel direction and in a perpendicular way to such direction. The output of these instruments remains registered in a continuous way over an analogical support and wi th a per iodici ty of ten minutes over digi tal support. These observations have allow us to reglster phenomena which may ha ve a great scientific interest. Taking on account the high accuracy of these instruments, the clinometric tide can be clearly seen in the records, obviously influenced by the strong oceanic effect which we have already commented. The two instruments designed, built and installed in collaboration with the E.C.G.S. and the O.R.B. offer, in the perlod of common register, clear samples of absolute coincidences pointing out the two of them distorsion phenomena, always of small amplitude, which have been taken place in the area of the tunnel where they are located. From the geodynamic point of view, there are some evidences of a very special interest in the records obtaines up to this momento In this way, we could observe that important tilts have taken place and have been registered in both instruments in those days previous to the two seismlc perceived, which have taken place during 1990 in the area of the Canary Islands, both of them between the islands of Tenerife and Gran Canaria on January the 8 and May the 20. Obviusly it is not a very significative sample, but we beleave it is a interesting to point it out specially because it Is indicating us something that, if we could confirm it in a future happenings of the same kind, it would be of the greatest importance. On Figure 3 we can see an aspect of the digital register of several sensors, and on Figure 4 the record of the vertical pendulum preclsely correspondlng to the perlod of the selsm of January the elght. 3 0 ) Finally, in more than three years of continuous sea level record with the mareograh installed in the lake, several phenomena have be en detected: period oscillations with a range of some minutes which could be related to other phenomena, may be atmospheric ones. We must point out that these oscillations have 5

6 been likewise registered in the gravimeters, pendulum and long base clinometers installed in the same tunnel at something less than 1 km distance. The harmonic analysis of the mareographic series can be seen on Table 3. at present we are studing some long period modulations which affect to the amplitude of the main harmonics (C. Toro, 1989) and which possible are from astronomic origino In the same manner, the desphases existing with respect to the mareograph located in the Arrecife port, at around 15 km distance, are a very clear sample of the peculiar hydrodinamic regime of the volcanic tube, whose connection with the ocean has not been clearly shown by the speleological investigations which have taken place, reaching the last of them up to almost two kilometers without finding a clear comunication with the ocean. Taking on account our philosophy on what we conslder a laboratory of experiences, the installation of new sensors is planned for a near future, as well as the transfer of a gravimeter beloglng to the O.R.B. to the south of the Island, and more exactly to the National Par k of T.imanfaya, where the most important geothermal anomalies take place (V. Araña et al. ~ 1973; V. Araña et al., 1984), in this way we could investigate the more than probable difference In the answer of the shell to the forces derived from the astronomical potential and obtain interesting conclusions about possible correlations already indicated by some works published (A. L. Yanshin et al., 1986; E. S. Robinson, 1989). ACKNO\lLEDGHENTS These investigations take place wi thin the frame of the project PB presently financed by the D.G. I.C.Y.T. as well as with the important collaboration of the E.C.G.S., the O.R.B. and the Cabildo Insular de Lanzarote. The authors wlsh to acknowledge their generous personal contrlbution to Joaquín Naverán, Jesús Soto and Orlando Hernández who, fron the la Casa de los Volcanes, have collaborated day by day to the success of these investlgatlons. REFERENCES Araña, V.; Diez, J.L.; Or t í.z, R. and Yuguero, J.: "ConvecUon of Geothermal Fluids in the Timanfaya Volcanic Area (Lanzarote Canary Islands)". Bull. Volcanologique, Vol. 47, pp (1984). 6

7 asue Araña, V.; Or t í.z, R. and Yuguero, J.: "Thermal Anomalles in Lanzarote (Canary Inslands)". Geothermics,. Vol. 2, pp (1973). Banda, E.; Dafiobeltia, J.J.; Surifiach, E. and Ansorge, J.: "Features of Crustal Structure Under the Canary IsIands" Earth Planet. Sci. Lett., Vol. 55, pp (1981). Bravo, T.: "El volcán y el malpaís de la Corona. La 'Cueva de los Verdes' y los 'Jameos'''. Publicaciones del Cabildo Insular de Lanzarote. Arrecife (1964). Camacho, A.G. and Vieira, R.: "Structural Gravlmetric Model of Lanzarote Island". (Thls issue) (1990). Fernández, J. and Arnoso, J.: "Informe Sobre la Instrumentación Instalada en el Complejo Geodlnámico Cueva de los Verdes-Jameos del Agua-Casa de los Volcanes. Lanzarote, Islas Canarias ( )". Instituto de Astronomía y Geodesia; internal repport; (1990(a». Fernández, J.; Van Ruymbeke, M. and Vieira, R.: "High Precision Thermal Measurements in the Volcanic Tube of 'La Corona' (Lanzarote)". (Th í s í ) (1990(b». Fernández, J.; Vieira, R.; Lambas, F.; and Toro, C.: "Data acquisltlon systems in the "Valle de los Caldos" and "Cueva de los verdes" stations." Proc. of the XI Int. Symp. on Earth Tides. Helsinki, 12 pp. (In press) (1989). Lambas, F.; Vieira, R. and Gimenez, E.: "Automatic Control Module of Tilts, Calibrations and Data Acquisltion for LaCoste Romberg Gravimeters, Models G and D". Proc. of the IX Int.Symp. on Earth Tides. New York City, 1981; pp Edit. J.T.Kuo. E. Schweizerbart'sche Verlagsbuchhandhung; (1983). Macau, F.: "Tubos Volcánicos en Lanzarote 'La Cueva de los Verdes'''. Anuario de Estudios Atlanticos, n.11 (1965) Orejana, M. and Vieira, R.: "Transforming an Askania GS-15 Gravimeter into a Zero-Gravimeter". Proc. of the IX Int.Symp. on Earth Tides. New York City, 1981; pp Edit. J.T.Kuo. E. Schweizerbart'sche Verlagsbuchhandhung; (1983). Orejana, M.; Vieira, R. and Toro, C.: "Development of an Electronic Pendulum for Microinclination Recordings". Proc. of the IX Int.Symp. on Earth Tides. New York City, 1981; pp Edit. J.T.Kuo. E. Schwelzerbart'sche Verlagsbuchhandhung; (1983). 7

8 asue Robinson, E.S.: "Tidal Gravity, Heat Flow, and the Upper Crust". Physics of the Earth and Planetary Interiors, Vol. 56, pp (1989). Toro, C. : "Determinación y Evaluación de las Variaciones Periódicas de la Gravedad y de las Desviaciones de la Vertical en la Península Ibérica Producidas por las Mareas Oceánicas". Ph. D.; Universidad Complutense de Madr id (1989). Toro, C. and Vieira, R.: "Variaciones Periódicas de la Gravedad Observadas en la Facultad de Ciencias Físicas de Oviedo". Publ. del Inst. de Astr. y Geod., n.166, pp. 7-9 (1988). Van Ruymbe~e, M.: "Transformation of nine LaCoste Romberg Gravimeters in Feedback Systems". Marees Terrestres Bulletin Dinformations, n.93, pp (1985). í Van Ruymbeke, M. and D'Oreye, N.: "Design and Construction of Instruments Adapted to Volcanic Zones". (Thi s ) (1990). Vieira, R.; Araña, V.; Ortiz, R. and Sevilla, M. J.: "Métodos y Técnicas de Auscultación en Zonas Volcánicas. Investigaciones en las Islas Canarias". International Meeting 'Catastrophes and Society'.Lectures and papers. Pp Fundación MAPFRE. ITSEMAP. (1989(a». Vieira, R.; Fernández, J.; Toro, C.; and Camacho A.G.:"Estación Geodinámica del complejo Jameos de Agua-Cueva de los Verdes (Lanzarote). Objetivos científicos y estado actual de las instalaciones." Publicaciones del Inst.ituto de Astronomía y Geodesia, n 164, pp. 1-6, (1988(c». Vieira, R.; Fernández, J.; and Toro, C.: La estación de la Cueva de los Verdes (Lanzarote): primeros resultados de las experiencias realizadas." Revista de la Real academia de Ciencias Exactas, Físicas y Naturales de Madrid. Tomo LXXXII, cuaderno 2. pp (1988(d». Vieira, R.; Fernández, J. ; and Toro, C. :"Las variaciones periódicas de la gravedad observadas en el tunel volcánico de La Cueva de los Verdes (Lanzarote)." Publicaciones del Insti tuto de Astronomía y Geodesia, n0164, pp , (1988(e». Vieira, R.; Fernández, J.; Toro, C.; and Camacho, A.G.: "Stuctural and oceanic effects in the gravimetric tides observations in Lanzarote.". Proc. of the XI lnt. Symp. on Earth Tides. He Ls Ink i, 10 pp. (In press) (1989(b)). 8

9 Vieira, R.; Fernández, J.; Toro, C.; Camacho, A.G. :and Van Ruymbeke, M.: "Dos años de observaciones en la estación geodinámica de Lanzarote" ESF meeting on Canarian Volcanism. Edit. E.S.F.-C.S.I.C, pp Lanzarote (1989(d)). Vieira, R.; Camacho, A.G. and Toro, C.: "Deformaciones de Origen Térmico del Edificio de la Facultad de Ciencias Geológicas de Oviedo a partir de las Observaciones de Marea Gravimétrica". Pub L. Inst. Astr. y Geod. n. 166, pp (1988(a)). Vieira, R. and Toro, C.: "Modificaciones en el gravimetro Askania GS-15 n~ 212 y Resultados Comparativos de las Series Observadas ". Pub l. Inst. Astr. y Geod. n, 166, pp. 1-6; (1988(b) i. Vieira, R.; Toro, C. and Fernández, J.: "Ocean Tides in the Nearby of the Iberian Peninsula. Part II:S2 Iberian Map". Proceed. of the X Int. Symp. on Earth Tides; pp Madrid, Sc. Edit. R. Vieira. C.S.I.C. (1986(a)). Vieira, R.; Toro, C. and Megias, E. "Ocean Tides in the Nearby of the Iberian Peninsula. Part 1: M2 Iberian Map". Proceed. of the X Int. Symp. on Earth Tides; pp Madrid, Sc. Edit. R. Vieira. C.S.I.C. (1986(b)). Vieira, R.; TorroJa, J. M. and Toro, C.: "A general Discussion About the Normalization of Gravimeters in the Iberian Gravity Tide Profile". Proceed. of the X Int. Symp. on Earth Tides; pp Madrid, Sc. Edit. R. Vieira. C.S.I.C. (1986(a)). Yanshin, A.L.; Melchior, P.; Kellls-Borok, V. l.; Becker, M.; Ducarme, B. and Sadovsky, A.M.: "Global Distribution of Tidal Anomalies arid an Attempt of its Geotectonic Interpretation". Proceed. of the X Int. Symp. on Earth Tldes; pp Madrid, Sc. Edit. R. Vieira. C.S.l.C. (1986(a)). 9

10 1,,) ClIFV A nt:, 0<; VWnI'S Ih).T"'~'F(l<; 11Ft. Ar;TIA (el CAsA IJE tos VOI.CANF:5

11 CI - I.ACOSTf: nohnrnr. cn1.vlhr.tm N" 414 TI 11~1.2.3) - IIIGII rnf:cision mf.nhohr.trns (0.001 In Ilr -,"JHIOJTY sntson (X) T" - TIlF.nHnHf:n:n ron AI,"IF.tI'1.I. TF:Hrf:nAl1Jnf: f() r" - A1HOSrllF.nIC rl1f.ssijnf. 10. m") t'v _ VF.I1T1r.AI.rrtlm"JJH m t.rttr.lnj(sf:tlstl1l1.jty, O.(;9(; "/V IF.-\l): 0.(;00; "/V IN-sil \lti - \l1.trn ltmf: N"I (r.-\l) (1-1.3 m I.rllr.ltt) ISrtlSll1ILJTY, O.JlJ "/V) \112 - \latf11 runr N"1 (r.-\l) (R.1 m l.r.tlgtii) (SrNSJnIl.ItY, O. Rot4 " V) S. A. O. - nata Ar.I]UISITIOII svsrr.h (0.1 mv nrsot.lit101l) r.a. - rol/m SllrrLY n. A. - AIIALOGIC nrconn svsrrns 16 UlIIIS) o r '~,. >. lt D(-'~======~===-~====~=-w~"=-= ~._--[J T"\)1,, 1 11

12 ' lo I (,J 12

13 C1"vA o, In< Yf,",,~ VflllCAt COW'('IIIf.".rl,. 'J la V ftl,8 te, eo,... C.t.f.C, U.C.M. fa[hu_o ~f,,""na!; tt"f"u,r.a s. lf11"t.n. ""OlUD r.1t~vutr:t,,! \Ar:O!>" 'l)ti""",...,.r. 11 1,'( fm tu (M.VANI"'""HU Ifl';l"U'('4t! Hlunr!:C"lt CAtI"''''''''': VA"'!tf to'; CAlno~. ftlnna"ulll!uuoll '"~lala' 10th. Vil 11A, J. "'NllfIOU MAlU",lIur, t O. "un.",", J.MA'lfU. ro,,'" '.II\ {A"\11tIGn' 1A1\U '0o,., CCJlt"ltf tltvt\or M('" CC-1f111IJ1t; Ofll'l er U"'Vf."f\IiIO cowtuunu DI MAnltO r"tn"" '''".1ftl "'orf,,~,n ("1M t)o/'il' \fa~f ~""AIF. ANAlun, ytw'dlroy "un!; OM "R UClJ't, I rtor.u''''if''l. huralm( 'NtlHM {MIt'CtlON,..nrOlIlOtIAl In lit' MIlfUf or. r.u. 'tho1 lfo'tllm"attl)jf 'Ar: '01 tltasf lar "l ,,,, n. '" ''''''''-'II''''''l lag 17'.1" tii. cnnrrtlnw,,,. ""'f".'ut """"U'"" "1/ "1 /Mrflf.1I O' / /8r 6 3 8r 711/e7l011 8rl111/8rl l 31M 215 (1'. epl 11~,ee, 4 M l 8/e~ 314 8e ll7/ee 00 8e 1 '/ee 6 7 ee 6191M 7ll n. e~ 127/ee 9 9 8e 97910e'0 1 8e'01!/ n/88'0IZ ee'ol7/88'no C]I /0e'110 8? 1 '/e? 1 4 n1 110'87 2'1 8? 276/8? /891 1 "", e? 5 I/e? '" 81 5l5/e? 527 e? HO/ /e /e9 6.6." "' f.21'8' 7, n1 711.,,,, n8/e? 81! 81 8fT/8? eft 81 en/e9 8l' ~]" " 11]0'''9?, / e11015/e1tat, 1910'0/0110]0 89" ~/81"ll ~l' 87112S tt/ lie/90 l 1 90 l 8190 " /90 412,] , 1S/90 U "' III/?O III 0t'I "",on ~" /00 ~10 9ft ""10ft 1 7 on 'IU?",,, 9ft ""/?O "" fin, """""A' "U.tI nn, ~'''I'l''tun "'r.t 48 Ilot:". UJ\V[ r.."", [.;ttua"" "lifl. A'"l. rll ~' U~'nuAl! "fa" ""r:tl"'''' W UAVf. H.,. f.rt".. H.~. ti,,,..m.'. "H"l. "". n 1Htl''''''( INvf1I'f{n t{anl"c~ "~. U'e t t,'c,,,,, 0.1', f:l2 1l~JI O l.6i O.Ol 10.9 O.re '2'. 'l6. 10 l0' O e5 O Ol IlTl6 O.Ol~O 1.l e.es., 'l7 In. " ~Ir:t."1 O 9. O Ol 1 22'.2 o 0:?O 'B. -ns. 20 ", 5.96 O ft" o OOll l.06 Q.16 Oll ' 'H. 11? '.Il o Ol , , l O Ol "',. 1',' O Ol 1.1/ O.Ol ]5.18 "'6.. U? lo,~ul O." O.Ol 0.970r O.lO s. Tl l1 '~l. '115. " Nn' l t.1,10.006' 0.5. O." 0.04 te l.' l. " 1~6.. '~e. 11:1' 0.'.( '~ll < O.Ol O." '61. ",'. 'o r, ".7e O.Ol O 0011 O." e.I. ".66 1M. lm. l st l76 0.0?01 l. " 8ll O. " O.U M. 'o., 1,1." o ttol 0.000' ' 9 ' Z. 1". ",tu, 0.< ".n', O.Ol 1l ' " J' 1.'0 o Ol 1151\ O.Je 0.0' C 'e', '01 O J6 O Ol '.0')6' 0.0'.'-( o ,010 ft7.' O.U 10".. "" M' r,n 0.01.,." 0.001' 1.0' 0.'6 O.Ol 1161 l.le.?t.. I?,. 1'. Mil n.,t ".", t.",,, n.n'.~ '-"" '-." 0.n1 1\7.1 0.(1. 'IrIvt'''D 'fa"i"r.! 111. lll. 0.1,' 0.02 LO"" ll5.9 0.(6 lb. ll'.,1) 2M2 f e, l1 o 70 o 18 I6e.l 1.37 "" 1l7. l,.. 10 HU' 1.71 O.Ol 0.? <. 60Z 1.66,,,,. 2','. "." '0.~1 O.Ol I.Il '0.46 1'.6.,,,e. 11 IIV' Z O.'6 O Z 1.01 l~l. l'e. 21', "~ ".~l O.Ol 1.010' 0.000' 1.61 O.Ol 9.0' '61.8 ".9' 16l. 2M.,,,,un' O.IIO.Ol l05tl l." IIr. O." l". ll.5. 'U \ l.l' 0.50 O lo IU.t 1.66 l67. 27l. 1 'l r. 60 O.Ol 1.Oll6 O OO~? l.61 0.'5 O l. 151& 160 li'. ln. I SZ?8.l1 O.Ol O al J.Sl 110. I 18.l9,,, " e tu.l '.77 lsl. l~5. 1\ "01 0.<1 0.0' 1.0,060.0l6' 6. Z I.U o or nc l.l " 'r n.nl 1.n~"~O.M12 '." 3.Il O.~I.tM'''r.~ '".1,NvttUO ", I~.t 0.01 '1.0!IAllf'I.U(),""vI.nON o L 72 ';0 '''1'1'''' un". 'U O'f.H~ ~1~1~'.?A 1.18 lo 01,t' 1.0'01 ' 01/' tf t. 'n'.6 ""01 0.'"\''' CU'U, frnr:" fjj.,u7"6."

14 r \ ~.1\ ti. 1\ [1 (\ 1\ f\ " \/\ '\ 1\ \1 V -v-\ - \1 -~- I--'J _. -.- _ ~.- f fi s»:.- - -v"\ \1.,,~"\ \ r.~ I~ V.vP \,... Iv -.- e-' f r ITI f\ I 1\1 \ I L.I ~I,11 V- r 'r _ A - _ VI~ VIV v v f ~ -~- \J- r r-- o i_ - f _._- -, ~ _. X\ nd\ 1- tj) í\jí.. t--- r f- fu\ V '\ " I- _ , ? ~ ~v IV L I /t. '''\J.\ L_ I- _. L--. v' V~r t!,:;., r",,<i lum (F.-II) r!8"''' :1 14

15 "-S vt nr I CIIL re NlJtllUII rvvnr18r 001 GEOOINAHIC STATION "CUEVA DE LOS VEnIJES" (L A ti Z liil o tr C A N 11n y I S L A 1'10 S ) ( ) 15

16 !ila""" SItU""otI ""r.i\hloo:u flmi[ryr.'ul.rn.rel!':"'i\"'r IN~I"I '" 1m, r'" Inl)I\' ION """Ir"I\"rr: """InIO; JIU'f.O~ nrt ACtJI\. rao:a nr Inoo: vnlr.atlr~. '''''711DO''. n 01 N lj ~'5 v INS'III"o er I\l:;llrtlll'."1I., r.rnoroo:ia ( r,s I.r.. H.r.H. ) 00' on2 -;7' f"rw:flpl:; m "pr~r:fmr) (J""~nnnr. R.Vnln" Ir. VTr Iftl\ J.''''\lfRI\PI. O.lIrp"","orz It"'S1!l;IJUII.nt.vtur nr.nv fllhijo; m, IN1fAVI\!o; O' 1.8 1I0IlR$. f'mnllll\l (ADnmlr.11J 11\" 'Ir rrm,,,. n_.",, l',., \1'1 "' '''U'. llfe.a.<:ioi or AHI '.JUIOE, "1tA'~[ AlW PESH1IIAlS AII" f n'u "'H' "IT" A,.~, lo f'o"".if\rj"ft J t f, f nsn~,,. r t utt e '''''VT"~ItT "IIM'O.,t,,," lnlrftv'" rr "tllr. l." H..41"1. ""nr'~,,"n Of' o n7 7"/"7 "I? e7 9 0/0710 7,.11017/M ","; "Hr unrnvm M 61'/ / ~8 "21/""," " enlolo/8? 1.16 n?12 I,/."n "n "id JlJ/"iO 1.2" "'17 I/n?17 1 I,nf: IN,rnvM 90 "27/70 7'" n 721 "01.0 fll\yiij 19nnAnrtlnlllr.o: '7 "1 "':"0: UJl.V{ r,lrnrr r~""",ro IUfI"l """, rllm[ A{~I"'J"'l S "Dr.""rNI. lf UI\vr """l.ji,h.!i:. '''clon A.H.S. mr r, R.M.S. lutf l. """OO:[ x, 1t 51r.ltt'l '''''20.11H 1.17 ~6.8? O. le ?'. 1?~. 10?o1 O. le 0.01 o ft')?l 0.OJ \,5" r.tlAt ~el 0.0?78 31.? us ',5ft " " ] In ~ol 0.10 o O.0~', I 1'.l. 11,'5. 16 o, 4. ',8 o M Jl \ "'6.."'? 10 '''TI' o.n~ O.M 0.1' , ,2 17' 6 15>.. 1';5. 15 Mn' "1') lo n?o 2.',6 leo.0 "6. 15e. 1 kl' O.M ? ',? "3 17', ~2. lt11 o. O'. 0,0' o Qf,71 o.o"e "7. ]S \ e.0 1~l. 1~1. 7 rl l M 'M., M". 3 ~, o 80 O "'60.n?] \ "ti 5.) ' H.H O 11 ~1. 77 '15.' ',6. 2 1' J ~ ". 7 r nr t J \. " IF. fa' 0.07 O.Ol 0.151Z 0.050" ~2 tj 0."8 171 l t.\j el \ ~1. lel. 7 ~o' O.11M 0.06'.5 \9.95 1J."6 0.\0 17"." te' nol ~ e ft,"1' n."1 o.n~ n.n",,, n.nlnl,,n.n') 91. In n.76 17? n. 17 [ts? 0." ?B.".62 5.".1 O. J] ~. lo ~"2 1.? O.OJOl J i,. lo lu? O.0?\6 1'5.9" l 66.1,',1. 11". 1].? 1] n J.5 21,6.,2' liu? 2.5~ "2 65.HO " ', "1. 26". '5 '~"n ~ \1 1j7.68 t.ez 1. \9 m.e S! 49.M 1.99 t. 1,8 lb ~ '2? O.I1M H.'" 0.12 '''.36 ns,. 271, ~ , ',2 \J tll O e5. 15 [1~? O J O j 5.51, o IjS "..,?o:;. 11 7t? n.n6 n.n, " """' n.,,,,,, f! 7.no 1".H n.h B5. ",1, <) O J le f,5 J". l75. t t, n 7? n,ol n.1o;,,? n.nf7"; 17.,.en n n S,,,ND"" OFV'''"ol, 0.'9 so 0.1,1 '"rros! or!lfunrnf 'U-"5(,H) 7n),1.,,, Ol/k' LIno 1 0'1' kl n.?771 "='/0' ~ """0 trwirat rrnrn 'J.I- 7f,t,1O;1,1." '" In n.ii 0.1 " 1'"hl~ 3 16