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Quantitatively structural control of the karst based on
speleological cave
survey data: Cabeza Llerosos massif (Picos de Europa, Spain)
Daniel Ballesteros1, Montserrat Jimnez-Snchez1, 2, Joaqun
Garca-Sansegundo1 and Miguel Borreguero3.
1Geology Departament, Oviedo University, c/ Jess Arias de
Velasco s/n 33015 Oviedo (Spain) [email protected]
2Institute Earth Sciences Jaume Almera, c/ Sol i Sabars s/n
08028 Barcelona (Spain)
3Socit Suisse de Splologie, section Troglolog, case postale 1332
CH-2301 La Chaux-de-Fonds (Swiss)
INTRODUCTIONe influence of Tectonics on speleogenesis has been
qualitatively studied by several previous works (e.g. Skoglundd
Lauritzen, 2010) based on 1) observations from bedrock outcrops, 2)
geological maps, 3) geological cross-ctions and 4) collection of
joints and bedding plane measurements in caves and data projection
on caves surveys.ve survey data can be statistically analyzed and
compared with the geometry of the massif discontinuities. The
m of this work is to establish quantitatively the influence of
the structural factor in eight several vertical cavessed on
speleological cave survey data, joint and bedding measurements and
stereographic projection.
Europa (Cantabrian Mountains, North of Spain) (figure 1). Picos
de Europa Mountains are manly formed by1,000 m of carboniferous
limestone affected by a NW-SE to E-W trending, sub-vertical and
SW-directed thrustssystem and other faults (Merino-Tom et al,
2009). The landscape is dominated by karstic, glacial,
periglacial,snow and gravity forms (Moreno et al, 2011). The
cavities studied are eight vertical caves (shafts) witch
lengthranges from 500 to 4,400 m and its depths vary from 130 to
738 m (table 1).
e method includes:cave survey collection (10,866 m)geological
map and cross-sections with the cavities projectiondata collection
(152 measurements) of bedding and joints in caves and near
outcrops
RESULTSbeza Llerosos massif is mainly formed by 1,000 m of
massive, laminated or stratified carboniferous limestone affected
by an NW-SE trending, sub-vertical and SW-directed thrusts andher
faults which direction is SE-NW, SW-NE or N-S (figure 2). The cave
projections on the geological map and on the geological cross
section are parallel to the trace of thrusts, othersults and
bedding. Seven families of joints shown in table 2 have been
distinguished in all the area of study. Five groups of cave
passages have been defined, but these groups are notpresented in
all caves (table 3).
DISCUSSIONe definition of the groups of cave passages on
ereographic projection varies little due to theatistic
parameters (range and number of contours)ed to elaborate the
analysis of density of therections and dips of the cavity.
Nevertheless, thefinition of each group of passages has beenecked
by field observations and the cave survey.ble 4 resumes the
structural control of each groupcave passages highlighted in figure
2. 64 % of the
hole of cave passages is represented by A and groups, being
controlled by sub-vertical jointsd their intersections. 26 % of
cave passages ispresented by B and C groups, ruled by thetersection
between sub-vertical and sub-horizontalnts. D group represents the
6 % and is forced by
e bedding. Some cave shows groups of cavessages that are not
present in the others. Thefferences about the development of cave
passagesone cave or another can not be explained only by
ructural criteria. Perhaps, geomorphological ordrological
factors controlled these differences.
6. CONCLUSIONS1.- The endokarst morphology is strongly
controlled by the structure. Sub-vertical joints rule the 64 % of
the cave passages and the intersectionsbetween sub-vertical and
sub-horizontal joints condition the 26 %.2.- The influence of
joints on the caves is more important than theguidance of bedding.
The stratification forces only the 6% of the cavepassages.3.- The
qualitatively determination of the structural control on
endokarstby the representation of cave survey, joints and bedding
data instereographic projection just depends on the criteria of
density analyses.
knowledgementsresearch has been funded through CONTRACT project
(CN-06-177) provided by Asturias
ernment-Oviedo University, CALIBRE project (C AVECAL)
(CGL2006-13327-C04/CLI) provided bysterio de Educacin y Cultura,
and GRACCIE project (CONSOLIDER PROGRAM) (CSD2007-
67) provided by Centro de Investigacin Cientfica y Tecnolgica.
We acknowledge J.amonde, . Merino, G. Sendra, I. de Felipe, P.
Solares, S. Suisse de Splologie, A. Dep. Gema,speleolgico Polifemo,
G. Splologique du Doubs and GES Montaeiros Celtas for there
help.
References Ballesteros et al(2009) Semun 2009 Exploracin
espeleolgica en Pea Jascal, Picos de Europa, NO de Espaa. Oviedo,
Spain. Unpublished. 41p. Ballesteros et al(2010) Torca Teyera.
Subterrnea30:24-26. Borreguero (1986) Special Picos: Puertos de
Ondn. Neuchtel, Swiss. Unpublished. 118 p. Colectivo Asturiano de
Espeleologa et al(2011) Memoria de la campaa de exploracin
espeleolgica Pea H.ascal 2010. Macizo del Cornin, Picos de Europa.
Ons y Cabrales, Asturies. Unpublished. 41p. Groupe Splologique du
Doubs (1988) Camps dt dans les Picos de Europa (1987-1988).
Unpublished. 47 p. Merino-Tom et al (2009) Emplacement of the Cuera
and Picos de Europa imbrcate system at the core of
Iberian-Armorican arc (Cantabrian zona, north Spain): New
precisions concerning the timing of the arc cl ousure. Geological
Society of America 121, 5-6, 729-751. Moreno et al (2010) The last
deglaciation in the Picos de Europa National Park (Cantabrian
Mountains, northern Spain).Journal Quaternary Science
25,7,1076-1091. Skoglund and Lauritzen (2010) Morphology and
speleogenesis of Okshola (Fauske, northern Norway): example of a
multi-stage network cave in a glacial landscape. Norwegian Journal
of Geology90, 123-139.1
Caves Development (m) Depth (m)El Frailn 1,084 349Torca Llorosa
1,817 686Torca Teyera 4,438 738Torca del Camino 759 406Torca del
Zapo 544 230Torca E 511 130Bocn de las Ancolas 875 255Gralleros de
Salinas 838 381
TOTAL 10,866
Table 1.- Relation of the cave studied. Cave survey data is from
Borreguero (1986),Ballesteros et al(2009, 2010) and Colectivo
Asturiano de Espelelogos et al(2011).
2. SETTINGThe area of study is located in CabezaLlerosos massif,
in the North of Picos de
Joint families Trend (o)
J1 N63/68SEJ2 N29E/46NWJ3 N146E/78SWJ4 N52E/72NWJ5 129E/17NEJ6
N167E/57NEJ7 N180E/26E
Bedding (S0) N30-55/60-80NE
Table 2.- Trend of joint families and the bedding.
Group of
passagesTrend (o)
% of cave
total
A sub-vertical 61B N10W-N10E/3-20N 13C N20-70E/0-50NE 13D
N125-145E 6E N105-151W/38-65SW 3
TOTAL 96
Group of passages Structural control
A J1, J2, J4, J6 and their intersections
B Intersections of J5 and J6C Intersections of J1, J2, J4, J5,
J7
D BeddingE J1, J2, J3, J4
Table 3.- Trend of cave passage groups.
Figure 2.- Geological map and cross section. The stereographic
projections show the density analyses of the cave survey data and
the media plane of thebedding and the families of joints.
METHODOLOGY 4) establishment of the families of joints and
bedding by stereographic projection5) definition of groups of cave
passages from stereographic projection (based on their
directionsand dips)6) the comparison between bedding, families of
joints and cave survey data by stereographicprojection
bstract: Speleological cave survey, joints and bedding data is
statistically analyzed and compared with each on stereographic
projection to determinate quantitatively the structural control.
Themparison includes the definition of families of joints and
groups of cave passages according its direction and dip. 10,866 m
of eight cave from a calcareous massif are studied to illustrate
this method.e results shows the percentage of the influence on the
karst of each joint family and the bedding.
Table 4.- Structural control of cave passages.
Figure 1.-
Situation ofthe area ofstudy.
DRT 2011
Meeting
Oviedo
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