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Cave Notes

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Title:
Cave Notes
Series Title:
Caves and Karst: Research in Speleology
Alternate Title:
Caves and karst: Research in speleology
Creator:
Cave Research Associates
Publisher:
Cave Research Associates
Tumbling Creek Cave Foundation
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Language:
English

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Subjects / Keywords:
Geology ( local )
Genre:
Newsletter
serial ( sobekcm )

Notes

General Note:
Content: Formation of solution bevels at intersections of joints and bedding planes / Lou R. Goodman -- Discussion: Resistivity surveys in the Mendip area, south-west England, U.K. / A. D. Oldham -- Annotated bibliography. Cave Notes(vols. 1-8) and Caves and Karst: Research in Speleology(vols. 9-15) were published by Cave Research Associates from 1959-1973. In 1975, the Tumbling Creek Cave Foundation compiled complete sets of the journals in three volumes. The Foundation sells hardbound copies of the material to support its activities.
Restriction:
Open Access - Permission by Publisher
Original Location:
Tumbling Creek Cave Foundation Collection
Original Version:
Vol. 7, no. 4 (1965)
General Note:
See Extended description for more information.

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University of South Florida Library
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University of South Florida
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Resource Identifier:
K26-00651 ( USFLDC DOI )
k26.651 ( USFLDC Handle )
13722 ( karstportal - original NodeID )
0008-8625 ( ISSN )

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Karst Information Portal

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PAGE 1

CAVE NOTES A Review of Cave and Karst Research Volume 7. No.4 July/ August, 1965 Frontispiece. Entrance to Sophienh8hle, Germany, showing effect of solution along an open parting between bedding planes (see page 29). ** FORMATION OF SOLUTION BEVELS AT INTERSECTIONS OF JOlliTS AND BEDDlliG PLANES by Lou R. Good:man* When two rock units in contact dissolve at different rates in a unifo r-rn fluid, the resulting forms, called bevels, are characteristic of the rates of solution and duration (Lange, 1964). The simplest case to consider is that of the vertical plane wall in cross-section. containing a horizontal contact (Figure 1). The resulting form, as shown, is a planar bevel, whose dimensions are given by Lange. A more complex Ioz-rrr should result where a vertical joint plane terminates at a horizontal bedding plane, with solutional enlargement proceeding along the joint in a submerged condition (Figures 3 and 5). This paper explores the results of the process acting on this structure and its variations. In order to examine the resulting form, consider first the profile produced by enlargement of an elongated fissure in homogeneous rock undergoing uniform solution. It develops into a semicircular, nave-like ceiling meeting parallel, vertical walls, as shown in Figure 2 (Lange, 1959). If the *Naturhistorische Gesellschaft, Nilrnberg, Germany **All photographs by author. 25

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CAVE NOTES CAVE NOTES CAVE NOTES is a publication of Cave Research Associates. Subscriptions are available for $2.00 per year (six issues), or on exchange. Mid-year subscriptions receive the earlier numbers of the ~olume. eorrespondence, contributions, and subscriptions should be addressed to: CAVE RESEARCH ASSOCIATES, 3842 Brookdale Blvd, Castro Valley, Calif. Editor: Arthur L. Lange, Cave Research Associates Associate Edi tor: Ronald A. Brandon, Department of Zoology, Southern Illinois University, Carbondale, Illinois Managing Editor: R. deSaussure, Cave Research Associates. @ Copyright 1965, Cave Research Associates. fissure ter-minates instead at a contact with material having a different rate of solution than the fissure walls (Figure 3), then the profile produced will depend in addition on the following conditions: I) solution rate ratio; 2) presence of an interstitial laminar bedding plane fill and its solution rate relative to that of the adjacent s n-ata: 3) nature of contact: open or closed. Non-laminar contacts: In the absence of a lamination at the bedding plane, the form is determined by the ratio of solution rates and the nature of the contact. Since an open contact can be considered as a type of lamination, the non-laminar forms are here developed for closed contacts. Although these forms are independent of orientation, as are bevels, they will be examined, for simplicity, with the joint in the lower stratum oriented perpendicular to a horizontal bedding plane. Two forms result, depending on whether or not the stratum of greater solution rate contains the joint. Case I (vl)Va): When the rate of solution VI above the contact exceeds that of the rock containing the enlarging fissure (joint), the form can be derived from the initial stage by examining the contact. While enlargement proceeds radially at a rate Vi above the contact, as in Figure 2, the fissure below expands at the lesser rate va Since the plane of the contact runs through the center of the circular section and is, therefore, a diameter of that circle it is also normal to the fissure and can be tr-eated as a simple bevel forming along a wall (Figure I). The result, drawn in Figure 3, is characterized by a semi-circular arched ceiling down to the contact, where positive bevels slant toward the fissure walls. This shape resembles ----contact 26 Figure 1. Bevel formed at contact. To, initial structure; Tn' later form. Rate of so1ut~'on V2) v 1 ......... / ( I I I I I I I I I I I I I Figure 2. Uniformly dissolved fissure in homogeneous rock.

PAGE 3

VOLUME 7, NO.4 the familiar "keyhole profile", often atrliii~~~¤~¤~i~ll[l tributed to cor-rae ion. but here formed by solution. Sptlcker (l9(J3) discusses and illustrates an example of an "e rosional keyhole" profile in the Grosse Spielberg Htlhle of southern Bavaria. He - .. -..... interprets this profile to be the result I of "erosional" development in lithologic -,-.-.4._._._.J_._._. units of varying solubility, but he does ",/ not refer directly to the nature of the I contacts, only to the profile produced. I The example of "keyho Ie" profile : shown in Figure 5. Zigeunerloeh near I F'Ischs tedn, Germany. is in dolomite I country rock. Concurrent sedimentation I such as would produce planes of repose I (Lange. 1963) cannot be totally ruled out; : however. evidence is present in this ex1 ample and associated bevels that a dis T tinct solution rate diffe rence exists at Lc::_---::_--:::--~T~o:,--:_n::...--:_-J the bedding plane contact; the upper unit Figure 3. Bevel formation at inappears to be the faster dissolving. tersection of joint and bedding plane, where v 1 >V Z Case II (vi (Va): If the fissure lies in the stratum of greater solution rate, the bevels form in the upper member. The production of this form can be traced in Figure 4. If the fissure had run through both strata. a simple bevel, 'as in Figure I, would have formed (Outline A-A', considered here only for the right-hand side of the diagram); however. the arc produced from the apex of the fissure expands upward to a point of tangency B with the bevels. Thus the form is characterized by an arched ceiling connecting tangentially with bevels down to the contact, where the expanded fissure walls take over. Figure 4. of joint Circular solution Bevel formation at intersection and bedding plane where V2)Vl' cylinders fllustrate successive stages of upper stratum at Tn' In Figure 6. the profile from Sophienhtlhle near Burg Rabenstein, Germany, such an arched ceiling does display bevels down to the contacts. An additional factor in the production of this particular profile will be discussed in detail below. Laminar contacts: If the fissure terminates at an interstitial lamina. or relatively thin stratum, the solution rate of the intermediate layer must be considered. For simplicity of analysis, we shall consider that the solution rate of the lamina v. differs from that of the enel6sing rock, here regarded as being uniform above and below (Figure 7). Case III (v.=O): When the laminar structfire is insoluble, the resulting profile is rec 27

PAGE 4

CAVE NOTES Figure 5. Meeting of a joint and a bedding plane in Zigeunerloch. Germany. Ra te of solution is greater in the upper e tra tum. Figure 6. Meeting of a joint.and a bedding plane in Sophienh8hle, Germany. Rate of solution is greater in the lower stratum. tangular (Figure SA) unless mechanical penetration occurs. Without mechanical penetration, the extent of the insoluble material would not be determinable (Figure 9). Case, IV (v,(v c ): Where the rate of solution of the laminar unit is le~s than that of £he enclosing country rock, bevels form in the lamina as m Figure 4, until the lamina is penetrated. From this time on. the upper stratum can dissolve radially at the same rate as the fissure walls are receding, but bevels tending to form at the upper contact are consumed by the receding of the bevel within the lamina (Figure 8B). 28

PAGE 5

VOLUME 7, NO. 4 Case V (vi =vc): Where the rate of solution of the lamina is the same as that of the country rock, the laminar structure in the walls may be observed, but no particular form is produced by its presence (Figure Be). Case VI (Vi)Vc): Where the rate of solution of the lamina is greater than that of the enclosing country rock, or where the re is an open contact that can be characterized as the absence of a lamina, the resulting form is a superposition of the forms produced in Cases I and II. These forms, however, develop simultaneously in the country rock with the net result that the profile produced is composed of two bevelled incisions connected by an arched ceiling, as in Figure aD. The open contact can be characterized as the absence of a lamina, or as a "negative" lamina in which the rate of solution is extremely high. Lange (1964) considered an open joint enlarging in the ceiling of a passage. but in our case, the enlargement is horizontally and symmetrically oriented. The form produced by the open contact requires a vertical joint for initiation of solution and is not dependent on a difference of solution rates above and below the parting. We would expect to encounter it particularly in passage profiles of caves exhibiting prominent bedding. ¤erban {e t a L, 1961) shows a fine illustration of such a profile which he titles "Fossiler unterirdischer Wasserlauf" (fossil underground streambed)(Figure 10). An example of this open fissure, doubte-beve I structure is seen in the Frontispiece of this article. Here, in Sophienht\hle. the upper unit also has the aspect of a lower rate of solution. This cave demonstrates a solution rate change not only in the vertical direction but also in the horizontal. A comparison of the Frontispiece and Figure 6, a profile deeper in the cave, shows that the interior displays steeper bevels, due to a diminished solution rate differential and a contact that is almost closed. Further penetration into the cave reveals that the bevel influence on profiles diminishes with depth, until it is no longer evident. The stratum forming the ceiling of the profiles in Figure 6 and the Frontispiece is approximately one meter thick. Between these two locations it exhibits the bottleneck profile of Figure 8B, having been penetrated and thus permitted to form a hemispherical dome, approximately three meters in diameter. FigUre 7. Ff s sur-e terminating at lamina separating strata of equal solution rates. A B c D Figure 8. A) Result of solution below lamina without pene'tr-at.f on ; B) Result of solution above and below lamina, where vc > Vi; £) Same, with-vc = Vi; Q) Result of dissolVing, where ve cvr29

PAGE 6

CAVE NOTES Figure 9. Profile influenced by insoluble laminae, Manitou II Cave, Colorado. Lower laminae have been breached, apparently by mechanical ~eans, the upper has not. The Franken dolomite of Sophienhdhle has been studied (Gtltze, 1947) with the conclusion that it arose from the penetration of magnesiumbearing waters into fossil sponge configurations. Where a layer of different permeability occurs between one colony and the next, not only is a bedding plane in evidence, but also it is likely that a variation in solution rate occurs horizontally as well as vertically, due to the impeded yertical circulation. The author's observations in the caves of the Franken dolomite in the Fr!:lnkische Schweiz, Germany, have disclosed the examples cited, but in none of the cases can corrasion or concurrent sedimentation be totally ruled out. The caves. nevertheless, do provide examples which, if not pure bevels, illust'rate the role that bevel formation can play in the influencing of the development of passage profiles formed at the juncture of a vertical joint and horizontal contact. fig'!!re 10. Profile resulting from open contact as in Figure BD (drawn cy author from photograph in ~ERBANJ et a..L, 1961>'. 30

PAGE 7

VOLUME 7, NO. 4 Refe rences: GOTZE, F. Ein Beitrag zur Entstehung des Franken Dolomites. Deutsche Gesellschaft fill' Karstforschung, Mitteilungen, Heft 2, S. 21-24. 1947. lANGE, A. Introductory notes on the changing geometry of cave structures. Cave Studies, no. 11, p 69-90. 1959. -LANGE, A. Planes of repose in caves. Cave Notes l vol. 5, no. 6, p. 41-48. 1963. lANGE, A. Solution bevels in limestone caves. Cave No t.es voL 6, no. 5, p. 3438. 1964. ¤ERBAN. M., I. VIEHMANN. and D. COMAN. HHhlen Rumanians. Meridiens-Editions, Bucharest. 1961 (Plate 14). S.Ptk::KER, R. G; KarstmorPho~ogische Untersuchungen im Laubenstein Gebiet. Jahresheft fUr Karstuod Hohlenkunde, Heft 3, S. 175-178. 1963. * * DISCUSSION RESISTIVITY SURVEYS IN THE MENDIP AREA, SOUTH-WEST ENGLAND, U. K. Following the introductory discussions by J. G. Day (1964) on cave detection by geoelectrical methods, I wish to add eome remarks on the application of electrical surveys to the Mendip karst. Geoelectrical surveys in this area have been solely the work of the late Prof. L. S. Palmer. As early as 1938, he used a Geophysical Megger Earth Tester (megger) in his survey of Lamb Lair Cavern, a cave discovered by lead miners in the 17th Century, consisting mainly of a large natural cham.ber 36 meters high. The war postponed further work and it was not until 1947 that he instituted a new series of investigations. The site chosen was near Tyning's Farm on the central Mendip plateau. Members of the University of Bristol Spelaeological Society were clearing a rift and wished to determine whether it widened at a greater depth. The conclusions indicated an open bedding plane but the rift was not excavated sufficiently to confirm this (Palmer, 1946-48). In 1949 and 1950. a geoelectrica1 survey was conducted near Burrington Combe on the northern edge of the Mendip plateau. This survey accurately located the previously known cave system of Ro dte Pot and also disclosed an open rift passage descending from the nearby choked depression of Bath Swallet. Because of practical difficulties of digging in an active swallet, and the constricted nature of the passages, the system. was never explored (Palmer, 1949*50). The climax of Pafmer-t e work was his survey in 1956 at Pen Park Hole, Bristol. The entrance to this cave-cum-lead mine was filled in over 100 years ago, and subsequently lost, but due to the proximity of a new housing estate the local council wished to detexmtne the position of the cave in order' to avoid building over it. In a space of seven working days. involving 800 readings along 42 traverses with 40 stations, a general impression of the cave was gained. Such features as the height and shape of the main chamber and the position of an old choked entrance were ascertained. The entrance was later located within one-third meter (Tratman, 1963). In 1957 Palmer carried out further field work over Lamb Lair Cavern. These tests (with better equipment) were intended mainly to check the .results of 1938. From his data he concluded that a large cavern, pos s ib l'y 31

PAGE 8

CAVE NOTES larger than the main chamber. existed only 45 meters away (palmer. 1958). In the succeeding eight years the Mendip Nature Research Committee have been digging both in the cave and on the surface in an attempt to locate "Palmer's Chamber". To date excavations have produced a 180 meter long "rabbit warren" of muddy cxawfwaya A. D. Oldham Bristol, England References: DAY, J. G. Cave detection by geoelectrical methods. Part 1. Resiativity. Cave Notes, voL 6, no. 6, p. 41-45. 1964. PAI1I1ER, L. S. Prelimina:ty report on some earth resistance aeasurenent a made near Tyning's Farm on the Mendip Hills. Somerset. ~r8ity of ~ Spelaeological Society Pr-oc. vol. 6, no. 1, p. 27-36. 1946-48. PALMER, L. S. Earth electrical resistance measurements near Bath Swallet, Mendip Hills, Somerset. University.2! Bristol Spelaeological Society, Froc., voL 6, no. 2, p. 208-212. 1949-50. PAlMER, L. S. Some Lamb Lair Cavern. results of Wessex Cave a geoelectrical survey in the neighbourhood of Club Journal, vol. 5, no. 67, p. 30-35. 1958. 'lRA'DlAN, E. K., Ed. Report on the investigation of Pen Park Hole, BristoL Cave Research Group .£!. Great ~, PubL no. 12. 1963. ANNOTATED BIBLIOGRAPHY MILLER, LOYE. Bird remains from an archaeological site in the Beaverhead Mountains of southeastern Idaho (with an appendix by Hind Sadek). ~, vol. 8, no. I, p 17-28. 1965. About 550 bones and fragments were collected from Jaguar Cave, an archaeological s1 te at about 7400 feet elevation in arid country. Two radiocarbon dates of approximately 10,000 and 11,500 years have been obtained. At least three extinct mammals are in association, and it is felt that at least 80% of the bones are at least 10,000 years of age. Details of identification and distribution of the material are documented. --R. deseus sure ORR, P. C., and R. BERGER. Radiocarbon age of a Nevada mummy. Science, vol. 148, p 1466-1467. April 16, 1965. Skin tissue, bone collagen, and vegetal clothing from a well-preserved Indian mummy from a dry cave in Nevada have been analyzed radio-chemically. The age is about 2500 years; the ages obtained for the various samples were in close agreement. -e-Aut hore WHITE, W. B., J. F. HAMAN, and G. J;.. JEFFERSON. Note on the mineralogy of Cueva del uuacnaro. Sociedad Venezolana de Cienc1as Naturales, Bol., t 25, no. 106, p. 155-162, 1963. The mineralogy of Cueva del uuecnaro is described. Calc! te and gypsum are the common minerals. Dripstone is plentiful and internally monocrystalline forms are corsmon. Relicti tee occur frequently and are almost invariably internally monocrystalline with a few externally monocrystalline forms occurring. Gypsum occurs as a gypsum crust and as cockscomb stalagmites. --Authors. 32


Description
Content: Formation of solution bevels at intersections of
joints and bedding planes / Lou R. Goodman --
Discussion: Resistivity surveys in the Mendip area,
south-west England, U.K. / A. D. Oldham --
Annotated bibliography.
Cave Notes(vols. 1-8) and
Caves and Karst: Research in Speleology(vols. 9-15)
were published by Cave Research Associates from 1959-1973. In
1975, the Tumbling Creek Cave Foundation compiled complete
sets of the journals in three volumes. The Foundation sells
hardbound copies of the material to support its
activities.