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An occurrence of stevensite and kerolite in the Devonian Crousa gabbro at Dean Quarry, The Lizard, Cornwall, England

Published online by Cambridge University Press:  09 July 2018

N. J. Elton ,
J. J. Hooper  and
V. A. D. Holyer
N. J. Elton
Affiliation:
Tregears, Little Treviscoe, St A ustell, Cornwall PL26 7QL
J. J. Hooper
Affiliation:
48 St Julitta, Luxulyan, Bodmin, Cornwall PL30 5ED
V. A. D. Holyer
Affiliation:
The Cornerstone, 7 Tregonning Park, St Keverne, Helston, Cornwall TR12 6QT, UK
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Abstract

Stevensite has been found at Dean Quarry, The Lizard, Cornwall, associated intimately with the disordered, hydrated variety of talc known as kerolite. Both minerals occur as pseudomorphs after pectolite and as microcrystalline anhedral masses filling cavities and veins in gabbro. Associated minerals include calcite and prehnite. The XRD data show that stevensite occurs as a physical mixture with kerolite, rather than as mixed-layer stevensite-kerolite. Kerolite is unaffected by glycerol treatment whilst stevensite readily expands: this test provides the only reliable distinction between the two minerals. Differences in IR and chemical data for stevensite and kerolite are subtle; data are broadly similar to those in the literature. Both minerals are readily decomposed to amorphous silica by hot concentrated HCl. Stevensite dehydroxylated at 400°C for 1.5 h is virtually indistinguishable from kerolite. The Dean Quarry occurrence is similar to many others worldwide. Stevensite and kerolite formed after prehnite, calcite, analcime, pectolite and natrolite during a phase of decomposition and alteration of these earlier minerals. ‘Stevensite’ from the first British occurrence in the Whin Sill, North Tyne, has been re-examined and appears to be kerolite or ‘hydrated-talc’.

Type
Research Article
Information
Clay Minerals , Volume 32 , Issue 2 , June 1997 , pp. 241 - 252
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1997

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References

Bradley, W.H. & Fahay, J.J. (1962) Occurrence of stevensite in the Green River formation of Wyoming. Am. Miner. 47, 996–998.Google Scholar
Brindley, G.W. (1955) Stevensite, a montmorillonitetype mineral showing mixed-layer characteristics. Am. Miner. 40, 239–247.Google Scholar
Brindley, G.W., Bish, D.L. & Wan, H.-M. (1977) The nature of kerolite, its relation to talc and stevensite. Mineral. Mag. 41, 443–452.Google Scholar
Brindley, G.W., Bish, D.L. & Wan, H.-M. (1979) Compositions, structures and properties of nickelcontaining minerals in the kerolite-pimelite series. Mineral. Mag. 64, 615–625.Google Scholar
Bristow, C.M. (1996) Cornwall's Geology and Scenery.” An Introduction. Cornwall Hillside Publications, St Austell.Google Scholar
Craw, D. & Landis, C.A. (1980) Authigenic pectolite, stevensite and pyroaurite in a quarternary debris flow, Southland, New Zealand. J. Sed. Pet. 50, 497–504.Google Scholar
Cuevas, J., Pelayo, M., Rivas, P. & Leguey, S. (1993) Characterisation of Mg-clays from the Neogene of the Madrid Basin and their potential as backfilling and sealing material in high-level radioactive waste disposal. Appl. Clay Sci. 7, 383–406.Google Scholar
Davidson, P.J. (1989) Stevensite, a smectite-group mineral from Costorphine Hill, Edinburgh. Scott. J. Geol. 25, 63–67.Google Scholar
DeRudder, R.D. & Beck, C.W. (1963) Stevensite and talc – hydrothermal alteration products of wollastonite. Clays Clay Miner. 10, 188–199.Google Scholar
Duringer, P., Ais, M. & Chahi, A. (1995) Geodynamic context and depositional sedimentary environment of the Miocene stevensite deposit (rhassoul) or Morocco Lacustrine or evaporitic environment. Bull. Soc. Geol. France, 166, 169–179.Google Scholar
Eberl, D.D., Jones, B.F. & Khoury, H.N. (1982) Mixedlayer kerolite/stevensite from the Amargosa Desert, Navada. Clays Clay Miner. 20, 321–326.Google Scholar
Elton, N.J., Salt, P.D. & Adams, J.M. (1992) The determination of low levels of quartz in commercial kaolins by X-ray diffraction. Powd. Diffr. 7, 71–76.Google Scholar
Faust, G.T. & Murata, K.J. (1953) Stevensite, redefined as a member of the montmorillonite group. Am. Miner. 38, 973–987.Google Scholar
Faust, G.T., Hathaway, J.C. & Millot, G. (1959) A restudy of stevensite and allied minerals. Am. Miner. 44, 342–370.Google Scholar
Flett, J.S. (1946) Geology of the Lizard and Meneage. Mere. Geol. Surv. 2nd ed.Google Scholar
Güven, N. & Carney, L.L. (1979) The hydrothermal transformation of sepiolite to stevensite and the effect of added chlorides and hydroxides. Clays Clay Miner. 27, 253–260.Google Scholar
Hay, R.L., Hughes, R.E., Kyser, T.K., Glass, H.D. & Liu, J. (1995) Magnesium-rich clays of the meerschaum mines in the Amboseli Basin, Tanzania and Kenya. Clays Clay Miner. 43, 455–466.Google Scholar
Ianovici, V., Neascu, G. & Neascu, V. (1990) Li-bearing stevensite from Moldova Noua, Romania. Clays Clay Miner. 38, 171–178.Google Scholar
Imai, N., Otsuka, R. & Nakamura, T. (1970) Stevensite from the Atatani Mine, Nigata Prefecture, northeastern Japan. Clay Sci. 4, 11–29.Google Scholar
Imai, N., Otsuka, R., Nakamura, T., Tsunashima, A. & Sakamoto, T. (1973) “Hydrated talc” – an alteration product of wollastonite by reaction with magnesiumbearing hydrothermal solution. Clay Sci. 4, 175–191.Google Scholar
Jones, B.F. & Weir, A.H. (1983) Clay minerals of Lake Albert, an alkaline, saline lake. Clays Clay Miner. 31, 161–172.Google Scholar
Khoury, H.N., Eberl, D.D. & Jones, B.F. (1982) Origin of magnesium clays from the Amargosa Desert, Nevada. Clays Clay Miner. 30, 327–336.Google Scholar
Leeds, A.R. (1873) Contributions to mineralog. Am. J. Sci. 6, 22–26.Google Scholar
Maksimovic, Z. (1966) B-kerolite-pimelite series from the Goles Mountain, Yugoslavia. Proc. Int. Clay Conf. Jerusalem, 1, 97–105.Google Scholar
Martin de Vidales, J.L., Alia, J.M., Garcia Navarro, F. & Rull, F. (1990) Caracteres estructurales de las rases interstratificadas irregularmente: kerolite/estevensit. Bull. Soc. Espaniola de Min. 13, 69–80.Google Scholar
Otsu, H. & Yasuda, T. (1964) Thermal behaviour of interlayer water in stevensite. Mineral. J. 4, 94–114.Google Scholar
Otsuka, R., Imai, N. & Sakamoto, T. (1972) Stability of stevensite under hydrothermal conditions. Memoirs of the School of Science and Engineering, Waseda University, No. 36.Google Scholar
Otsu, H., Shimazaki, Y. & Omachi, K. (1963) Stevensite from the Ohori mine. Bull. Geol. Surv. Japan, 14, 591–599 (in Japanese).Google Scholar
Randall, B.A.O. (1959) Stevensite from the Whin Sill in the region of the North Tyne. Mineral. Mag. 32, 218–225.Google Scholar
Sakamoto, T., Otsuka, R. & Imai, N. (1975) Stevensite from the Kamaishi Mine, Iwate Prefecture, Japan. J. Japanese Assoc. Mineral. Petrol. Econ. Geol. 70, 1–11.Google Scholar
Sakamoto, T., Koshimizu, H., Shimoda, S. & Otsuka, R. (1981) Hydrothermal transformation of some minerals into stevensite. Proc. 7th Int. Clay Conf., Bologna & Pavia, 537-546.Google Scholar
Seager, A. (1969) Zeolites and other minerals from Dean Quarry, the Lizard, Cornwall. Mineral. Mag. 37, 147–148.Google Scholar
Seager, A. (1971) Mineralisation and paragenesis at Dean Quarry, the Lizard, Cornwall. Trans. Roy. Geol. Soc. Corn. 20, 97–113.Google Scholar
Shimoda, S. (1971) Mineralogical studies of a species of stevensite from the Obori Mine, Yamagata prefecture, Japan. Clay Miner. 9, 185–192.Google Scholar
Torres-Ruiz, J., Lopez-Galino, A., Gonzalez-Lopez, J.M. & Delgano, A. (1994) Geochemistry of Spanish sepiolite-palygorskite deposits: genetic considerations based on trace elements and isotopes. Chem. Geol. 112, 221–245.Google Scholar
White, W.B. (1974) Order-disorder effects. Pp. 87-110 in: The Infra-red Spectra of Minerals (Farmer, V.C., editor) Mineralogical Society, London.Google Scholar
Wiewióra, A., Dubińska, E. & Iwasińska, I. (1981) Mixedlayering in Ni-containing talc-like minerals from Szklary, Lower Silesia, Poland. Proc. 7th Int. Clay Conf., Bologna & Pavia, 111-125.Google Scholar
Young, B. & Schofield, D. (1990) Stevensite from Upper Teesdale, Co Durham, a second British occurrence. Trans. Nat. Hist. Soc. Northumbria, 55, 150.Google Scholar