We use cookies to ensure that we give you the best experience on our website. You can change your cookie settings at any time. Otherwise, we'll assume you're OK to continue.

Department of Earth Sciences

Staff and Postgraduate Students

Publication details for Prof Jon Davidson

Tepley, F.J & Davidson, J.P (2003). Mineral-Scale Sr-Isotope Constraints on Magma Evolution and Chamber Dynamics in the Rum Layered Intrusion, Scotland. Contributions to Mineralogy and Petrology 145(5): 628-641.

Author(s) from Durham


Sr isotopic zoning within single plagioclase crystals from rocks from Unit 9 of the Rum layered intrusion is used to infer events during crystal growth in a magma undergoing contamination. The 87Sr/86Sr diversity among minerals and between cores and rims of plagioclase crystals increases as the boundary between unit 9 and the overlying Unit 10 peridotite is approached. Models of near-solidus interaction of the cumulate with a fluid or melt, or large scale textural re-equilibration, cannot easily account for the systematic differences in 87Sr/86Sr between small crystals and the rims of larger crystals. We propose a simple interpretation in which crystal growth is concentrated along the cool margins of the reservoir. Crystals are subsequently advected to a site of accumulation at the base of the reservoir, probably by episodic plume-like dense downwellings allowing mixing of isotopically zoned and unzoned crystals. If the core-rim isotope variations are inherited from primary magmatic growth, then the small distances over which they are now preserved (1–2 mm) place constraints on the minimum cooling rate of the intrusion. Although the length scale of diffusive equilibration is influenced by a number of poorly-constrained variables (starting temperature, feldspar composition, temperature-time path) cooling was clearly very rapid with cooling to effective closure (1,000 C) within a few thousand years.


Be΄ dard JH, Sparks RSJ, Renner R, Cheadle MJ, Hallworth MA
(1988) Peridotite sills and metasomatic gabbros in the Eastern
Layered Series of the Rhum complex. J Geol Soc Lond
Brandeis G, Jaupart C (1987) The kinetics of nucleation and crystal
growth and scaling laws for magmatic crystallization. Contrib
Mineral Petrol 96:24–34
Brown GM (1956) The layered ultrabasic rocks of Rhum, Inner
Hebrides. Philos Trans R Soc Lond B240:1–53
Davidson JP, Tepley FJ III, Palacz Z, Meffan-Main S (2001)
Magma recharge, contamination and residence times revealed
by in situ laser ablation isotopic analysis of feldspar in volcanic
rocks. Earth Planet Sci Lett 184:427–442
Davidson JP, Tepley FJ III (1997) Recharge in volcanic systems;
evidence from isotope profiles of phenocrysts. Science 275:826–
Davidson JP, Tepley FJ III, Knesel K (1998) Isotopic fingerprinting
may provide insights into evolution of magmatic systems.
Eos Trans Am Geophys Union 79:185, 189, 193
Dickin AP (1981) Isotope geochemistry of Tertiary igneous rocks
from the Isle of Skye, N.W. Scotland. J Petrol 22:155–189
Dunham AC, Wadsworth WJ (1978) Cryptic variation in the
Rhum layered intrusion. Mineral Mag 42:347–356
Elliot MT, Cheadle MJ, Jerram DA (1997) On the identification of
textural equilibrium in rocks using dihedral angle measurements.
Geology 25:355–358
Elderfield H, Greaves MJ (1981) Strontium isotope geochemistry of
Icelandic geothermal systems and implication for sea water.
Geochim Cosmochim Acta 45:2201–2212
Emeleus CH (1997) Geology of Rum and the adjacent islands.
Memoir British Geol Survey, Sheet 60 (Scotland)
Emeleus CH, Cheadle MJ, Hunter RH, Upton BGJ, Wadsworth
WJ (1996) The Rum layered suite. In: Cawthorn RG (ed)
Layered intrusions, Elsevier, Amsterdam
Feldstein SN, Halliday AN, Davies GR, Hall CM (1994) Isotope
and chemical microsampling; constraints on the history of an
S-type rhyolite, San Vincenzo, Tuscany, Italy. Geochim
Cosmochim Acta 58:943–958
Giletti BJ, Casserly JED (1994) Strontium diffusion kinetics in
plagioclase feldspars. Geochim Cosmochim Acta 58:3785–3793
Greenwood RC, Donaldson CH, Emeleus CH (1990) The contact
zone of the Rhum ultrabasic intrusion: evidence of peridotite
formation from magnesian magmas. J Geol Soc Lond 147:209–
Greenwood RC, Fallick AE, Donaldson CH (1992) Oxygen isotope
evidence for major fluid flow along the contact zone of the
Rhum ultrabasic intrusion. Geol Mag 129:243–246
Hamilton MA, Pearson DG, Thompson RN, Kelley SP, Emeleus
CH (1998) Rapid eruption of Skye lavas inferred from precise
U-Pb and Ar-Ar dating of the Rum and Cuillin plutonic
complexes. Nature 394:260–263
Harker A (1908) The geology of the small Isles of Inverness-shire
(Sheet 60, Rhum, Canna, Eigg, Muck, etc.). Mem Geol Survey
Great Britain, HMSO
Hunter RH (1987) Textural equilibrium in layered igneous rocks,
In: Parsons I (ed) Origins of igneous layering. Reidel, Dordrecht,
pp 473–503
Hunter RH (1996) Texture development in cumulate rocks, In:
Cawthorn RG (ed) Layered intrusions, Elsevier, Amsterdam
New York, pp 77–101
Huppert HE, Sparks RSJ (1980) The fluid dynamics of a basaltic
magma chamber replenished by influx of hot, dense ultrabasic
magma. Contrib Mineral Petrol 75:279–289
Knesel KM, Davidson JP, Duffield WA (1999) Evolution of silicic
magma through assimilation and subsequent recharge; evidence
from Sr isotopes in sanidine phenocrysts, Taylor Creek Rhyolite,
NM. J Petrol 40:773–786
Langmuir CH (1989) Geochemical consequences of in situ crystallization.
Nature 340:199–205
Marsh BD (1996) Solidification fronts and magmatic evolution.
Mineral Mag 60:5-40
Marsh BD (2000) Magma chambers, In: Sigurdsson H (ed)
Encyclopedia of volcanoes, Academic Press, New York,
pp 191–206
McQuillin R, Tuson J (1963) Gravity measurements over the
Rhum Tertiary plutonic complex. Nature 199:1276–1277
Nakada S, Bacon CR, Gartner AE (1994) Origin of phenocrysts
and compositional diversity in pre-Mazama rhyodacite lavas,
Crater Lake, Oregon. J Petrol 35:127–162
Palacz ZA (1983) Isotopic evidence for the dynamic behaviour of
the Rhum magma chamber. Unpubl. PhD Thesis, University of
Leeds, 243 pp
Palacz ZA (1984) Isotopic and geochemical evidence for the evolution
of a cyclic unit in the Rhum Intrusion, northwest Scotland.
Nature 307:618–620
Palacz ZA, Tait SR (1985) Isotopic and geochemical investigations
of cyclic unit 10 from the Eastern Layered Series of the Rhum
intrusion. Geol Mag 122:485–490
Palacz ZA (1985) Sr–Nd–Pb isotopic evidence for crystal contamination
in the Rhum intrusion. Earth Planet Sci Lett 74:35–44
Philpotts AR, Shi J, Brustman C (1998) Role of plagioclase crystal
chains in the differentiation of partly crystallized basaltic
magma. Nature 395:343–346
Philpotts AR, Carroll M (1996) Physical properties of partly melted
tholeiitic basalt. Geology 24:1029–1032
Philpotts AR, Dickson LD (2000) The formation of plagioclase
chains during convective transfer in basaltic magma. Nature
Philpotts AR, Dickson LD (2002) Millimeter-scale modal layering
and the nature of the upper solidification zone in thick floodbasalt
flows and other sheets of magma. J Struct Geol 24:1171–
Pickles CS, Kelley SP, Reddy SM, Wheeler J (1997) Determination
of high spatial resolution argon isotope variations in metamorphic
biotites. Geochim Cosmochim Acta 61:3809–3833
Reddy SM, Kelley SP, Wheeler J (1996) A 40Ar/39Ar laser probe
study of micas from the Seisa zone, Italian Alps: Implications
for metamorphic and deformation histories. J Metamorph Geol
Renner R, Palacz Z (1987) Basaltic replenishment of the Rhum
magma chamber evidence from unit 14. J Geol Soc London
Sneeringer M, Hart S (1978) Sr diffusion in diopside, Eos Trans
Abstr Am Geophys Union 59:402
Tait SR (1985) Fluid dynamics and geochemical evolution of cyclic
unit 10. Rhum, Eastern Layered Series. Geol Mag 122:469–484
Tepley FJ III, Davidson JP, Clynne MA (1999) Magmatic interactions
as recorded in plagioclase phenocrysts of Chaos Crags,
Lassen Volcanic Center, California. J Petrol 40:787–806
Tepley FJ III, Davidson JP, Tilling RI, Arth JG (2000) Magma
mixing, recharge and eruption histories recorded in plagioclase
phenocrysts from El Chicho΄ n volcano, Mexico. J Petrol
Thirlwall MF, Jones NW (1983) Isotope geochemistry and contamination
mechanics of Tertiary lavas from Skye, northwest
Scotland. In: Hawkesworth CJ, Norry MJ (eds) Continental
basalts and mantle xenoliths, Shiva Publishing, Cheshire, UK,
pp 186–208
Thompson RN (1982) Magmatism of the British Tertiary Volcanic
Province. Scott J Geol 18:49–107
Upton BGJ, McKlurg J, Skovgaard AC, Kirstein L, Cheadle M,
Emeleus CH, Wadsworth WJ, FallickAE(2002) Picritic magmas
and the Rum ultramafic complex, Scotland. Geol Mag (in press)
Upton BGJ (1988) History of Tertiary igneous activity in the N
Atlantic borderlands. In: Morton AC, Parson LM (eds) Early
Tertiary volcanism and the opening of the NE Atlantic. Special
publication of the Geological Society, London 39, pp 429–454
Wadsworth WJ (1961) The layered ultrabasic rocks of southwest
Rhum. Inner Hebrides. Philos Trans R Soc Lond 244B:21–64
Waight TE, Maas R, Nicholls IA (2000) Fingerprinting feldspar
phenocrysts using crystal isotopic composition stratigraphy:
implications for crystal transfer and magma mingling in S-type
granites. Contrib Mineral Petrol 139:227–239
Wolff JA, Ramos FC, Davidson JP (1999) Sr isotope disequilibrium
during differentiation of the Bandelier Tuff: constraints on
the crystallization of a large rhyolitic magma chamber. Geology
Worrell LM (2002) The origin of igneous cumulates: integrated
studies of peridotites from the Western Layered Series of the
Rum layered intrusion. PhD Thesis, University of Liverpool,
UK, 275 pp
Young IM, Donaldson CH (1985) Formation of granular-textured
layers and laminae within the Rhum crystal pile. Geol Mag