Formation And Occurrences Of Laumontite And Related Minerals In The Carolinas And Virginia, Middle Mesozoic Zeolite Facies Metamorphism Southern Appalachian Piedmont
Formation And Occurrences Of Laumontite And Related Minerals
In The Carolinas And Virginia, Middle Mesozoic Zeolite Facies
Metamorphism Southern Appalachian Piedmont
Donald R. Privett, P.G.
S.T.A. R. Environmental
1 Circle Street
Great Falls, SC 29055
A 175 -150 Ma hydrothermal zeolite grade metamorphic event altered most pre-Jurassic rocks in the southern
Appalachian Piedmont from south central Georgia to southern Virginia. Laumontite fills fractures and replaces
plagioclase in exposed and in drilled and cored subsurface rocks. A swarm of 200 Ma northwest/north striking
diabase dikes were injected and basalt flowed into into rift valleys during initial Atlantic rifting, followed by filling of
half grabens with immature clastic sediments. Fractures (joints and faults) served as conduits for calcium-saturated
warmed water that crystallized laumontite, prehnite, calcite and other zeolites. This period of zeolite grade thermal
alteration metamorphism is widespread.
Piedmont Neoproterozoic and Paleozoic igneous, metamorphic, and Triassic igneous and sedimentary
rocks of the Southern Appalachians were subjected to a period of zeolite grade thermal metamorphism about 175150 Ma evidenced by the widespread zeolite occurrences in older and younger intrusive and in older
metamorphosed host rocks mostly diorites and granites. Figure 1 is a tectonic map (Hatcher, et. al., 2007) showing
the area geologic structures.
Zeolite grade thermal metamorphism refers to the crystallization of fracture-filling and replacement zeolites
and prehnite in host rocks. The zeolite facies is considered to represent low grade (low temperatures and low
pressure) hydrothermal metamorphism to encompass all mineral, textural, and chemical changes resulting from hot
waters, steam or/and gas at lower T/P than greenschist facies metamorphism.
Laumontite and other zeolites have been the subject of theoretical considerations and experimental limit
determinations (Coombs, 1952) ( Thompson, 1971, Frost, 1980, Loui, 1971) plus detailed paragenesis studies
(Boles and Coombs, 1977 and Suranam, 1973). Still there is considerable disparity between theoretical and
experimental temperature and pressure limits, and the independently determined substantially lower temperatures
of natural formation. Complex ever-changing variables lower and inhibit formation.
Boles and Coombs (1977) summarized the parameters thought to control the temperature and pressures of
formation of zeolites. Experimentally determined temperatures are both higher and lower than values obtained
under natural conditions. Fluid pressure gradients, CO2 and H2O, activities of CO2, H20, ratio of water and CO2,
the permeability, nucleation and reaction kinetics, oxygen fugacity and presence of additional ions can alter the
temperatures of formation. Stability limits determined vary widely; Loui (1971) obtained upper limits of 230º – 325º
C at 0.5 kb, while Thompson (1971) obtained values of 250ºC at 2.75 kb. The lower limit is in even greater conflict
with natural occurrences. Loui (1971) obtained values of 150º - 200º C at 1 kb where p f = p t the lowest recorded
temperature of formation is 43º C (McCulloh, 1981) for laumontite that crystallized on rocks exposed at the Suspe
Hot Springs, California. Temperatures of 50º C for laumontite, 90º C for prehnite (Boles and Coombs, 1977) and
104º C (Castino and Sparks, 1974) have been estimated for laumontite in buried sedimentary rocks. Siki, (1969)
reported 75º + 5° C for laumontite formed in hot springs. Using calcite fluid inclusions Meghan, Robinson and
Delaney (1982) determined that laumontite filled amygdules in lava flows in Iceland formed at 140º - 200º C.
Zeolites occur in the geothermal areas of Iceland, (Kristmannedottir and Tomanson,1978), (Mehegan,
Robinson and Delaney, 1982) and New Zealand thermal areas (Barnes, 1977) and in metamorphic rocks of
California, (Madsen, and Murata, 1970).
Laumontite is present in the majority of rock exposed in the Piedmont region. Laumontite has been
identified from over 100 separate locations in North Carolina, South Carolina, Georgia and southern Virgina in
relatively unweathered outcrops and in rock exposed in foundations, trenches, quarries, mined caverns, and in
cores from borings for power plants and cuttings from water wells and exploratory test wells. Table 1 and Figure 2
shows the general geographic area of interest and earlier referenced laumontite occurrences. The geographic
distribution of additional laumontite in the Carolinas, Georgia and Virginia is shown in Table 2 and Figure 3.
Table 1 shows the previously reported occurrences. It occurs in gneisses of the Inner Piedmont;
metamorphosed and unmetamorphosed igneous rock and metasedimentary rocks of the Charlotte Belt (Privett,
1974a) and the Kings Mountain Belt; metavolcanic and metasedimentary rock of the Carolina Slate Belt and
Triassic - Jurassic sedimentary and igneous rocks.
The discovery of laumontite in the buried Triassic rocks and in cored basement below the Triassic of South
Carolina and south central Georgia suggest that laumonatization is even more extensive,because, laumontite fills
amygdules and replaces plagioclase in a 184 +/- 3 myo basalt from Dorchester county, S.C. (Gotten et.al.,1983)
and is present in Triassic sedimentary and older igneous rocks from South Central Georgia (Chowns and
Laumontite occurs as: (1) single pink and white euhedral crystals in druses and incompletely filled veins
where it crystallized on host rock, (prehnite, epidote and quartz ) (Figure 4), (2) veinlets of matted
interpenetrating crystal aggregates filling single and multiple narrow fractures and joints (Figure 5), and (3)
common replacement of plagioclase forming partial to complete "mosaic pseudomorphs" of laumontite after
plagioclase which are composed of minute laumontite crystals and albite (Figures 6 ). Laumontite is identified by
microscopic study, in diffuse plane light, laumontized plagioclase (Figure 7A and B) displays a mottled texture
(Figure 8 A and B), and polysynthetic twinning of plagioclase is destroyed; partly replaced plagioclase retains its
twinning, however, plagioclase develops a mottled texture.
Laumontite imparts a pinkish color to the altered and replaced plagioclase. This color change is a good indication
of, and appears to be directly proportional to, the intensity of laumontization. The sequence is shown by partly
replaced laumontite; calcite crytallized at the interior of the vein. Coarse grained microscopic crystals of laumontite
under crossed polars (Figure 9) display a somewhat wavy extinction. Rock cores (Figures 10 and 11) contain
replacement and fracture filling laumontite. Intenesly altered rocks are sometimes veined with laumonitite-calcite
(Figures 12 and 13) where calcite crystallized at lower T/P fills the interior of veins. Figures 14 and 15 show
fine grained replacement and fracture filling laumontite in outcrop and on an exposed weathered surface of
saprolite. Coarsly crystallized white laumontite (Figure 16) is occasionaly present on broken rock surfaces.
The x-ray reflections (Table 3) vary with the relative humidity; therefore, the material is best described as
laumontite-leonhardite. Laumontite readily dehydrates to leonhardite unless the sample is kept under conditions of
100% relative humidity. Partial re-hydration of leonardite to laumontite can be observed under the polarizing
microscope when placed in water.
Tectonic activity about 175 -150 my, in the Triassic and Jurassic consisted of the rifting and separation
following the breakup of Pangea and susequent seperation of Laurasia. This tectonism fractured old weaker
shears, forming new joints and faults. Siliceous cataclasite and quartz mylonites formed in the stressed rocks.
Immature clastics were deposited in subsiding half grabens with later basaltic flows, injection of diabase dikes and
basaltic to diabase sills. Basalt flows present in Triassic sedimentary rock heated circulating groundwaters which
probably mixed with hydrothermal fluids to react with plagioclase forming prehnite and laumontite. The excessive
calcium reacted with silica to produce the fracture filling laumontite and calcite with even lower temperatures other
zeolites crystalllized. Two generations of diabase dikes are evident; suggesting that igneous activity persisted as
stress changed. (Ragland, Hatcher and Whittington, D., 1983 ) As temperatures subsided, other zeolites
crystallized( heulandite and stilbite). This period of zeolite grade thermal alteration metamorphism is widespread in
rocks of the southern Appalachians especially Charlotte Terrane.
I thank Dr. Robert D. Hatcher, Jr.,UT Distinguished Scientist and Professor of Geology, Department of Geological
Sciences, University of Tennessee Knoxville, Tennessee for his insightful and complete review of my manuscript
and preparation of Figures 1, 2 and 3. Phoebe Hoffman kindly directed me to correct context errors, thank you.
Table I SUMMARY OF PREVIOUSLY REPORTED LAUMONTITE OCCURRENCES
Near Durham, NC
FF R D
and crystal tuffs
Foote mine Cleveland Spodumene pegmatites and
Nello Teer Quarry,
Near Great Falls,
Western Rowan Co.,NC Diorite intruded by 300 ma.
Southern Fairfield Co.,
Near Apex, Wake Co.,
Eastern Cherokee Co.,
Eastern Fairfield Co.,
Near Tirzah North
Central York Co.,SC
almandine amphibolite ? (no
Probe) and granodiorite
Diabase dikes and Triassic
Rhyolites and felsic gneiss
Other Secondary Minerals References
prehnite and about 80
Granite and hornblende
gneiss and 300 m.y. adamellite
Metadiorite, diorite, mafic dikes x
and Triassic diabase dikes
North Central York Co., metamorphosed mafic dikes x
Center off US 58
Hylas zone - central
6 km. south of V.C.
Summer N. P.
Dorchester Co, SC
South central Georgia
Granite, gneiss, hornblende
Sheared gneiss, schist and
early Jurassic basalt
diabase, sandstone and felsic x
barite and saponite
epidote, calcite chlorite Law Engineering,
calcite, epidote, chlorite,
Keystone Blue quarry, Elberton fine-grained biotite
northeastern Georgia granite cut by dikes of
pegmatitic granite and diabase.
prehnite, calcite epidote, Privett, I973b
chabazite heulandite flourite
Gas and Electric,
Bobyarchick and Glover,
Old Pineville Quarry,
York Co. SC
Iredell Co., NC between schist
I- 40 and US 64/70.
Brevard Zone near
amphibolite grade gneiss and x
Atlanta Chattahochee schist crosscuts regional
Tunnel, Cobb County, foliation.
chabazite and the
radiating zeolite ?
0.1 to 1.0 mm, well
calcite prehnite epidote
calcite and (2).orange
staining of albite and
replacement of biotite by
Fluorite-chloritepyrite-quartz, and calcite
Chones and Williams,
Burnley, P.C. , et.al.,
Bulger, Dan, et.al., 2008
*FF = Fracture filling R=Replacement D= Druse
Table 2. Summary of Additional Laumontite Occurrences
Other Zeolites and
McGuire Nuclear Sta. and Cowans Ford Dam
Foundation borings northwestern Mecklenburg and
Lincoln Co., NC, Duke Power core repository.
hornblende schist cut by
Augen granite gneiss and
biotite gneiss and porphyry
Metagranite and mafic dikes
Pineville Quarry southern Mecklenburg Co., NC off
Hwy. 51 rock core. Duke Power core repository.
Boring, N.E. Gaston Co. NC .2 mi. east of US 16 on
the Catawba River (Riverbend) Duke Power core
Arrowood Quarry 0.4 mi; east I-77 Mecklenburg Co.
NC, Duke Power core repository
Hyco Reservoir, Person Co. NC (road below dam)
Whitnel Quarry near Lenior, Caldwell Co., NC
Hickory Quarry 0.5 mi. north US 321, 0.8 mi. East
County Road 1536, Catawba Co. NC
Quarry off SC 901, northeastern Fairfield Co.
Borrow Pit off SC 72, S.W. Chester Co. SC also in
roadcuts for new bridge 2007.
Borings North Cabarrus, Northeastern Rowan,
Davidson, Davie, Guilford, Stokes and Alamance
counties,NC 52 occurrences, Duke Power core
South Boston, VA.
Boring Rock Hill Printing, White St. Rock Hill, SC,
Duke Power core repository.
Apt. Complex off SC 161,Rock Hill, SC.
Great Falls, SC, Chester County Rd. borrow pit.
North Quarry, west of Winston-Salem, Forsythe
Stokesdale Quarry 1 mile west NC 158 Guilford
Jamestown Quarry, off County road 1147, 1.5
miles east of I-85. Guilford Co. NC.
Lexington Quarry off county Road 1646, 0.7 mi.
east US 52 Davidson Co. NC.
Granite, diorite sheared
hornblende gneiss cut by
Foliated granite to
cut by mafic dikes
Hornblende gneiss and
Albite granite - (300 m.y.)
27 separate borings[
Churchland pluton-Davie and
Davidson Counties, NC Duke Power core
Boring Marshall Steam Station off Hwy. 150
eastern Catawba Co. NC, Duke Power core
Smith Grove Quarry, Davie Co. NC
Central Rock Products Quarry, east 421. central
Guilford Co. NC
Pomona Quarry south 1-40 at end of Co. Road
Chlorite schist and granite
Inactive quarry, Kings Creek, western York, Co.,
4 borings near Kings Creek eastern Cherokee
Co. , SC (across creek from above), Duke Power
*FF = Fracture filling R=Replacement D= Druse
X-Ray Diffraction Powder Data laumontite-leonhardite
9.46 100 9.44
4.16 100 4.15
Euhedral white crystal on diorite. Woodleaf (luarry. Rowan County
Pink asicular crystals, Lexin 9ton Quarry, Davidson County, North Carolina
Laumontite, pink asicular crystals from -790 feet in well drilled in East Spencer,
Rowan County, NC, Isenhour Brick and Tile Company.
Leonhardite. Madsen and Murata, 1970, p. 193
Laumontite, LIou, 1971, p. 386.
after Liou, 1971, p. 386.
Barnes, Ivan, 1977, Warm Springs, South Island, New Zealand, and their potentials to yield laumonite: abs. : G.S.A.
Abstracts with Programs, vol. 9, no. 2, p. 116.
Bobyarchick, A R. and Glover, I., III, 1979, Deformation and metamorphism in the Hylas Zone and adjacent parts of
the eastern Piedmont in Virginia: G.S.A. Bull., vol. 90, p 739-752.
Boles JR and Coombs DS, 1977, Zeolite facies alteration of sandstones in the Southland Syncline, New Zealand:
Am J Sci v. 277, pp. 982–1012.
Bulger, D. Wehby, Jennifer, Freeman, et. al., 2008, Mineralogy of zeolites from the Keystone Blue Quarry, Elberton
Batholith, northeast Georgia, Southeastern section GSA, p
Burnley, P.C. Raymer, J, and Terrell, J. R.., 2008, Characterization of veins and associated alteration observed in
the Chattahochee Tunnel, Cobb County, Ga , GSA, Abstracts, p. .
Butler, J. R., 1976, Geology of the propane storage near Tirzah central York County, South Carolina SC. Devel.
Board, Division of Geology, Geologic Votes, v. 20, n. 1. p. 26-32.
Butler,J.R.,1983, Geologic History of the Charlotte Belt at the Old Pineville Quarry Northeastern York County
SC: SC Geologic Notes, vol. 27, p. 13-24.
Castano, J. P. and Sparks, D. M., 1977, Interpretation of vitrinite reflectance measurements in sedimentary rocks
and determination of burial history using vitrinite reflectance and authigenic minerals: G.S.A., Spec. Pap. 153, p. 3152.
Chowns, T. M. and Williams, C. T., 1983, Pre-Creteceous rocks beneath the Georgia Coastal Plain-Regional
implications, in Gohn, G.S., ed., Studies related to the Charleston. South Carolina, earthquake of 1886- Tectonics
and Seismicity: U.S. Geological Survey Professional Paper, 1313, p. L1-L42.
Coombs, D., 1952, Cell size, optical properties, and chemical composition of laumontite and leonhardite: Amer.
Mineral., 37, p. 822-830
Daniels, D. L., Ziet, Isadore, and Popenoc, Peter, 1983, Distribution of subsurface lower Mesozoic rocks in the
Southeastern United States as interpreted from regional areomagmatic and gravity maps, in Gohn, G.S., ed., studies
related to the Charleston, South Carolina earthquake of 1886- Tectonics and seismicity. Geological Survey
Professional Paper 1313, p. Kl-K24.
DeBoer J., 2, 1983, Magnetic and paleomagnetic evidence bearing on hot spot models for Mesozoic magnetism:
GSA, Abstracts with Programs, v. 15, p. 91
DeBoer, J, and Snider, F. G., 1979, Magnetic and chemical variations of Mesozoic diabase dikes from eastern North
America: Evidence for a hot spot in the Carolina's: G.S.A. Bull., v. 90, p. 185-198.
Frost, B. R. ,1980, Observations on the boundary between zeolite facies and prehnite-pumpellyite facies,
Contributions. Mineral. Petrology, v. 73, p-365-373.
Furbish, W. J.,1965, Laumontite-leonhardite from Durham County. N.C., Southeastern Geology, v. 6, p. 189-200.
Gottfried, D., Annell, C. S., and Byerly, G. R., 1983, Geochemistry and tectonic significance of subsurface basalts
near Charleston, South Carolina – Clubhouse Crossroads test holes #2 and #3, Chapter D of Gohn, G. S., ed.,
Studies related to the Charleston, South Carolina,earthquake of 1886 – Tectonics and seismicity: U.S. Geological
Survey Professional Paper 1313-D, 17 p.
Hatcher, R. D., Bream,, B. R. and Merschat.,A. J. 2007, Tectonic map of the southern and central Appalachians: a
tale of three orogens and a complete Wilson Cycle: Memoirs-Geological Society of America 200: p. 595.
Kristmannedottir, H. and Tomanson, J.,1978, Zeolite zones in geothermal areas in Iceland, natural zeolites
occurrences, properties, use: edited by L. B. Sand and F. M. Mumpton, Pergamon, New York, 546 pp.
Law Engineering. 1975, Geology of the Wateree Nuclear Site, interim report to Duke Power.
Liou, J. G. 1971a, P-T stabilities of laumonite-wairakite, lawsonite and related minerals in the system of CaAl2 SiO2H2O: J. Petrology, v. 12, p. 379-411.
Loui, J, G., 1971b, Synthesis and stability relations of prehnite, Ca2Al2Si3010(OH)2: Am. Mineral. V. 56, p. 507-531.
Madsen, P. M. and Murata, K.J.., 1970, Occurrence of laumontite is Tertiary sandstones of the Central Coast
Ranges, California.. US Geol. Surv. Prof. Pap. 7OO-D, D188--D195.
McCulloh. T. H., Frizzell, V. A., Jr., Stewart, R. J., and Barnes, I.,1981, Precipitation of laumontite with quartz,
thenardite, and gypsum at Sespe Hot Springs, western Transverse Ranges, California.. Clays and Clay Minerals, v.
29, p. 353-364.
Mehegan, J. M., Robinson, P. T. and Delaney, J.R.., 1982, Secondary mineralization and hydrothermal alteration in
the Reydarfjordur drill core, eastern Iceland, J. Geophys. Res., v. 87, p. 6511-6524.
Goldsmith, Richard, Milton, Daniel J., and Horton, Jr., 1988, Geologic Map of the Charlotte 1 x 2 Quadrangle,
North Carolina and South Carolina: U.S. Geological Survey Miscellaneous Investigations Series, Map I-1251-E,
Miyashiro, A and Shido, F., 1970, Progressive metamorphism in zeolite assemblages: Lithos v. 31, p.251-260.
Privett, D. R., 1973a, Laumontization near the northern margin of the Liberty Hill batholith, southern Chester County,
South Carolina: South Carolina Geological Survey. Geologic Notes, v. 17, no. 3, p 49-54..
Privett, D.R., 1973b, Paragenesis of an unusual hydrothermal zeolite assemblage in a diorite-granite contact zone,
Woodleaf, Rowan County, North Carolina: Southeastern Geology, v. 15, no. 2, p. 105-118.
Privett, D. R., 1974a, widespread laumontization in the central Piedmont of North Carolina and southern Virginia
(abs. J, Geological Survey of America Abstracts with Programs, v. 6, no. 4,p. 389-390.
Privett, D. R., 1974b, Laumontization in the Kings Mountain belt rocks, Cherokee county, S. C.: Geologic Notes,S. C.
Dev. Bd., Div of Geology, v. 18, p. 31 - 35.
Privett, D. R., 1977a, Widespread zeolitization in the central Charlotte Belt, north-central York county, South Carolina
(abs.): Geological Society of America Abstracts with Programs, v. 9, no 2, p. 176.
Privett, D R., 1977b, An unusual octahedral flourite, stilbite, laumontite, calcite and quartz assemblage in Danville.
Virginia. Va. Minerals, v. 23, p. 7-9.
Ragand, P.C,, 1977, The use of zeolites to determine the age of last motion on a fault: a case history (abs.): Geol.
Soc. Amer. Abstracts with Program. V. 9, P- 176-177.
Ragland, P.C., Hatcher, R.D., Jr., and Whittington, D., 1983, Juxtaposed Mesozoic diabase dike sets from the
Carolinas: A preliminary assessment: Geology, v.
11, p. 394–399.
Seki, Y., 1969, Facies series in low-grade metamorphism: Geol. Soc. Japan. v. 75; p. 255-66.
Secor, D. T.,Jr., Peck, L. S., Pitcher, D. M., Prowell, D. C., Simpson, D. H., Smith, W A. and Snoke. A. W., 1982,
Geology of the area of induced seismic activity at Monticello reservoir, South Carolina: Jour. Geophysics. Res., v. 87,
S.C.E. and G. Company,1977, Virgil C. Summer Nuclear station, Final Safety Analysis Report, 1977, v. 2, Columbia,
Surdam, R. C., 1973, Low- grade metamorphism of tuffaceous rocks in the Karmutsen Group, Vancouver Island,
British Columbia, Geol. Soc. Am. Bull.v. 84, p. 1911-1922.
Thompson, A, B., 1970, Laumontite equilibria and the zeolite facies, Am. Jr. Sci.,v.269, p. 267-275.
Thompson, A. B., 1971, P C02 in low-grade metamorphism; zeolite. carbonate, clay mineral, prehnite relations in the
system CaO-Al203-Si02-C02-H20: Contrib. Mineral. Petrology. 33: p.145-161.
White, J. S., Jr,, 1969, A lithiophosphate occurrence in North Carolina: Am. Mineral, v- 54, p. 1467-1469.
Zen, E. and Thompson, A. B., 1974, Low-grade regional metamorphism: mineral equilibrium relations; Annual Rev.
of Earth and planetary Sci., v. 2, p. 179-212.
Figure 1. Geologic Provinces SC, NC, Va., and Ga. Hatcher, Tectonic index map, 2007.
Figure 4. Carse-grained white laumontite on fracture in diorite, Woodleaf Quarry, Rowan County, NC.
Figure 5. Brecciated diorite with vein filled by white calcite and pink laumontite.
Lexington Quarry, Davidson County, NC
Figure 6A and B “Pseudomorph” of laumontite after plagioclase, displaying the typical mottled mosaic
texture seen in plane light.
Figure 7 Texture of partly laumonitized plagioclase in quartz monzonite, mottled texture, center unaltered. Plane light.
Lexington Quarry, Davidson County, NC
Figure 8 A and B. Texture of partly laumontized plagioclase in quartz monzonite, Lexington Quarry Davidson County,
NC. The plagioclase crystal in the center bottom still retains twinning while twinning is nearly destroyed in the
more completely altered crystal at the right. A. plane light. B. crossed polars
Figure 9. Coarse grained laumontite crystals crossed polars. Lexington Quarry, Davidson County, NC
Figure 10.. Coarse Laumontite - calcite. Small calcite crystals at margins. Crossed polars.
Figure 11. Pink fracture filling – replacement laumontite in core. Churchland Granite. Davie Co, NC. Duke Energy
Figure 12. Rock core containing fracture filling veinlets of acicular laumontite. Duke Energy core.
Cherokee County, SC.
Figure 13. Intensely altered rock, with fracture filling laumontite-calcite, crossed polars.
Figure 14. Fracture filling laumontite veinlets,crossed polars scale 1 cm 0.5 mm. Lexington Quarry, Davidson
Figure 15. Intensely altered metadiorite? With replacement and fracture filling laumontite - leonhardite.
Compass left bottom scale.
Figure 16. Coarse grained white laumontite, Cherokee County, SC Cherokee Nuclear Site. .
Duke Energy 1 cm equals 1 cm.