Bacterial metabolism and the δ13C composition of ground water, Floridan aquifer system, South Carolina

Chapelle, Francis H.; Morris, James T.; McMahon, Peter B.; Zelibor, Joseph L.

doi:10.1130/0091-7613(1988)016<0117:bmatcc>2.3.co;2

Cited by 70 publications

(33 citation statements)

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“…'IWOsamples from the Middendorf Formation (McQueen Branch Aquifer) in a borehole near Aiken yielded C02 production rates of 9.5 x 105 and 6.4 x 104 mmol C02/1/yr using these assumptions. These values are approximately two orders of magnitude lower than C02 production rates estimated for the shallower aquifers near Hilton Head, South Carolina (Chapelle et al 1988), but are in the same range as other determinations made on sediment samples from South Carolina Coastal Plain sediments (McMahon et al 1990). …”

Section: Chapter 6-groundwater Qualitysupporting

confidence: 66%

SRS Geology/Hydrogeology Environmental Information Document

Denham¹

1999

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Section: Chapter 6-groundwater Qualitysupporting

confidence: 66%

SRS Geology/Hydrogeology Environmental Information Document

Denham¹

1999

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“…Field and laboratory studies have shown that compositional variations in the kaolins relate not so much to differences in source area and depositional environment as to location within the groundwater system and differing degrees of kaolinization and diagenesis, which most of the time relate to age. Variations in the lithology of the source area are detectable in studies of heavy minerals (Hurst 1952-54, unpublished) and trace elements (Dombrowski and Murray 1984;Dombrowski 1992Dombrowski , 1993, Information about the abundance of subsurface microorganisms in this region and the importance of microbial mediation in weathering reactions that produced the kaolins has become available mostly during the last decade (Chapelle et al 1988;Chapelle and Lovley 1990;Chapelle 1993;Ehrlich 1996).…”

Section: Synopsis Of New Evidence Bearing On Originmentioning

confidence: 99%

“…Mineralogical changes are possible by degradative changes in a solid, recrystallizational transformations sometimes called "diagenesis" and by mobilization and translocation of a colloidal phase. Changes in mineralogy tend to reflect the composition of the pore fluid because they are particularly responsive to the relative purity and rate of flow of incoming water and to microbial activity (Chapelle et al 1988;Chapelle and Lovley 1990;Chapelle 1993;Ehrlich 1996). Viable microbes are virtually ubiquitous in sediments.…”

Section: Compositional Changes During Kaolinizationmentioning

confidence: 99%

“…It drew support from several assumptions n o w k n o w n to be untenable and did not c o n s i d e r i m p o r t a n t factors like the r e g i o n a l groundwater system, the genetic relationship b e t w e e n associated kaolins and bauxites and the key role of microbially mediated reactions. These factors could not be recognized until sufficient petrologic and groundwater i n f o r m a t i o n had accumulated, developm e n t of electron microscopes enabled petrographic study of clays and research in m i c r o b i o l o g y revealed the high microbial populations and chemical reactions they mediate in Coastal Plain rocks (Chapelle et al 1988;Chapelle and Lovley 1990;Chapelle 1993;Ehrlich 1996).Detailed studies of chemistry, mineralogy and petrology b e g a n with the work of Jonas (1964) Detailed mineralogic and petrologic studies of the kaolins b e g a n in the 1960s and 1970s, w h e n electron microscopes b e c a m e generally available ( B o h o r and Randall 1971; A u s t i …”

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confidence: 99%

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Origin and Classification of Coastal Plain Kaolins, Southeastern USA, and the Role of Groundwater and Microbial Action

Hurst

1997

Clays and clay miner.

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Abstract--Along the inner Coastal Plain, kaolinite-metahalloysite-rich, neritic muds of Cretaceous-Eocene age have undergone intense postdepositional alteration in the recharge area of the regional groundwater system. Weathering processes have had the following profound effects on the original sediments: 1) strong compositional and textural modification of both clay and non-clay minerals; 2) whitening of the originally darker sediments by partial removal of organic matter, Fe and Mn; and 3) recrystallization of kaolinite and metahalloysite, most conspicuous where there are coarse stacks and vermiforms. Where the combination of initial sediment composition and alteration intensity was most favorable, these changes have produced important deposits of commercial quality, which now sustain the world's largest kaolin production district. The earliest change was partial sequestration of iron as sulfide and concurrent destruction of some organic matter, mediated by sulfate-reducing bacteria. Subsequent weathering resulted in gradual leaching of alkalies, alkaline earths, iron and silica, and attendant nucleation and growth of minerals compatible with the compositional changes. The existence of several closely spaced erosional unconformities, separated by neritic sediments, is proof that weathering conditions commonly changed at a given site, in response to changes in thickness or lithology of the overlying rocks. Dsyoxic ---) ~--oxic reversals modified both the rate and kind of alteration. ("Dysoxic" refers to molecular oxygen concentration too low to be toxic to anaerobes or cause abiotic oxidation; less extreme than "anoxic".) Kaolins were produced partly by slower dysoxic weathering in saturated groundwater zones but mainly by more rapid oxic weathering in unsaturated zones, where bauxites also locally formed. Gradual transformation of some sediments to kaolin rarely began and ended in the same epoch. At several places most of the kaolinization (see "Definitions") took place during Recent time, tens of millions of years after deposition of the sediments. Since the kaolins resulted from postdepositional alteration rather than sedimentary processes, they are better referred to as "Coastal Plain" rather than "sedimentary" kaolins.Key Words--Bauxite Origin, Kaolin Classification, Kaolin Origin, Microbial Weathering, Weathering. I N T R O D U C T I O NT h e early interpretation of a s e d i m e n t a r y origin for these kaolins was suggested by their m e g a s c o p i c features and geologic occurrence in sedimentary rocks (Ladd 1898;Veatch 1909;Smith 1929; L e G r a n d and Furcron 1956;Kesler 1963). It drew support from several assumptions n o w k n o w n to be untenable and did not c o n s i d e r i m p o r t a n t factors like the r e g i o n a l groundwater system, the genetic relationship b e t w e e n associated kaolins and bauxites and the key role of microbially mediated reactions. These factors could not be recognized until sufficient petrologic and groundwater i n f o r m a t i o n had accumulated, developm e...

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“…The study has shown that microorganisms are present at depth, and active than had been expected from the scientific literature, and thus an enhanced role might be expected for microorganisms that influence the groundwater chemistry (37,38) and the geological processes.…”

Section: Discussionmentioning

confidence: 88%