A genetic link between remagnetization and potassic metasomatism in the Devonian Onondaga Formation, Northern Appalachian Basin

Lu, Gang; McCabe, Chad; Hanor, Jeffrey S.; Ferrell, Ray E.

doi:10.1029/91gl02665

Cited by 33 publications

(14 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, the origin of these CRMs is still debated. Evoked mechanisms are early diagenesis [ Roberts and Weaver , 2005; Rowan and Roberts , 2005], geochemical degradation along methane horizons [ Larrasoaña et al , 2007], smectite‐to‐illite transformation [ Lu et al , 1990, 1991; Katz et al , 2000], pyrite alteration [ Brothers et al , 1996; Gillett , 2003], fluid circulation [ Oliver , 1986; Katz et al , 1998; Evans et al , 2000; Elmore et al , 2001], deformation [ Lewchuk et al , 2003], and the maturation of organic matter [ Banerjee et al , 1997]. Laboratory heating experiments from 95 to 250°C on claystones [ Cairanne et al , 2004; Moreau et al , 2005, Aubourg et al , 2008; Aubourg and Pozzi , 2010; Aubourg et al , 2012] have demonstrated that temperature alone leads to the rapid formation of minute amounts of magnetic minerals.…”

Section: Introductionmentioning

confidence: 99%

Continuous production of nanosized magnetite through low grade burial

Kars

Aubourg

Pozzi

et al. 2012

Geochem Geophys Geosyst

View full text Add to dashboard Cite

[1] Geological processes, such as burial, can lead to remagnetization in rocks due to neoformed magnetic minerals that have passed a critical volume, called blocking volume. In this study, we designed a heating experiment for claystones obtained from the Paris Basin (France), in the 50-130 C temperature range, in order to simulate <4 km burial remagnetization. At a given temperature, remanence increased rapidly within a couple of days and stabilized afterward. There was a positive relation between the experimental temperature and the obtained remanence. Remanence was determined to be carried equally by stable chemical remanent magnetization and unstable thermo-viscous remanent magnetization. By assuming that magnetite formed during the experiment, we interpreted the increase of chemical remanent magnetization and the increase of thermo-viscous remanent magnetization as the continuous growth of the >20 nm and $20 nm minerals respectively. This result led us to propose a conceptual model of nucleation-and-growth process of magnetite during low grade burial from $2 to $4 km depth. Ultrafine magnetite (≤20 nm) was predominant over single domain magnetite (>20 nm) for <4 km depth. Transposed to natural conditions, our heating steps experiment suggested that claystone-type rocks are remagnetized during burial. For temperatures higher than 200 C, the extrapolation of our results indicated that burial remagnetization, due to the chemical remanent magnetization, might be larger than the natural remanent magnetization.

show abstract

Section: Introductionmentioning

confidence: 99%

Continuous production of nanosized magnetite through low grade burial

Kars

Aubourg

Pozzi

et al. 2012

Geochem Geophys Geosyst

View full text Add to dashboard Cite

show abstract

“…Migration of orogenic fluids has also been proposed as an explanation for some regional trends in magnetite authigenesis (e.g. Jackson et al 1988;Lu et al 1991;Saffer & McCabe 1992). Syntilting CRMs have been related to alteration caused by fluids activated during deformation (e.g.…”

Section: Orogenic Fluidsmentioning

confidence: 99%

“…Lu et al 1991;Hirt et al 1993;Katz et al 1998Katz et al , 2000Gill et al 2002;Woods et al 2002;Zegers et al 2003;Blumstein et al 2004;Moreau et al 2005;Tohver et al 2008). Many of these studies incorporated presence/absence tests (e.g.…”

Section: Smectite To Illitementioning

confidence: 99%

Remagnetization and chemical alteration of sedimentary rocks

Elmore

Muxworthy

Aldana

2012

View full text Add to dashboard Cite

Chemical remagnetization is a very common phenomenon in sedimentary rocks and developing a greater understanding of the mechanisms has several benefits. Acquisition of a secondary magnetization is usually tangible evidence of a diagenetic event that can be dated by isolation of the chemical remanent magnetization and comparison of the pole position to the apparent polar wander path. This can be important because diagenetic investigations are frequently limited by the difficulty in constraining the time frames in which most past events have occurred. Remagnetization can commonly obscure a primary magnetization; developing a better understanding of remagnetization could improve our ability to uncover primary magnetizations. Many chemical remagnetization mechanisms have been proposed, including those associated with chemical alteration by a number of different fluids (orogenic, basinal and hydrocarbons), burial diagenetic processes (clay diagenesis and maturation of organic matter) or other processes. This paper summarizes our current knowledge of these chemical remagnetization mechanisms, with a focus on examples where there is a connection with chemical alteration.

show abstract

“…In this study, the trend of increasing intensity of NRM (reflecting the magnetite content) with increasing total organic content from top to bottom in the Longmaxi Shale (Figure a) [ Lu et al , ; Fruit et al , ; Manning and Elmore , ] is inferred to indicate a link between remagnetization and the maturation of organic matter. Generally, black shale that contains clay minerals and organic matter should produce water through dehydration of the clays, organic acids, and/or hydrocarbons by maturation of organic matter when the rock is heated to around 150°C [ Powell et al ., ; Barth and Bjorlykke , ; Moreau et al , ].…”

Section: Discussionmentioning

confidence: 60%

“…One of the reasons is that extraordinary pervasive remagnetization has occurred in these units [e.g., Kent et al , ; Dobson and Heller , ; Wang and Van Der Voo , ]. Indeed, such pervasive remagnetizations can obscure or remove the primary magnetization; however, remagnetization, especially chemical remanent magnetization (CRM), can also provide information on the processes of burial diagenesis, including the thermal maturation of organic matter and smectite‐to‐illite conversion [e.g., Lu et al , ; Woods et al , ; Zegers et al , ; Blumstein et al , ; Moreau et al , ; Manning and Elmore , ], and information on alteration events triggered by orogenic fluids, mineralizing fluids, migrated hydrocarbons, or weathering‐related fluids [e.g., Kilgore and Elmore , ; McCabe and Elmore , ; Elmore et al , , and references therein]. Presently, remagnetization data from south China, however, have rarely been applied in this way, and even the origin of the pervasive remagnetizations is still not fully understood.…”

Section: Introductionmentioning

confidence: 99%

Remagnetization of lower Silurian black shale and insights into shale gas in the Sichuan Basin, south China

et al. 2016

View full text Add to dashboard Cite

The organic‐rich lower Silurian shale of the Longmaxi Formation in the Sichuan Basin is the most important target for shale‐gas exploration in China. Most Paleozoic rocks of the Sichuan Basin have experienced extraordinarily pervasive remagnetizations. To test a hypothesized connection between hydrocarbon generation and remagnetization and contribute to shale‐gas exploration in the region, we undertook an integrated magnetic, geochemical, and petrographic study of 160 specimens from the shale. The results suggest that the shale contains a reliable remanent magnetization (Dec = 41.4°, Inc = 40.8°, and α95 = 6.8°). The magnetization predates tilting, and the paleopole plots close to the Late Triassic segment of the south China apparent polar wander path. The rock magnetic data and scanning electron microscope (SEM) observations confirm that framboidal magnetites carry the bulk of the magnetization, which suggest a Late Triassic chemical remanent magnetization in the shale. 87Sr/86Sr and magnetic analyses indicate that the amount of magnetite was unaffected by fluid alterations around the veins but is strongly covariant with the amount of total organic matter. Moreover, SEM observations reveal possible evidence of the replacement of pyrite framboids by magnetite, probably in the presence of organic acids. These analyses, therefore, suggest that the remagnetization was caused by organic maturation rather than orogenic fluids and that the maturation occurred in the Late Triassic. This timing of organic maturation has been validated by independent modeling studies and provides important constraints on the complex thermal history of the Longmaxi Shale as well as contributing to shale‐gas exploration efforts.

show abstract

A genetic link between remagnetization and potassic metasomatism in the Devonian Onondaga Formation, Northern Appalachian Basin

Cited by 33 publications

References 17 publications

Continuous production of nanosized magnetite through low grade burial

Continuous production of nanosized magnetite through low grade burial

Remagnetization and chemical alteration of sedimentary rocks

Remagnetization of lower Silurian black shale and insights into shale gas in the Sichuan Basin, south China

Contact Info

Product

Resources

About