Mg, Sr and Na fluctuations in the test of modern and recent Globigerina bulloides

Puechmaille, C.

doi:10.1016/0009-2541(94)90163-5

Cited by 11 publications

(8 citation statements)

References 7 publications

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“…For SIMS, the relatively large standard deviations shown arise from true compositional variance among the multiple spots analyzed. Such intratest variability can currently only be examined accurately using high‐resolution techniques such as SIMS (this study), laser ablation ICP‐MS [e.g., Hathorne et al , 2003] or electron microprobe [ Puechmaille , 1994; Brown and Elderfield , 1996]. This variance is averaged out in ICP‐MS measurements of multiple (or single) individuals.…”

Section: Resultsmentioning

confidence: 99%

Application of secondary ion mass spectrometry to the determination of Mg/Ca in rare, delicate, or altered planktonic foraminifera: Examples from the Holocene, Paleogene, and Cretaceous

Bice

Layne

Dahl

2005

Geochem Geophys Geosyst

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[1] Secondary ion mass spectrometry (SIMS) is useful for measuring Mg/Ca in both primary calcite and diagenetic minerals in planktonic foraminifera. The excellent spatial resolution (<10 mm) and small amount of material removed (<2 ng) makes it easy to avoid targets that include obvious embedding material and encrusting or infilling minerals such as secondary calcite and authigenic clays in diagenetically altered samples. Because analyses can be performed on individuals, SIMS is also a viable technique for generating Mg/Ca values from sediment samples in which foraminifera are rare or have low mass. For clean primary calcite samples, Mg/Ca ratios from SIMS compare well to those obtained using inductively coupled plasma mass spectrometry (ICP-MS), while maintaining information regarding the true variability of elemental ratios within individual tests. For samples with secondary calcite or stubbornly adhering clays, SIMS enables us to accurately measure primary calcite compositions and to assess and reconcile contamination problems in bulk samples analyzed by solution-based ICP-MS. We have observed that SIMS is an invaluable and reliable tool for the identification and avoidance of problems of diagenesis and the analysis of rare or delicate planktonic foraminifera. However, because of operator time required to properly target delicate (thin-walled) or contaminated planktonic foraminifera, SIMS may not be feasible for Mg/Ca studies where large numbers (hundreds) of samples must be processed and bulk measurements on multiple individuals will suffice.

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Section: Resultsmentioning

confidence: 99%

Application of secondary ion mass spectrometry to the determination of Mg/Ca in rare, delicate, or altered planktonic foraminifera: Examples from the Holocene, Paleogene, and Cretaceous

Bice

Layne

Dahl

2005

Geochem Geophys Geosyst

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“…This study builds upon a large number of earlier microanalytical studies, mostly using the electron microprobe, and which are notable for almost exclusively having employed point analysis strategies. These studies have established that the outer (gametogenic) calcite crust precipitated by many planktonic species typically has a lower Mg/Ca composition (by up to a factor of 3) than the inner (ontogenetic) layers of the test [ Duckworth , 1977; Lohmann and Rosenthal , 1993; Puechmaille , 1994; Brown and Elderfield , 1996; Elderfield and Ganssen , 2000; Jha and Elderfield , 2000; Hathorne et al , 2003], although this finding has been contradicted by the reported increase of Mg concentration (by up to 230%) in gametogenic calcite that was precipitated by Globigerinoides sacculifer under controlled temperature laboratory experiments [ Nürnberg et al , 1996]. These observations have been augmented recently by studies employing techniques such as PIXE [ Gehlen et al , 2004], SIMS [ Allison and Austin , 2003], and particularly laser ablation ICPMS [e.g., Eggins et al , 2003, 2004; Hathorne et al , 2003].…”

Section: Introductionmentioning

confidence: 99%

Characterization of Mg/Ca distributions in planktonic foraminifera species by electron microprobe mapping

Sadekov

Eggins

Deckker

2005

Geochem Geophys Geosyst

160

178

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[1] The distribution of Mg/Ca within the tests of eight modern planktonic foraminifer species has been characterized using electron microprobe mapping. Species include several that are commonly used for estimation of past seawater temperatures (Globigerinoides ruber, G. sacculifer, Neogloboquadrina incompta (synonym of N. pachyderma dex.), N. dutertrei, and G. truncatulinoides). Each of the investigated species displays large variations in Mg/Ca composition within individual tests. However, the pattern of Mg/Ca variation is notably different between symbiont-bearing and symbiont-free species. In symbiotic species, cyclic Mg/Ca compositional banding occurs that is characterized by narrow (<1-3 mm), high-Mg/Ca (typically 8-11 mmol/mol) bands, intercalated between broader low Mg/Ca (typically 1-5 mmol/mol) bands. This factor of 2-3 difference equates to an apparent calcification temperature change of 10°C or more. Such temperature changes are considered highly improbable and suggest vital effects significantly modify the incorporation of Mg/Ca into the tests of symbiont-bearing species. These vital effects remain poorly understood and demand further careful evaluation as they may need to be accounted for when making reliable reconstructions of past oceanic temperatures. Symbiont-free species typically have fewer and broader compositional bands that may reflect more closely changes in calcification temperature as these species migrate within a water column.Components: 7725 words, 6 figures.

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“…The marls of the Dahr el Baidar Member and the Hammana Fm exhibit the highest Ti contents (1.37 and 0.54 wt% TiO 2 , respectively). Other than dolomitization, relatively higher Mg contents have been related also to the presence of some clay minerals and organic matter, as well as microfossils in some Mg-rich carbonate units (Gill 1995;Puechmaille 1994). The relatively higher Mg concentrations in the Hammana marl compared to those of the Dahr el Baidar marl can be explained by the relative abundance of both dolomite and organic matter in the Hammana Fm.…”

Section: Major Elementsmentioning

confidence: 95%

“…The moderate to high contents of Na in the lower strata of the Chekka Fm (C 6 ) may also be related to the common presence of foraminifera in this mostly chalky unit; modern forams incorporate elements such as Mg, Sr and Na depending on climatic conditions (e.g. Puechmaille 1994). The typical marl of the Chekka Fm (C 6 ) exhibits a relatively moderate to high Na content (0.18 wt% Na 2 O), which is consistent with a deep marine depositional environment (Walley 1997).…”

Section: Major Elementsmentioning

confidence: 99%

Characterization of the Lebanese Jurassic–Cretaceous carbonate stratigraphic sequence: a geochemical approach

Abdel-Rahman

Nader

2002

Geological Journal

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The Lebanese crustal segment is part of a much larger carbonate platform deposited along the northwestern margin of the Arabian Plate, in the eastern Mediterranean region. It is made up mainly of Jurassic–Cretaceous carbonate rocks. Most of this stratigraphic sequence is exposed in the Nahr Ibrahim canyon and surrounding areas in central Lebanon. The various formations, from the oldest unit (the Lower Jurassic Kesrouane Formation) to the Upper Cretaceous Chekka Formation, are made up of different types of carbonate rocks including micritic limestone, medium‐ to coarse‐grained dolostone, biomicritic (chalk), biosparrudite limestone, micritic dolostone, pelmicrite, marl and marly limestone.Results of this first chemical investigation on the Lebanese carbonate platform show that the micritic limestone of the Kesrouane Formation is relatively enriched in Ca, Na and Sc, and has low rare‐earth element (REE) contents. The marl units of the Hammana Formation are enriched in Al, Fe, K, Ti, Rb, Ga, Nb, U, Th and REE. The chalk of the Chekka Formation shows the highest phosphorus content. A significant increase in P and Sr contents with time (from the Lower Jurassic to the Upper Cretaceous carbonate units) characterizes the Lebanese sequence; this is interpreted to be related to a possible increase in continental weathering rates during the Mesozoic. Enrichment in Ni, Ti and Nb in some formations is interpreted to be linked to Mesozoic volcanism in central Lebanon. The Cretaceous formations are subdivided according to their REE patterns into two distinct groups: limestones (Mdairej, Sannine and Maameltain formations) which are depleted in REE; and marl/chalk (Hammana and Chekka formations) which are significantly enriched in REE. On several geochemical variation diagrams, such as the K–Ti–P triangular plot, the Lebanese Mesozoic carbonate formations are found to occupy distinct compositional fields. Thus, carbonate geochemistry could prove to be a powerful tool (especially when combined with petrographic data) in characterizing and correlating carbonate formations (chemical stratigraphy), particularly in regions where field evidence may be limited. Results of this study have significant implications for the entire carbonate platform that covers a large part of the eastern Mediterranean region. Copyright © 2002 John Wiley & Sons, Ltd.

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Mg, Sr and Na fluctuations in the test of modern and recent Globigerina bulloides

Cited by 11 publications

References 7 publications

Application of secondary ion mass spectrometry to the determination of Mg/Ca in rare, delicate, or altered planktonic foraminifera: Examples from the Holocene, Paleogene, and Cretaceous

Application of secondary ion mass spectrometry to the determination of Mg/Ca in rare, delicate, or altered planktonic foraminifera: Examples from the Holocene, Paleogene, and Cretaceous

Characterization of Mg/Ca distributions in planktonic foraminifera species by electron microprobe mapping

Characterization of the Lebanese Jurassic–Cretaceous carbonate stratigraphic sequence: a geochemical approach

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