Age and Origin of Silicocarbonate Pegmatites of the Adirondack Region

Chiarenzelli, Jeffrey R.; Lupulescu, Marian; Robinson, Grace; Bailey, David G.; Singer, Jared W.

doi:10.3390/min9090508

Cited by 6 publications

(15 citation statements)

References 40 publications

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“…The Silver Crater Mine is located in southern Ontario, Canada in the Grenville geologic province (Figure 1). This region was extensively deformed during the Grenville orogenic cycle and is associated with the assembly of the supercontinent of Rodinia [11,12]. Intrusive complexes associated with this orogenic cycle comprise anorthosites, granitic pegmatites, syenites, carbonatites, and others whose ages cluster in a bimodal distribution associated with the Shawinigan and Ottawan pulses of the Grenville orogenic cycle at c. 1165 Ma and c. 1050 Ma respectively [12,13].…”

Section: Geology Of the Silver Crater Minementioning

confidence: 99%

“…This region was extensively deformed during the Grenville orogenic cycle and is associated with the assembly of the supercontinent of Rodinia [11,12]. Intrusive complexes associated with this orogenic cycle comprise anorthosites, granitic pegmatites, syenites, carbonatites, and others whose ages cluster in a bimodal distribution associated with the Shawinigan and Ottawan pulses of the Grenville orogenic cycle at c. 1165 Ma and c. 1050 Ma respectively [12,13]. The Grenville-aged basement rock exposed in southeastern Ontario has a rich mineralogy hosted in a miscellany of deposits including granitic pegmatites, skarns, and carbonatites [12][13][14].…”

Section: Geology Of the Silver Crater Minementioning

confidence: 99%

“…Intrusive complexes associated with this orogenic cycle comprise anorthosites, granitic pegmatites, syenites, carbonatites, and others whose ages cluster in a bimodal distribution associated with the Shawinigan and Ottawan pulses of the Grenville orogenic cycle at c. 1165 Ma and c. 1050 Ma respectively [12,13]. The Grenville-aged basement rock exposed in southeastern Ontario has a rich mineralogy hosted in a miscellany of deposits including granitic pegmatites, skarns, and carbonatites [12][13][14]. There is a long history of mining and exploration in this region with most activity having occurred during the late 19th and early 20th centuries in the pursuit of mica, phosphate, and feldspar [14,15].…”

Section: Geology Of the Silver Crater Minementioning

confidence: 99%

“…More famous perhaps than any commercially exploitable resource are the wonderful mineral specimens which have been streaming steadily and inexhaustibly from this region for well over one hundred years [15]. World class crystals of apatite, titanite, mica, and zircon (among others) have made their way into museum collections worldwide [12,15,16]. Despite the abundance of specimens, very little modern work has been done on many of the historic localities in this region [12].…”

Section: Geology Of the Silver Crater Minementioning

confidence: 99%

“…World class crystals of apatite, titanite, mica, and zircon (among others) have made their way into museum collections worldwide [12,15,16]. Despite the abundance of specimens, very little modern work has been done on many of the historic localities in this region [12].…”

Section: Geology Of the Silver Crater Minementioning

confidence: 99%

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The Crystallinity of Apatite in Contact with Metamict Pyrochlore from the Silver Crater Mine, ON, Canada

et al. 2020

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The purpose of this work is to evaluate the long-term effects of radiation on the structure of naturally occurring apatite in the hope of assessing its potential for use as a solid nuclear waste form for actinide sequestration over geologically relevant timescales. When a crystal is exposed to radioactivity from unstable constituent atoms undergoing decay, the crystal’s structure may become damaged. Crystalline materials rendered partially or wholly amorphous in this way are deemed “partially metamict” or “metamict” respectively. Intimate proximity of a non-radioactive mineral to a radioactive one may also cause damage in the former, evident, for example, in pleochroic haloes surrounding zircon inclusions in micas. Radiation damage may be repaired through the process of annealing. Experimental evidence suggests that apatite may anneal during alpha particle bombardment (termed “self-annealing”), which, combined with a low solubility in aqueous fluids and propensity to incorporate actinide elements, makes this mineral a promising phase for nuclear waste storage. Apatite evaluated in this study occurs in a Grenville-aged crustal carbonatite at the Silver Crater Mine in direct contact with U-bearing pyrochlore (var. betafite)—a highly radioactive mineral. Stable isotope analyses of calcite from the carbonatite yield δ18O and δ13C consistent with other similar deposits in the Grenville Province. Although apatite and betafite imaged using cathodoluminescence (CL) show textures indicative of fracture-controlled alteration, Pb isotope analyses of betafite from the Silver Crater Mine reported in previous work are consistent with a model of long term Pb loss from diffusion, suggesting the alteration was not recent. Thus, it is interpreted that these minerals remained juxtaposed with no further metamorphic overprint for ≈1.0 Ga, and therefore provide an ideal opportunity to study the effects of natural, actinide-sourced radiation on the apatite structure over long timescales. Through broad and focused X-ray beam analyses and electron backscatter diffraction (EBSD) mapping, the pyrochlore is shown to be completely metamict—exhibiting no discernible diffraction associated with crystallinity. Meanwhile, apatite evaluated with these methods is confirmed to be highly crystalline with no detectable radiation damage. However, the depth of α-decay damage is not well-understood, with reported depths ranging from tens of microns to just a few nanometers. EBSD, a surface sensitive technique, was therefore used to evaluate the crystallinity of apatite surfaces which had been in direct contact with radioactive pyrochlore, and the entire volume of small apatite crystals whose cores may have received significant radiation doses. The EBSD results demonstrate that apatite remains crystalline, as derived from sharp and correctly-indexed Kikuchi patterns, even on surfaces in direct contact with a highly radioactive source for prolonged periods in natural systems.

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Section: Geology Of the Silver Crater Minementioning

confidence: 99%

Section: Geology Of the Silver Crater Minementioning

confidence: 99%

Section: Geology Of the Silver Crater Minementioning

confidence: 99%

Section: Geology Of the Silver Crater Minementioning

confidence: 99%

Section: Geology Of the Silver Crater Minementioning

confidence: 99%

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The Crystallinity of Apatite in Contact with Metamict Pyrochlore from the Silver Crater Mine, ON, Canada

et al. 2020

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The origin of carbonatites from the eastern Armutlu Peninsula (NW Turkey)

Özkan

Çelik

Marzoli

et al. 2021

JGS

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Unusual carbonate dykes, which have a thickness of up to 4 meters, crosscut the amphibolites from the high-grade metamorphic rocks in the Armutlu Peninsula (NW Turkey). They are described as carbonatites based on their petrographic, geochemical, and isotope-geochemical characteristics. The carbonatites, which show commonly equigranular texture, are composed of calcite and clinopyroxene with other minor phases of plagioclase, mica, garnet, K-feldspar, quartz, epidote, titanite, and opaque minerals. They contain abundant xenoliths of pyroxenite and amphibolite. Geochemical characteristics of the carbonatites are significantly different from those of mantle-derived carbonatites. They have remarkably low incompatible elements (e.g. Ba, Th, Nb) and total REE contents (11-91 ppm) compared to mantle-derived carbonatites. The high 87Sr/86Sr(i) (0.70797-0.70924) and low εNd(t) (-8.08 to -9.57) of the carbonatites confirm that they were derived from the continental crust rather than from a mantle source. Mica from carbonatite was dated by the 40Ar/39Ar method and yielded Late Jurassic – Early Cretaceous (148-137 Ma). This age is significantly younger from the age (Upper Triassic) of adjacent amphibolites. All data from field studies, as well as petrographic, geochemical and geochronological observations, suggest that these carbonatites were formed from the anatectic melting of a carbonated source area in the continental crust.Supplementary material: A complete description of the analytical methods (Whole rock chemistry, mineral chemistry, Strontium and Neodymium isotopes and 40Ar/39Ar measurements) and mineral chemistry and 40Ar-39Ar dating results are available at https://doi.org/ 10.6084/m9.figshare.12946955

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Boron isotope compositions establish the origin of marble from metamorphic complexes: Québec, New York, and Sri Lanka

Kuebler

Simonetti

et al. 2022

American Mineralogist

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The origin of an array of marble samples found in both the Grenville Province and southwestern Sri Lanka remains uncertain, whether magmatic, sedimentary, or mixed, due to their proximity to both carbonatite bodies and carbonate-rich metasedimentary rocks. This study reports boron and trace element abundances, in addition to carbon, oxygen, boron, and strontium isotopic compositions in order to determine the petrogenesis of these carbonate-rich samples.Boron abundances for all of the samples are relatively high and variable (1.48 -71.1 ppm) compared to those for carbonatites worldwide (≤ 1 ppm), and mostly overlap those documented for sedimentary sources (up to 54 ppm). The rare earth element (REE) abundances (0.5 -1068 ppm) for the marbles studied are similar to those for local sedimentary units, and thus contain, in general, lower REE contents than both the average worldwide calcio-carbonatite and respective neighboring carbonatite bodies. The δ 13 C V-PDB and δ 18 O V-SMOW compositions for all of the This is the peer-reviewed, final accepted version for American Mineralogist, published by the Mineralogical Society of America.The published version is subject to change. Cite as Authors (Year) Title. American Mineralogist, in press.

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Age and Origin of Silicocarbonate Pegmatites of the Adirondack Region

Cited by 6 publications

References 40 publications

The Crystallinity of Apatite in Contact with Metamict Pyrochlore from the Silver Crater Mine, ON, Canada

The Crystallinity of Apatite in Contact with Metamict Pyrochlore from the Silver Crater Mine, ON, Canada

The origin of carbonatites from the eastern Armutlu Peninsula (NW Turkey)

Boron isotope compositions establish the origin of marble from metamorphic complexes: Québec, New York, and Sri Lanka

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