Compositional variation in apatite from various host rocks: clues with regards to source composition and crystallization conditions

Teiber, Holger; Marks, Michael A.W.; Arzamastsev, A. A.; Wenzel, Thomas J.; Markl, Gregor

doi:10.1127/njma/2015/0277

Cited by 35 publications

(20 citation statements)

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“…Our modeling aimed at determining data‐driven solutions, i. e., at finding T–t paths consistent with the AFT data, with minimal bias by deliberate or inadvertent constraints. A detailed discussion of the methodology can be found in the supporting information S1 [ Donelick , ; Donelick et al ., ; Ketcham et al ., ; Ketcham , ; Ketcham et al ., ; Teiber et al ., ; Webster and Piccoli , ]. To this end, we set three identical box constraints (10–140°C; 0–1.5 × t FT ; t FT = AFT age) plus the fixed bar constraint at 0 Ma.…”

Section: Sampling and Methodsmentioning

confidence: 99%

Cenozoic intracontinental deformation and exhumation at the northwestern tip of the India-Asia collision-southwestern Tian Shan, Tajikistan, and Kyrgyzstan

et al. 2016

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Along the Ghissar-Alai Range of the southwestern Tian Shan (southwestern Kyrgyzstan, northern Tajikistan), the deformation front of the India-Asia collision-the Pamir-Tibet orogen-is interacting with the intracontinental Tian Shan orogen without the intervening Tarim Craton. Apatite fission track (n = 33,~3.3-145.6 Ma, 27% <10 Ma) and (U-Th)/He (n = 32,~1.9-26.1 Ma, 56% <10 Ma) thermochronologic ages suggest approximate isothermal holding (very slow cooling to weak reheating) during relative tectonic quiescence between~150 and 15 Ma. Accelerated exhumation (~0.2-1.0 km/Myr, median~0.5 km/Myr) and cooling (11-16°C/Myr) occurred over the last~10 Myr. Geomorphologic parameters-incision, river steepness, and concavity-confirm the youth of the southwestern Tian Shan's mountain building. High exhumation/cooling rates are correlated with pronounced local relief, produced by Cenozoic faults reactivating inherited (Late Paleozoic) structures. Regions with similarly young exhumation are centered along rims of rigid crustal blocks in the central and eastern Tian Shan. Structurally, the Ghissar-Alai Range is a broad, east trending zone of dextral transpression that includes the northern Tajik Basin (Illiak Fault Zone) and the Pamir Thrust System of the frontal northern Pamir. It is the particular deformation field at the northwestern tip of the India-Asia collision-the interaction of the westward gravitational collapse of the Pamir Plateau into the Tajik Basin with the bulk northward motion of the Pamir-that transformed the southwestern Tian Shan into a dextral transpression belt. The dextral transpression in the southwestern Tian Shan contrasts with sinistral strike-slip shear localized along inherited fault zones, accommodating dominant north-south shortening, in the central and eastern Tian Shan. The deformation field influenced by the Pamir and the associated young exhumation make the Ghissar-Alai Range a unique feature in the Tian Shan orogen.

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Section: Sampling and Methodsmentioning

confidence: 99%

Cenozoic intracontinental deformation and exhumation at the northwestern tip of the India-Asia collision-southwestern Tian Shan, Tajikistan, and Kyrgyzstan

et al. 2016

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“…( Barbarand and Pagel, 2001a, b;Barbarand et al, 2003a;Belousova et al, 2002;Carlson et al, 1999;Goldoff et al, 2012;Marks et al, 2012;McCubbin et al, 2010;Morishita et al, 2008;Patiño Douce et al, 2011;Roeder et al, 1987;Rogers et al, 1984;Teiber et al, 2015;Yang et al, 2014;Young et al, 1969). The actinide concentrations are ca.…”

Section: Samples and Experimentsmentioning

confidence: 99%

Standardless fission-track dating of the Durango apatite age standard

2015

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Five dating strategies were used for determining the standardless fission-track age of the Durango apatite. These use the same fossil-track densities but differ in the manner in which the induced-track densities are determined. A conventional age calculation, without correction for experimental factors, gives inconsistent ages with methodrelated differences N 15%. Correcting for these factors brings the ages in line with each other and with the reference age but leaves no room for a partial-annealing correction based on the confined-track lengths. Three further reasons suggest that a length correction is not appropriate. (1) The evidence for lengthbased corrections is inconclusive. (2) The plateau age of the Durango apatite is consistent with its apparent fission-track age to within 1%. (3) The calculated effective etchable length of the fossil tracks agrees within error with that of the induced tracks; both are further consistent with the measured mean length of confined induced tracks. The circumstance that the (U,Th)/He ages of the accepted and proposed apatite age standards are consistent with their reference ages leaves no margin for a lowered fission-track age resulting from partial annealing, although the case of the Durango apatite itself is inconclusive because of its exceptional crystal size. It is conjectured that the shortening of the fossil tacks in the Durango apatite is due to a lowering of the track etch rate over time. In this case, annealing equations fitted to induced-track data underestimate the extent of confined-track-length reduction in geological samples.

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“…Os dados químicos dos cristais analisados agrupam-se ao longo dos vértices FAp e HAp, demarcando uma área aproximadamente similar à ocupada pela composição da apatita de muscovita granitos [37], diferindo apenas pelos maiores conteúdos de OH. Resultados semelhantes são obtidos na projeção P-Si-S [37], onde as amostras se distribuem entre os vértices P e Si (Figura 14B).…”

Section: Apatitaunclassified

“…Apatita com teores elevados de F e baixos de Cl são comumente descritas em granitos evoluídos [37,38]. Em rochas híbridas, que não correspondem aos típicos granitos I ou S, este comportamento pode ser atribuído à abundância de halogêneos nas rochas-fonte de origem sedimentar, que sofrem perda preferencial de Cl durante os processos de intemperização, devido à alta solubilidade deste elemento em soluções aquosas [38].…”

Section: Apatitaunclassified

“…Adicionalmente, a cristalização fracionada por si só também pode aumentar os conteúdos de F relativamente ao Cl, resultando em altas razões F/Cl nos fracionados magmáticos mais evoluídos [38]. 2,000 2,000 2,000 2,000 2,000 2,000 2,000 2,000 2,000 2,000 2,000 2,000 2,000 [37], com base em dados químicos de apatita de corpos ígneos da Austrália [38], Tibete [39], Alemanha e Grécia [40].…”

Section: Apatitaunclassified

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Química mineral dos granitos leucocráticos do Stock Lagoa de Dentro, Sul da Província Borborema, Nordeste do Brasil

et al. 2017

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Corpos leucograníticos relacionados ao Ciclo Brasiliano apresentam ampla distribuição no Sistema Orogênico Sergipano, localizado no setor extremo sul da Província Borborema. O Stock Lagoa de Dentro (SLD) é um representante desse magmatismo, que intrude as rochas metassupracrustais do Domínio Macururé, na porção centro-norte do estado de Sergipe. Trata-se de uma intrusão com cerca de 13 km2 de área aflorante, constituída por monzogranitos e álcali-feldspato granitos à duas micas. Neste artigo são apresentados e discutidos dados químicos dos principais minerais identificados nas rochas do SLD. Os feldspatos são homogêneos em composição e geralmente ocorrem como fases puras de ortoclásio (Or92-97) e albita (An1-7). A mica dioctaédrica possui composição intermediária entre muscovita e celadonita, dada pela substituição de VIAl por Fe+Mg nos sítios octaédricos, acompanhada pela substituição de IVAl por Si nas posições tetraédricas. A biotita é ferrosa e mostra sinais de reequilíbrio, refletindo variados graus de cloritização e oxidação observados nos estudos petrográficos. Em diagramas de associações magmáticas, a biotita exibe afinidade com as suítes graníticas peraluminosas e caráter transicional entre as séries Cálcio-Alcalina e Alumino-Potássica. O epídoto (Ps18-24) é aluminoso e ocorre como um mineral primário, cristalizado precocemente, e como produto de alteração hidrotermal de plagioclásio. A apatita corresponde a fluorapatita (FAp51-82) e o zircão possui assinatura de granitos anatéticos, derivados de fontes crustais (Zr/Hf~30). As composições da ilmenita mostram-se enriquecidas nas moléculas de pirofanita (Php3-14) e ecandrewsita (Ec1-20) e sugerem que o SLD se cristalizou a partir de um magma com baixa fugacidade de oxigênio.

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Compositional variation in apatite from various host rocks: clues with regards to source composition and crystallization conditions

Cited by 35 publications

References 0 publications

Cenozoic intracontinental deformation and exhumation at the northwestern tip of the India-Asia collision-southwestern Tian Shan, Tajikistan, and Kyrgyzstan

Cenozoic intracontinental deformation and exhumation at the northwestern tip of the India-Asia collision-southwestern Tian Shan, Tajikistan, and Kyrgyzstan

Standardless fission-track dating of the Durango apatite age standard

Química mineral dos granitos leucocráticos do Stock Lagoa de Dentro, Sul da Província Borborema, Nordeste do Brasil

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