Removing a mask of alteration: Geochemistry and age of the Karadag volcanic sequence in SE Crimea

Popov, Daniil; Brovchenko, V. D.; Nekrylov, Nikolai; Plechov, P. Yu.; Spikings, Richard; Tyutyunnik, O. A.; Krigman, L. V.; Аносова, М. О.; Kostitsyn, Yu. A.; Soloviev, A. V.

doi:10.1016/j.lithos.2018.11.024

Cited by 17 publications

(6 citation statements)

References 53 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The "plateau age" variations largely exceeding the 2 sigma level imply instead that at most one of the "plateaus" can reflect ideal behaviour, whereas all others do not. This reproduces results obtained by Foland (1983) and Popov et al (2019), calling into question the identification of "plateaus" with sample ideality. Therefore, the questions should be: what brings about the observed variations, what diagnostic tools does the 40 Ar/ 39 Ar systematics provide, what correction (if any) can be applied, and what do our findings imply for the viability of micas as precise half-life calibrators?…”

Section: Resultssupporting

confidence: 88%

Subgrain 40Ar/39Ar dating of museum-quality micas reveals intragrain heterogeneity

et al. 2021

View full text Add to dashboard Cite

Section: Resultssupporting

confidence: 88%

Subgrain 40Ar/39Ar dating of museum-quality micas reveals intragrain heterogeneity

et al. 2021

View full text Add to dashboard Cite

“…chlorite or clays) that can overprint the K-bearing phases such as muscovite, potentially leading to modification of the ages through recoil along fine-grained mineralogical intergrowths (e.g. Lo and Onstott, 1989;Foland et al, 1992;Di Vincenzo et al, 2003;Popov et al, 2019). Mineralogically, most samples are dominated by muscovite as the major K-bearing phase, although 3779554 and 3779555 have appreciable microcline in addition.…”

Section: Discussionmentioning

confidence: 99%

Complex ⁴⁰Ar ∕ ³⁹Ar age spectra from low-grade metamorphic rocks: resolving the input of detrital and metamorphic components in a case study from the Delamerian Orogen

Reid

Forster²,

Preiss³

et al. 2022

Geochronology

View full text Add to dashboard Cite

Abstract. In this study, we provide 40Ar / 39Ar geochronology data from a suite of variably deformed rocks from a region of low-grade metamorphism within the Cambro–Ordovician Delamerian Orogen, South Australia. Low-grade metamorphic rocks such as these can contain both detrital minerals and minerals newly grown or partly recrystallised during diagenesis and metamorphism. Hence, they typically yield complex 40Ar / 39Ar age spectra that can be difficult to interpret. Therefore, we have undertaken furnace step heating 40Ar / 39Ar geochronology to obtain age spectra with many steps to allow for application of the method of asymptotes and limits and recognition of the effects of mixing. The samples analysed range from siltstone and shale to phyllite and contain muscovite or phengite with minor microcline as determined by hyperspectral mineralogical characterisation. Whole rock 40Ar / 39Ar analyses were undertaken in most samples due to their very fine-grained nature. All samples are dominated by radiogenic 40Ar, and contain minimal evidence for atmospheric Ca- or Cl-derived argon. Chloritisation may have resulted in limited recoil, causing 39Ar argon loss in some samples, which is especially evident within the first few percent of gas released. Most of the age data, however, appear to have some geological significance. Viewed with respect to the known depositional ages of the stratigraphic units, the age spectra from this study do appear to record both detrital mineral ages and ages related to the varying influence of either cooling or deformation-induced recrystallisation. The shape of the age spectra and the degree of deformation in the phyllites suggest the younger ages may record recrystallisation of detrital minerals and/or new mica growth during deformation. Given that the younger limit of deformation recorded in the high-metamorphic-grade regions of the Delamerian Orogen is ca. 490 Ma, the ca. 470 to ca. 458 Ma ages obtained in this study suggest deformation in low-grade shear zones within the Delamerian Orogen may have persisted until ca. 20–32 million years after high-temperature ductile deformation in the high-grade regions of the orogen. We suggest that these younger ages for deformation could reflect reactivation of older structures formed both during rift basin formation and during the main peak of the Delamerian orogeny itself. The younger ca. 470 to ca. 458 Ma deformation may have been facilitated by far-field tectonic processes occurring along the eastern paleo-Pacific margin of Gondwana.

show abstract

“…Вулканический массив Карадаг расположен в юго-восточной части Крымского полуострова и представляет собой мощную вулканогенную толщу, подвергшуюся значительным изменениям при низкоградном метаморфизме. Методами изучения расплавных включений, локальной геохимии стекол и минералов и Ar-Ar изотопии нам удалось (Popov et al, 2019) выявить влияние вторичных изменений, оценить первичные химические составы пород и состав расплава (включая геохимическую характеристику). Расплавные включения были изучены в плагиоклазе, клино-и ортопироксене (рис.…”

Section: вулканический массив карадагunclassified

Важнейшие Научные Результаты Минералогического Музея Им. А.Е. Ферсмана В 2019 Году

Плечов¹,

Pekov²,

Паутов³

et al. 2021

Новые Данные О Минералах

View full text Add to dashboard Cite

Статья представляет собой сводку основных научных результатов сотрудников Минералогического музея им. А.Е. Ферсмана РАН (Минмузея РАН) за 2019 год. Приведены краткие описания 20 новых минеральных видов: фторапофиллит-(Cs), гмалимит, ферроефремовит, нишанбаевит, дрицит, патынит, малетойваямит, хинганит-(Nd), перклевеит-(La), радекшкодаит-(Ce), виттинкиит, крейтерит, оксивисмутомикролит, сергеванит, полиарсит, юргенсонит, евсеевит, чийокоит, алекскузнецовит-(La), натроафтиталит. В статье суммированы текущие результаты изучения выдающихся минералогических объектов, типоморфных минералов месторождений Поморья, Якутии, Камчатки, Урала, Кавказа, Крыма, Памира и Тянь-Шаня. Приведены данные по детальному изучению монтичеллита, минералов надгруппы эпидота, группы мелилита, а также результаты изучения включений в оливине, плагиоклазе, клинопироксене, ортопироксене и кварце из различных магматических объектов.

show abstract

Removing a mask of alteration: Geochemistry and age of the Karadag volcanic sequence in SE Crimea

Cited by 17 publications

References 53 publications

Subgrain 40Ar/39Ar dating of museum-quality micas reveals intragrain heterogeneity

Subgrain 40Ar/39Ar dating of museum-quality micas reveals intragrain heterogeneity

Complex ⁴⁰Ar ∕ ³⁹Ar age spectra from low-grade metamorphic rocks: resolving the input of detrital and metamorphic components in a case study from the Delamerian Orogen

Важнейшие Научные Результаты Минералогического Музея Им. А.Е. Ферсмана В 2019 Году

Contact Info

Product

Resources

About

Removing a mask of alteration: Geochemistry and age of the Karadag volcanic sequence in SE Crimea

Cited by 17 publications

References 53 publications

Subgrain 40Ar/39Ar dating of museum-quality micas reveals intragrain heterogeneity

Subgrain 40Ar/39Ar dating of museum-quality micas reveals intragrain heterogeneity

Complex 40Ar ∕ 39Ar age spectra from low-grade metamorphic rocks: resolving the input of detrital and metamorphic components in a case study from the Delamerian Orogen

Важнейшие Научные Результаты Минералогического Музея Им. А.Е. Ферсмана В 2019 Году

Contact Info

Product

Resources

About

Complex ⁴⁰Ar ∕ ³⁹Ar age spectra from low-grade metamorphic rocks: resolving the input of detrital and metamorphic components in a case study from the Delamerian Orogen