Phosphate minerals from Albian phosphorites in Bulgaria

Pages: 
pp. 191-197
Geological Institute at Bulgarian Academy of Sciences, Sofia 1113
Abstract: 

Results from X-ray diffraction analyses of Albian phosphorites from deposits Sanadinovo, Dekoy and Brushlen indicate presence mainly of fluorapatite and partly of chlorapatite and carbonate fluorapatite (francolite). The microprobe analyses of phosphate grains, coatings, cements, ammonite, wood, and shark tooth determined the following contents (in weight %): 26,65-41,02 P2O5 45,19-57,17 CaO, 2,58-4,64 F, up to 0,80 CI, and silicate components from the admixtures in phosphate minerals. Fifteen crystallochemical formulae were calculated. They are characteristic with Ca9.54-9.58[PO4]5.77-5.78FI1.48-2.81 and Cl0.06-0.30. Generally fluorapaiIte was determimid in 9 samples; and chlorine containing fluorapatite - in 6 samples.
   The exemplary crystallochemical formulae are:
   Ca9.54[PO4]5.78F2.75 - fluorapatite
   Ca9.58[PO4]5.77F1.94CI0.30 - chlorine containing fluorapatite
   The presence of CO3- and OH in the phosphate minerals was not substantiated by direct data. The studied phosphate minerals show high solubility in lemon acid (30-80%). This indicates defects in the crystal lattices caused by the presence of chlorine and most probably of carbonate group.

И. Начев. Фосфатные минералы альбских фосфоритов в Болгарии. Альбские фосфориты из месторождений Санадиново, Деков и Брышлян исследованы рентгено-структурным дифракционным методом. Установлено, что фосфориты сложены главным образом фторапатитом (франколитом). Под электронным микроскопом исследованы фосфатные зерна, внешние зоны зерен, образцы цимента, аммонит, обломок древесины и акулий зуб. Исследования показали, что фосфаты содержат (в весовых %): Р2О – 26,65-41,02%; СаО – 45,19-57,17%; F – 2,58-4,64%; Cl – более 0,80%, а также – силикатны компонент, котороы смешан с фосфотными минералами. Вычислено 15 кристаллохимических формул.
   Для них характерны следующие соотношения:
   Са9,54-9,58[PO4]5,77-5,78F1,48-2,81 и Cl0,06-0,30. Хлорапатит с представителной формулой Са9,54[PO4]5,78F2,75 установлен в 9 образцах, а хлор-содержащий фторапатит (представительная формула - Са9,58[PO4]5,77F1,94Cl0,30) – в 6 образцах.
   Присуствие СО3- и ОН в фосфатных минералах не доказано непосредственно. Фосфатные минералы слабо растворяются в 30-80% ли монной кислоте. Эта особенность связана с дефектами кристаллов в связи с присуствием хлора и по всей вероятности – карбонатной группы.

Keywords: 

fluorapatite, chlorine containing fluorapatite, chlorapatite and carbonate fluorapatite

VOLUME 32 (2-4)/December 2002 110th Anniversary of Acad. Prof. Strashimir Dimitrov; XVII Congress of the Carpathian-Balkan Geological Association

Geologica Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev St., bl. 24, 1113 Sofia, Bulgaria

Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia, Akad. G. Bonchev Str., block 24
|
Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia, Akad. G. Bonchev Str., block 24
|
Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia, Akad. G. Bonchev Str., block 24
|
Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia, Akad. G. Bonchev Str., block 24
|
Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia, Akad. G. Bonchev Str., block 24
|
Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia, Akad. G. Bonchev Str., block 24
|
Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia, Akad. G. Bonchev Str., block 24

Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev str. Bl. 24

Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia
|
Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia

Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia
|
Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia

Geological Institute, Bulgarian Academy of Sciences,Sofia 1113, Bulgaria, Acad. G. Bonchev str, bl. 24
|
Geological Institute, Bulgarian Academy of Sciences,Sofia 1113, Bulgaria, Acad. G. Bonchev str, bl. 24
|
Earth Science Section of the Uviversity of Geneva, 13, rue des Maraîchers, 1211 Geneva 4, Switzerland
|
Earth Science Section of the Uviversity of Geneva, 13, rue des Maraîchers, 1211 Geneva 4, Switzerland

Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria
|
Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria

Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria

Geological Institute BAS, Acad. G. Bonchev Str., Bl. 24 1113 Sofia, Bulgaria

Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria
|
Sofia University "Sv. Kliment Ohridski", 1504 Sofia, Bulgaria

Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia
|
Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia
|
Sofia University "Sv. Kliment Ohridski", Tsar Osvobodilel Blvd, 15, 1000 Sofia
|
Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia

Geological institute, Bulgarian Academy of Sciences, 1113, Sofia, Bulgaria
|
Geological institute, Bulgarian Academy of Sciences, 1113, Sofia, Bulgaria
|
Geological institute, Bulgarian Academy of Sciences, 1113, Sofia, Bulgaria
|
University of Mining and Geology "Sv. Ivan Rilski", 1700, Sofia

Geological institute, Bulgarian Academy of Sciences, 1113, Sofia, Bulgaria

Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia
|
Institute of Geochemistry, Siberian branch of the Russian Academy of Sciences, P.O.B. 4019, 664033 Irkutsk
|
Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia
|
Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia

Geological Institute, Bulgarian Academy of Sciences, Sofia, 1113
|
Geological Institute, Bulgarian Academy of Sciences, Sofia, 1113
|
Geological Institute, Bulgarian Academy of Sciences, Sofia, 1113
|
Geological Institute, Bulgarian Academy of Sciences, Sofia, 1113
|
Geological Institute, Bulgarian Academy of Sciences, Sofia, 1113
|
Geological Institute, Bulgarian Academy of Sciences, Sofia, 1113

Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia

Geological Institute, Bulgarian Academy of Sciences, Sofia, 1113

Geological Institute, Bulgarian Academy of Sciences

Geological Institute, BAS, Acad. G. Bonchev Street Bl. 24, 1113 Sofia, Bulgaria

Geological Institute of BAS, 24 Acad. G. Bonchev Sir., BG - 1113 Sofia
|
Geological Institute of BAS, 24 Acad. G. Bonchev Sir., BG - 1113 Sofia
|
Geological Institute of BAS, 24 Acad. G. Bonchev Sir., BG - 1113 Sofia

Geological Institute at the Bulgarian Academy of Sciences, Acad. G. Bonchev Str., 1113 Sofia, Bulgaria
|
Geological Institute at the Bulgarian Academy of Sciences, Acad. G. Bonchev Str., 1113 Sofia, Bulgaria
|
Geological Institute at the Bulgarian Academy of Sciences, Acad. G. Bonchev Str., 1113 Sofia, Bulgaria

University of Mining and Geology, Studentski grad, Sofia, 1100, Bulgaria
|
Geological Institute of Romania, Caransebes Str. No 1, Bucharest, RO-78344, Romania
|
University of Belgrade, Dusina 7, Belgrad, 11000, Yugoslavia
|
Geological Institute of Romania, Caransebes Str. No 1, Bucharest, RO-78344, Romania

Geological Institute at Bulgarian Academy of Sciences, Sofia 1113

Sofia University "Sv. Kl. Ohridski", Department of Geology and Palaeontology, 1504 Sofia