Domain structure of volcanics’ ferromagnetic grains: A case study of the Saatly ultradeep well, Azerbaijan
Various magnetic properties of magnetic minerals show strong grain-size depen-dence. This dependency occurs because these parameters are influenced by the magnetic grain-size (domain state) of the samples. Natural rocks often contain a mixture of different magnetic minerals with different grain-size...
Збережено в:
| Дата: | 2019 |
|---|---|
| Автор: | |
| Формат: | Стаття |
| Мова: | English |
| Опубліковано: |
Інститут геофізики ім. С.I. Субботіна НАН України
2019
|
| Назва видання: | Геофизический журнал |
| Онлайн доступ: | http://dspace.nbuv.gov.ua/handle/123456789/158547 |
| Теги: |
Додати тег
Немає тегів, Будьте першим, хто поставить тег для цього запису!
|
| Назва журналу: | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| Цитувати: | Domain structure of volcanics’ ferromagnetic grains: A case study of the Saatly ultradeep well, Azerbaijan / Z.A. Novruzov // Геофизический журнал. — 2019. — Т. 41, № 3. — С. 203-210. — Бібліогр.: 5 назв. — англ. |
Репозитарії
Digital Library of Periodicals of National Academy of Sciences of Ukraine| id |
irk-123456789-158547 |
|---|---|
| record_format |
dspace |
| spelling |
irk-123456789-1585472019-09-05T01:26:20Z Domain structure of volcanics’ ferromagnetic grains: A case study of the Saatly ultradeep well, Azerbaijan Novruzov, Z.A. Various magnetic properties of magnetic minerals show strong grain-size depen-dence. This dependency occurs because these parameters are influenced by the magnetic grain-size (domain state) of the samples. Natural rocks often contain a mixture of different magnetic minerals with different grain-size (domain states). Thus determination of the domain state is important. The Saatly ultradeep well’s volcanics were used as a research material. In the depth intervals of 3540—8126 m the volcanics had been revealed by the borehole. Магнитные свойства различных магнитных минералов очень зависят от размера зерен (доменного состояния). Горные породы часто содержат смесь различных магнитных минералов с различными размерами зерен (доменных состояний). В качестве материала для определения доменного состояния зерен минералов использовано вулканиты с сверхглубокой скважины Саатлы в интервале глубин 3540-8126 м. Магнітні властивості різних магнітних мінералів дуже залежать від розміру зерен (доменного стану). Гірські породи часто містять суміш різних магнітних мінералів з різними розмірами зерен (доменних станів). Як матеріал для визначення доменного стану зерен мінералів використано вулканіти з надглибокої свердловини Саатлі в інтервалі глибин 3540—8126 м. 2019 Article Domain structure of volcanics’ ferromagnetic grains: A case study of the Saatly ultradeep well, Azerbaijan / Z.A. Novruzov // Геофизический журнал. — 2019. — Т. 41, № 3. — С. 203-210. — Бібліогр.: 5 назв. — англ. 0203-3100 DOI: 10.24028/gzh.0203-3100.v41i3.2019.172474 http://dspace.nbuv.gov.ua/handle/123456789/158547 538.245+550.382):551.24:552(622.241:479.24 en Геофизический журнал Інститут геофізики ім. С.I. Субботіна НАН України |
| institution |
Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| collection |
DSpace DC |
| language |
English |
| description |
Various magnetic properties of magnetic minerals show strong grain-size depen-dence. This dependency occurs because these parameters are influenced by the magnetic grain-size (domain state) of the samples. Natural rocks often contain a mixture of different magnetic minerals with different grain-size (domain states). Thus determination of the domain state is important. The Saatly ultradeep well’s volcanics were used as a research material. In the depth intervals of 3540—8126 m the volcanics had been revealed by the borehole. |
| format |
Article |
| author |
Novruzov, Z.A. |
| spellingShingle |
Novruzov, Z.A. Domain structure of volcanics’ ferromagnetic grains: A case study of the Saatly ultradeep well, Azerbaijan Геофизический журнал |
| author_facet |
Novruzov, Z.A. |
| author_sort |
Novruzov, Z.A. |
| title |
Domain structure of volcanics’ ferromagnetic grains: A case study of the Saatly ultradeep well, Azerbaijan |
| title_short |
Domain structure of volcanics’ ferromagnetic grains: A case study of the Saatly ultradeep well, Azerbaijan |
| title_full |
Domain structure of volcanics’ ferromagnetic grains: A case study of the Saatly ultradeep well, Azerbaijan |
| title_fullStr |
Domain structure of volcanics’ ferromagnetic grains: A case study of the Saatly ultradeep well, Azerbaijan |
| title_full_unstemmed |
Domain structure of volcanics’ ferromagnetic grains: A case study of the Saatly ultradeep well, Azerbaijan |
| title_sort |
domain structure of volcanics’ ferromagnetic grains: a case study of the saatly ultradeep well, azerbaijan |
| publisher |
Інститут геофізики ім. С.I. Субботіна НАН України |
| publishDate |
2019 |
| url |
http://dspace.nbuv.gov.ua/handle/123456789/158547 |
| citation_txt |
Domain structure of volcanics’ ferromagnetic grains: A case study of the Saatly ultradeep well, Azerbaijan / Z.A. Novruzov // Геофизический журнал. — 2019. — Т. 41, № 3. — С. 203-210. — Бібліогр.: 5 назв. — англ. |
| series |
Геофизический журнал |
| work_keys_str_mv |
AT novruzovza domainstructureofvolcanicsferromagneticgrainsacasestudyofthesaatlyultradeepwellazerbaijan |
| first_indexed |
2025-07-14T11:07:31Z |
| last_indexed |
2025-07-14T11:07:31Z |
| _version_ |
1837620266746773504 |
| fulltext |
DOMAIN STRUCTURE OF VOLCANICS� FERROMAGNETIC GRAINS ... AZERBAIJAN
Ãåîôèçè÷åñêèé æóðíàë ¹ 3, Ò. 41, 2019 203
Domain structure of volcanics� ferromagnetic grains:
A case study of the Saatly ultradeep well, Azerbaijan
Z. A. Novruzov, 2019
Institute of Geology and Geophysics of NAS of Azerbaijan, Baku, Azerbaijan
Received 21 November 2018
Ìàãí³òí³ âëàñòèâîñò³ ð³çíèõ ìàãí³òíèõ ì³íåðàë³â äóæå çàëåæàòü â³ä ðîçì³ðó çå-
ðåí (äîìåííîãî ñòàíó). óðñüê³ ïîðîäè ÷àñòî ì³ñòÿòü ñóì³ø ð³çíèõ ìàãí³òíèõ ì³íå-
ðàë³â ç ð³çíèìè ðîçì³ðàìè çåðåí (äîìåííèõ ñòàí³â). ßê ìàòåð³àë äëÿ âèçíà÷åííÿ äî-
ìåííîãî ñòàíó çåðåí ì³íåðàë³â âèêîðèñòàíî âóëêàí³òè ç íàäãëèáîêî¿ ñâåðäëîâèíè
Ñààòë³ â ³íòåðâàë³ ãëèáèí 3540�8126 ì. Çà äàíèìè ïåòðîãðàô³÷íîãî òà åëåêòðîííî-
ì³êðîñêîï³÷íîãî àíàë³ç³â ó âåðõí³é ÷àñòèí³ ðîçð³çó (3540�5500 ì) öèõ ïîð³ä çåðíà
ðóäíèõ ì³íåðàë³â ïðåäñòàâëåí³ äâîìà ãåíåðàö³ÿìè: 1) âåëèê³ çåðíà òèòàíîìàãíåòè-
òó (á³äí³ íà òèòàí), ãîìîãåíí³ àáî ç³ ñòðóêòóðàìè ðîçïàäó; 2) íåâåëèê³ çà ðîçì³ðîì,
çàçâè÷àé äîáðå îãðàíîâàí³ çåðíà ïðàêòè÷íî ñòåõ³îìåòðè÷íîãî ìàãíåòèòó. Ãîìîãåíí³
íåâåëèê³ çåðíà àáî ôðàãìåíòè ðîçïàäó âåëèêèõ çåðåí (ÿê³ äóæå çì³íåí³ õ³ì³÷íî) ìî-
æóòü ìàòè âëàñòèâîñò³ îäíîäîìåííèõ ÷àñòèíîê; ôåðîìàãí³òí³ çåðíà ÷àñòî âèçíà÷à-
þòü ÿê ïñåâäîîäèíè÷íèé äîìåí. Ó íèæí³é ÷àñòèí³ ðîçð³çó (5500�8126 ì) ìóëüòèäî-
ìåíí³ çåðíà òèòàíîìàãíåòèòó çá³äíåí³ òèòàíîì. Ç ãëèáèí 7000 ì ñïîñòåð³ãàºòüñÿ òà-
êîæ îêèñíåíèé ìàãíåòèò. Ïñåâäîîäíîäîìåííèõ çåðåí çàô³êñîâàíî çíà÷íî ìåíøå,
í³æ ó âåðõí³é ÷àñòèí³ ðîçð³çó. Ç ãëèáèíè 7300 ì ³ íèæ÷å âîíè ïîâí³ñòþ â³äñóòí³. Çà
ðåçóëüòàòàìè äîñë³äæåíü, ôåðîìàãíåòèê ïðåäñòàâëåíèé ³ñòîòíî ìóëüòèäîìåííèìè
çåðíàìè. Ñë³ä çàçíà÷èòè, ùî êðèòåð³é Ëîð³�Ôóëëåðà íåïðèäàòíèé ïðè ³äåíòèô³-
êàö³¿ äîìåííî¿ ñòðóêòóðè ñêëàäíîãî ñïîëó÷åííÿ ôåðîìàãí³òíèõ çåðåí.
Êëþ÷îâ³ ñëîâà: íåïðÿì³ ìàãí³òí³ êðèòåð³¿, ìàãí³òíèé äîìåííèé ñòàí, âóëêàíîãåí-
í³ ïîðîäè, íàäãëèáîêà ñâåðäëîâèíà.
Introduction. For the first time magne-
tometric researches of volcanogenic rock co-
re of the super deep Saatly well have been
conducted by the staff of department �Geo-
magnetism� of the Institute of Geology and
Geophysics of Azerbaijan National Acade-
my of Science (ANAS). The necessity in the
magnetic researches of a core of the Saat-
ly super deep well has been dictated by ne-
ed in obtaining the petromagnetic data used
at interpretations of results of geophysical
activity. The ore minerals� magnetic research
together with microprobe analysis of them
[Novruzov, Tselmovich, 2018] revealed that
magnetic properties of rocks are bound with
magnetite and Ti-poor titanomagnetite.
Environmental conditions of generation
of ferromagnetic minerals and changes of
them leave traces on magnetic domain struc-
ture [Stackey, Banerjee, 1974]. Application
of the rock magnetic method for identifica-
tion of domain structure of magnetic grains
is the purpose of the proposed article. For
realization of this purpose we used four mag-
netic criteria. The criteria are based on cha-
racteristics of various magnetic parameters
of magnetic grains with different magnetic
domain structures.
Description of the object. The superde-
ep well is located near the city of Saatly (λ =
= 39.91 °N, ϕ = 48.36 °E), Azerbaijan (Fig. 1).
The region of the well location (design depth
DOI: https://doi.org/10.24028/gzh.0203-3100.v41i3.2019.172474
ÓÄÊ (538.245+550.382):551.24:552(622.241:479.24)
Z. A. NOVRUZOV
204 Ãåîôèçè÷åñêèé æóðíàë ¹ 3, Ò. 41, 2019
of 15 km) is spaced in the Kur basin placed
between the Greater Caucasus and the Les-
ser Caucasus (the large tectonic construc-
tions). According to deep structure the Kur
basin is subdivided into three depressions:
upper Kura basin, middle Kura basin and
lower Kura basin. The Saatly superdeep well
is located within the middle Kura basin.
According to geophysical data interpre-
tation the crystalline basement (around the
Saatly local gravitational maximum) posses-
ses a block structure (where there are rocks
of persilicic and basic composition at a depth
of 8 km). Debatable idea of crustal structu-
re within the Saatly local gravitational maxi-
mum was formed in two points of view. Ac-
cording to the first � the Earth crust con-
sists of granite and basalt layers, according
to the second � the Earth crust is single-
layer and it is presented by mafic rocks on-
ly. Features of the Earth crust and the redu-
ced thickness of a sedimentary cover at Sa-
atly territory formed a basis for drilling of
the super deep well.
Object of our researches are the volca-
nics located in the depths interval of 3540�
8126 m. According to research papers [Ab-
dullaev, Salakhov, 1983; Abdullaev et al. ,
1984] the development of the low-tempera-
ture metamorphism (depth of 3540�7000m)
has been noted in the volcanogenic rocks.
But from depths of 7000 m and deeper the
development of the low-temperature meta-
somatism is revealed. The quantities of the
studied volcanic rocks were 49. Three dup-
licate with cubic form (1 cm) were sawn from
each sample.
The depth interval of 3540�3900m is cha-
racterized by plagioclase basalts and is ma-
inly presented by volcanogenic facies. Ba-
salts contain the potassium-enriched and so-
dium-enriched alkalinity.
The depth interval of 3900�4850 m con-
tains porphyritic olivine-pyroxene-plagio-
clase-basalts and pyroxene-plagioclase-ba-
salts. Basalts are low-alkaline (low-potassium).
The depth interval of 4850�5209 m pos-
sesses much bigger phases of rocks. Except
Fig. 1. The Saatly super deep well location.
DOMAIN STRUCTURE OF VOLCANICS� FERROMAGNETIC GRAINS ... AZERBAIJAN
Ãåîôèçè÷åñêèé æóðíàë ¹ 3, Ò. 41, 2019 205
basalts their amfibole-contaning phases and
andesites are noted. Along with low-potas-
sium basalts potassium-enriched groups ha-
ve been discovered.
In the depth interval of 5209�6100m the
double-pyroxene-plagioclase basalts and an-
desite-basalts prevail. These rocks possess
the alkalescence and the strong fracturing.
There are andesites in the depth interval
of 6100�6800 m. The microdolerite sills are
noted as well.
Upper parts of 6800�8000m depth inter-
val are presented by dacites, dacite-tuffs and
pumiceous breccia. In the middle horizons
and lower ones of the interval dacites are al-
ternating with plagiorhyolite and andesites.
Thus, the studied columnvolcanics chan-
ge with depth: from the mafics (andesite-ba-
salts, basalts) to intermediate rocks (andesi-
tes) and then to persilicrocks (rhyodacites,
dacites).
Technique of works. During the magne-
tic researches of volcanogenic rocks of the
superdeep Saatly well the following magne-
tic parameters were measured: a natural re-
manent magnetization (NRM ) and magne-
tic susceptibility (χ ). At the laboratory on
each duplicate sample (for each one the NRM
and the χ were measured) saturation isother-
mal remanent magnetization (SIRM) and iso-
thermal remanent magnetization (IRM) in the
field of 1.5 T have been created. At the la-
boratory a thermal remanent magnetizati-
on (TRM) was created on each duplicate of
sample by means of cooling from tempera-
tures above the Curie point (more than 600
°C) in the presence of magnetic field equal
to 0.5 ⋅ 10–4 Ò. Partial thermal remanent mag-
netizations (PTRM) were created from tem-
peratures 200�500 °C (mainly from 200 °C)
to 20 °C in the field of 0.5 ⋅ 10–4 Ò.
Saturation isothermal remanent magneti-
zation (SIRM), isothermal remanent magne-
tization (IRS) and the thermoremanent mag-
netization (TRM) were measured at the labo-
ratory.
All laboratory measurements were car-
ried out at the laboratory of �The main geo-
magnetic field and a petromagnetizm� of the
Institute of Physics of Solid Earth of RAS.
Natural remanent magnetization (NRM) and
thermal remanent magnetization (TRM) we-
re measured on a magnetometer JR-4 (Brno,
Czech Republic). SIRM (Mrs) was measured
on an automatic thermomagnetometer with
sensitivity 1 ⋅ 10–4 A/m. A saturation magne-
tization (Ms) was measured on a vibromag-
netometer with sensitivity 1 ⋅ 10–1 A/m. The
magnetic susceptibility was measured on a
Kappabridge KLY -2 (Brno, Czech Republic).
Stepwise demagnetization by increasing
alternating field was carried out on the RUV
semi-automatic installation in the range of
fields of 0�80 A/m. The PTRM were ther-
mally demagnetized by a routine technique
[Kobayashi, Fuller, 1967].
Results of the researches. Magnetic re-
searches of the well volcanogenic rocks sho-
wed that the measured magnetic parame-
ters of Mrs and Ms and TRM and Qn are
changing according to depth. Changes of
these parameters reflect variations of grain
size. Magnetic parameters of NRM, χ, SIRM
(Mrs), Ms and TRM were measured for study
of a minerals� magnetic domain state of the
Saatly superdeep well. There are three types
of different magnetic behavior, depending
on the grain size. The defined parameters
allowed calculating Qn factor and magni-
tude of Mrs
/Ms.
For use of magnetothermal criterion the
partial thermal remanent magnetizations (PTRM)
were created. The PTRM were acquired in
the range of temperatures 200�500 °C. For
identification of a magnetic domain state of
volcanic ferromagnetic grains of the Saatly
well the four magnetic criteria were used:
factor Qn, Mrs
/Ms, Lauri-Fuller�s criterion
and thermal magnetic criterion.
Short consideration of identification cri-
teria of a magnetic domain state had bro-
ught to light that that any of criteria does
not work completely well , even in case of
ensembles of �pure� grains. The found struc-
tural heterogeneities of grains [Novruzov,
Tselmovich, 2018] and also grains various
by structure and the sizes (magnetic rese-
arches of the structure and concentration)
make impossible to use only one of the men-
tioned criteria. Therefore in this article, the
Z. A. NOVRUZOV
206 Ãåîôèçè÷åñêèé æóðíàë ¹ 3, Ò. 41, 2019
The experimental results of definition of a magnetic domain structure of ferromagnetic
grains of volcanogenic rocks of the Saatly well section (interval of 3540�8126 m)
Criterion
Type
of rock Depts, m
Qn
Domain
state M rs /M s
Domain
state
Lauri�
Fuller
Thermo-
mag-
netic
Total
Andesite-
basalt
3540�3546 0,15 MD 0,04 SD � MD MD
Basalt 3660�3666 2,03 PSD 0,26 SD (PSD) � MD MD (PSD)
Basalt 3761�3767 0,29 MD 0,17 PSD SD MD MD
Basalt 3820�3825 0,51 MD 0,13 PSD SD � MD (PSD)
Basalt 3975�3981 1,71 PSD 0,13 PSD SD � PSD
Basalt 4062�4067 0,33 MD 0,10 PSD ? � MD (PSD)
Basalt 4165�4171 2,55 PSD 0,24 PSD SD MD PSD
Basalt 4250�4255 0,41 MD 0,12 PSD SD MD MD (PSD)
Basalt 4310�4315 0,18 MD 0,04 MD SD MD MD
Andesite-
basalt
4423�4428 0,31 MD 0,07 MD (PSD) SD � MD
Basalt 4516�4522 0,83 MD 0,06 MD (PSD) SD � MD
Basalt 4600�4608 1,30 PSD 0,03 MD SD MD MD (PSD)
Basalt 4634�4640 0,68 MD 0,07 MD (PSD) SD MD MD
Basalt 4686�4692 0,74 MD 0,08 MD (PSD) SD MD MD
Dolerite 4714�4719 0,32 MD 0,07 MD (PSD) SD � MD
Dolerite 4770�4777 0,81 MD 0,05 MD SD MD MD
Andesite-
basalt
4800�4807 1,82 PSD 0,04 MD MD � MD
Andesite-
basalt
4881�4885 0,60 MD 0,02 MD SD � MD
Basalt 4915�4922 1,39 PSD 0,02 MD SD MD MD (PSD)
Andesine 5036�5040 0,30 MD 0,04 MD SD MD MD
Gabbros-
norite
5129�5132 0,35 MD 0,06 MD (PSD) SD MD MD
Basalt 5185�5190 0,69 MD 0,03 MD SD MD MD
Basalt 5270�5273 3,00 PSD 0,06 MD (PSD) SD MD MD (PSD)
Basalt 5385�5390 1,40 PSD 0,04 MD SD � MD (PSD)
most often used in rock magnetism the four
criteria are applied. At the same time the
judgment of a magnetic domain state was
based on coincidence of results of identifi-
cation by the two or the three criteria.
The results of identification of a magne-
tic domain state of the ferromagnetic grains
are presented in Table. In Fig. 2 and Fig. 3
typical demagnetization curves of TRM and
SIRM in alternating magnetic field (Lauri-
DOMAIN STRUCTURE OF VOLCANICS� FERROMAGNETIC GRAINS ... AZERBAIJAN
Ãåîôèçè÷åñêèé æóðíàë ¹ 3, Ò. 41, 2019 207
SD � single-domain particles; PSD � pseudo-single-domain particles; MD � multi-domain
particles.
Continuation of Table
Basalt 5467�5474 0,53 MD 0,05 MD SD � MD
Andesite 5544�5550 1,89 PSD 0,07 MD (PSD) SD MD MD (PSD)
Basalt 5634�5636 5,95 PSD 0,08 MD (PSD) SD MD MD (PSD)
Andesite-
basalt
5746�5750 2,12 PSD 0,11 PSD SD MD PSD
Andesite 5828�5830 5,48 PSD 0,08 MD (PSD) SD MD MD (PSD)
Andesite 6000�6003 1,36 PSD 0,07 MD (PSD) SD � MD (PSD)
Andesite 6174�6178 0,68 MD 0,03 MD ? � MD
Andesite-
basalt
6290�6295 1,00 MD 0,05 MD ? � MD
Andesite 6430�6435 1,00 MD (PSD) 0,07 MD (PSD) SD � MD (PSD)
Andesite 6581�6583 1,72 PSD 0,08 MD (PSD) SD MD0 MD (PSD)
Andesite-
basalt
6740�6745 2,90 PSD 0,03 MD SD � MD (PSD)
Andesite 6877�6882 1,15 MD
(PSD)
0,06 MD (PSD) SD � MD (PSD)
Dolerite 6994�7003 1,87 PSD 0,13 PSD SD MD MD (PSD)
Dacite 7038�7048 0,50 MD 0,07 MD (PSD) MD � MD
Dacite 7172�7176 2,15 PSD 0,05 MD (PSD) SD � MD (PSD)
Rhyodacite 7264�7276 0,29 MD 0,31 SD (PSD) SD � MD (PSD)
Dolerite 7332�7343 0,49 MD 0,03 MD SD � MD
Rhyodacite 7420�7428 0,50 MD 0,04 MD SD MD MD
Dacite 7576�7578 0,85 MD 0,06 MD (PSD) SD MD MD
Dacite 7642�7646 0,25 MD 0,04 MD ? � MD
Dacite 7729�7738 1,77 PSD 0,05 MD (PSD) SD MD MD
Rhyodacite 7874�7878 0,21 MD 0,02 MD SD MD MD
Andesite-
dacite
7991�7993 0,65 MD 0,04 MD SD MD MD
Rhyolite 8103�8108 0,57 MD 0,03 MD SD MD MD
Dacite 8108�8126 0,80 MD 0,05 MD SD � MD
Fuller�s criterion) are represented. In Fig. 4
typical thermal demagnetization curves of
PTRM acquired at different temperatures (ther-
mal magnetic criterion) are presented.
We can see in the table that in most ca-
ses grains of magnetic minerals (carriers of
remanent magnetization), are in a multido-
main state. For an upper part of a section
of volcanogenic rocks (3540�5500 m), espe-
cially in the depth interval of 3540�5000m,
Z. A. NOVRUZOV
208 Ãåîôèçè÷åñêèé æóðíàë ¹ 3, Ò. 41, 2019
the pseudo-single-domain state often beco-
mes apparent. It demonstrates that rema-
nent magnetization carriers in this interval
of depths are the finest grains. These grains,
most probably, belong, to the second gene-
ration of grains of magnetite and the Ti-po-
or titanomagnetite determined on the basis
of microprobe analysis [Novruzov, Tselmo-
vich, 2018].
In the bottom of a section (5500�8126m)
is more often, and in the depth interval 7300�
8126 m one and all studied rocks contain
only multidomain grains of ferromagnetic
minerals.
This result presumably can be bound to
that circumstance that the low-temperature
metamorphism, especially metasomatism,
results in partial or complete collapse (repla-
cement) of fine grains of the ferromagnetic
minerals in the bottom of a section which
are contained in rocks.
At the same time artificial �enrichment�
of rocks with more coarse magnetic grains
is observed. As shown by means of micro-
probe [Novruzov, Tselmovich, 2018] of ore
grains the fine fraction of the deepest rocks
is presented, mainly, by fragments of the
crushed large grains.
Discussion of results. The done petro-
magnetic researches showed that in most
cases grains of magnetic minerals (carriers
of remanent magnetization) represent an en-
semble of multidomain particles. In upper
part of the section (3540�5500), especially
in the depth interval 3540�5000 m, the pse-
udo-single domain state is often presented.
It demonstrates that in this depth interval,
except of course (large volume) multidoma-
in grain generation, fine grains of other gene-
ration can bear a remanent magnetization.
The results of identification of a domain
structure presented in the summary table,
in the deeper section (5500�8126 m) are
more often, and in the depth interval 7300�
8126 m one and all ferromagnetic minerals
are demonstrating only multidomain grains
content. This result presumably can be ca-
used by the fact that in the deeper section
the generation (rather) of fine ferromagne-
tic grains can be partially or entirely destro-
yed due to occurrence of the low-tempera-
ture metamorphism (metasomatism). As a re-
Fig. 2. The alternating magnetic field demagne-
tization curves (TRM and SIRM) as Lauri-Fuller�s
criterion for upper part of section.
Fig. 4. Thermal demagnetization of the PTRM as
thermomagnetic criterion of identification of type
of domain state.
Fig. 3. The alternating magnetic field demagne-
tization curves (TRM and SIRM) as Lauri-Fuller�s
criterion for bottom part of section.
DOMAIN STRUCTURE OF VOLCANICS� FERROMAGNETIC GRAINS ... AZERBAIJAN
Ãåîôèçè÷åñêèé æóðíàë ¹ 3, Ò. 41, 2019 209
sult the share of the ferrimagnetic coarse
grains possessing a multidomain structure
increases.
As is obvious from the table the Lauri-
Fuller�s criterion is inapplicable for the com-
plex ensemble of ferromagnetic grains. Use
of this criterion eventuates in the diametri-
cally opposite data received on the basis of
the two or the three other criteria of doma-
in structure identificationThe thermal mag-
netic criterion is sensitive to manifestation
of single-domain (pseudo-single-domain) and
of multidomain ferromagnetic grains of in
the complex ensemble of grains.
Domain structure of volcanics� ferromagnetic grains:
A case study of the Saatly ultradeep well, Azerbaijan
Z. A. Novruzov, 2019
Various magnetic properties of magnetic minerals show strong grain-size depen-
dence. This dependency occurs because these parameters are influenced by the magne-
tic grain-size (domain state) of the samples. Natural rocks often contain a mixture of dif-
ferent magnetic minerals with different grain-size (domain states). Thus determination of
the domain state is important. The Saatly ultradeep well�s volcanics were used as a re-
search material. In the depth intervals of 3540�8126 m the volcanics had been revea-
led by the borehole. According to data of the petrographic and microprobe analysis the
volcanogenics of the ultradeep borehole is conditionally divided into a two parts: 1) the
upper part (an interval of depths of 3540�5500 m); 2) the bottom part (an interval of
depths of 5500�8126 m). In the upper part of section according to microprobe analysis
of volcanogenic rocks ore grains are presented by two generations: 1) large grain of ti-
tanomagnetites (Ti-poor), homogeneous or with a decay structures; 2) small-sized usual-
ly well faced grain of practically stoichiometric magnetite. So, homogeneous small-si-
zed grains or fragments of decay large grains (which are strongly changed chemically)
can have properties of single-domain particles. Here the ferromagnetic grains (especi-
ally in the depth interval 3540�5000 m) are often noted as a pseudo-single domain. In
the bottom part of the section the presence of multidomain grains of the Ti-poor titano-
magnetite is noted. And since depths of 7000 m the oxidized magnetite is also observed.
The pseudo-single-domain grains are fixed much less than in the upper section. And,
since a depth mark of 7300 m and deeper, they are absent wholly. In the result of rese-
arch it turned out that the ferromagnetic is presented by basically multidomain grains.
It should be noted that Lauri-Fuller�s Criterion is not applicable at identification of a
domain structure of the complex ensemble of the ferromagnetic grains.
Key words: indirect magnetic criteria, magnetic domain state, volcanogenic rocks,
super deep well.
References
Abdullaev, R. N., & Salakhov, A. S. (1983). Com-
parative characteristics of Jurassic volcanics
Kurdamir-Saatli buried uplift and the north-
eastern part of the Lesser Caucasus. Izvestiya
AN AzSSR, ser. Nauka o Zemle, (4), 14�23 (in
Russian).
Abdullaev, R. N., Salayeva, F. O., & Salakhov, A. S.
(1984). Magmatic complexes of the Middle Ku-
rin depression. In Questions of mineralogy and
lithology (pp. 85�90). Baku (in Russian).
Kobayashi, K., & Fuller, M. D. (1967). Vibrati-
on magnetometer. In D. W. Collinson, K. M. Cre-
er, & S. K. Runcorn (Eds.), Methods in palaeo-
Z. A. NOVRUZOV
210 Ãåîôèçè÷åñêèé æóðíàë ¹ 3, Ò. 41, 2019
magnetism (pp. 450�456). Amsterdam-Lon-
don-New York: Elsevier.
Novruzov, Z. A., & Tselmovich, V. A. (2018). Mic-
roroentgen spectral ore mineral analysis of Sa-
atly column well volcanic (depth interval 3540�
8126 m). Stratigraphy and sedimentology of
oil-gas basins (International scientific journal),
(2), 70�84.
Stackey, F. D., & Banerjee, S. K. (1974). The phy-
sical principles of rock magnetism. Amster-
dam: Elsevier, 195 p.
|