Access to this full-text is provided by Springer Nature.
Content available from Scientific Reports
This content is subject to copyright. Terms and conditions apply.
1
Scientific RepoRTS | (2018) 8:6923 | DOI:10.1038/s41598-018-25037-z
www.nature.com/scientificreports
Spectroscopic features of ultrahigh-
pressure impact glasses of the Kara
astrobleme
T. G. Shumilova1,2, V. P. Lutoev1, S. I. Isaenko1, N. S. Kovalchuk1, B. A. Makeev1, A. Yu. Lysiuk1,
A. A. Zubov1 & K. Ernstson3
The state of substances under ultrahigh pressures and temperatures (UHPHT) now raises a special
interest as a matter existing under extreme conditions and as potential new material. Under laboratory
conditions only small amounts of micrometer-sized matter are produced at a pressure up to 100 GPa
and at room temperature. Simultaneous combination of ultrahigh pressures and temperatures in
a lab still requires serious technological eort. Here we describe the composition and structure of
the UHPHT vein-like impact glass discovered by us in 2015 on the territory of the Kara astrobleme
(Russia) and compare its properties with impact glass from the Ries crater (Germany). A complex of
structural and spectroscopic methods presents unusual high pressure marks of structural elements in
8-fold co-ordination that had been described earlier neither in synthetic nor natural glasses. The Kara
natural UHPHT glasses being about 70 Ma old have well preserved initial structure, presenting some
heterogeneity as a result of partial liquation and crystallization dierentiation where an amorphous
component is proposed to originate from low level polymerization. Homogeneous parts of the UHPHT
glasses can be used to deepened fundamental investigation of a substance under extreme PT conditions
and to technological studies for novel material creations.
e state of substances under ultrahigh temperatures and pressures now raises a special interest both from the
point of view of fundamental questions of the existence of matter under extreme conditions1–7, and from the
point of view of practical interest with the aim of evaluating them as possible potential new types of materials8–11.
Under laboratory conditions, at extremely high pressures, only small amounts of matter are produced, which
are limited to particles of micrometer size at a pressure up to 100 GPa, where the synthesis is carried out preferably
at room temperature1–5. Simultaneous combination of ultrahigh temperatures and pressures can theoretically be
accompanied by the formation of specic materials7, which still requires a serious study. Among the objects of
natural origin, impact glasses represent interest12–16, and UHPHT melt-type varieties are of particular interest,
since their formation is caused by high pressures (35–90 GPa, up to hundreds of GPa) with fast subsynchronous
high-temperature impact (up to 3000 °C and higher)17–19. Within the considered problem, the advantage of nat-
ural impact glasses is also their much larger volume and preservation of their structure over millions of years.
During our studies of diamond-bearing impactites of the 70 Ma old Kara astrobleme (Russia), we for the rst
time discovered high pressure post-impact liquation glasses with coesite20, which may be interesting for deepened
research of their phase state and evaluation of physical properties.
In the context of a large interest in high-pressure glasses as novel promising materials and with regard to
strongly limited experimentally produced matter we suggest that the recent nd of natural vein-like UHPHT
glasses at the Kara astrobleme20 could be pioneering. e glasses, which were formed under extreme PT condi-
tions as essentially macroscopic bodies, can be perspective as possible UHPHT materials and/or valuable sub-
stance for fundamental study of matter under extreme conditions. With a complex of spectroscopic methods, we
examined the natural UHPHT impact glasses to understand specics of their composition, structure and char-
acter of UHPHT memory through 70 Ma age and level of post impact alteration. For the latter we compare the
Kara UHPHT glasses characteristics with substantially younger diamond-bearing glasses from the about 15 Ma
old Ries impact crater (Germany).
1Institute of Geology, Komi Scientic Center of Ural Division of Russian Academy of Sciences, Pervomayskaya st. 54,
Syktyvkar, 167982, Russia. 2Hawaii Institute of Geophysics and Planetology, University of Hawaii at Manoa, 1680
East-West Road, Honolulu, HI, 96822, USA. 3Faculty of Philosophy I, University of Würzburg, Würzburg, Germany.
Correspondence and requests for materials should be addressed to T.G.S. (email: tg_shumilova@mail.ru)
Received: 3 November 2017
Accepted: 13 April 2018
Published: xx xx xxxx
OPEN
Content courtesy of Springer Nature, terms of use apply. Rights reserved
www.nature.com/scientificreports/
2
Scientific RepoRTS | (2018) 8:6923 | DOI:10.1038/s41598-018-25037-z
Geological position and sampling regions. Two impact craters, Kara (ca. 60 km) and Ust`-Kara
(ca. 25 km, predicted), are located in the north-east of the European part of Russia, and they belong to the
North-Eastern part of the Pay-Khoy Ridge structure (SM 1). e Kara astrobleme is completely set on land sur-
face, while Ust`-Kara is generally at seawater depth. At present the Kara astrobleme is observed as depression in
landscape and well expressed in the gravity and magnetic elds21,22.
It is proposed that these two astroblemes were formed about 70 Ma past21–23 by one bolide, which had been
destructed before its contact with the target. e geological structure of the Kara astrobleme is presented by a tar-
get consisting of Ordovician-Permian units of black shales, sandstones, limestones and other sedimentary rocks
with a total thickness more than 5 km, and by impactites – tagamites (massive melt rocks) and suevites21,22. Just
this year a complex of vein-like impact melt bodies with coesite has been discovered20 (Figs1 and 2). A unique
Figure 1. Massive impactite with vein-like ultrahigh pressure melt glasses in contact with black shales of the
Kara astrobleme target. (A) Outcrop on the right bank of the Kara river, (B) magnied part (red square in (A)),
red lines tracing the vein-like bodies of UHPHT melt glasses. (C–E) thin sections in transparent light, (C,E)
parallel polarizers, (D,F) crossed polarizers; (C,D) UHPHT glass (Gl) in suevite (Sv) transporting lithoclasts
(Lc). (E,F) crystallized impact melt (CIM) clast, CIM clast within suevite. Photos and microimages were made
by T.G.Shumilova.
Content courtesy of Springer Nature, terms of use apply. Rights reserved
www.nature.com/scientificreports/
3
Scientific RepoRTS | (2018) 8:6923 | DOI:10.1038/s41598-018-25037-z
feature of the Kara astrobleme are abundant aercoal diamonds20,24,25 formed aer bitumen coal-like carbona-
ceous matter, widely spread within the sedimentary rock target.
For the study we collected samples from natural outcrops at banks of the rivers: Kara (suevite, melt rock,
vein-like UHPHT glass), Anaroga (clast-poor melt rock) and Sopchau (suevite) at the southern part of the Kara
astrobleme close to the outer rim of the impact structure (SM 1).
e about 15 Ma old 26 km-diameter Ries crater in Bavaria (Germany) (also named Nördlinger Ries or Ries
Basin) is one of the most studied impact craters on the Earth26, which is accepted as a classic middle-size impact
structure in a mixed, sedimentary-crystalline target. e geology of the crater and impact glasses have been
described elsewhere26–30. In this work we used suevites sampled in the Altenbürg and disused Polsingen quarries.
Results
Chemical and phase composition of impact glasses. e solidied impact melts of the Kara astrob-
leme and the Ries crater are in various degree crystallized melts (Fig.2, SM 2, 3) represented by massive bodies
of tagamites; lenses, bombs and ashes in suevites, and also by vein-like formations in massive complexes, recently
discovered by us.
e analysis of the geochemical specicity of impact glasses (IG) and crystallized impact melts (CIM) of the
Kara astrobleme and the Ries crater generally showed aluminosilicate compositions (SM 4), which occupy a wide
eld, covering the regions from basic to ultra-acid composition and a wide range of contents of alkaline com-
ponents (Fig.3, SM 5). Such a diversity of impact glass compositions can be explained rst of all by the impact
melting process having aected a complex lithological interbedding of heterogeneous sedimentary rocks.
X-ray diraction of the impact glasses material from the Kara astrobleme shows an amorphous component of
quartz-feldspar glass (Fig.4). e X-ray patterns show reexes indicating the presence of feldspar, variously disor-
dered due to the degree of crystallization of the impact melt, as well as of quartz. A weak and strongly broadened
reex corresponds to interplanar spacing 1.4 nm of clay minerals, while a small narrow reex, corresponding to
0.309 nm be referred to the coesite lattice planes 040.
e diraction patterns of the glasses from the Ries crater (Fig.4) are characterized by a similar amorphous
halo reecting the presence of a signicant fraction of an amorphous component, and they also have reexes of
feldspar, quartz and weak broadened reections 0.253 and 0.171 nm, which possibly refer to the reections from
the magnetite lattice planes 311 and 422 (SM 6).
Local analysis by Raman spectroscopy. Raman spectroscopy of the Kara impact glasses was carried
out to identify in detail the components of solidied impact melts from UHPHT vein-like bodies from the Kara
astrobleme and the impact glasses of the Altenburg suevites (Ries crater) for comparison. e diagnostics was
performed in locally homogeneous areas, where the analysis points were focused on optically visible crystallites
and amorphous regions. In both cases the impact glasses proved to be relatively inhomogeneous, characterized
by dierent amounts of microcrystallites of pyroxene and coesite (for the Kara astrobleme) and magnetite (for
both astroblemes) (Fig.5, SM 7, 8). UHPHT impact glasses of the Kara astrobleme are also characterized by the
presence of a carbon matter in the graphite-like (glass-like) state or in the state of amorphous carbon - sputtered
a-C carbon31. At that in a number of cases we determined the co-occurrence of UHPHT silica glass, coesite and
carbon matter in a conned volume of only about 1 μm3 (Fig.5, spectrum KR-115-p19, SM 7, 8).
Figure 2. SEM images of dierent regions in UHPHT impact glass from a vein-like body in the Kara
astrobleme, Kr-12–115, Kara river. (A) aluminosilicate glass with some pyroxene crystallites, (B) coesite-
bearing silica glass drop within aluminosilicate glass surrounding matter. Black rounded regions in (B) are
pores, produced probably at vacuum probe preparing by recovering of liquid (water-rich) inclusions in glass.
GlFsp and GlSiO2 – feldspar and quartz melting glasses, Coe – coesite, Px – pyroxene, Py – pyrite.
Content courtesy of Springer Nature, terms of use apply. Rights reserved
www.nature.com/scientificreports/
4
Scientific RepoRTS | (2018) 8:6923 | DOI:10.1038/s41598-018-25037-z
Feldspar glasses (Fig.5, spectrum KR-117-p6, KR-118a-p10, SM 7, 8) are characterized by dierent position
and structure of the general glass band pointing to variety in polymerization level toward to very small structural
elements and their heterogenity. In some cases the maximum band position can be downshied up to 80 cm−1
compare to glass produced at the ambient pressure.
According to the obtained spectra, the UHPHT impact glasses of the Kara astrobleme are characterized by a
wide general band, oen asymmetric with a broad non-structured or structured shoulder toward a red shi in the
Figure 3. e feldspar ternary diagram of compositions of clastogenic impact glasses from suevites and
UHPHT vein-like glasses of the Kara and Ries astroblemes: 1 – Anaroga river; 2 – Kara river; 3 – Sopchau river;
4 – Ries astrobleme, Altenbürg quarry. Points belonging to UHPHT vein-like glasses from the Kara river are
encircled in green.
Figure 4. Diraction patterns of solidied impact melts with dierent level of crystallinity. Fls – feldspar, Qtz –
quarts, Coe – coesite, Clc – calcite, Anc – analcim, Mgt – magnetite, Mc – mica, Chl – chlorite, Smt – smectite.
Content courtesy of Springer Nature, terms of use apply. Rights reserved
www.nature.com/scientificreports/
5
Scientific RepoRTS | (2018) 8:6923 | DOI:10.1038/s41598-018-25037-z
spectrum. e general structural band of the impact silica glasses has a full width at half maximum (FWHM) of
about 200 cm−1 and corresponds to δ(Si-O-Si) bonds of the polymerized structure with a maximum position at
416 cm−1, which is substantially shied from the usual position32 at 440 cm−1. Unlike glasses, produced at normal
pressure, the Raman spectra of UHPHT silica impact glasses are also characterized by the absence of D1 and D2
bands (490 and 603 cm−1 respectively) that refer to the three- and four-membered rings of SiO4 tetrahedra in sil-
ica glass32. ese features probably characterize the substantially smaller sizes of the structured regions as a result
of the lower degree of polymerization caused by a rapid cooling of UHPHT impact melt.
e feldspar glasses are characterized by dierently positioned general Raman bands with similar FWHM to
low pressure glasses (about 250–300 cm−1). Sometimes the UHPHT feldspar glasses have a complicated general
band consisting of several sub-bands with a single FWHM about 100 cm−1 in total getting up to 400–500 cm−1
(Fig.5, SM 5, spectrum KR12-118-p10).
e presence of a glass-like carbon matter within the UPH silica glasses is determined by the presence of the
bands D = 1347 cm−1 and G = 1606 cm−1, as well as by a broad band of the second order - 2937 cm−1. Sputtered
a-C carbon (Fig.5, spectrum KR12–118-p10, SM 5) is diagnosed according to31 by broad bands of 1424, 1608,
2912 cm−1, corresponding respectively to D, G and second order bands.
e presence of a large amount of water with a dierent structural state in glass is noteworthy for UHPHT
impact glasses from the Kara astrobleme. e water is predominant in the molecular (absorbed) form, but can
partly be chemically bonded to structural radicals in the glass (Fig.5, spectrum Kr-2-15-p4, SM 7, 8). e Raman
spectroscopy allowed us to estimate to some extent the relative water content in UHPHT impact glasses according
to the ratio of the integrated intensities of the structural band of the glass-forming component and water. is
ratio in the studied material ranges from 0 to 4.5, which indicates a signicant inhomogeneity of the uid in the
solidied impact melts. According to experimental data33, the water content in UHPHT glasses can make several
percent, which conforms with our previous studies using gas chromatography and thermogravimetric analysis20.
FTIR spectroscopy characteristics. e main features of the FTIR spectra of the samples from the Kara
crater and the Ries relate to vibrational modes of framework aluminosilicate melt glasses (Fig.6). e most
intense IR absorption bands are due to the stretching asymmetric (1000–1200 cm−1) and bending (∼470 cm−1)
vibrations of the bridge oxygen of the glass Si-O-Si bonds. In addition a weak broad band at ∼800 cm−1 refers
to the symmetric stretching vibration of SiO4 units of this matrix. Against the background of the last band, very
weak traces of the characteristic doublet (779, 798 cm−1) of crystalline quartz are noticeable. In the spectra of all
glass samples, the high-frequency shoulder of the 470 cm−1 band is complicated by weak bands in the region of
540–640 cm−1 that relate to the bending vibration O-Si (Al) -O and O-Si-O bands in the plagioclase lattice. e
presence of weak bands at 1430 and 880 cm−1 in the FTIR spectra indicates an insignicant amount of carbonate
and pyroxene in the glass samples.
Iron state in UHPHT impact glasses by Mössbauer spectroscopy data. e obtained Mössbauer
spectra of the impact glasses of both astroblemes contain only paramagnetic doublets (Fig.7). A sextet structure
from magnetic phases is not detected against noise background, although X-ray phase analysis and Raman spec-
troscopy revealed traces of magnetite in the sample of the glass from the Ries crater (Fig.4). Analogous spectra
Figure 5. Raman spectra of impact glasses from the Kara astrobleme (KR) and the Ries crater (R). e color
marked elds correspond to spectral ranges of glass, carbon and water. Color marked elds – regions of glass
(Glass), carbon substance (CS) and H2O bands.
Content courtesy of Springer Nature, terms of use apply. Rights reserved
www.nature.com/scientificreports/
6
Scientific RepoRTS | (2018) 8:6923 | DOI:10.1038/s41598-018-25037-z
were observed in basaltic and meteorite glasses, as well as in tektites34–38. e main feature of the obtained spectra
is an asymmetric doublet with quadrupole splitting (QS) of about 2 mm/s and isomer shi (IS) of 1 mm/s, typical
for Fe2+ ions in 4–6 fold oxygen polyhedron sites. e high velocity peak is slightly wider and less intense than
the low velocity peak.
As shown by the simulation, the spectra of the Ries crater glass are satisfactorily approximated by a pair of
Fe2+ doublets (D1, D2) with dierent values of IS, QS and weak broadened Fe3+ doublet (D3). In similar spectra
of glass from the Kara crater against the background of the low velocity peak of Fe2+ doublets (D1, D2), a broad
component with a typically for Fe3+ ions small quadrupole splitting is clearly observed. It is a superposition of
at least two Fe3+ doublets (D3, D4) with dierent QS values. Besides these broadened doublets related to the
glass-like matrix, an additional doublet with narrow peaks (D′), sharpening the main doublets of Fe2+, is observed
in the spectrum of the glass from the Ries crater. And in the spectrum of the glass from the Kara crater there is a
high velocity peak at ∼3 mm/s (D″). e result of decomposition of the spectra in this model and parameters of
doublets, obtained in the tting, are shown in the Fig.7.
ESR of impact glasses. e obtained spectra of glasses in the range of the polarizing magnetic eld 0–0.7 T
are shown in Fig.8. ey contain a wide band with g = 2.2–2.3 (line widths at extremum points ΔBpp = 210 mT),
on which narrow lines with g-factors 4.3 and 2.02 (ΔBpp ∼ 8 and 20 mT, respectively) are superimposed, and also
a low-intense sextet of Mn2+ ions in the lattice of calcite impurities. e ESR spectrum of the Ries crater glass
is dominated by narrow lines 4.3 and 2.02 contrasting with a broad band 2.2–2.3 in the Kara crater glass. With
a ratio of 10:7 the integral intensity of a signal 4.3 (IΔBpp2, where I – peak intensity, ΔBpp - width at extremum
points) in the spectra of the glasses from the Ries and Kara craters does not dier signicantly. In both glasses
the wide band is weakly anisotropic, since the shape of its low-eld part slightly changes when the tube with the
sample rotates in the resonator. Lines 4.3 and 2.02 are isotropic. When the sample is grinded, the anisotropy of the
broad band decreases. is signal can be attributed to Fe3+ ions in ferrous mineral inclusions (pyroxenes) in glass
or clusters of iron ions in the glass framework.
A narrow signal of free radicals with g = 2.00 is also present in the spectra of the Kara samples, the detailed
structure of which is shown in the Fig.8B. e free radical line is formed by a singlet with g = 2.0025–2.0028
(ΔBpp ∼ 0.3–0.5 mT) and a quartet of approximately equidistant lines with dierent intensities and widths. e
singlet line refers to carbon radicals (•C) in the carbon matter. e quartet is characterized by a medium g-factor
2.0035 and a hyperne splitting 2.44 mT. Structure-analogous signals are oen observed in the EPR powder spec-
tra of alkali feldspars and silica with impurities of organic matter. In feldspar spectra, this signal is usually attrib-
uted to the ammonia radical39 NH3+, and in the spectra of silica to the methyl radical40CH3. e value of g-factor
and hyperne splitting of the radicals in the Kara glass spectrum allows attributing them to the NH3+ radical41.
Discussion
e character of the geochemical specicity of the studied impact glasses, determined by overlapping with the
most part of volcanic rock elds on the TAS diagram (SM 5), as well as a signicant coverage of “forbidden eld”
Figure 6. FTIR absorption spectra of impact glasses and standard samples: Fls – plagioclase (labrador An50–70),
Gl – aluminosilicate glass, Qtz – quartz, Aug – pyroxene (augite), Clc– calcite.
Content courtesy of Springer Nature, terms of use apply. Rights reserved
www.nature.com/scientificreports/
7
Scientific RepoRTS | (2018) 8:6923 | DOI:10.1038/s41598-018-25037-z
for feldspars (Fig.3) indicates a signicant geochemical dierence between the impact glasses and CIM glasses
of the Kara astrobleme and glasses of volcanic origin42–45, characterized by a more homogeneous composition for
individual volcanic structures and batch eruptions.
During structural studies we established that the massive bodies of melt impactites, as well as numerous inclu-
sions of bombs, lens-like bodies, and ash material in suevites, are largely represented by substantially crystallized
impact melts (Fig.2A). erefore, in the context of the study, the embedded real vein-like glass bodies including
UHPHT glass with a signicant share of coesite are the most interesting features for further detailed study.
e water found by Raman spectroscopy in the impact glass could greatly aect impact melt solidication
temperature, lowering it signicantly, thereby intensively decreasing the viscosity of the impact melt and, hence,
substantially increasing its mobility. Besides, the presence of water can also aect the preservation of impact dia-
monds. It should also be noted that the water inclusions nding within the UHPHT impact glasses support the
hypothesis of the Kara impactites formation at aquagenic conditions21. e studied samples of impact glass from
the Ries crater generally do not contain water, and the analyzed optically homogeneous glass regions are charac-
terized by almost complete absence of a crystalline component. e position and structure of the general Raman
bands are close to ordinary low-pressure aluminosilicate glasses (Fig.5, spectrum R13-5-1-p3).
Comparing the obtained Raman spectra of impact glasses, it should be noted that unlike the glasses from the
Ries crater, the Kara vein-like UHPHT impact glasses are characterized by a signicantly greater heterogeneity
with respect to the degree of polymerization, which is signicantly lower compared to conventional glasses32. is
heterogeneity of the UHPHT aluminosilicate glass matrix is attributed to drops of pure silica glasses with coesite
(Fig.2B) and carboniferous matter (Fig.5, spectrum KR12-115-p19).
Figure 7. Mössbauer spectra of the impact glasses of the Ries (A) and Kara (B) craters. Indicated components
are the results of the best ts. Residual spectra are shown below. Mössbauer parameters of the best ts
components, where IS (mm/s), QS (mm/s), (mm/s), A (%) – isomer shi, quadrupole splitting, half-width
of doublet peaks, relative area of the doublet. Fe3+/ΣFe = ΣAFe3+/(ΣAFe2+. + kΣAFe3+), where k is the ratio of
probabilities of Mössbauer transition of octahedral complexes Fe3+ and Fe2+, k is taken equal to 1.232,33.
Content courtesy of Springer Nature, terms of use apply. Rights reserved
www.nature.com/scientificreports/
8
Scientific RepoRTS | (2018) 8:6923 | DOI:10.1038/s41598-018-25037-z
e FTIR data of bulk specimens do not allow revealing the specic atomic-level structure of the UHPHT
impact glasses, including its ne structure. For a more informative analysis local methods of IR spectroscopy with
reference to various homogeneous parts of the vein-like type impact glass are required.
From local detailed Raman spectroscopy it is evident that the crystalline quartz and feldspar X-ray reections
and characteristic IR absorption bands rather originate from a certain quantity of relict quartz crystal-clasts and
lithoclasts of polymictic sandstones from the target rocks. Raman studies at microlevel do not reveal any newly
formed inclusions of quartz and feldspars directly in the UHPHT impact glasses.
e presence of iron in UHPHT impact glasses allows studying some ne features of the glasses structure
under the study, since it significantly expands the possibilities of applying sensitive methods, in particular
Mössbauer spectroscopy and electron spin resonance. Wide asymmetric peaks from iron sites in the glass and
relatively narrow peaks from iron sites of included crystalline phases are characteristic of Mössbauer spectra.
In the Mössbauer spectra of glasses from Kara and Ries craters (Fig.7), the most intense doublet D1 with
nearly equally large widths (0.5–0.6 mm/s) and the contribution to the total area of the spectral contour is char-
acterized by IS, characteristic of 6-fold oxygen polyhedra with Fe2+, that is, the octahedral type of sites in the
aluminosilicate glass46–49. e QS parameter in the glass from the Kara crater is thus signicantly higher than in
the glass from the Ries crater. Taking into account the dependence of QS on the degree of distortion of octahedral
polyhedra48, it can be concluded that the Fe2+ octahedral sites in the glass from the Kara crater is characterized by
relatively low distortion. e second doublet Fe2+ (D2) has a smaller QS value (1.8–1.9 mm/s) and a much smaller
isomer shi (0.9–1.0 mm/s). A decrease of IS parameter indicates a decrease of the coordination number of oxy-
gen polyhedron Fe2+ to 4, that corresponds to the tetrahedral type of the position. For the glass from the Ries cra-
ter, the representativeness of the Fe2+ tetrahedral sites is three times higher than in the glass from the Kara crater.
e additional low-intense doublet D′ Fe2+ in the spectrum of the glass from the Ries crater has a small width
of peaks, which is a characteristic of a crystalline phase, and possibly relates to one of the Fe2+ octahedral sites
of the pyroxene lattice49. In the spectrum of the glass from the Kara crater, the doublet D″ with a relatively small
peak width has high values of IS and QS (1.35 and 3.5 mm/s). Note that the doublets with the IS and QS large
values in our data were observed earlier neither in synthetic nor natural aluminosilicate glasses nor in impact
meteorite and tektites glasses34–38. Similar values of these parameters were observed for Fe2+ ions in 8-fold sites
of garnets48,49, which lack an independent conrmation among the crystalline inclusions within the Kara glass.
Perhaps 8-fold sites of Fe2+ in the Kara UHPHT glass directly evolved at the glass network formation under
UHPHT conditions.
Isomer shis of Fe3+ doublets (0.35–0.38 mm/s) correspond to octahedral sites of iron within dierent sil-
ica glass and mineral substances46,49. A doublet D3 with the same values of IS, QS also presents in the Kara
sample spectrum, but it is supplemented by a strongly broadened doublet D4 with a large quadrupole splitting
(1.14 mm/s). e areas of the spectral contours of D3, D4 doublets are approximately equal (Fig.7C). In the case
of Fe3+ ions, the rising of the QS value indicates increased distortion of octahedral sites for the D4 doublet. For
Ries crater glass spectra only one low-intense doublet D3 with a large peak width and QS ∼ 0.7 mm/s is deter-
mined. It is known that the Fe3+ doublets can be explained by iron both in aluminosilicate glass framework and
mineral inclusions, for example, pyroxene. In contrast with the glass from the Ries crater, pyroxene a Fe2+ doublet
in octahedral sites was not detected in the spectrum of the glass from the Kara crater. For the latter the Mössbauer
data show the degree of iron oxidation (Fe3+/ΣFe in Fig.7C) 3 times higher than in the Ries impact glass. It is
possible that Fe-ions in pyroxene of the Kara crater glass were oxidized to Fe3+ state.
Figure 8. ESR spectra of impact glasses from the Kara astrobleme (upper spectrum) and Ries crater (bottom
spectrum): A – the full range spectra; B – magnied part region of g = 2.00. Power of the microwave eld is 35
and 7 mW for A and B). e spectra of samples are reduced to the same registration conditions.
Content courtesy of Springer Nature, terms of use apply. Rights reserved
www.nature.com/scientificreports/
9
Scientific RepoRTS | (2018) 8:6923 | DOI:10.1038/s41598-018-25037-z
e ESR method detects only the signals from Fe3+ ions in iron-containing glass matrix at room temperature.
e lines of bivalent iron, due to a very strong spin-phonon interaction, were resolved in EPR spectra only for
the specimens cooled to liquid helium temperature. e isotropic lines with g = 4.3 and 2.02 are the characteris-
tics of ESR spectra of various glasses with an impurity of isolated Fe3+ ions, including aluminosilicate ones50–53.
It is considered that these signals are associated with two types of Fe3+ ions isolated in the glass framework:
(1) g = 4.3 − ions in purely rhombic strong crystal eld, E/D = 1/3, D >> hν (D, E − parameters of axial and
rhombic component of crystalline elds, hν ∼ 10 GHz); (2) g = 2.0 - ions in a strong axial eld E/D = 0). Fe3+
ions in the rhombic eld relate to strongly rhombic distorted tetrahedral positions and iron ions in the axial eld
(g = 2.0) − to axially distorted octahedral positions. In the Mössbauer spectra (Fig.7) the doublet of the tetrahe-
dral positions of ferric iron (IS = 0.2–0.32 mm/s) may have been masked by the intense components of the other
iron positions.
e unusual feature of the UHPHT glass from the Kara crater is the tiny presence of carbon and ammonia rad-
icals (NH3+) described in the ESR data (Fig.8B). In mineral matrixes, such as K-feldspars, the ammonia radicals
are formed usually from NH4+ cations under ionizing radiation being stable below 200 °C39–41. Precursors (NH4+)
of the analyzed ammonia radicals in the Kara crater glasses perhaps were formed by the interaction of nitrogen
oxides with organic matter during heating of the target rocks. Following the high temperature impact conditions
the carbon radicals were formed during thermal carbonization of the organic matter. As for the paramagnetic
NH3+ radicals, they could have originated under natural radiation aer cooling of the vein-like glasses.
Conclusions
Our studies show that the UHPHT glasses generally consist of an amorphous matter of feldspar composition.
Compared to the clastic glasses in suevites, the compositions of the vein-like glasses are localized within a small region
in the chemical diagrams having quite stable anorthoclase content and contain small drops of coesite-containing silica
glass. A complex of structural and spectroscopic methods presents unusual high pressure marks of structural elements
in 8-fold co-ordination that had been described earlier neither in synthetic nor natural glasses.
is comprehensive and complex study for the rst time resulted in a rather detailed characterization of the
impact glasses of the Kara astrobleme, including a low degree of polymerization of silicate framework on the basis
of Raman spectroscopy data. By complex spectroscopic and microscopic data we also determined a signicant
structure and composition heterogeneity of the UHPHT glasses probably connected with fast partial liquation
and crystallization dierentiation. In spite of the long post-impact period of about 70 Ma, this type of glasses
preserve mostly the initial structure without essential altering over time and under hydrothermal processes. us,
the Kara UHPHT glasses can be used to deeper fundamental studies by local and high resolution methods for
understanding of a substance state under extreme PT conditions.
Methods
For the study we selected monomineral fractions of impact glasses by a binocular from impactites of Kara astrob-
leme and Ries crater, sampled during eldwork in 2013–2017. e analysis of UHPHT glasses of the Kara astrob-
leme was performed in comparison with glasses from the Ries crater. e analytical works were carried out by the
equipment of Center for Collective Usage “Geonauka” of Institute of Geology Komi SC UB RAS.
e preliminary optical observations were performed using POLAM R-312 polarization microscope (LOMO,
Russia) with and without an analyzer.
e elemental composition of the glasses was analyzed by microprobe analysis combined with scanning elec-
tron microscopy20,45,54,55, which is common today and most informative to study natural inhomogeneous sys-
tems, including impactites, where the detrital component introduces signicant distortions during the study by
chemical methods. We used a scanning electron microscope TESCAN VEGA3 (Czech Republic) with Oxford
instruments X-Max energy dispersive device, analyst S.S. Shevchuk.
For a high-quality assessment of the phase mineral composition of the impact glasses in volume we used
X-ray phase analysis (XRD) with a Shimadzu XRD-6000 diractometer. e conditions of the survey – CuKα, 30
m, 30 kV, Ni-lter, scanning step 2θ 0.05°, 1 deg/min. We used pounded specimens placed on a at aluminum
substrate. e local analysis of the structure of the impact glasses and the phase diagnostics of its inclusions were
performed using a high-resolution Raman spectrometer LabRam HR 800 (Horiba Jobin Yvon). e conditions
for recording the spectra were as follows: monochromator grating - 600 g/mm, confocal hole - 300 μm, slit - 100
μm, exposure time 10 sec, number of signal accumulation cycles - 3, power of an excitation Ar + laser (488 nm)
1.2 mW. e size of analyzed regions of the samples was 2.5 μm2. e spectra were recorded at room temperature.
To analyze ne features of the structure of impact glasses we used infrared spectroscopy. Infrared spectra were
obtained by a FTIR spectrometer Lumex FT-02 in the range 400–4000 cm−1 at 256 scans and with an instrumental
resolution 2 cm−1. e specimens were prepared as pressed pellets of 800 mg KBr and 1.4–1.7 mg of a powder specimen.
Electron spin resonance (ESR) spectra were obtained by a radiospectrometer SE/X-2547 (“RadioPAN”,
Poland) in X-frequency range with 100 kHz HF modulation at room temperature of the samples. We used RX102
rectangular resonator with TE102 mode. g-Factors were calibrated according to the standard Li0:LiF (g0 = 2.00229).
e samples weighed from 30 to 60 mg and were rubbed in a jasper mortar to the state of “powder”. e recorded
spectra were reduced to the same value of the frequency of SHF quantum, amplication and sample weight. In
some cases, the averaging of the spectrum for 3–5 scans was performed to reduce noise.
e Mössbauer 57Fe spectra were recorded on a spectrometer MS-1104Em in the mode of a thin absorber in
the range of −11 to +11 and −4 to +4 mm/s at room temperature of the preparation. Pounded samples (10–
20 mg) were used for spectra accumulation. e accumulation time of spectra was from 100 to 200 hours. e
isomer shi was determined relatively to α-Fe. When processing the spectra, Univem standard soware of the
spectrometer was used.
Content courtesy of Springer Nature, terms of use apply. Rights reserved
www.nature.com/scientificreports/
10
Scientific RepoRTS | (2018) 8:6923 | DOI:10.1038/s41598-018-25037-z
References
1. Benmore, C. J. et al. Structural and topological changes in silica glass at pressure. Phys. ev. B 81, 054105, https://doi.org/10.1103/
PhysevB.81.054105 (2010).
2. Bolmatov, D., Brazhin, V. V., Tracheno, . ermodynamic behavior of supercritical matter. Nature Communications 4, Article
Number 2331, https://doi.org/10.1038/ncomms3391 (2013).
3. Deschamps, T., Margueritat, J., Martinet, C., Mermet, A. & Champagnon, B. Elastic Moduli of Permanently Densied Silica Glasses.
Scientic eports 4, 7193, https://doi.org/10.1038/srep07193 (2014).
4. ono, Y. et al. Ultrahigh-pressure polyamorphism in GeO2 glass with coordination number 6. PNAS 113(13), 3436–3441 (2016).
5. Pronin, A. A. et al. A. Glassy dynamics under superhigh pressure. Phys. ev. E. 81, 041503 (2010).
6. Sato, T. & Funamori, N. High-pressure structural transformation of SiO2 glass up to 100 GPa. Phys. ev. B 82, 184102 (2010).
7. Guerette, M. et al. Structure and Properties of Silica Glass Densied in Cold Compression and Hot Compression. Scientic eports
5, 15343, https://doi.org/10.1038/srep15343 (2015).
8. Shultz, M. M. & Mazurin, O. V. Contemporary concept of glass structure and their properties. Leningrad: Science. 200 p. (in
ussian) (1988).
9. Brazhin, V. V., Fomin, Y. D., Lyapin, A. G., yzhov, V. N. & Tracheno, . Two Liquid States of Matter: A Dynamical Line on a
Phase Diagram. Phys. ev. E 85, 031203 (2012).
10. Stebbin, sJ. F. & Poe, B. T. Pentacoordinate silicon in high-pressure crystalline and glassy phases of calcium disilicate (CaSi2O5).
Geophys. es. Lett. 26, 2521–2523 (1999).
11. Xue, X., Stebbins, J. F., anzai, M. & Trønnes, . G. Silicon coordination and speciation changes in a silicate liquid at high pressures.
Science. 245, 962–964 (1989).
12. Impact craters at the Mesozoic and Cenozoic boundary. Ed. Masaitis V. L., Leningrad: Naua, 191 p. (in ussian) (1990).
13. Lyutoev, V. P., Lysyu, A. Yu. Structure and texture of silica of impactites of the ara astrobleme. Vestni IG omi SC UB AS. 9,
24–32 (in ussian) (2015).
14. French, B. M. Traces of Catastrophe: A Handboo of Shoc-Metamorphic Eects in Terrestrial Meteorite Impact Structures. LPI
Contribution No. 954. Lunar and Planetary Institute, Houston, Texas. 120 pp. (1998).
15. Melosh, H. J. Impact cratering – A geological process. Oxford Univ. Press, New Yor (1989).
16. obertson, P. B. & Grieve, . A. F. Shoc attenuation at terrestrial impact structures. In: oddy, D. J., Pepin, P. O. and Merill, . B.
(eds) Impact and explosion cratering. Pergamon Press, New Yor, 687–702 (1977).
17. Langenhorst, F. & Deutsch, A. Shoc experiments on pre-heated α-and β- quartz: I. Optical and density data, Earth Planet. Science
Letters 125, 407–420 (1994).
18. Schmitt, . T. Shoc experiments with the H6 chondrite ernouvé: pressure calibration of microscopic shoc eects. Meteoritics &
Planet. Sci. 35, 545–560 (2000).
19. Stöer, D. Glasses formed by hypervelocity impact. J. Non-Cryst. Solids. 67, 465–502 (1984).
20. Shumilova, T. G., Isaeno, S. I., Maeev, B. A. & Zubov, A. A. Liquation features of impact melt under ultrahigh pressure conditions.
Abstract volume: 200th Anniversary Meeting of the ussian Mineralogical Society, Saint-Petersburg, St. Petersburg Mining
University, 10–13 October 2017 (2017).
21. Mashcha, M. S. Morphology and structure of the ara and Ust'-ara astroblemes. International Geology eview. 33(5),
433–447, https://doi.org/10.1080/00206819109465701 (1991).
22. Shishin, M. A. et al. State Geological Map. Scale 1:1000000 (3rd editing). South-arsaya series. -41 – Amderma. eport. Saint-
Petersburg, VSEGEI, 383 p. (in ussian) (2012).
23. Trielo, M., Deutsch, A. & Jessberger, E. . e age of the ara impact structure, ussia. Meteoritics & Planetary Science. 33,
361–372 (1998).
24. Yezersiy, V. A. High pressure polymorphs produced by the shoc transformation of coals. International Geology eview. 28(2),
221–228, https://doi.org/10.1080/00206818609466264 (1986).
25. Shumilova, T. G., Isaeno, S. I., Ulyashev, V. V., azaov, V. A. & Maeev, B. A. Aer-coal diamonds: an enigmatic type of impact
diamonds/European Journal of Mineralogy. https://doi.org/10.1127/ejm/2018/0030-2715 (2018).
26. Pohl, J., Stöer, D., Gall, H., Ernstson, . e ies impact crater. Impact andExplosion Cratering (Ed. by oddy, D. J. Pepin, . O.
and Merrill, . B.), Pergamon Press, New Yor. 343–404 (1977).
27. Stöer, D. et al. ies crater and suevite revisited — Observations and modeling Part I: Observations. Meteoritics & Planetary Science.
48, 515–589 (2013).
28. Stöer, D. esearch drilling Nerdlingen 1973: Polymict breccias, crater basement, and cratering model of the ies impact structure.
Geologica Bavarica. 75, 443–458 (1977).
29. Osinsi, G. . Impact glasses in fallout suevites from the ies impact structure, Germany: An analytical SEM study. Meteoritics &
Planetary Science. 38(Nr 11), 1641–1667 (2003).
30. Osinsi, G. . Impact melt rocs from the ies structure, Germany: an origin as impact melt ows? Earth and Planetary Science
Letters. 226, 529–543 (2004).
31. Ferrari, A. C. & obertson, J. aman spectroscopy of amorphous, nanostructured, diamond-lie carbon, and nanodiamond. Phil.
Trans. . Soc. Lond. A. 362, 2477–2512 (2004).
32. Van Tran, T. T. et al. Controlled SnO2 nanocrystal growth in SiO2–SnO2 glass-ceramic monoliths. J. aman Spectros; https://doi.
org/10.1002/jrs.3099 (2011).
33. Qiang, S., Hongsen, X., Haifei, Z., Jie, G. & Dongye, D. Experimental studies of interaction between water and albite melts. Science
in China (Series D). 45(No. 11), 999–1007 (2002).
34. Dunlap, . A. An investigation of Fe oxidation states and site distributions in a Tibetan tetite. Hyperne Interactions. 110, 217–225
(1997).
35. ossano, S. et al. 57Fe Mössbauer spectroscopy of tetites. Phys. Chem. Minerals. 26, 530–538 (1999).
36. Lebedeva, S. M., Eremyashev, V. E. & Byov, V. N. Investigation of natural basalt glasses by the Mössbauer spectroscopy method.
Electronic scientic information journal “Bulletin of the Department of Earth Sciences of AS”. 1(21), (in ussian) (2003).
37. Abdu, Y. A. et al. Mössbauer study of glasses in meteorites: the D’Orbigny angrite and Cachari eucrite. Hyperne Interactions. 166,
543–547 (2005).
38. Fern, G. ., Mather, T. A. & Pyl, D. M. Investigation of near-source basaltic glasses using 57Fe Mössbauer spectroscopy. Hyperne
Interactions. 166, 705–708 (2005).
39. Matyash, I. V., Bagmut, N. N., Litovcheno, A. S. & Prosho, V. Y. Electron paramagnetic resonance study of new paramagnetrc
centers in microcline-perthites from pegmatites. . Physics and Chemistry of Minerals. 8, 149–152 (1982).
40. Ieya, M. New applications of electron spin resonance: dating, dosimetry and microscopy/copy ed. by Zimmerman, M.. &
Whitehead, N. Singapore; iver Edge: World Scientic, 500 p. (1993).
41. Sasaoa, H., Yamana, C. & Ieya, M. Is the quartet due toCH3 and C2H5 or NH3+ in alali feldspars? Appl. adiat. Isol. 47(No.
11/12), 1415–1417 (1996).
42. Albert, P. J. Volcanic glass geochemistry of Italian proximal deposits lined to distal archives in the central Mediterranean region.
PhD thesis, University of London (August 2012).
Content courtesy of Springer Nature, terms of use apply. Rights reserved
www.nature.com/scientificreports/
11
Scientific RepoRTS | (2018) 8:6923 | DOI:10.1038/s41598-018-25037-z
43. Fujioa, ., Furuta, T. & Arai, F. Petrography and geochemistry of volcanic glass: Leg 57, Deep Sea Drilling Project. In: Scientic
Party, Initial eports of the Deep Sea Drilling Project, 56/57 (eds), Initial eports of the Deep Sea Drilling Project (U.S. Govt.
Printing Oce), 56–57, 1049–1066 (1980).
44. Popov, V. ., Sahno, V. G., uzmin, Y. V., Glascoc, M. D. & Choi, B. . Geochemistry of Volcanic Glasses from the Paetusan
Volcano. Dolady Earth Sciences. 403(No. 5), 803–807 (2005).
45. Nichols, A. . L., Beier, C., Brandl, P. A., Buchs, D. M. & rumm, S. H. Geochemistry of volcanic glasses from the Louisville
Seamount Trail (IODP Expedition 330): Implications for eruption environments and mantle melting Geochemistry, Geophysics,
Geosystems. 1–21; https://doi.org/10.1002/2013GC005086 (2014).
46. D yar, M. D. A review of Mössbauer data on inorganic glasses: the eects of composition on iron valency and coordination. American
Mineralogist. 70, 304–316 (1985).
47. Menil, F. Systematic trends of the 57Fe Mössbauer isomer Shis in (FeOn) and (FeFn) polyhedral. Evidance of a new correlation
between the isomer shi and the inductive eect of the competing bond T − X (→Fe) (where X is O or F and T any element with a
formal positive charge). J. Phys. Solids. 46(No. 7), 763–789 (1985).
48. Burns, . G. Mineral Mössbauer spectroscopy: Correlations between chemical shi and quadrupole sptting parameters. Hyperne
Interactions. 91, 739–745 (1994).
49. Vandenberghe, . E. & De Grave E. Application of Mössbauer Spectroscopy in Earth Sciences. Mössbauer Spectroscopy. Tutorial
Boo (Ed. by Yutaa Yoshida and Guido Langouche). Springer-Verlag Berlin Heidelberg, 91–186 (2013).
50. Brodbec, C. M. Investigation of g-value correlations associated with the g = 4.3 ES signal of Fe3+ in glass. J. of Non-Crystalline
Solids. 40, 305–313 (1980).
51. lyava, Y. G. EP spectroscopy of disordered solid bodies. iga: Zinatie, 320 p. (in ussian) (1988).
52. Antoni, E. et al. Structural characteriuzation of iron-alumino-silicate glasses. J. of Non-Crystalline Solids. 345–346, 66–69 (2004).
53. Dunaeva, E. S., Ugolova, E. A., Emov, N. N., Minin, V. V. & Novotortsev, V. M. ES spectroscopy of FeIII ions in sodium silicate
glass. ussian Chemical Bulletin. 63(No. 1), 60–63 (2014).
54. asche, U., Schmitt, . T. & eimold, W.U. Petrography and geochemistry of impactites and volcanic bedroc in the ICDP drill
core D1c from lae El’gyytgyn, NE ussia. Meteoritics & Planetary Science. 48, No. 7, 1251–1286; https://doi.org/10.1111/
maps.12087 (2013).
55. owe, M. C., Ellios, B. S. & Lindeberg, A. Quantifying crystallization and devitrication of rhyolites by means of X-ray diraction
and electron microprobe analysis. American Mineralogist 97, 1685–1699, https://doi.org/10.2138/am.2012.4006 (2012).
Acknowledgements
e authors kindly thank M.F. Samotolkova and S.S.Shevchuk for help in analytical works with IR spectroscopy
and microprobe analysis, correspondently. e study has been nancially supported by the Russian Scientic
Foundation, project # 17-17-01080.
Author Contributions
T.Sh. introduced the original goal, organized and led the eld work of the Russian team, prepared specimens for
analytical work, participated in analytical studies, provided the data analysis and wrote the paper. V.L. provided
EPR spectroscopy, analyzed Mössbauer and IR spectroscopy, interpretation of X-ray diraction data, wrote the
paper. S.I. took part in eld studies, provided detailed high resolution Raman studies, conducted the analysis of all
Raman data, and contributed to writing the paper. N.K. took part in eld studies, in microprobe studies and data
interpretation, B.M. took part in eld studies, provided X-ray diraction. A.L. realized Mössbauer spectroscopy.
A.Z. took part in optical and Raman spectroscopy studies. K.E. organized sampling at the Ries impact structure
and took part at the paper editing.
Additional Information
Supplementary information accompanies this paper at https://doi.org/10.1038/s41598-018-25037-z.
Competing Interests: e authors declare no competing interests.
Publisher's note: Springer Nature remains neutral with regard to jurisdictional claims in published maps and
institutional aliations.
Open Access This article is licensed under a Creative Commons Attribution 4.0 International
License, which permits use, sharing, adaptation, distribution and reproduction in any medium or
format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Cre-
ative Commons license, and indicate if changes were made. e images or other third party material in this
article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the
material. If material is not included in the article’s Creative Commons license and your intended use is not per-
mitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the
copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.
© e Author(s) 2018
Content courtesy of Springer Nature, terms of use apply. Rights reserved
1.
2.
3.
4.
5.
6.
Terms and Conditions
Springer Nature journal content, brought to you courtesy of Springer Nature Customer Service Center GmbH (“Springer Nature”).
Springer Nature supports a reasonable amount of sharing of research papers by authors, subscribers and authorised users (“Users”), for small-
scale personal, non-commercial use provided that all copyright, trade and service marks and other proprietary notices are maintained. By
accessing, sharing, receiving or otherwise using the Springer Nature journal content you agree to these terms of use (“Terms”). For these
purposes, Springer Nature considers academic use (by researchers and students) to be non-commercial.
These Terms are supplementary and will apply in addition to any applicable website terms and conditions, a relevant site licence or a personal
subscription. These Terms will prevail over any conflict or ambiguity with regards to the relevant terms, a site licence or a personal subscription
(to the extent of the conflict or ambiguity only). For Creative Commons-licensed articles, the terms of the Creative Commons license used will
apply.
We collect and use personal data to provide access to the Springer Nature journal content. We may also use these personal data internally within
ResearchGate and Springer Nature and as agreed share it, in an anonymised way, for purposes of tracking, analysis and reporting. We will not
otherwise disclose your personal data outside the ResearchGate or the Springer Nature group of companies unless we have your permission as
detailed in the Privacy Policy.
While Users may use the Springer Nature journal content for small scale, personal non-commercial use, it is important to note that Users may
not:
use such content for the purpose of providing other users with access on a regular or large scale basis or as a means to circumvent access
control;
use such content where to do so would be considered a criminal or statutory offence in any jurisdiction, or gives rise to civil liability, or is
otherwise unlawful;
falsely or misleadingly imply or suggest endorsement, approval , sponsorship, or association unless explicitly agreed to by Springer Nature in
writing;
use bots or other automated methods to access the content or redirect messages
override any security feature or exclusionary protocol; or
share the content in order to create substitute for Springer Nature products or services or a systematic database of Springer Nature journal
content.
In line with the restriction against commercial use, Springer Nature does not permit the creation of a product or service that creates revenue,
royalties, rent or income from our content or its inclusion as part of a paid for service or for other commercial gain. Springer Nature journal
content cannot be used for inter-library loans and librarians may not upload Springer Nature journal content on a large scale into their, or any
other, institutional repository.
These terms of use are reviewed regularly and may be amended at any time. Springer Nature is not obligated to publish any information or
content on this website and may remove it or features or functionality at our sole discretion, at any time with or without notice. Springer Nature
may revoke this licence to you at any time and remove access to any copies of the Springer Nature journal content which have been saved.
To the fullest extent permitted by law, Springer Nature makes no warranties, representations or guarantees to Users, either express or implied
with respect to the Springer nature journal content and all parties disclaim and waive any implied warranties or warranties imposed by law,
including merchantability or fitness for any particular purpose.
Please note that these rights do not automatically extend to content, data or other material published by Springer Nature that may be licensed
from third parties.
If you would like to use or distribute our Springer Nature journal content to a wider audience or on a regular basis or in any other manner not
expressly permitted by these Terms, please contact Springer Nature at
onlineservice@springernature.com
Content uploaded by Tatyana Shumilova
Author content
All content in this area was uploaded by Tatyana Shumilova on May 02, 2018
Content may be subject to copyright.
Content uploaded by Tatyana Shumilova
Author content
All content in this area was uploaded by Tatyana Shumilova on May 02, 2018
Content may be subject to copyright.