Cryogenic separation of glauconite and foraminifera from the Cretaceous/Paleogene boundary interval at Nasiłów, Poland, for radiometric dating and stratigraphy - Biblioteka UMCS

(1)

A N N A L E S

U N I V E R S I T A T I S M A R I A E C U R I E - S K à 2 ' 2 : S K A L U B L I N – P 2 L 2 N I A

V2L L;I; SECTI2 AAA 2014

CR<2ENIC SEPARATI2N 2) LAUC2NITE AN' )2RAMINI)ERA )R2M

THE CRETACE2USPALE2*ENE B2UN'AR<

INTERVAL AT NASIàÏ:, P2LAN',

)2R RA'I2METRIC 'ATIN* AN' STRATI*RAPH<

Artur :yMtoZicz

^1*

, Tomasz PieĔNos

¹

, StanisáaZ Haáas

¹

, 'anuta Peryt

²

Tomasz 'uraNieZicz

³

, AgnieszNa MáyneN

⁴

1 Mass Spectrometry Laboratory, Institute oI Physics, UMCS, 20-031 Lublin, Poland

2 Institute oI Paleobiology, Polish Academy oI Sciences, 00-818 :arsaZ, Poland

3 Los Alamos National Laboratory, Condensed Matter and Thermal Physics Los Alamos, NM 87545, USA

4 Chair and 'epartment oI Biophysics, Medical UniYersity oI Lublin 20-074 Lublin, Poland

*Corresponding author E-mail address arturZoMtoZicz#umcspl

ABSTRACT

:e haYe demonstrated that cryogenic separation oI glauconite and IoraminiIera Irom the host rocN alloZs to preserYe the integrity oI e[tracted specimens, assures minimal damage and causes no artiIicial Iractionation The KAr dating oI tZo glauconite samples Irom CretaceousPaleogene boundary in the NasiáyZ outcrop yields 20 and

3 Ma The discrepancy in these dates, much larger than e[pected Irom analytical precision, may result Irom too loZ K, Zhich Zas 591 and 573, respectiYely

Keywords IoraminiIera, glauconite, cryogenic separation, K-Ar dating

(2)

A. :ÏJTO:IC= ET AL.

22

1. INTRODUCTION

Mineral or specimen separation Irom the host rocN is a crucial part oI the sample preparation process. Commonly used methods include acid etching and/or dissolution, mechanical grinding and subseTuent use oI heaYy liTuids as Zell as magnetic separation. SuccessIul separation must be perIormed in a Zay ensuring:

(i) mechanical integrity oI separated specimens, (ii) lacN oI contamination,

(iii) minimal chemical damage,

(iY) lacN oI Zeight or size-deriYed Iractionation oI the separate.

By ³mechanical integrity´ one Zould understand lacN oI cracNs, breaNs and Iractures either on the surIace or penetrating through the bulN oI separated specimens. Such mechanical damage is common, e.g. in calcite crystals separated by grinding the host rocN. Also, a grain should be Zell-separated in a sense oI not being contaminated by other minerals. Chemical damage occurs Zhen acids are used to dissolYe the host rocN, e.g. in the case oI specimen e[traction Irom limestone. :eight or size–deriYed Iractionation becomes a serious problem Zhen a giYen Iraction oI the separate, e.g. the smallest grains or the largest shells, are more damaged than other Iractions oI the separate, or eYen destroyed in the process.

Cryogenic separation is a method that meets all the aboYe reTuirements.

Series oI Ireezing-thaZing cycles, Zith each cycle lasting only tens oI minutes, alloZs Zater to penetrate the grain boundaries eYen in rocNs as hard as granite.

BeloZ 4^oC Zater e[pands, and subseTuently becomes ice beloZ 0^oC. Ice crystals continue to e[pand Zhen temperature drops, thereIore increasing the distance betZeen grains. The conYenient desNtop apparatus oI our construction Zas described in >1@, including schematic diagrams. It should be noted, that our design is based on the use oI Peltier eIIect, contains no moYable parts and it is enYironmentally Iriendly.

)or testing purposes Ze haYe chosen a Zell-NnoZn Cretaceous/Paleogene boundary section at NasiáyZ. Up to 0.5 m thicN layer oI glauconitic sandstone is deposited directly on the uppermost Maastrichtian hard limestone (see )ig. 1).

Description oI the proIile and our preYious stable isotope and radiogenic dating results Zere published beIore in >2@. In )ig. 2 a concentrate oI glauconite grains is presented. )igures 3 and 4 shoZ e[amples oI IoraminiIera. Both glauconites and IoraminiIera Zere separated Irom the host rocN (sandstone) by the use oI appro[imately 48 hours oI repetitiYe Ireezing-thaZing cycles in our cryogenic separation apparatus.

(3)

FIG. 1. The Cretaceous/Paleogene boundary proIile in the NasiáyZ Tuarry. *lauconitic sandstone oYerlies an intensiYely burroZed hard limestone terminating the uppermost Maastrichtian siliceous limestone.

FIG. 2. Cryogenic separate oI glauconites Irom the NasiáyZ Tuarry, 1mm scale on the right.

(4)

24

FIG. 3. Planoglobulina carseyae (Plummer).

FIG. 4. Globoconusa daubjergensis (Br|nnimann).

(5)

2. RESULTS AND DISCUSSION

As it can be seen in )ig. 2, glauconite grains are Yery Zell separated, Zithout traces oI etching or contamination. Results oI potassium content determination are giYen in Table 1, Zhereas the K/Ar dating results are presented in Table 2.

Sample D Zas taNen Irom a burroZ Iilled Zith glauconitic sandstone located 5 cm beloZ the hardground, Zhereas sample ) Zas taNen Irom the glauconitic sandstone 11 cm aboYe the Maastrichtian hard limestone surIace. Cautious reader Zill immediately note that age in Table 2 is apparently reYersed: sample D appears to be younger than sample ).

This result is not surprising iI one considers the comple[ sedimentological history oI the K/P boundary at NasiáyZ as Zell as the geochemistry oI glauconite.

)aunal condensation and mi[ing oI Danian and Maastrichtian Iossils in the glaucontic sandstone, oYerlying the Maastrichtian hard limestone, are interpreted as being the result oI the erosion oI part oI the section including the uppermost Maastrichtian and loZermost Danian (e.g. >3-@). The unit itselI has been included either in Maastrichtian (e.g. >7@, >8@) or in Danian (e.g. >3@, >@, >9@,

>10@). During the deposition oI the glauconitic sands the topmost surIace oI the Maastrichtian rocN has been intensiYely burroZed and Iilled Zith that sediment.

E[istence oI multiple burroZs penetrating the glauconitic sandstone and the Maastrichtian chalN, together Zith possible multiple bioturbation in the Iresh sediment, Zhere the reZorNed Maastrichtian material Zas also present, points to a Yertical mi[ing as one possible source oI age reYersal in K/Ar dating. Another, perhaps eYen more conYincing e[planation comes Irom the geochemical point oI YieZ. *lauconite is a comple[ geochemical system, Zhich attains maturity oYer an e[tended period oI burial time. Mature glauconite is closed to isotope e[change Zith its enYironment. One oI the geochemical signatures oI mature glauconite is the potassium content >11@.

)or loZ potassium contents, the radiometric age oI glauconite is artiIicially increased. As it Zas shoZn beIore >2@ glauconite Irom the NasiáyZ section may be considered mature at potassium contents larger than .3. Samples analyzed here reYealed potassium content beloZ and thereIore are located on the slope oI maturity curYe. Entire 4.3 Ma age diIIerence betZeen our samples may thereIore be considered as artiIicial.

At the present stage oI inYestigation, the conclusion is, that the 2Ma is an appro[imate age oI the oldest Paleocene sediments in this proIile. More detailed study, inYolYing stable isotopes and grain size separates is needed in order to Iinally resolYe the NasiáyZ puzzle.

(6)

2

Table 1. Results o I potas sium conten t de te rmina tion o I t Z o sa mple s o I g la uconite. Sa mple Tota l Z ei ght >mg @

Anal ys ed Z ei ght >mg @

mi[K41K39 ¸¸ ¹· ¨¨ ©§

K A Yera ge K

Re la ti Ye standard error > @ sa mple spi Ne Nasi áyZ D 94.78 4.20 4131.02

2.57 5.97 5.91 0.34

2.53 5.8 2.47 5.70 2.58 .01 2.50 5.79 2.55 5.92 2.57 5.98 2.54 5.90 2.59 .04 Nasi áyZ ) 71.47 4.91 5587.17

2.21 5.75 5.73 0.35

2.23 5.84 2.21 5.75 2.25 5.89 2.18 5. 7 2.18 5. 7 2.19 5. 9 2.17 5.59

Tab le 1.

(7)

TABLE 2. Results oI the radiometric dating oI glauconite samples.

Sample: NasiáyZ D NasiáyZ )

:eight >mg@ 48.55 47.41

Potassium content >@ 5.91 5.73

38Ar dose >pmol@ 71.21 71.21

40Ar/³⁸Ar ratio 0.5 0.502

40Ar/³Ar ratio 1330 1457

Radiogenic ⁴⁰Ar >pmol/g@ 4.5 70.9

oI radiogenic Ar 77.8 79.7

Radiometric age >Ma@ 2.0 .3

Cryogenic method used in e[tracting IoraminiIers Irom the glauconitic sandstone ZorNs as Zell as Ior glauconites. Obtained Irom that rocN minute, thin-shelled and Iragile Danian (and Maastrichtian) planNtonic IoraminiIera are clean and Yery Zell preserYed (see )igs 3 and 4). PlanNtonic IoraminiIera are the minor component oI the IoraminiIeral assemblage. Danian species are represented by Globoconusa daubjergensis (Br|nnimann), Parasubbotina pseudobulloides (Plummer), Globanomalina sp., Chiloguembelina sp., Globotruncanella caravacaensis (Smit).

e el ect ri cal propert i es oI mi crocryst al l i ne CdSxSe1-x Ii l ms (0. 5 x 1. 0) manuIact ured by t he improYed R) sput t eri ng t echnol ogy under i nIl uence oI hydrogen pl asma t reatment and Iol l oZi ng anneal i ng i n diIIerent regimes are descri bed. It Zas e[hi bi t ed t hat i ncorporat i on oI hydrogen Irom pl asma produced drast i c changes Zhi ch occurred i n t he darN I–V charact eri sti cs and resi st iYi t y oI t he Iil ms. DarN conduct ance reYeal ed i ncreasi ng under hydrogenat i on and a l ong-t i me rel a[at i on (decrease) Zit h t i me Ior l oZ temperat ure hydrogenat i on. The nonmonot oni c i nIl uence oI t he Ii lm dimensi ons on darN conduct ance and I–V charact eri st i cs i s shoZn, Zhi ch i s di IIerenti at ed Ior as-recei Yed and hydrogenat ed Ii l ms and depends on regimes oI hydrogen pl asma treat ment . Such behaYi our i s associ at ed Zi t h transIormat i on oI pot ent i al rel i eI oI hydrogenat ed Ii lms.

1. INTRODUCTION CdSxSe1-x Ii l ms are bei ng st udi ed Zit h reneZed i nt erest oZi ng t o t hei r use i n opt oel ect roni c deYi ces and pot ent i al appl i cat i on i n sol ar cell st ruct ures >1@. HoZeYer, t he reproduci bi l i t y oI phot oel ect ri c and ot her propert i es oI CdSxSe1-x t hi n Ii lms i s rat her sensi t iYe t o t he t echnol ogy oI t hei r manuIact uri ng. Thi s i s due t o pol ycryst al l i ne st ruct ure, nat iYe deIect s i n t he grai n bulN and surIace cont ami nat i on oI t he Ii lms >2, 3@.

To prepare CdSxSe1-x t hi n Ii l ms Zi t h t he desi red phot oel ect roni c prop ert i es, usual l y diIIerent dopi ng t echniTues are used >1, 2@. At t he same t ime, neZ t echni Tues such as pl asma hydrogenat i on and i on i mpl ant at i on oI hydrogen, Zhi ch are appl i ed i n a l arge scal e i n semi conduct or deYi ces t echnol ogy, haYe been l ess st udi ed Zi t h respect t o II–VI compounds, especi al l y CdSxSe1-x Ii l ms >4@. Among ot her Iact ors Zhi ch det ermi ne necessi t y oI hydrogenat i on, t he pol ycryst al l i ne st ruct ure oI t he Ii l ms i s oI prime i mportance due t o t he i nIl uence oI e[t ended deIect s (grai n boundari es, di sl ocat i ons, preci pi t at es, Il uct uat i ons oI composi t i on, et c. ) and nat iYe deIect s i n t he grai n bulN. Passi Yat i on oI t hese deIect s and possi bl e dopi ng eIIect s under hydrogen t reatment oI CdSxSe1-x Ii l ms can si gni Ii cant l y change t hei r el ect ri c propert i es >4@. HoZeYer, i I Ior such semi conduct ors as si l i con and III–V compounds, t he processes proceedi ng under hydrogenat i on haYe been cl ariIi ed t o a l arge degree >5, @, Ior II–VI compounds t hey haYe not been adeTuat el y i nYest i gat ed.

3. CONCLUSIONS

In this study Ze haYe demonstrated that cryogenic separation oI glauconite and IoraminiIera Irom the host rocN is a simple and conYenient method. Use oI cryogenic separation alloZs to preserYe the integrity oI e[tracted sample, assures minimal damage and no artiIicial Iractionation. Its applicability Zas shoZn in the preYiously published paper >1@ also Ior the granite-Iorming minerals and other host rocNs liNe tuIas.

(8)

28

RE)ERENCES

1. NoZaN J., DuraNieZicz T., Haáas, S. (2002) Separation of single-mineral grains by means of cryogenic disintegrator and the LST heavy liquid for radiometric dating, Materials oI the ³^th Session on Dating oI Minerals and RocNs´, :arsaZ, Poland, 2002, 40-47.

2. DuraNieZicz T., :yMtoZicz A., BanaĞ M., KalicNa L., (1997) Isotopic composition of oxygen in Tertiary glauconites dated by K/Ar method, Materials oI the ³4^th Session on Dating oI Minerals and RocNs´, 11-12 December 1997, Lublin, 27-40.

3. PoĪarysNa K. (195) Foraminifera and biostratigraphy of the Danian and Montian in Poland, Palaeontologia Polonica 14, 1-15.

4. MachalsNi M., :alaszczyN I. (1987) Faunal condensation and mixing in the uppermost Maastrichtian/Danian Greensand (Middle Vistula Valley, Central Poland), Acta *eologica Polonica 37, 1-2, 75-91.

5. Hansen H.J., Rasmussen K.L., *ZyĨdĨ, R., Hansen, J.M., RadZaĔsNi, A. (1989) The Cretaceous/Tertiary boundary in Central Poland, Acta *eologica Polonica 39, 1-4, 1-12.

. MachalsNi M. (1998) Granica kreda-WU]HFLRU]ĊG ZSU]HáRPLH :LVá\, Przegl. *eol.

46, 11, 1153-111.

7. PoĪarysNi :. (1938) Stratygrafia senonu Z SU]HáRPLH :LVá\ PLĊG]\ 5DFKRZHP L

3XáDZDPL 6HQRQVWUDWLJUDSKLHLP'XUFKEUXFKGHU:HLFKVHO]ZLVFKHQ5DFKyZXQG

3XáDZ\LQ0LWWHOSROHQ, Bull. *eol. SurY. Poland 6, 1-94.

8. Abdel-*aZad *. I. (198) Maastrichtian non-cephalopod mollusks (Scaphopoda, Gastropoda and Bivalvia) of the Middle Vistula Valley, Central Poland, Acta

*eologica Polonica 36, 1-3, 9-224.

9. Peryt D. (1988) Maastrichtian extinctions of planktonic Foraminifera in Central and Eastern Poland, ReYista Espaxola de Paleontologia 3, 105-114.

10. ĩarsNi M., JaNuboZsNi *., *aZor-BiedoZa E. (1998) The first Polish find of a /RZHU 3DOHRFHQH FURFRGLOH Thoracosaurus Leidy, 1852: geological and palaeontological description, *eological 4uarterly 42, 2, 121-130.

11. Odin *.S., Dodson M.M., Zero isotopic age of glauconites, in: *.S. Odin (ed.), Numerical Dating in Stratigraphy, :iley (1982) 277-305.