Some seismic signatures in the Romanian crust

TECTONOPHYSICS ELSEVIER

l"ccl~moph.,,xicx 288 ( 199X ! 127.. 13¢~

Some seismic signatures in the Romanian crust V. Rfiileanu :::, C.C. D i a c o n e s c u I ~:OtlonOI Institute lbr l:arlh PIn ~ic ~. F~(]. Bo~ M(;.2. Bm halew-Ma.,.'urele. R, mhtnt, i

Abstract Some new seismic rellection data in the W of the Moesian platform. Foc~ani depression and l'ransyl',ania depression show seismic patterns which reflect the local structure and evolution of the each area. These local areas were all~ected by subsidence which over-printed the changes on the old pattern. The old and more or less reltecti\e lower on, st v.a~, fractured and some rigid blocks have preserved the rellectivity up to the present. The B.aile~ti section illustrate,, a transparent or diffracti,,e upper crust and a well-marked lower crust by an alternation of reltecti~e anti non-rellecti~e /ones. The crystalline crust of the Rfimnicu S'arat section has tv, o patterns: one relati,,ely rellective, near the bottom of the depression (the W side), whilst the other, on the E flank of depression, ix transparent. The E flank seems Io he more fractured due to some tensile fractures originating m the bending stress during subsidence. The Tfirgu Mure~ section has a specitic crustal pattern. A near-transparent crystalline crust overlies a very large crust-mantle transition ,'one which ix lragmented m alternated reflective and transparent blocks. (~2 199g Elsevier Science B.V. All rights reserved.

Kcvword~: crust: Moho: reflectivity" diffractions; subsidence; fractures

!. Introduction

structure and evolution of these areas. This paper c o n t i n u e s the series of the works on the Romanian

Three deep seismic retlection lilacs supplied new data on the depth of areas which to date have not been well investigated: the southeastern Moesian platform; the Foc~ani depression; and the Transylvanian depression. The primary task of the these lines has been the sedimentary cover, but with slight changes in the field acquisition parameters and a careful data processing some interesting results were obtained. In the following, the authors tried to Ix~int out the most signilicant peculiarities of the seismic sections and their connections with the deep

lithosphere based on the seismic rellection dala, including papers by Rfidulescu et al. (1984). Raileanu et al. ( 1994): and l)iaconescu et al. (1996).

2. Seismic data The three deep seismic reflection lines described into this section cover a small area of the Moesian platform IFig. 1, line A). the Carpathian foredccp (line B) and the Transylvanian depression (line (71. 2.1. 77w B(~il(',sti line

• Corresponding authol. Fax: +40 (l) 789-7620: E-mail: raivic(a'in fp.i fa.ro Pre~ent addrcs:,: Institute for Study of the Continents. ('orncll tJmxer~,it'.. Ithaca. NY. 14853. LISA

The B~'tile~ti line (Fig. 1, line A} ix located in the SW part of the Moesian platform, which consolidated during the Early Paleozoic age (S~ndulescu.

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I'ig. I. A s i m p l i f i e d l e c l o n i c m a p o f the R o m a n i a ,.~,ith three d e e p s e i s m i c r e l l e c l h m Imcs (s
1984). Here, the crystalline basement was intruded by granites, granodiorites and gabbros during the Hercinyan orogeny. The intrusions are contemporaneous with some of the Paleozoic layers of the sedimentary cover (Sfindulescu, 1984). This fact suggested a high mobility of the W sector of the Moesian platform in the Paleozoic time (Visarion e! al.. 1988). Two main fault systems with parallel and orthogonal directions It) the orogen structures (the Southern Carpathian) generated a struclure with unleveled blocks and with different evolutions in time. Two of these structures the Strehaia-Vidin uplift and the Craiova-Vidin depression, with N E - S W directions, are crossed by the seismic line A. A deep retraction line, (Fig. 1. GT Xll) at the S and W of

Craiova shows a increasing depth to the basement from 4 km (central part) to 6 kin (S part) and a seismic velocity Vp = 6.2-6.4 km/s for the central part of the line (R~dulescu et al., 1977). Also. a high velocity layer with Vp = 6.7-6.8 krn/s has been detected at a depth of about 9 - 1 0 km (a basic intrusion?) in the S halt" of the line. A refracted horizon at a depth of about 14-15 km was assigned to the Conrad, while the Moho seems to sink slightly from 30 km in the central part of the line to 32 km at its S end (Visarion ct al., 1984). The B~ilc:~ti line was recorded over ~ 3 8 km with a NW to SE orientation {Fig. 1). The seismic section (Fig. 2) shows, in its upper part, the sedimentary sequence down to about 3 - 4 s. The reflectivity is

V ROilecmu. ('.('. I)iacom'~cu/'l'i'clOnol;lnxics 2,~'b; t 199,4! 127 136

very high over the uppermost part of the section due to the Tertiary and partly Mesozoic sequences. Although it is harder to see due to the high frequencies and very compressed scale of the seismic section, the rellectivity decreases with depth. The Mesozoic and Paleozoic sequences appear with more rare, short and less continuous reflections, Two seismic inarkers show the contact between the Badenian and the Cretaceous tFig. 2, Tert/Mz) and the top of the Paleozoic strata I Mz/Pz). The two markers point out a thickening of the Tertiary and especially of the Me/,ozoic sequences from the NW to the SE. which outlines the Strehaia-Vidin uplift and the C r a i m a Lore depression. The crystalline basement surfacc is marked by a decrease in reflectivhy with a depth at 3 - 4 s correlative with refraction data collected in the area (R'adulescu el al.. 1977L It has to remark a quasiconstant thickness of the Paleozoic layer along the whole line. The upper crust appears to be ahnost mmsparent, with rare, short, dipping reflections, suggesting a brittle medium. Demetrescu et al. {1993) show,, in this area. temperatures of ~1('~(). 300 and 520"(" at threc depths {10, 20 and 30 km). In the upper crust (14-15 km deep or ~ 6 s, Radulescu el al., 1977). the temperatures stay under 300°C and a brittle slate ix expected (Wever c t a l . , 1987). The SE half of the seismic section shows at the upper crust levels more dipping events having a verv possible diffractive nature and suggesting a state of high fracturing. Also. the presence of some intrusivc bodies al these levels is very possible, taking into account Ihc refracted hertz.on with Vp = 6.7-6.8 km/s on the GT XII seismic section. S~.ndulescu (1984) showed that the origin of Permo-Triasic magmatism of the Moesian platlorm, which is subsequent to thc tlercvnian, oro,,eny~ , could be explained by a rnodel based on the taphrogenic processes rather than on Ihe subduclJon ones, the latter being already stopped at thai time. But the iaphrogeny ilwoh'e the tk~rmalion of new strtlcturcs, s u c h as. grabens, by extension processes. Ba.sed on the quasi-constant thickness of the Paleozoic layer, the subsidence of the Craiova-Lore depression seems to have begun m the earliest at the end of the Paleozoic time and rather in the Mesozoic time. The Mesozoic sequence is better developed within the C r a i o v a - L o m depression than in the Strehaia-Vidin uplift, proving an activc sub-

12~J

sidence at that time. The fracture along which the bottom of the depression has been lowered during subsidence, allowed the deep magmas to intrude at the higher levels. The top of the lower crust is marked by, a f e w groups of reflections in the central part and ill the northeasternmost part of the section in the 6- to 7-s interval. The lower crust becomes more reflective with depth, with reflections increasing to 3 5 km length. The retlectivity of the lower crust is unevenly distributed along the line. A few sectors with an evidently higher reflectivity alternate with others having less or no reflection. The sectors from the NW end (0-7 km distance) and central part (20-27 kin) are very reflective over almost the whole lower crust. Two other intervals (12-15 and 3 2 - 3 6 km) have a more stressed retlectivity towards the base of the lower crust. The areas between the four reflcclive sectors are devoid of reflection. The hasc of the strongly rellective packages observed at 8.0-10.2 • in the NW part and at 9.5--11.0 s to the SE section marks the Moho according to the refraction data on the GT Xil. The reflectivity of the lower crust can be due to different causes. The extensional processes since the end of Paleozoic lime and in the Mesozoic time haxe led to a subsidence within the Craiova Lore depression. In the lirst stage, the lower c r u s t was stretched l\~rmmg a lamellarly retlective s t r u c t u r e (Meissner, 1989). In the subsequent stage, the lower crust was fractured and the lamellar reflectors have been interrupted by faults. The Fresnel thcor\ states the least reflector length over the 6 - 1 0 s T W T interval must to be >2.5 to 4-.5 kin, respectixcly. The presence of some crustal blocks with a reflectivc lower crust suggcsls that these blocks behaved like a rigid body preserving its old structure. These rigM blocks with a width of > 4 - 5 km are separated h\ deformed zones, without reflections. Alternativel,,, the zones without reflections could be interpreted a• intrusivc bodies, these Ixydies also being rigM. l)uring the subsidence, the Moho was lowered and an isostalic hahmcing process started. As the subsidencc r a t e decreased and then ceased (very probably in the Tertiary lime) a new Moho formed at a shallowcr depth. Some short reflections under the Moho I sec Fig. 2) suggest some relic reflections preserved of lhe old lower crust, which was incompletely assimilated by thc upper mantle. During the Alpine omgcn.x.

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I:i~. 2. Sci,mic ,cclion ul the BfLilc~ti line clinc ,I in Fig. I). Scdilucnlar) ~cqucncc ~ll~\~s tx~o sci,mic markers: 7~,rff,ll: at lhc contact I~clx~ccn Nco~cnc xc,,lilllClll:~ ,llld Ihc ('rclaccotln OliOs: LLI](] .~,I:IP- LLI Ihc -LII'I'~I~.'¢ {1l" lhc Palco/~)ic la)cl's. TIle ('raioxa l.~m ulcprc,~ion i, marked h\ a lhickcnin~ ~1 the Xlc,oz~fic ncqtncncc \Vhilc lhc tl]~l~¢l Crlls[ i~ rclali~cJ) Ir~lll~:l)drelll. \~ ilhin Iilc Io~.~cr ~l-Us[. sOlilC icl]ccli~c scclt)ls dJlcl'lltllC ~ ilh II1¢ ll~lll~J~[lrcIll onc~. J'hc Irdll~i3tllCll[ sccb~l~ could hc dUC [o (r,~¢[LIlln~ ~r/and nla~nlalic inlru~i~¢ hodic~. ~c¢ le'd. M o h o i, oullincd al Lh¢ h,l~c o f Ihc reFtccli\c Io~¢r cruel.

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this sector of the Moesian platfltrm was involved in the compressional rnovements which led to the formation of the Southern Carpathians. An alternative hypothesis on the lower crust reflectivity is that it behaved as a ductile layer (or at least its bottom part} due to some temperatures of 3(X)°C or more. Along this layer, a decoupling process took place between the two horizontal and more rigid layers (the upper crust and upper mantle). The horizontal differential movements of the two rigid layers led to a lamellarly reltectivc structure within the ductile lower crust (Wever el al., 1987). Later, the older or new active fractures interrupted the new lamellar structure and so the present picture was created. Even if the Alpine orogeny had an influence on the deep structure, in our opinion, the extent of this influence would bc less than that of previously tectonic processes. 2.2.

The R a m n i c u S a i n t l i n e

The Rfimnicu S'arat line (Fig. 1. line B) is located on the eastern tlank of the Carpathian foredeep and crosses the deepest depression in Romania, the Focsani depression. The Carpathian foredeep lk)rms a wedge of elastic rocks and evaporites which thickens toward the Carpathians. It was formed by subsidence during three orogenic phases: early-middle Miocene, late Miocene, and Plicx:ene. The sedimentary cover of the basin is ~ 1 8 km deep, the first 1 0 - I I km ()f sediments being Tertiary in age (Rfidulescu et al.. 1976). The crystalline basement in this area is plattk>rm-type and bekmgs to the eastern sector ( D o b r o g e a n ) o f the Moesian platform. This sector is bound to the SW by the lntramoesian fault (Fig. I, I.M.F.), and to the north-east by the Pccencaga-Camena fault (EC.F.). These two faults arc considered to be crustal and penetrating with a NW to SE orientation: they also are composite faults with displacements both in the vertical and Ilorizontal plane. Between these two faults, the Palazu fauh (P.F.) penetrates the crust at least down to the mid crus! IVisarion et al., 1988). and crosses the western part of Ramnicu S'arat line. The Palazu fault is also considered to be a composite fauh having a dextral translation, it is still active, being characterized by crustal earthquakes {Visarion et al., 1988). According to previous studies (Rgidulescu et ;.ll., Iq76L the region between the Intramoesian and

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Peceneaga-Camena fimlts accmnmodates displacement with respect to the surrounding areas towards the Carpathians. 3M'o refraction lines: GT XI and GT Xll (Fig. I), cross the Foc~ani depression. The GT XlL cuts the R'~mnicu Sfirat line at the 20-kin distance and points out some geologic boundaries within the crust: the Tertiary/Mesozoic contact at a depth of ~ 9 kin; the sedimentary/basement boundary at a depth of ~ 17 km and the Moho at a depth of 4 2 - 4 4 km (Enescu et al., 1972; Rfidulescu, 1981 ). The R~mnicu S~rat line cuts the E flank of the Foe,sani depression on the rna×imum deepening direction of the plattbrm under Neogene sediments and it is ~ 3 7 km in length. The shallow' part of the seismic section shows the highly reflective Tertiary layers to ~3.5 s in the E and ~5.2 s in the W (Fig. 3. Tcrt/Mzt. The underlying Meso~,oic ,,equence appears to be characterized by sparse shorter reflections cut by diffractions that could be caused by erosion surfaces or strong faulting. These series of diffractions can be followed, from 6.2 s m lhe W (at ~ 3 2 km distance) to 5.8 s (-~21 kmL and 3.5 s in the E. A decrease of thc retleetion coherency: is observed beneath the surface expression of the Palazu fault {Figs. 1 and 3) at 0.3--3.8 s from 23 to 27 km distance. This region is bound lalcrally by continuous rellections on either side of this domain with no offset, proving the strike-slip character of the Palazu fimlt. Between 3.8 and 5.0 ,,. some diffractions (Fig. 3, "Difr.') cut the section. The crystalline crust appears with a lot of the coherent events down to the Moho within the W hall" in contrast to the E halt" which is nearly Iransparent. This pattern suggests that the E half could be very fractured (see observation on thc Fresnel zone above) and possibly pierced by some intrusixe bodies, whilst the W hall" is fractured to a lesser extent. Also. the W half is nearer It) the bottom of the depression, where fracturing during the subsidence was less intensc than on its F. llank. An additional line of e,~idence is the increase from the E to the W of the sequence thickness between two markers: Me/Sa {Meothian/Sannathian)and Tert/Mz (base of the Tertiary and top of the Cretaceous layer). The higher rate of subsidence of the W part in coral')arisen with the E part means a lithosphere bending during subsidence and a tensile stress on the E llank at lhe upper lithosr)here levels. Thc tensile fractures

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Fig. 3. S e i s m i c ,,eCtlOn o f the Rfimnicu-Sfirat line i l i n e B in Fi,..:. Ii. "lhc Imc cuts the ca:,lern flank o f the Fo,:~ani d e p r e s s i o n Oll the m a x h n u m d e e p e n i n g d i r e c t i o n o f the f~hltform u n d e r the N c o g c n s e d i m e n t s . T h e ,..'rtlstal P a l a / u latlll (P/"I d o e s n()t sho',~, all.~ (~t't'scl al least to 01¢ Terfiar,,. la',cr levels. S o m e mten~,J,,e d J f f r a c l i o n s

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a e r o s i o n relief. N o t i c e an i n c r e a • c in Ihc t h i c k n e s x o f the scqtl,31lcc h,._'l'.A.CCll Ihc M e o t h i a n / S a r n l a l h i a n f l ~ l ' / D l l and I',a,,c o f [k'rtiar', s e q u e n c e / t o p o l Ihe ('rctaccou~, la,,cr

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upper crust le\els. T h e lov, er crust has ,i clearer retlectivity at least ill two /.ones centered around a distance of 2 5 k m a t 12 13s, and 1 9 k m a t 1 3 - 1 b s . Moho is outlined by a good rctlection in the central part near 15.1) s and it is. according to refraction data. about 42 krn deep (Encscu et al.. 19721. The seismic pattern of this lithospheric segment reflects a part of the conlplcx tectonic evolution of the active plate inargin involved in the subduction process still aclivc in the Vrancea region (Fucs et al.. 1977). 2.3. 77w 7~h:~,tt Mttre,~ l i n e The Targu Mure,s line
I',

'Tile upper crystalline crust 14-b ,, and 9-15 kill deep~ is dexoJd of rellections, even though the minimum expected length el +reflections should he 2-3 krn. according to the Fresnel ,,one theory. Rheoh)gitally, the crustal material is brittle, with temperatures of 150-200"C (l)iaconescu et ill., 1994). Short and dipping events withirt the upper crust tire inferred to be diffractions. No obvious rellection is observed on tile seismic line ;.it the depth of tile Conrad (12 14 km on tile GT Xl). The Iov+er crust (6-10 s and 15 30 kill deep) appears to be almost trilnspilrenl ;.is w ell and ix characterized by temperatures of 2(Xi-380°( ". The reltectivity increases bctv+een 9.5 and 15.() s 127-47 kill deep) ahmg the lille and the pattcrn shows vertical zones with prominent relleclions separated by other transparent zones: 16-21 km distance and lrom 40 km to the SE (Fig. 4). Ill the first inlcrval, some diffractions it!. --4.1 s T W T are evidence for a possible crtlstal fauh in the S side of the section. laJetwccn 43 and 48 k s , the interruption and offset of rellections both in the shallo,a part of the section i I)'I ;.uld basement)and in the deeper one, suggest another potential deep penetrating fault ,tagc through Ilexure. iX,; shear strengths v,crc exceeded, the itcconlnlodittJon to stress occurred b\ the fracturing of the lithospheric column. The nearhorizontal to slightly dipping events between 22 ;.lnd 40 km uhmg the seismic section ;.ire interpretecl Io he reflections mixed with diffractions. This lithosphcric dumain belv+een 24 and 40 km appears to ha'+c u Io,a.er position than the adjacent/ones, with thc basc of the crust being interpreted ;.it --, 15 s 147 kill deepl compared to 13.5 s ~--42 kill deep) with respect to the NW ;.uca. The deeper rellectivity in tile l'/irgu Mtiies lille hus to be related to tile tectonic processes during the ('retaceous and/or Tertiary orogenic phases. l h c rellcction ]oncs observed in tile 9.5-15.0 s intcr\ul could he+ alternatively: reinnunts of some Cl-tlMal roots fortncd during the Cretaceous collision lind partly preservcd as a result of a low thermal rcgilnc IMeissncr el al., 1991)" due to a dehunmation of the lo,acr ciuM Hnd part (71 the tlppei'lllOSl tllalillle

I 10 k m

G T XI

i20 T

a

r

n

a

v

130 a

D

e

p

r

140 • e s s

i

o

n

I 50 kin 0

T W T (s)

SE

t:i~. 4. Su'i.mic ncctltm o l Ihu l , ' l l ~ u - X h l l ¢ . : lin¢ Ilillc ( ill Ii~ I!. "lh¢ lIlle cl~.s~_'. Ihu' d~'ol~c~t Part o f the l r d l l ~ , ) l \ a n K I n d¢l~ic~itul, km~x\n ~l~ Ihc l','uli~t\~i ,lu'l~iu'..i~rl The l)¢1 [ul'l f / ) T ) i. a neb.mi~ llldlkcl" IIc:ll 1he bu.c L+I the N¢~,~¢t1¢ ",¢qucncc+ 7~'rr/,~l: m~uk~ on the N \ V II~mk Ihc tr~m~ilitm l l o n l N c ~ c n ¢ ncgucnc¢ 1~ lh¢ ('rut,i~cuL,. ~+n¢. l)o',t-lccl~+nlc .+.'~Y',¢r ;lll(l ]+H'c ~'It+[:Ik'dtiLln nCt]LICl+ICt.'n mQ u'~hciunl ¢\+nl. tm /lie 54".\ I~
T W T (s)

NW

IJ

~: R~Tih',/I,. ( \ ( ' . l)./((,~('~(I~/ li'(l~,~,lUIX ~/('~ 2W.'~ ~ /Vt,~'~, / 2 7

(a suciion process, Royden, 1988), which perrnhied the inlilinilion
3. Discussion and conclusions 'fhree ne\\ seismic retlcclion lines recorded W tit the Moesian phitfom~. Focsani depression and Triinsvl\'ania depression ,,ht/v, seismic patterns w.hich rellecl Ihe local SllUCiure Lind evolution of each aleLi. ,~()nle peculiarities alC COIlllllt)ll lO all lines, whilc tlttlels arc specilic. All scisinic sections present a depressional slructurc l~,lrmed h\. subsidence, a process which left its signalurc on lhe present cruslal structure. Before the subsidence, under some faxolable rheohlgical condil i o n s [ h e I o w e f o r r i s [ w a s i n t l f e e l less r e l l e c t i v c

due

io diffcrcnl c;.luses: extension (lille A), deh.iminalion or du¢lilc dc¢oupling time (') oi- olhei's (line BI. l)uring ,,ubsiden¢c. ~.i fr;.lciuririg process segrlleilled crtlSl in rigid block,, separated by deltlrnled zones. The rigid blocks f~reser\ed ihe relleciive nifuCltlre and Ihis Call he seismic imaged i f file block ~vidihs ;.ll'L' ];.ii'gL'f ih;.in ;.i I:resnel ZOllC (4--5 kin). Through Ihcse frilClUfeS, the nlagmns penelraled it) the upper crtisl;.il h_'\els cr¢;.llillg inirusi\e bodies imaged b\ a Iransparcncy or ralhcr b) diffraclions. The la;~'iil¢~li scciion ,,he,a,\ a IfanspLllenl or dil'fracIi~¢ uppef Cl'USt and a wcll-nl;.irked lower crusl b) all allernalion of rellecliVe and non-reflcciive zones. A fc'.#, i;_lle and shorl relleclions under ihe Moho Stlggesl Ihiil ihc is(,slalic balancing is alnlosl closed.

135

//6

The R(nnlliCti S{'irl.il section is quile dit'ferent frolll the oiher t,ao. The cryslalline Cl-l.isl has l,,Vo pallerns: one relali\el) relleclive over Ihe ~,\hole LTUSl ((ill lhe ~.: side. lhal is neaf the bollOln of depression) liild tile olher lransparenl (till the l{ side. thai is till the I~ lh.ink o1 the cieprensiOll). The E I];.ink can be nitlre fracluied due Io sonic tensile fr:_lCltlres originaling in the bendhlg SlleSs dtlrhlg subsidence. The "l'(irgu Mul'e~ scctitm has a specilic ClU,qal paucrn. A ilear-lrallSpalenl crvslalline C l t l s l ;.lnd ;.i \ e i y hugc ClUSl--nlanlie li;.nlnilion zone \vhJch is fr;.i.,~nlCllled in ;.illerllaled rellccli\c nlltt Irnnspiucnl blocks.

Acknowledt~ements The author,, thank the Pt'TI'R()M R.A. and R ( ) M G A Z R.A.
dul,',cu. I . .\ndr,'c,,~u. 5,1.. |)cincllc~ciL ('. luOJ<. Xh~dclarc ~coli/lu'al ",1 IcLhlIliC.'L pC ill1 prolll din ]~,i/llltll ]f:Lllnil\alllCi. Nalhma] ,~.~llipII/lllill tll (k'oph.',,Ic-. I{t,uharc,I. N~,', . I~)t)l ( III RIHII~InI,III I ('.. Railcantl. V.. I)lac~mc,,ctl. ,N1. Radulcwu. I.. Ihullpllian. \ . . Ihlcr. \I.. It)Of~. •t.'inlllit. i.JLllU~,I Ihc ('dll'lillhhtll hllcch.'cl~ I'pilnclll~.'lll { ROIllilllid I In: ( )llkCll. { ) . I:IID,~211 ( ilid,,.L t{a,,cmctH ~'ch~llicn. \'~l] I I Khl~,'i \cadclmc. Nclhcrhmd,. pp. 125 140 ]-I1Cskl.I. I ) . ('I~I'IICU. [ . (.'onnlalllllllc~,~.'tl. p . I~(Idulc,cu. I.. I~llltll. ])IdColIC>,CLI.

~.. I )

~,ll'l.IClLll'il nCtldl'[¢i

IOI'?~,II'c ~1 ~l III~IIII~IICI

xtll)'~'litl~llu'

III

/(ula curhulli ('arpa{ilor. ,'41. ( ' c r c (~ct~l (;c~,li/ (~cogr Nt'l (;c~l. I(I i I). -~?, 41. iN Rolnanian. I-ucx. K.. cl al.. 1077. IhL' Rolllalllall c,lllhqllakc e l ~,Lilch. 1977 II \llcl ~h~,cks and I111}_'I'HIIIHIIll lhc xt.'islllit,alt.'ll\H\

"lVcionoph) sic~ 63. 225-247. ]tlllCnCU. I:.. I)oh)nic. I).. "['codl)rc~ctl. V.. ltJg6. NIltlClllr;i M illl}l'loh)gia l)epresiunii Trunsil\aulici pc h;.iza dalclor gcoli/icc. %1. ('crc. (fool. (ic~,li/. (lcogl. 24. 17 2I). in l~,onlaninn. Mcis~llcr. R.. lcJb~t). RuplUlC. Cl'c'cll. IdlllL'llac illid crocodiles: happening, in Ille conlincnial t-rti,,l. Tc'l-l;.i N~l\..i I. 17-2ph.~s. 5B (41. 365 374. Mcis,ncr. R.. \Vcxcr. Th.. 5kldl>\\iclk. It. 19c~1. (.'tmlincnial collie,ions and sL'i~inic ~,i~2rlalUl'C~,. ( icoph\ ~. J. hll. IO5. 15 - 23. R:.]dulcscu. t'.. 19bll. ('l'tl,,ial ~ci~nlic ,,ludicx ill Rlllnania. Re\. Ruuln. (Tool. (ieoph)~. (icugr. Scr. (icoph.xs. 25. 57-'7,4. R,]dulescu. 1).t>. ('orllca. I.. SAildulc~,c'u. m.. ('l>nMalllillC~Ctl. P.. Radulcsctl, I:.. Pt)lnpiliuil. :\.. 1976. SIluClulc tic la cr~)ul~." tcrrL'MIC cn ROtllllanK'. l{,,ai d'illlCrlllchilioli dL'~ cltidc ",i,qlliqtic proh)nde..\11, h>.t. (;col. (;c(lli/. 1. 50. 5 3(x hi French. Rikhllcsc'u. I'.. l)onlpiliun. ,,\.. /Smci. A,. 1~)77. I)eep ~ci,,inic ,,Otllldiilg ill Ri)lllalli:.l I('r;.iiO\Cl I)clrosl.ini al-Cal. Re\. R(lullI. (Tool. (icoph)~. (icoTl. SoL (;copll)~. 21 I ] i . 273 276. in Rollll.iniall. R&lulcscu. I'.. R~-lilcanu. V.. {'~.lrllc;.i.I.. IC.IM4. ('orilribu{ii ale iilclodci ~,ci',nlicc tic rcrlcXiL" la dc~,cifrarcci Mruclurii crtlMalc. tic ad(lncilnc. ,~1. ('crc. (i¢~1. (lc.li/. (icogr. S¢1". (icoli/. 22. I 1 - 17. hi Ri)lliani:.ln. R(iilcaliU. V.. I)i;.il.'OliC~cu. ('.('.. R/]dulcscu. 1".. 19i)4. ('haraclCl'islics of Rolil:.inl/.in liih()~pherc holll deep ~ci,nlic rclicL'TlOli

proliling. |~.,~_t~m~ph.',,,iL:,, 23U. 165 I~5. Ro\i.Icn. I.II. I~)S~. late (.'Cllt)l(licl'cClolliL'~,ol the l)aimon Kin IId'~in , \ , l c i l l . hi: R-\dcu. 1..11.. l l o l \ a l h . F. II:d,.i. l'hc I>aniltmian ba,,in. ,l ,lud\ in basin c\olutilm. \ A I ' ( ; Mcin. 45. 27- 4K N~'IIIduic,cu. M.. It)£4 (iclllccl(llllCa I<~un(lnici. "l'cdulic,iI Ptlbli,dling Ih)u,,c. IhichalC,,t. 330 pl ). (ill Rlluianiiin i. 5;~'lntltilc~cu. M.. I t),RN. (.'on\l/ill\" It'cl~ulic hi,re)r\ o l IIw ('arpalhi/.ill',. hi: Ro\dcn. I . I t . . t h , \ a l h . 1;. It'.d',.I. The I)annllni,ln Basin. a Y,ltid\ hl ll*,l',ill I{\olLllion...\.\P(.; Mcin. 45. 17 25 Vi,,arlOll. M . Sl(Inica. I).. Si(Inica. M.. Iro~l~ (Tool. 15. (}1 (ik. ill t'icnc'h \Vc~ or. Th.. Sath~\~ itlk. I t. I LJLJI. ('l'tl',Itll SlrLIClUrC /t)I1L'~: ~t'i',illlC XI~II;IItlI'C alid MI'LICItlICll ililc.rprclLilit)n. In: Mcis,mc'r. k. cl al. il{d~.). ('lHIlinL'llldl I.ilh.~pllcrc: l)ccp Sc'lSlillt" Rcllccii~m,. [ icod~ naniic,, Scr 2-~. \Vashingllln. I)('. pp. 371 .175. \VC\Cl. l . . lrappc. II.. \.lci~ncr. R.. I~Jb47. t)<~,iDIL" icl,ilion~ bcl\~,C'L'n Cl'tiM,il I'cllt't. li\ il). t'rtiMal ,l~t.'. HL'Lil Iltl\\. anti \ i~cliMl\ ~,1 ihc i_t~lllillCnl~..\lilt ( icoph),. 5B ~.I I. 255 2(~6.