OBVESTILO O RAZISKAVAH KREDNIH SEDIMENTOV
V POSAVSKIH GUBAH
Karel Grad
Na območju Posavskih gub so bili doslej znani zgomjekredni sedi-
menti le v bližini Domžal ter v okolici Krškega in Velikega trna.
Na Gorjancih in v Krškem hribovju so našli Dévidé, Pleni-
čar, Ramovš in Žlebnik na več krajih kredne sedimente v raz-
voju scaglie in fliša, zato je bilo pričakovati, da so ohranjeni podobni
sedimenti tudi na vmesnem prostoru med Domžalami in Krškim hri-
bovjem.
Res se je posrečilo najti kredne sedimente na več krajih na območju
litijske antiklinale. Dosedanja raziskovanja so pokazala, da je znaten del
psevdoziljskih skrilavcev in peščenjakov z vložki apnencev zgornjekredne
starosti. Poleg teh sedimentov, ki ustrezajo zgomjekrednemu flišu med'
Tolminom in Kobaridom, opazujemo ponekod še sivkaste in rožnate
ploščaste laporne apnence z redkimi roženci. Ti apnenci leže normalno
v bazi fliša; po svojem razvoju zelo spominjajo na ^^volčanske« apnence
iz okolice Tolmina, ki so bogati z globotrunkanami in so po Dévidé-
jevi spodnjesenonske starosti.
Sive in rdečkaste apnence z globotrunkanami sem našel naj zahodneje
v Posavskih gubah severno od Rašice pri Ljubljani. Poleg apnencev so
ohranjeni flišni sedimenti, v katerih so značilni vložki apnenče'/ih breč.
Vzhodno od Rašice so podobni apnenci ohranjeni pri vasi Dobeno.
V zbruskih apnenca opazujemo številne radiolarije, globigerine in spikule.
Na manuskriptni geološki karti Ljubljana 1:75.000 je Kossmat te
sedimente prišteval psevdoziljskim plastem.
Apnenci z globotrunkanami, med katerimi je posebno številna
Glohotruncana lapparenti lapparenti Brotzen, in ghneno laporni skrilavci
z vložki apnenčevih breč, v katerih so pogostne miliohde, tekstularije in
orbitoline, so ohranjeni severno od Kresnic med prelazom Grmače in
vasjo Zapodje. Flišni sedimenti so razkriti tudi severozahodno od Slivne
med Stebalijo in Kovačijo.
Laporje in laporne apnence z gümbelinami sem našel tudi v bližini
Vač in vzhodno od Sv. Gore pri Kobiljeku.
Enaki sedimenti z globotrunkanami so ohranjeni na severnem obrobju
laške sinklinale med Goričico in Kosezami. Večina teh sedimentov po
dosedanjih geoloških kartah Ljubljana in Celje—Radeče merila 1: 75.000
pripada ladinskim psevdoziljskim plastem.
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v vzhodnih Posavskih gubah so ohranjeni sivkasti gUnasti skrilavci
z vložki apnenčevih breč in peščenih apnencev vzhodno in severno od
Bohorja in na Orlici. V apnenčevih brečah in peščenjakih so pogostne
miliolide in orbitoline. Te sedimente je prišteval D reg er wengenu.
Na tem območju zaenkrat še niso ugotovljeni apnenci z globotrunkanami.
Na območju Posavskih gub so ohranjeni zgornjekredni sedimenti
kot erozijski ostanki, kar kaže, da so bili nekoč mnogo bolj razširjeni;
prekrivali so precejšnji del litijske antiklinale. Nadaljnje raziskave bodo
pokazale, kako daleč so bili odloženi proti severu. Glede na podoben raz-
voj zgornjekrednih sedimentov v Posavskih gubah ter ob zgornji in
srednji Soči je morala obstajati zveza med obema območjema. Erozija je
kasneje to zvezo prekinila.
NOTE ON THE INVESTIGATIONS
OF CRETACEOUS SEDIMENTS IN THE SAVA FOLDS
In the Sava folds region Upper Cretaceous sediments have up to
now been known only east of Domžale (northeast of Ljubljana, and in the
environs of Krško and Veliki Tm.
Devi^dé, Pleničar, Ramovš and 21 e b n i k found in
several localities in the Gorjanci-Mountains and Krško-Hills Cretaceous
sediments of the scaglia and flysch facies. It has, therefore, been expected
that similar sediments would occur also in the intermediate region
between Domžale and the Krško-Hills. And, indeed, in the region of
the Litija anticline Cretaceous sediments have been found in several
places. Up to now investigations have shown that a considerable part
of the Pseudo-Zilian slates and sandstones with limestone intercalations,
is Upper Cretaceous in age.
Besides these sediments which correspond to Upper Cretaceous flysch
between Tolmin and Kobarid also grayish and pink platy marly limestone
with rare homstones have been observed here and there. This limestone
is usually overlain, by flysch. Their facies resembles that of the Voice
limestones from the environs of Tolmin which abound with foraminifera
of the genus Globotruncana and are according to Dévidé Lower Se-
nonian in age.
Rašica (north of Ljubljana) is the westernmost locality in the region
of the Sava folds where gray and reddish limestones with globotruncanas
have been encountered by the present writer. Besides the limestones
also flysch sediments with typical intercalations of limestone breccias
occur. East of Rašica similar limestones are preserved near the village
of Dobeno. In the thin sections of the limestone numerous Radiolaria and
Foraminifera with Glohigerina among them, have been observed. In
Kossmat's handdrawn map of Ljubljana (1:75.000) these sediments are
referred to the Pseudo-Zilian strata.
North of Kresnice between the Grmače Pass and the village of
Zapodje there occur limestones with globotruncanas especially Gloho-
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truncana lapparenti lapparenti Brotzen and dayey and marly shalt>s
containing intercalations of limestone breccia with miliolids, textularias
and orbitolinas. Outcrops of flysch occur also northwest of SUvna between
Stebalija and Kovačija.
The present writer found marls and marly limestones with gümbe-
linas also near Vače and east of Sv. Gora near Kobiljek.
Similar sediments with Glohotruncana are preserved at the northern
margin of the Laško synchne between Goričica and Koseze. The present
geological maps of Ljubljana and Celje—Radeče (1:75.000) refer these
sediments to the Ladinian Pseudo-Zilian strata.
In the eastern Sava folds grayish clayey and marly shales with
intercalations of limestone breccia and sandy limestones are preserved
east and north of Bohor and on ОгИса. The limestone breccia and
sandstones contain numerous foraminifera of the families Miliolidae and
Orbitolinidae. D r e g e r referred these sediments to the Wengen stage.
In this region no limestone with Glohotruncana has been found up
to now.
In the Sava folds the Upper Cretaceous sediments are preserved in
several places as erosion rests, a fact indicating that formerly the se-
diments were markedly more extensive. The location of Cretaceous
sediments shows that they had covered a considerable portion of the
southern Sava folds, i. e., the region of the litija anticline. Since the Sava
folds have as yet not been explored in full it is impossible to say how
far northward the Cretaceous sediments extend.
In view of the fact that the fades of the sediments of the Sava folds
is similar to that of the sediments encountered along the upper and
middle course of the Soča River, it might be assumed that a connection
must have existed between the two regions. The sediments which might
indicate such a connection were eroded later. s
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