Kamnolom v naselju Podpeč pri Ljubljani velja za glavni kamnolom rimske kolonije Emone (Ljubljana). Obstoj antičnega kamnoloma v Podpeči je bil do sedaj utemeljen le na podlagi makroskopske ...podobnosti med Členom litiotidnega apnenca, ki izdanja v Podpeči, in z njim povezanimi rimskimi spomeniki, odkritimi v Ljubljani. V okviru pričujočega dela smo skušali poiskati oprijemljive arheološke in geoarheološke dokaze za njegov obstoj. V skrajno severnem delu kamnoloma smo izvedli arheološko sondiranje, hkrati pa natančno določili sestavo apnenca na tem območju in v 288 izdelkih iz antične Emone. Sondiranje severno od modernega kamnoloma je odkrilo dobro ohranjene sledove rimskodobne kamnoseške dejavnosti. Hkrati je litološka analiza spomenikov iz Emone razkrila, da je kar 182 (ali 64 odstotkov) analiziranih spomenikov izdelanih iz apnenca, litološko identičnega različkom, ki izdanjajo v Podpeči. Ti različki se prostorsko grupirajo severno od modernega kamnoloma. Pri tem sicer ostaja odprto vprašanje pripadnosti nekaterih različkov apnenca v izdelkih, ki so brez diagnostičnih komponent in bi lahko pripadali tudi nekoliko starejšemu Členu krkinega apnenca. Rekonstrukcijo obsega starega kamnoloma omogoča primerjava faciesov izvornih litostratigrafskih enot in izdelkov, pa tudi historična analiza zgodnjih kartografskih in katastrskih dokumentov. Analiza najzgodnejših izdelkov je omogočila hipotezo o prihodu kamnosekov iz kamnoloma v Nabrežini.
Purpose
This study deals with the identification of CH
4
and CO
2
sources in the high-carbonate wetland Lake Podpeč in the Ljubljana Marshes, Slovenia.
Materials and methods
Lake Podpeč is situated ...on the periphery of the Ljubljana Marshes in central Slovenia. A combination of chemical analysis and natural abundance analysis of stable carbon and hydrogen isotopes of CH
4
, along with analysis of dissolved inorganic carbon (DIC), was employed in an incubation experiment.
Results and discussion
The isotopic composition of dissolved inorganic carbon (
δ
13
C
DIC
) suggests three main processes occurring during incubation: oxic degradation of organic matter (OM), anoxic OM degradation, and methanogenesis. During oxic degradation of OM, the
δ
13
C
DIC
values slightly decrease from − 13.2 to − 14.5‰. However, after 50 days, the
δ
13
C
DIC
values started to increase, reaching − 12.2‰ by the end of the experiment.
13
C enrichment coincided with the formation of CH
4
, which began to increase simultaneously. The CH
4
produced had an average
δ
13
C
CH4
value of − 67 ± 1‰ and
δ
2
H
CH4
value of − 389 ± 3‰, suggesting that CH
4
is formed through acetate fermentation. The contribution of calcite dissolution to DIC increased during the degradation of OM by 53%. However, during methanogenesis, there was no significant change in the concentrations of Ca, and the estimated contribution to DIC was only 3%.
Conclusions
This study enhances our understanding of methane production in wetland Lake Podpeč and its relevance in the context of other high-carbonate lakes. The findings offer insights into the complex interactions between OM degradation, methane production pathways, and carbonate dissolution, which has implications for the global carbon cycle and greenhouse gas emissions.
Zvon v Podpeči, Istra 1960Podpeč, vas pod Kraškim robom, se je pred stoletji namestila v zavetni in prisojni legi ob izviru žive vode. Ugodno, če ne bi nad njo kot Damoklejev meč že od njenega ...nastanka viselo odsekano apnenčasto kraško skalovje. In če je ne bi zdaj uklepala še železnica Kožina–Koper, ki z iskrenjem zavor pod vse težjimi tovori karnaprej grozi z ognjem.Stara cerkev sv. Helene je iz sredine 15. stoletja. Ponaša se s kakih 100 let mlajšimi freskami. Nima pa zvonika. A brez zvona ljudje očitno niso mogli. Pa so ga obesili kar na gavge. In tudi tako je vdano služil svojemu namenu. – Fotografija je bila posneta spomladi 1960, ko so primorski študentje na svojem tridnevnem pohodu po vaseh Slovenske Istre obiskali tudi Podpeč. (sf)
The “Podpeč limestone” outcropping south of Ljubljana (Central Slovenia), deposited at the northern edge of the Dinaric Carbonate Platform, comprises mostly dark grey and black thick bedded oolitic ...limestone, and is renowned for several horizons of lithiotid bivalves. Foraminifera, especially Orbitopsella spp., are rather frequent, but no detailed distribution of foraminiferal taxa was given. Furthermore, documentation of foraminiferal species is scarce, with few photographs. In order to give a comprehensive picture of foraminiferal assemblage of the “Podpeč limestone” and its distribution, three sections were measured in detail and sampled. The foraminiferal assemblage consists of 17 species, described in detail. On the basis of foraminifera, the investigated part of the “Podpeč limestone” belongs to the Lituosepta recoarensis and Orbitopsella praecursor biozones of early Late Sinemurian and Early Pliensbachian age, respectively.
The lithiotid limestone is characteristic for many Late Sinemurian – Pliensbachian tropical and subtropical carbonate platforms of the Neotethys and the Piemont-Liguria Oceans. On the northern edge ...of the ancient Adriatic Carbonate Platform (present NW External Dinarides) the lithiotid limestone forms a few hundred kilometres long belt. Sedimentological characteristics of the lithiotid limestone have been recorded in samples taken from three sections located in central Slovenia. Peloids, ooids, aggregate (lump) grains, benthic foraminifera, and micritised bivalve shells (cortoids) are the dominant grains. The microfacies association suggests restricted to open marine interior of a carbonate platform bordered by marginal sand shoals, or an inner ramp setting. Subtidal conditions were occasionally interrupted by emersions.
The article analyses the rate of subsidence of Ljubljansko barje (the Ljubljana marshland)during Holocene. The analysis is based on the reinterpretation of data from pollen diagrams taken in the BV–1 ...borehole north of Podpeč and in the borehole BV–2 southof ^rna vas. The reinterpretation was carried out on the basis of comparison with absolutely dated pollen diagrams in the sediment of Podpe{ko jezero and diagrams at other locations in Slovenia. The main markers, which the reinterpretation is based on, are the Pinus, the concentration of which starts decreasing at 11.2 ka, and the occurrence of Fagus and Abies. The concentration of Fagus starts rising at 8.7 ka, and Abies reaches its peak at 6.4/6.9 ka and at 3.0 ka. On the basis of relation between age and depth at which the sediment occurs a simple sedimentation-consolidation model was constructed, showing that the neotectonic subsidence of the Ljubljana Moore in Holocene was uniform. The subsidence in the area of borehole BV–1 was 1.24m/ka and the subsidence in the area of borehole BV–2 1.36 m/ka. The article also poses the hypothesis that the transition from younger Pleistocene into Holocene starts in the red-brown cohesive clay representing the paleo-soil and not with the beginning of sedimentation of lake chalk.
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