https://doi.org/10.35463/j.apr.2020.01.01 ACTA PALAEONTOLOGICA ROMANIAE (2020) V.16 (1), P. 3-17 FOSSIL WOODS FROM BOZOVICI (SW ROMANIA) Stănilă Iamandei1*, Eugenia Iamandei1 & Tiberiu Stoia2 Received: 09 August 2019 / Accepted: 14 October 2019 / Published online: 25 October 2019 Abstract A palaeoxylotomical study was done on several samples from a private collection of petrified wood found in Bozovici area, which were taxonomically identified. Bozovici area is a small Badenian depression filled by coarse continental deposits, with some interbedded coal and volcanic tuffs. The frequent lateral facies variations and the few fossils of fresh water fauna make difficult a stratigraphic correlation of these deposits. Those samples of fossil wood were identified as remains of Glyptostroboxylon rudolphii Dolezych et Van der Burgh and Spiroplatanoxylon den- siradiatum (Petrescu) Süss and an extended discussion concerning the systematics of these taxa was made. Advanced studies on more numerous samples coming from Bozovici area could contribute to a better palaeoenvironmental and palaeoclimatic reconstruction of that area, during Badenian time. Keywords: Bozovici depression, Badenian coal, petrified wood, Glyptostroboxylon, Spiroplatanoxylon. INTRODUCTION Fifty years ago, geological prospections in this area, have described a coaly level between Bozovici and Lăpușnicul One of the authors of the present paper (T. Stoia), has Mare, on Lighidia and Agrişului valleys. This coaly sub- organized some outdoor exhibitions in Bocșa and Gărâna horizon consists of clay with pyrite concretions overlay- localities, (Banat, Romania), with stumps and logs of ing marls and green-greyish or red clay and being over- petrified woods collected from different places in Roma- lain by grey-yellowish marls and limestones with Corbu- nia. Some samples collected by him from Bozovici area la sp. and Terebralia bidentata Defrance, and a coaly bed (i.e. Almăj Depression) were brought to the National Ge- presenting numerous silicified tree trunks at its upper part ological Museum in Bucharest, and represent the subject (Iliescu et al., 1967). of the present study. In Bozovici Depression occurs a The upper sequence, "the Valea Slătinicului Member" coal-bearing geological formation of Badenian age, pre- (see Fig. 2), has a fluvial-lacustrine aspect, it is well but serving numerous remains of coalified wood and some- irregularly developed, having 50-150 m in thickness, and times petrified (Iliescu et al., 1967). Since there are no is attributed to the Badenian (i.e. upper part of Moravian paleoxylotomical studies ever done on this fossil wood, +/- basal Wielician), overlaying an unconformity (ero- we started a study of these samples in order to get new sional event) with a basal tuff (=Slătinic Tuff) followed informations about the composition of the ancient forest by silty sandstones and clay, and coarser intercalations up involved in the local coal -genesis. In this context, the to the basal tuffaceous level of Dalboșeț Formation purpose of the paper is firstly, to identify the petrified (Codrea, 2002; see Fig. 2). At the upper part of Valea wood remains from Bozovici Depression, and also to Slătinicului Member some coaly seams of variable thick- discuss palaeoenvironmental and palaeoclimatic recon- ness (up to 11 m) appear, containing also some petrified struction of that region during Badenian time. tree trunks (marked also by Barbu & Brănoiu, 2018, in Fig.2). GEOLOGICAL SETTING In the same deposits some micro-mammals were de- scribed from drilling material (Codrea, 2002). The age of The Bozovici Depression (also known as Almăj Depres- the geological formation supposed to be Early Miocene sion, Fig. 1) is located in South-Western part of Romania, by Grigorescu (1985), was specified by Petrescu & Nico- Caraș-Severin county (Fig. 1), in a small Badenian gra- rici (1989), based on the palynologic study of the drilling ben, probably initiated during the Early Miocene and is Lighidia 6442B. Stratigraphically analyzed, the spo- linked, to east, with Caransebeș-Mehadia depression, ropolinic association from the lower part of the sedimen- another tectonic Miocene corridor filled with similar tary succession indicates the Eggenburgian, and suggests Badenian continental coarse deposits: conglomerates, also the paleoclimate parameters (mean annual tempera- calcareous sandstones, sands, pebbles, marls, banded tures, MAT = 16-17ºC and mean annual precipitations, clay, interbedded coals and volcanic tuffs (Oprea, 2014). MAP = 1200-1800 mm). The frequent lateral facies variations and the fossils scar- In the upper part of the succession, the thermophilic spe- city (only a few fossils of fresh water fauna was reported) cies become fewer, while the temperate ones appear and bring difficulties in establishing a precise stratigraphic even indications of storeyed vegetation are documented, sequence of those deposits. Even if the region presented probably as a result of some landscape modifications by interest for coal and also for gold, many years ago (see tectonic uplift. The palynologic assemblage was inter- Pomârleanu & Mârza, 2002), few geological investiga- preted as indicating the Ottnangian stage (Petrescu, 2003, tions were done in the area. p. 161-163). The list of flora, suggested by the ________________________________ 1Geological Institute of Romania - 1st, Caransebeş street, Bucharest, Ro-012271, Romania; *Corresponding author: [email protected] 3 2Bocșa Română, Caraș-Severin county, Romania; [email protected] Stănilă Iamandei, Eugenia Iamandei & Tiberiu Stoia Fig. 1 Geological map of Bozovici Depression (redrawn after Codarcea et al., 1968. Geological maps 1:200,000, Sheet 31 - Reşiţa and Sheet 32 - Baia de Aramă). Graphic scale. Fig. 2 Correlated stratigraphic columns in Bozovici Basin (from Iliescu et al. 1967; Codrea, 2002). 4 Fossil woods from Bozovici (SW Romania) sporopolinic study of Petrescu (2003), beside numerous The transition from earlywood to latewood is gradual. Pteridophytes, possible Cycads and herbaceous Angio- The boundaries of the annual rings are distinct, marked sperms - with graminaceous, sparganiaceous, liliaceous by 3-15 tangential rows of thick-walled to very thick- taxa, numerous arboreal plants appear. Firstly, some coni- walled and smaller cells of the latewood. There are no fers as Abies, Picea, Pinus, Larix(?), Sciadopitys, and normal axial resin ducts and the ring boundaries are often Sequoia, some other Cupressaceae(?) and, probably wavy, probably due to the buttressed form of trunk. some Podocarpacee(?) also appear. Also numerous An- The tracheids are polygonal in cross section, with slightly giosperms were indicated - as Magnolia, Myrica, Ju- rounded corners in the earlywood and with radi- glans, Celtis, Engelhardia, Carya, Platycarya, Alnus, al/tangential diameters of 25-75/30-55 μm, smaller in the Betula, Carpinus, Ulmus, Tilia, Nyssa, Fagus, Quercus latewood, of 25-30/17-25 μm. The tracheidal wall has 5- and other diverse members of Symplocaceae, Onagrace- 10 μm in the early wood, growing to 12-17 μm the double ae, Caprifoliaceae, Elaeagnaceae, Proteaceae, Myrtaceae, wall, in the latewood. There are 2-11 radial regular rows Malpighiaceae, Ericaceae, Cyrillaceae, Sapotaceae, between two successive rays. On the tangential walls Compositae, and even Palms (see Petrescu, 2003, p. 161- there are few, uniseriate, spaced or slightly irregular abi- 163). etineous small bordered pits, of 6-8-10 μm in diameter, with small circular apertures, or vertical elliptic. The ra- MATERIAL AND METHODS dial pits is opposite, typical abietineous, of 12-16 μm in diameter and smaller in the latewood, in 1-4 vertical Five samples of petrified wood were collected from Bo- rows, spaced or contiguous, sometimes presenting small zovici depression from mid-Badenian deposits from the irregularities in their arrangement. Crassulae are occa- upper part of Valea Slătinicului Member, Lăpușnicul sionally present. No helical thickenings were seen on the Mare Formation (see Fig. 2). Two of them can be seen in tracheids. Fig. 3. The studied material is deposited in the Collection The axial parenchyma is few, dispersed, less visible in of the National Geological Museum. cross-section, since not always has dark content and it From each sample three thin sections of petrographic type appear similar to tracheids. In vertical view it appears as after the standard directions, (transversal, tangential and rectangular thin-walled cells (1-3 μm the simple wall), radial) were executed. These sections have been studied with thin terminal (horizontal) walls smooth, slightly ru- under the optic microscope and all anatomical details gose or nodular, with 1-3 nodules. Inside, it has large were described for each specimen. After this, by compar- dark resinous balls, or plugs with rounded endings, some- ison with previously described similar aspects of extant times with convex empty spaces, or as small remains. or fossil wood structures the identification of the un- The rays are usually uniseriate, sometimes with local known tree was performed. short biseriations or even biseriate, having 2-15-36 or more cells in height. Sometimes, they seem to be hetero- PALAEOXYLOTOMY geneous in tangential view, with often unequally sized cells, either higher, or wider (as wide as two cells when Family Cupressaceae Gray, 1822 nom. cons. (sensu occur in biseriate rays), and have lateral intercellular Farjon 2005b) spaces. Ray density is 4-8 rays per horizontal tangential mm and up to 40 rays