Ovidiu Gabriel Iancu | Universitatea Alexandru Ioan Cuza Iasi (original) (raw)

Papers by Ovidiu Gabriel Iancu

ABSTRACT Continental impact reveals an excavated crater that has few fresh fine ejecta showing ma... more ABSTRACT Continental impact reveals an excavated crater that has few fresh fine ejecta showing major high shock metamorphism due to weathering [1]. A giant ocean impact rarely remains as an excavated crater mainly due to crushing by dynamic plate-tectonic movements on the crust [2]. However, all impact materials, including fine-grained ejecta, can be obtained with artificial impact experiments [3]. The purpose of this study is to discuss material evidence for ocean impact based on shock-metamorphic experiments. Artificial impact experiments indicate that fine shocked quartz (SQ) aggregates can be formed on several target rocks (Table 1) [1]. It is found in Table 1 that (1) the largest-density deviation of SQ grain is found not at the wall-rock or the impact crater but at fine-grained ejecta, and (2) silica-poor rocks of basalt, gabbro, and anorthosite can also make fine SQ aggregates by impact. Table 1, which appears here in the hard copy, shows formations of fine shocked quartz aggregates from ocean-floor rocks of basalt, gabbroic anorthosite, and granite [3]. An asteroid (about 10 km across) hits the Earth ~65 m.y. ago [4] to result in global catastrophe by titanic explosion and climate change. But shocked quartz grains found in the K/T boundary layer were considered to come from crystalline continental rocks [5]. The present result as listed in Table 1 indicates that fine SQ aggregates can also be formed at sea-floor basaltic and gabbroic rocks [3]. The present result of formation of the SQ grains from sea- floor target rocks is nearly consistent with the finding of a sea-impact crater at the K/T boundary near the Caribbean [6]. Impact-induced volcanism at the K/T boundary can explained by the penetration from thin ocean crust to upper mantle reservoirs, if giant impact of a 10-km- diameter asteroid hit the ocean [2,7]. The present result can explain "phreatomagmatic (magmatic vapor) explosion," which is created by abrupt boiling between high-temperature magma and cold sea water to produce a titanic explosion of the asteroid disintegrated in a mass of exploding steam and vaporizing soil, including the SQ aggregates, and to create the Atlantic Ocean floor by the continental drift [8]. References: [1] Miura Y. (1991) Shock Waves, 1, 35-41. [2] Miura Y. and Takayama K. (1993) Symp. Shock Waves (Japan), 2, 193-196. [3] Miura Y. et al. (1992) Proc. Shock Waves, 18, 403-408, Springer-Verlag. [4] Alvarez L. W. et al. (1980) Science, 208, 1095-1107. [5] Bohor B. F. et al. (1984) Science, 224, 867-869. [6] Hildebrand A. R. et al. (1991) Geology, 19, 867-871. [7] Barlow N. G. (1990) Geol. Soc. Am. Spec. Pap. 247, 181-187. [8] Hartmann W. K. and Miller R. (1991) The History of Earth, 165, Workman.

Lunar and Planetary Institute …, 1994

... One of the crew members (Mr. T. Ayabe) who found many meteorite-like fragments on the deck of... more ... One of the crew members (Mr. T. Ayabe) who found many meteorite-like fragments on the deck of this ship anchored in ... meteorites (1)Obstacle Snowfields Iceflow Obstacle Many (2) Sea Snowfields Iceflow Sea None 918 LPSCLXI/ JAPANESE FOUND METEORITES; Miura Y. et ...

ABSTRACT Tektites are amorphous glass samples that form during the quenching of molten rock resul... more ABSTRACT Tektites are amorphous glass samples that form during the quenching of molten rock resulted after a meteorite impact or thermonuclear detonations. The terrestrial tektites reflect the chemical composition of the rocks from which they derive, with an advanced volatile depletion. The most used volatile to define the origin from an impact process is water. Water in tektites is low, reflecting the high temperature at which the terrestrial tektites have been exposed [1,2]. A terrestrial glass sample with unknown origin (with strong tektite macroscopic and microscopic characteristics) was analyzed along with other two tektite samples from known terrestrial strewnfields. The measurements are intended as a possible mean to positively identify new tektite samples, as well as to serve as completion for spectral libraries that are used for the characterization of planetary surfaces in the UV-VIS-NIR (0.3 - 3.3 μm) solar reflection range (SR).

The present study was conducted on a number of 14 tailings samples collected from the topstratum ... more The present study was conducted on a number of 14 tailings samples collected from the topstratum (0-20 cm depth) of three mine tailings deposits located within the Fundu Moldovei mining perimeter, Romania, namely Dealu Negru, Prașca I and Prașca II. The main objective of the study was to determine the mineralogy of these tailings by means of XRD, as well as to establish a link between the mineralogical composition and the conditions in which the tailings have been deposited. The Powder XRD analyses showed that the main minerals are quartz and Fe-rich chlorite, while the accessory minerals are muscovite-illite, sometimes pyrite or albite. The trace minerals identified were the following: albite, pyrite, jarosite (resulting from the weathering of pyrite), talc, gypsum and stilpnomelane.

International Journal of Environmental Research and Public Health, 2020

The levels and distribution of 9 trace elements in apples from two orchards in north-east (NE) Ro... more The levels and distribution of 9 trace elements in apples from two orchards in north-east (NE) Romania were measured by means of Atomic Absorption Spectroscopy (AAS) on 42 samples of 9 different apple varieties, with average content ranges of 0.909–4.458 mg·kg−1 Zn, 0.055–0.409 mg·kg−1 Cu, 0.700–2.476 mg·kg−1 Fe, 0.328–0.695 mg·kg−1 Mn, 0.054–0.257 mg·kg−1 Ni, 0.005–0.101 mg·kg−1 Cr, 0.027–0.420 mg·kg−1 Co, 0.413–1.149 mg·kg−1 Pb, and 0.025–0.127 mg·kg−1 Cd. For some apple varieties, Pb contents are 2 times higher than the maximum contents allowed according to national standards, Cd contents are 6 times higher, and in some cases Zn contents also exceed the national threshold, showing preferential accumulation on specific apple varieties. Whilst some research has been carried out on trace element distribution in apples, this study assessed the areal distribution of toxic trace elements in connection to the adjacent roads. The first apple orchard is located near a county road, with re...

Journal of African Earth Sciences, 2020

Tchabal Mbabo massif within the Cameroon Volcanic Line (CVL) at the junction with Adamawa line in... more Tchabal Mbabo massif within the Cameroon Volcanic Line (CVL) at the junction with Adamawa line in Central Africa is a huge (55 × 30km × 2340 m) Eocene-Oligocene volcano composed of frankly alkali lavas of basanites and basalts, trachybasalts, basaltic trachyandesites, trachyandesites, peralkaline trachytes and rhyolites. Lavas show flows and domes shape features and crop up along N160E, N135E and N70E Panafrican cracks. They have microlitic porphyritic textures and are composed of euhedral and subhedral phenocrysts and microcrysts of olivine, clinopyroxene, Ti-magnetite, ilmenite, amphibole (in basanite, basalt and trachybasalt as well as in peralkaline trachyte), plagioclase (in trachybasalt and basaltic trachyandesite), biotite and orthoclase (in trachyte and rhyolite). Same minerals occur in the matrices of the lavas (and moreover plagioclase in basalt). Spinel, olivine and diopside xenocrysts of mantle origin are present in some lavas. ICP-MS and ICP-AES geochemical analyses show that the basanites mostly contain one pyroxene (diopside), with abundant nepheline and olivine in their norms, linked to strong silica undersaturation. Trace element concentrations and ratios (Zr, Nb, Y) witness of alkali affinities, in intra-continental/within-plate anorogenic setting. Increased (Na2O, K2O, Ta, a.s.o.) or decreased (MgO, Fe2O3, TiO2, CaO, a.s.o.) compositional variations of majors and trace elements from basaltic lavas (dated at 28.6–28.9 Ma) to felsic lavas deal to a differentiated through fractional crystallization process. Trachyandesite lavas dated at 38.2 Ma do not belong to this series. Tchabal Mbabo basalts are the result of low partial melting rate of a lherzolite mantle source containing residual phlogopite + garnet, similar to those of the continental and oceanic sectors of the CVL. Melting of mantle source took place just at the base of the lithospheric mantle. Sr, Nd and Pb isotopic ratios of Tchabal Mbabo basaltic lavas are closed to the FOZO reservoir with (206Pb/204 Pb)i: 17.869407 to 19.747896. Tchabal Mbabo mafic and felsic lavas display variable but moderate (87Sr/86Sr)i ratios (0.703481–0.705053) and similar range of Ndi and Pbi isotopic ratios: 0.512526 < (143Nd/144Nd)i < 0.512771, 15.568709 < (207Pb/204 Pb)i < 15.735532 and 37.905174 < (208Pb/204 Pb)i < 39.579573. Values for trachyandesite and peralkaline trachyte are close to OIB rather than FOZO reservoir. Low (87Sr/86Sr)i ratios (0.703481) and positive eNd (+2.59) of basalt preclude any important crustal contamination. Meanwhile, magma mixing, fluid-rocks interaction and selective crustal contamination of felsic lava by underline Pan-African crust might have occurred later, during the differentiation of Tchabal Mbabo lavas series.

Revista de Chimie, 2018

Tinovul Mare Poiana Stampei is situated in the northern group of the Oriental Carpathians within ... more Tinovul Mare Poiana Stampei is situated in the northern group of the Oriental Carpathians within the Dornelor Depression, one of the richest peat areas in Romania. In this study we have performed analyses of certain heavy metals (Cr, Co, Ni, Cu, Zn, Pb, As and Cd) found in the forest soils adjacent to the Tinovul Mare Poiana Stampei peat bog. The analyses performed through X-ray fluorescence spectrometry indicated the following variation limits (mg/kg): Cr: 20-66; Co: 8-29; Ni: 16-78; Cu: 16-42; Zn: 36-199; Pb: 21-229; As: 5.5-36 and Cd: 0.01-1.4. The outcomes of the present study indicate high concentrations for certain (Ni, Pb and As). These concentrations exceed the alert threshold established by the Romanian Law, according to Order no. 756 of November, 3rd 1997.

Environmental Engineering and Management Journal, 2014

Environmental Engineering and Management Journal, 2018

Geochemistry, 2018

Abstract The upper reaches of the Bistrita drainage system were selected as a natural test site t... more Abstract The upper reaches of the Bistrita drainage system were selected as a natural test site to determine the geogenic and anthropogenic input into fluvio-lacustrine systems in humid mid-latitude morphoclimatic zones. The reason for this selection lies in the complex geology and its metallogenic evolution leading to a great variety of Fe, Mn, U, and polymetallic sulfides ore deposits. It sparked an intense mining activity during the past centuries with a strong impact on the drainage system similar to many mineralized sites in the world which are still under exploitation. Sediment samples from Bistrita River were analyzed by means of X-ray fluorescence spectrometry (XRF), X-ray diffraction (XRD), near-infrared (NIR) and micro-Raman spectroscopy (μ-Raman). Our results revealed that the chemical and mineralogical built-up of the stream sediments is mainly geogenic, with most of the trace elements accumulated in the river sediments derived from the source rocks exposed in catchment area of the River Bistrita. A strong input by man has been detected in the drainage system near abandoned mining sites. The trace elements are mainly accommodated in the structure of detrital minerals representative of the clastic aureole around the source rocks, and to a lesser extent adsorbed onto the surface of clay minerals. The REE incorporated into muscovite furnish evidence of having derived from the source rocks, prevalently mica schists exposed by supergene processes in the provenance area and rule out a neoformation of clay minerals on transport and deposition.