Speranta-Maria Popescu

GeoBioStratData.Consulting · Geology, Palynology, Biostratigraphy

The present-day intertropical climate is forced by yearly fluctuations of insolation reorganizing pressure cells. They control, via the wind system, the variations of the precipitation front known as the InterTropical Convergence Zone (ITCZ). Its latitudinal oscillation drives a strong seasonality of rainfalls over Africa. However, connections betw...

New insights into the geodynamic evolution, the paleogeographic framework and the paleoclimatic setting of the Upper Eocene-Oligocene lacustrine basins from South-East France have been provided by an integrative approach combining geochronology, micropaleontology and stable isotope analyses. Usingle bondPb dating on calcite, pollen-based climatostr...

Circulation of water masses, sediment, and biotope between the sub-basins of the Mediterranean Sea strongly depends on morphological oceanic gateways. These geological features react to geodynamic reorganisation through volcanism, vertical movements, and/or the segmentation of sedimentary basins. Despite the palaeogeographic relevance of straits an...

The numerous processes (superficial and deep) occurring on margins, their origins, consequences, interactions and quantifications are only very partially described and understood. The identification of the relative role of factors is sometimes completely contradictory between authors. Here, we showed the results of a long-term multidecadal and mult...

Aim Past pollen records reveal the changes in latitudinal distribution of plants in relation to climate, particularly their expansion in response to global warming. The maximum northward expansion of the mangrove genus Avicennia since the Early Eocene is known, but this information is missing for other mangrove taxa. Here, we evaluate the diversity...

The concept of a geologically istantaneous earliest Zanclean reflooding of the Mediterranean Basin after the Messinian drawdown has dominated geological thinking and is ingrained in the scientific literature. The base of the Trubi Formation in southern Italy -formally defined as the Zanclean Global Boundary Stratotype Section and Point (GSSP) at 5....

The French Massif Central is a key basement relief. This region experienced an intense period of alkaline volcanism, beginning with the Cantal Stratovolcano at 11 Ma and ending at 3 Ma. To quantify the palaeoelevation of the Cantal Stratovolcano and to replace it in the frame of the uplift history of the Massif Central, we first reconstructed the v...

Professor Dr. Waldo H. Zagwijn passed away on 26 June, 2018, in his ninetieth year. His thesis research (Zagwijn, 1960) stimulated palynological investigations into the Pliocene and early Quaternary, and caused a fundamental shift in our understanding of the transition from the warm and relatively stable climate of the late Neogene to the extreme g...

The Messinian Salinity Crisis

Sedimentological, micropaleontological and geochemical studies of IODP Leg 302 boreholes, M0004A and M0002A, drilled on the Lomonosov Ridge near the North pole, are reported to construct chronostratigraphy and helped unravel Paleogene palaeoclimatic. These studies concluded to a mean annual temperature of sea surface waters ranging between 21 and 2...

High-resolution pollen analyses were performed on two cores from the western Black Sea and one core from the Marmara Sea, covering the Late Glacial-Holocene transition using 14C chronology. Particular effort was invested in the botanical identification of pollen grains thereby significantly improving our knowledge of regional flora. When interprete...

Morphological sills condition sedimentary, water and fauna exchanges between different domains. In particular, sills are crucial factors to consider during the Messinian Salinity Crisis (MSC) palaeogeographic evolution (5.97–5.33 Ma) of the NW Mediterranean area. Here we focus on the Ebro River and its up to now unexplained short Messinian onshore...

During the Paleocene–Eocene, the Earth experienced the warmest conditions of the Cenozoic and reduced equator-to-pole temperature gradients. Compared to low- and mid-latitude sites, Paleogene environmental changes are less documented in Arctic regions, although such high latitude areas constitute a critical domain to constrain global climate change...

The Amazon continental shelf hosted one of the world's largest mixed carbonate-siliciclastic platforms from the late Paleocene onwards - the Amapá carbonates. The platform architecture, however, remains poorly understood and causes and timing of the cessation of carbonate deposition are still controversial. Here we present a stratigraphic analysis...

The Zambezi Delta draining the Southern African Plateau and the southern part of the East African Rift is one of a the largest delta of Africa with a long-lasting history starting during Early Cretaceous with more than 12 km of sediments deposited. The Zambezi Delta is therefore a unique archive of the past topographic evolution of southern and eas...

The Adriatic Basin (Central Mediterranean Sea) is the place of intense controversy concerning the sedimentary dynamics and palaeogeographic evolution during the Neogene, especially during the Messinian Salinity Crisis (MSC: 5.97 to 5.46 Ma). Following the various interpretations, this basin was totally disconnected or connected to the deep basins d...

Sediments deposited after the peak of the Messinian Salinity Crisis (MSC) in the Apennine foredeep of Italy embody a topic debated on both chronostratigraphic and palaeoenvironmental grounds. We performed micropalaeontological (calcareous nannofossil and dinoflagellate cyst) analyses on four stratigraphic sections (Monticino, Civitella del Tronto,...

The early Eocene (ca. 56-47.8 Ma) was an interval of exceptional warmth with reduced pole-to-equator temperature gradients. Climate proxies indicate mean annual air temperatures (MATs) and sea-surface temperatures (SSTs) exceeding 8-18 °C and frost-free, mild winters in polar areas, features that have proven difficult to reproduce with the most ela...

The calcareous nannofossil Ceratolithus acutus (= C. armatus) is an important species associated with the final flooding that ended the Messinian Salinity Crisis in the Mediterranean. We emphasize its robust identifying features and stratigraphic value in the global ocean. This species is particularly useful in recognising and constraining the Mess...

van Baak et al. provide magnetostratigraphy for DSDP Hole 380A along a 175 m interval and a 40Ar/39Ar date at 706.8 mbsf. The biostratigraphic basis for their interpretation is the first consistent occurrence (FCO) of the dinoflagellate cysts Galeacysta etrusca and Caspidinium rugosum at 841 and 850 mbsf, respectively (Groothe et al., 2014), instea...

Van Baak et al. (2015) provide magnetostratigraphy for DSDP Hole 380A along a 175 m interval and a 40Ar/39Ar date at 706.8 mbsf. The biostratigraphic basis for their interpretation is the first consistent occurrence (FCO) of the dinoflagellate cysts Galeacysta etrusca and Caspidinium rugosum at 841 and 850 mbsf, respectively (Grothe et al., 2014),...

The two sides of the Strandja Sill show a highly discontinuous stratigraphic succession since the Late Oligocene. This area, together with the Sea of Marmara Basin, is usually proposed as the gateway for the Paratethyan freshwaters and organisms that constituted the Lago Mare facies in the Mediterranean Sea during the Messinian Salinity Crisis (MSC...

The Roussillon Basin is a non-silled Miocene sedimentary basin filling a late Oligoceneeearly Miocene graben. The basin was intensively impacted by the Messinian fluvial erosion, as evidenced in exposed sections, in seismic profiles and in deep boreholes drilled for hydrocarbon exploration. As the basin was open to the Mediterranean Sea, the huge d...

The Sorbas Basin is the land reference of the Messinian Salinity Crisis (MSC) that affected the Mediterranean Sea in the latest Miocene. Its stratigraphy has been re-visited using calcareous nannofossils and planktonic foraminifers, which provide a reliable biostratigraphic frame and lead to particularly specify the relationships between the Sorbas...

Since the discovery of calcareous nannofossils, dinoflagellate cysts and planktonic foraminifers in deposits from the Dacic Basin, intensive research has been performed in order to evidence which gateway this microplankton used to connect Paratethys and the Mediterranean prior and after the Messinian Salinity Crisis (MSC). Such a gateway is also to...

We present a high-resolution analysis of planktonic foraminifers, calcareous nannofossils, ostracods, dinoflagellate cysts and pollen grains in four sequences from DSDPeODP holes in the southwestern Mediterranean Alboran and Balearic basins (976B, 977A, 978A and 134B) encompassing the previously defined MessinianeZanclean boundary. The study focuse...