When did the North Anatolian fault reach southern Marmara, Turkey?

We dated syntectonic calcites on fault planes from the southern branch of the western North Anatolian fault (NAF) in northern Turkey using U-Th geochronology. We selected strike-slip faults that are kinematically related to the current regional strain field. The isotopic ages cluster around different periods during the past ~700 k.y. The most prominent cluster peak of 510.5 ± 9.5 ka (1σ) is consistent with the maximum cumulative strike-slip offset data and tectonic plate motions measured by GPS data, highlighting the fact that the present configuration of the NAF in the southern Marmara region started at ca. 500 ka or earlier. These new isotopic ages, combined with previous considerations of regional tectonics, reveal that faulting along the western NAF initiated primarily in the southern Marmara region at least a few hundred thousand years earlier than the timing suggested for the northern branch of the western NAF. This study presents an innovative approach to constrain the timing of initiation of currently active fault segments along the NAF in southern Marmara. U-Th geochronology of fault-hosted calcite thus has a wide application in determining absolute ages of fault episodes in wider shear zones along plate boundaries.

Once again about the citadel of the Kilia fortress

The Kilia stone citadel (in fact, New-Kilia, today Kilia, Ukraine), located on the left bank of the northern branch of the Danube, was the oldest and most protected part of the medieval defensive ensemble. Most likely, it was built by the Genoeses that had their own colony, ruled by consuls in the second half of the XIV century. In order to supplement the data on the Kilia citadel (which does not exist today), the author uses the Ottoman and Russian topographic, iconographic and graphic sources of the late XVIII century. The citadel was a quadrangular fort, separated from the rest of the fortified complex by two ditches filled with water. The corners of the stone square were reinforced with four parallelepiped towers: the Commandant’s Tower (Dizdar Kulesi), the Agha Tower (Ağa Kulesi), the Ammunition Tower (Tophane Kulesi) and the Arsenal Tower (Cephane Kulesi). The Kilia citadel perfectly illustrates a mixed (combined) or transitional model with one or two peripheral donjons, with equal defense capabilities from all sides. It is based on a regular Italian quadrangular castle with four corner towers in the form of a parallelepiped.

Missionary activity of the orthodox monasteries of Transbaikal within the framework of the existence of the second Transbaikal ecclesiastical mission

The Second Transbaikal Ecclesiastical Mission significantly changed the situation with the spread of Orthodoxy among the indigenous population of the region – the Buryats, who, for the most part, were adherents of the northern branch of Buddhism – Lamaism. Its activities also had a significant impact on the Old Believer population of the region. The paper analyses the features of the activities of the Orthodox monasteries of Transbaikal, carried out by them within the framework of the missionary work of the second Transbaikal Ecclesiastical Mission, which in many ways changed the situation with Orthodoxy in the region. The mission began its work in 1861 (according to other sources, in 1862) and focused its activities on spreading Orthodoxy among the local Buryat population, predominantly Lamaists, and Old Believers. The author notes that this subject matter is understudied. At the same time, references are made to some archival documents. The result of the study was the conclusion that the Orthodox monasteries of the region quite actively took part in missionary activities.

Basin Progress – Active Deformation Analysis by Tectonostratigraphic Elements and Geophysical Methods on North Anatolian Fault System (Eastern Marmara Region, Turkey)

The Northern Branch of the North Anatolian Fault System controls and deforms the Izmit Basin and the Sapanca Lake Basin in the study area. Unlike the Sapanca Lake Basin, the oblique normal faults with WNW–ESE trending with maximum length of 5 km in the south of the basin have contributed to the deformation process in the formation of Izmit Basin. The fault sets mainly incline to the north. The N-S width of the dextral strike-slip active deformation was determined as 9 km at Izmit basin and 3.8 km at Sapanca Lake basin. Further, the minimum principal stress axes (σ3) vary in the trending ranges of N11°-74° E, which are caused by the transtensional stresses associated with strike-slip faulting in the Izmit Basin by a different tectonic source than the Sapanca Lake Basin. Besides, the crust depth of main strand of NAFS-NB was determined up to 1112 m by magnetic method. The secondary faults were determined by both magnetic and resistivity methods up to a depth of 110 m. The depression area between Izmit bay and Sapanca Lake on the northern Anatolian fault is an integrated basin with two dextral strike-slip tectonic origins. Thus, the Izmit Basin, along with the main strike-slip faulting, has been developed in the asymmetric negative flower structure, where only the southern boundary has become a fault. The Sapanca Lake Basin is a lazy-Z-shaped pull-apart system formed by the E–W trending fault as a releasing bend. A simple shear deformation ellipsoid with a long axis of approximately 35 km on the Northern Branch of the North Anatolian Fault System is defined for the Izmit – Sapanca integrated basin. Therefore, intra-basin deposits have different depths estimated from the gravity data in the Izmit – Sapanca integrated basin, and the maximum sediment thickness estimated is 2200 m in the middle of the Izmit Basin.

Contribution to the flora of Ulziit Mountain in forest steppe region of Mongolia

The Ulziit Mountain has a unique ecosystem which is one of northern branch mountains of Khangai mountain range in Mongolia. Several field survey were conducted in summer in all habitats in different altitudes. A total of 314 taxa were registered belonging to 161 genera from 52 families in Ulziit Mountain flora. The family Asteraceae was found to be the largest with 37 taxa, followed by Poaceae with 30 taxa, Ranunculaceae with 24 taxa, Cyperaceae, Caryophyllaceae and Rosaceae each with 17 taxa, Salicaceae with 16 taxa, and Fabaceae with 15 taxa; in total, these comprised 55.1% of all flora complements in this mountain. During the investigation, 5 species were newly recorded in the Khangai mountains forest-steppe region. The most represented life forms in the flora are hemicryptophytes (71.97%), which are common for mountain steppe vegetation. In a time of climate change, effective conservation of nature is needed at an ecosystem such as a single mountain particularly for endemic, relict and other salient species. Furthermore, such a detailed floristic survey is important for finding new records in the field of plant taxonomy and conservation of nature in these specific areas. Bangladesh J. Plant Taxon. 28(1): 195-215, 2021 (June)

Role of the climatological intertropical convergence zone in the seasonal footprinting mechanism of the El Niño-Southern Oscillation

The North Pacific Oscillation (NPO), a primary atmospheric mode over the North Pacific in boreal winter, is known to trigger the El Niño-Southern Oscillation (ENSO) in the following winter, the process of which is recognized as the seasonal footprinting mechanism (SFM). Based on the analysis of model simulations from the Coupled Model Intercomparison Project Phase 5 (CMIP5), we found that the SFM acts differently among models, and the correlation between the NPO and subsequent ENSO events, called the SFM efficiency, depends on the background mean state of the model. That is, SFM efficiency becomes stronger as the climatological position of the Pacific Intertropical Convergence Zone (ITCZ) moves poleward, representing an intensification of the northern branch of the ITCZ. When the Pacific ITCZ is located poleward, the wind-evaporation-sea surface temperature (SST) feedback becomes stronger as the precipitation response to the SST anomaly is stronger in higher latitudes compared to that of lower latitudes. In addition, such active ocean-atmosphere interactions enhance NPO variability, favoring the SFM to operate efficiently and trigger an ENSO event. Consistent with the model results, the observed SFM efficiency increased during the decades in which the northern branch of the climatological ITCZ was intensified, supporting the importance of the tropical mean state of precipitation around the Pacific ITCZ.

Deep sea benthic foraminiferal record from the Haymana Basin (Turkey): changes in abundance patterns and diversity across Cretaceous-Paleogene boundary

<p>In order to reveal the response of benthic foraminifera to Cretaceous-Paleogene (K/Pg) boundary event, a high-resolution benthic foraminiferal study was carried out from a land-based Haymana section which is biostratigraphically complete, and once located in the northern branch of the Tethyan Ocean. To this end, 25 samples collected from deep marine succession of the Haymana Basin were quantitatively assessed along with the utilization of quantification of species, morphogroup analysis and diversity indices to establish remarkable changes in biofacies which resulted from the boundary event.</p><p>Depositional environment is inferred as upper bathyal (200-600 m) throughout the studied section based on foraminiferal associations. Bathymetric marker species include mainly bi- to triserial forms in Maastrichtian, which favor this interval. Calcareous taxa including <em>Bolivinoides draco</em>,  <em>Eouvigerina subsculptura</em>, <em>Nonionellina</em> sp. 1, <em>Pseudouvigerina</em> <em>plummerae</em>, <em>Pyramidina</em> <em>minuta</em>, as well as species belonging to <em>Gyroidinoides</em>, <em>Laevidentalina</em>, <em>Lagena</em>, <em>Lenticulina</em>, <em>Pullenia</em>, and <em>Sitella</em> are together forming 30% of the whole assemblage in this study, which are also attributed as Shallow Bathyal Assemblage of Widmark and Speijer (1997b) from the upper bathyal environment. Accompanied agglutinated taxa are consisting of <em>Clavuinoides</em> <em>trilatera</em>, <em>Arenobulimina</em> sp., as well as species of <em>Dorothia</em>, <em>Gaudryina</em>, <em>Verneuilina</em>, and <em>Heterostomella</em>, which are reported from low and mid-latitude Slope Deep Water biofacies of Kuhnt et al. (1989). There was probably no paleobathymetric change in the Danian, as it is concluded from the structure of the faunal assemblage. Besides, calcareous taxa are found to be more abundant with respect to agglutinated taxa within the whole section, offering deposition over Carbonate Compensation Depth (CCD) level.</p><p>With this study, <em>Eouvigerina</em> <em>subsculptura</em> Acme Zone is newly offered for the uppermost Maastrichtian, and also aligned with <em>Bolivinoides draco</em> Zone, since it is existing as very abundant in all samples. Besides, <em>Angulogavelinella</em> <em>avnimelechi</em>-<em>Anomalinoides rubiginosus</em> Interval Zone (BB1) is assigned for the lowermost Danian section based on marker Paleocene species.</p><p>Based on this benthic foraminiferal record, a highly diverse foraminiferal assemblage is observed in the Maastrichtian, then it is replaced with a poor to moderate diversity assemblage in the Danian. This finding is presented by diversity indices (Fisher alpha, Shannon H and Berger Parker). Presence of diverse morphogroups together in the upper Maastrichtian section along with taxa preferring high nutrient levels including <em>E. Subsculptura</em> (11-23%), <em>Sliteria varsoviensis</em> (0-6%), <em>Praebulimina reussi</em> (2-9%), <em>Heterostomella</em> spp. (4-11%) and <em>Sitella</em> spp. (1-13%) suggests meso- to eutrophic conditions in this section. A sudden change in the faunal composition right after the K/Pg boundary offers depleted food flux into the bottom of the basin. Infaunal morpogroups decline after the boundary in the Danian section, whereas epifaunal morphogroups including mostly opportunistic <em>Cibicidoides</em> spp. (17%), increased in number in this section. The timing of this record is coinciding with the worldwide primary productivity collapse and planktonic foraminiferal mass extinction during the K/Pg boundary event.</p><p>Keywords: K/Pg boundary, deep sea benthic foraminifera, quantitative assessment, paleoenvironment, Haymana Basin</p>