SEDIMENTOLOGICAL PROPERTIES and DEPOSITIONAL ENVIRONMENTS of the HOLOCENE SEQUENCE in YENİKAPI, ISTANBUL

Abstract

During the salvage excavations in the area of the former Theodosian harbor in Yenikapı-İstanbul several ship wrecks from the Byzantine period, archaeological objects from different periods and a Holocene aged sedimentary sequence have been uncovered. In this study the lithological, lithostratigraphical and facies properties of the Holocene sequence are investigated in detail and its depositional environment is determined. For this purpose along four profiles (S1, S2, S3, S4) 14 different sections of a total thickness of 17.75 m are studied and 100 samples are collected. The grain size distribution and mineralogical composition of the samples are defined by sieve and sedigraph analysis and by XRD method, respectively. Results of these analyses and facies characteristics of this poorly known Holocene sequence are used for the definition of the depositional environment. Accordingly, the marine sediments are deposited in a near-shore environment, with a natural embayment or estuary transgressively. Terrigenous and anthropogenic material carried by the Lycos River, at the mouth of this natural embayment, resulted in first a regression and then a high-energy fluvial system in the study area.

Establishing a high‐resolution stratigraphy in the Holocene marine sequence of the ancient Theodosian harbor of Istanbul with the help of dendrochronology

“…All these give the impression that Unit 5 was formed by a sudden but very high‐energy process, such as a tsunami or a very strong storm or flood, typical of the type of event deposit described by Marriner et al (). Sezerer‐Bulut, Yalçın, and Algan () summarized discussions on the origin of this event deposit and came to the conclusion that further studies are required to differentiate between these possible causes. The problematic nature of such deposits is also emphasized by Marriner et al () as “These wide‐ranging examples underscore the challenges of interpreting the stratigraphic record of high‐energy coastal events and demonstrate that careful and detailed multiproxy analyses are important to effectively differentiate between geological archives of storms and tsunamis.” ; Unit 6 contains dominantly light colored, well‐sorted sands and silty clayey bands.…”

“…All these give the impression that Unit 5 was formed by a sudden but very high-energy process, such as a tsunami or a very strong storm or flood, typical of the type of event deposit described by Marriner et al (2017). Sezerer-Bulut, Yalçın, and Algan (2019) summarized discussions on the origin of this event deposit and came to the conclusion that further studies are required to differentiate between these possible causes. The problematic nature of such deposits is also emphasized by Marriner et al were uncovered (Kocabaş, 2010;Pulak, 2007;Pulak, et al, 2015).…”

Organic geochemical characterization of Early-Mid-Holocene swamp deposits near the Neolithic settlement in Yenikapı-Istanbul: Assessment of environmental variability and anthropogenic impacts

“…In addition to this, the sedimentary sequence exposed during the excavations was studied from geological and geoarchaeological points of view in order to obtain new data on the Black Sea-Mediterranean connection and sea-level changes during the Holocene (Algan et al, 2009, 2010, 2011; Perinçek, 2010a, 2010b; Yalçın et al, 2019). From top to bottom a sequence consisting of soil and artificial fill, fluvial deposits, marine sediments, a dark gray to black clay at the eastern part of the excavation area, and late Miocene deposits underlying these units have been uncovered (Algan et al, 2007, 2009, 2011; Bony et al, 2011; Sezerer-Bulut et al, 2019; Yalçın et al, 2019). Lithological properties, age, thickness, and areal extension of this dark-colored clay unit, which is a new unit of the geology of the Istanbul area, were recently addressed by Yalçın et al (2015).…”