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@article{1182781,
author = {Ghinassi, Massimiliano and Nemec, Wojciech and Aldinucci, Mauro and Nehyba, Slavomír and Özaksoy, Volkan and Fidolini, Francesco},
article_location = {Oxford},
article_number = {4},
doi = {http://dx.doi.org/10.1111/sed.12081},
keywords = {Boyabat Basin;fluvial palaeochannel;meander-bend transformation;Palaeogene;point-bar architecture;thalweg trajectory;Turkey},
language = {eng},
issn = {0037-0746},
journal = {Sedimentology},
title = {Plan-form evolution of ancient meandering rivers reconstructed from longitudinal outcrop sections},
volume = {61},
year = {2014}
}
TY - JOUR
ID - 1182781
AU - Ghinassi, Massimiliano - Nemec, Wojciech - Aldinucci, Mauro - Nehyba, Slavomír - Özaksoy, Volkan - Fidolini, Francesco
PY - 2014
TI - Plan-form evolution of ancient meandering rivers reconstructed from longitudinal outcrop sections
JF - Sedimentology
VL - 61
IS - 4
SP - 952-977
EP - 952-977
SN - 00370746
KW - Boyabat Basin;fluvial palaeochannel;meander-bend transformation;Palaeogene;point-bar architecture;thalweg trajectory;Turkey
N2 - he mode of channel-bend transformation (i.e. expansion, translation, rotation or a combination thereof) has a direct bearing on the dimensions, shape, bedding architecture and connectivity of point-bar sandstone bodies within a fluvial meander belt, but is generally difficult to recognize in vertical outcrops. This study demonstrates how the bend transformation mode and relative rate of channel-floor aggradation can be deciphered from longitudinal outcrop sections aligned parallel to the meander-belt axis, as a crucial methodological aid to the reconstruction of ancient fluvial systems and the development of outcrop analogue models for fluvial petroleum reservoirs. The study focuses on single-storey and multi-storey fluvial meander-belt sandstone bodies in the Palaeogene piggyback Boyabat Basin of north-central Turkey. The sandstone bodies are several hundred metres wide, 5 to 40 m thick and encased in muddy floodplain deposits. The individual channel-belt storeys are 5 to 9 m thick and their transverse sections show lateral-accretion bed packages representing point bars. Point bars in longitudinal sections are recognizable as broad mounds whose parts with downstream-inclined, subhorizontal and upstream-inclined bedding represent, respectively, the bar downstream, central and upstream parts. The inter-bar channel thalweg is recognizable as the transition zone between adjacent point-bar bedsets with opposing dip directions into or out of the outcrop section. The diverging or converging adjacent thalweg trajectories, or a trajectory migrating in up-valley direction, indicate point-bar broadening and hence channel-bend expansion. A concurrent down-valley migration of adjacent trajectories indicates channel-bend translation. Bend rotation is recognizable from the replacement of a depositional riffle by an erosional pool zone or vice versa along the thalweg trajectory. The steepness of the thalweg trajectory reflects the relative rate of channel-floor aggradation. This study discusses further how the late-stage foreland tectonics, with its alternating pulses of uplift and subsidence and a progressive narrowing of the basin, has forced aggradation of fluvial channels and caused vertical stacking of meander belts.
ER -
GHINASSI, Massimiliano, Wojciech NEMEC, Mauro ALDINUCCI, Slavomír NEHYBA, Volkan ÖZAKSOY a Francesco FIDOLINI. Plan-form evolution of ancient meandering rivers reconstructed from longitudinal outcrop sections. \textit{Sedimentology}. Oxford, 2014, roč.~61, č.~4, s.~952-977. ISSN~0037-0746. Dostupné z: https://dx.doi.org/10.1111/sed.12081.
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