Facies architecture of a Late Jurassic carbonate ramp: the Korallenoolith of the Lower Saxony Basin

Abstract

The sedimentary succession of a Late Jurassic (Oxfordian to basal Kimmeridgian) carbonate ramp is described and interpreted. The study area is located in the central part of the Lower Saxony Basin in NW Germany, which forms part of the Central European Basin. Eight well-exposed and undeformed sections of the study area (Süntel area, Wesergebirge and eastern part of the Wiehengebirge) provide detailed information about lithofacies and lateral thickness variations. Biostratigraphically, the age of these sediments is poorly constrained. Twenty microfacies types are recognized that can be grouped into seven facies associations: (a) strongly bioturbated marlstones deposited near storm wave base (SWB), (b) foraminifera-rich wackestones, (c) wackestones and floatstones with biostromes and (d) bioclastic limestones deposited between SWB and fair-weather wave base (FWWB), (e) oolitic and iron-oolitic limestones and (f) siliciclastic sediments deposited above FWWB, and (g) lagoonal deposits. These facies associations characterize a storm dominated shallow mixed carbonate-siliciclastic ramp. Based on facies changes, quartz content, and gamma ray logs, the Korallenoolith Formation can be subdivided into a lower carbonate-dominated and an upper siliciclastic-dominated part, build up by different scales of small-to large-scale deepening-and shallowing-upward cycles. A preliminary correlation of measured outcrops of this formation is presented.

Lower Kimmeridgian facies and sedimentary succession of a shallow-water coated-grain-dominated carbonate ramp of the northern peri-Tethyan shelf: an example from the Radomsko Folds (central Poland)

“…The ooid grainstones rep re sent the high-en ergy shoal en vi ron ment, which is doc u mented by well-sorted grains, low di ver sity of fauna liv ing on a mo bile sub strate or abraded biota. Sim i lar Kimmeridgian fa cies were de scribed by Bádenas and Aurell (2010) from oolitic-oncolitic-dom i nated ramp de pos its in northeast ern Spain, or from the high-en ergy shoal ramp set tings in north ern Ger many (e.g., Kästner et al, 2008;Zuo et al, 2018). A -ir reg u lar hardground sep a rat ing oolitic lime stones (FT 1) from oncolitic-oolitic-bioclastic lime stones (FT 2; dashed line), bi valve (white arrow) and bor ings (green ar rows) are ob served close to the hardground, no.…”

“…Sed i men ta tion dur ing most of de po si tion of the FT 5 fa cies oc curred in a fully ma rine la goon with low sedi men ta tion rate, as re vealed by the pres ence of type 3 oncoids (Védrine et al, 2007;Sequero et al, 2020). Gas tro pods and mass occurences of bi valve coquinas may be re lated to high, although ep i sodic, sup ply of nu tri ents to a re stricted la goon (see e.g., Dupraz and Strasser, 1999;Flügel, 2004;Kästner et al, 2008;Zuo et al, 2018). More over, the pres ence of sus pension-feed ing bi valves sug gests that large amounts of food par ticles were sus pended in the wa ter col umn (e.g., Flügel, 2004: 624).…”

Dinosaur tracks 2011

“…After local highstand and marine flooding of most of the incipient LSB during the Late Jurassic (e.g. Gramann et al 1997;Kästner et al 2008) a major fall in sea level and early basin subsidence led to isolated, shrinking perimarine water bodies in the developing LSB during deposition of the Tithonian through earliest Berriasian Münder Formation. Increasing precipitation during the earliest Berriasian resulted in reduced salinities and peripheral haloclinal stratification of the lagoons in peripheral areas (Hils Embayment), though a marine connection still existed (Arp & Mennerich 2008).…”

Vertebrate tracksites in the Obernkirchen Sandstone (late Berriasian, Early Cretaceous) of northwest Germany— their stratigraphical, palaeogeographical, palaeoecological, and historical context

“…After local highstand and marine flooding of most of the incipient LSB during the Late Jurassic (Gramann et al 1997;Kästner et al 2008), a major fall in sea level and Fig. 4 Berriasian palaeogeography (after Schott et al 1967Schott et al , 1969Kemper 1973, Pelzer 1998 and vertebrate tracksite occurrences in the Lower Saxony Basin Vertebrate tracksites in the Obernkirchen Sandstone 237 Encircled numbers refer to locality numbers in text.…”