Hydrodynamic control of sedimentation in the Ordovician (Arenig–Caradoc) Baltic Basin
Hydrodynamic control of sedimentation in the Ordovician (Arenig–Caradoc) Baltic Basin
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DOI：
10.1111/j.1502-3931.2008.00112.x
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发表时间：
2008-06
期刊：
影响因子：
1.5
通讯作者：
Enli Kiipli;T. Kallaste;T. Kiipli
中科院分区：
文献类型：
--
作者：
Enli Kiipli;T. Kallaste;T. Kiipli
Changes in mineralogy, geochemistry and grain size in a deep shelf succession from the Ordovician Baltic Basin are used to determine shifts in marine current direction and sea-level fluctuations. The analyses show a long-term, relatively stable interval in the Arenig–Llanvirn followed by shorter periods of perturbations and rearrangements in the early Caradoc. The Arenig deposits of the Aizpute-41 core have a high 2–10 µm terrigenous component. During the Llanvirn the proportion of this size fraction diminished. The grain size change was accompanied by mineralogical changes. In the early Caradoc the kaolinite disappeared, the muscovite content decreased, and quartz and albite increased. This and several geochemical indicators point to an input of considerable part of sediment from different sources than in the Arenig–Llanvirn. Two currents, a southwesterly for the Arenig and a westerly for the early Caradoc, are proposed. A red facies belt in the deep shelf marks the pathway of the Arenig–Llanvirn current. Smaller shifts in SiO2/Al2O3 ratio in the Aizpute-41 section are interpreted as reflecting transgressions and regressions corresponding to regional stage boundaries.
