Hanging-wall colluvial cementation along active normal faults
| Autor: | Ioannis Papanikolaou, Jack Mason, Silke Mechernich, Sascha Schneiderwind, Aggelos Pallikarakis, Klaus Reicherter |
|---|---|
| Rok vydání: | 2017 |
| Předmět: |
geography
geography.geographical_feature_category Cataclasite 010504 meteorology & atmospheric sciences Bedrock Geochemistry Fault (geology) 010502 geochemistry & geophysics Cementation (geology) 01 natural sciences Fault breccia Arts and Humanities (miscellaneous) Interglacial General Earth and Planetary Sciences Glacial period Geomorphology Geology 0105 earth and related environmental sciences Earth-Surface Processes Colluvium |
| Zdroj: | Quaternary Research. 88:39-59 |
| ISSN: | 1096-0287 0033-5894 |
| Popis: | Many active normal faults throughout the Aegean juxtapose footwall limestone against hanging-wall colluvium. In places, this colluvium becomes cemented and forms large hanging-wall lobes or sheets of varying thickness attached to the bedrock fault. Investigations at the Lastros Fault in eastern Crete allow us to define criteria to distinguish between cemented colluvium and fault cataclasite (tectonic breccia), which is often present at bedrock faults. Macro- and microscopic descriptions of the cemented colluvium show that the colluvium was originally deposited through both rockfalls and debris flows. Stable isotope analyses of oxygen and carbon from 83 samples indicate that cementation then occurred through meteoric fluid flow in the fault zone from springs at localised positions along strike. Palaeotemperature calculations of the parent water from which the calcite cement precipitated are indicative of a climate between 7°C and 10°C colder than Crete’s present average annual temperature. This most likely represents the transition between a glacial and interglacial period in the late Pleistocene. Ground-penetrating radar also indicates that cemented colluvium is present in the hanging-wall subsurface below uncemented colluvium. Using these results, a model for the temporal development of the fault and formation of the cemented colluvium is proposed. |
| Databáze: | OpenAIRE |
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