| Autor: |
Abdalla Z. Al-Zamel, Michael J. Duane |
| Rok vydání: |
1999 |
| Předmět: |
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| Zdroj: |
Sedimentary Geology. 127:237-245 |
| ISSN: |
0037-0738 |
| DOI: |
10.1016/s0037-0738(99)00022-6 |
| Popis: |
Although analogies between Recent sediment-binding cyanobacterial mats and ancient stromatolites have been described, debate on the exact mechanisms that lead to both ancient and modern stromatolite architecture in sabkha environments continues. In sabkhas of the northern Arabian Gulf (Kuwait) evidence is found that two morphologically different stromatolite communities construct a carbonate bioherm by alternating roles in the construction process. The erection of fingerlike microcolumns composed of aragonite by Type 1 communities (`cinder' type) occur in irregular weathering fractures, and growth is arrested only when exposed by spalling of the bioherm during erosion. Subsequently, an invasion of Type 2 community (`polygonal type') not only allows vertical and horizontal invasion of the intertidal zone, but also provides opportunities for utilizing the free carbonate scaffolding erected previously. This process allows for biohermal healing during severe erosion created by winter storms and may help explain the tenacity of stromatolites in the sabkha environment. These observations have important implications for both modern and Precambrian sabkha models of carbonate growth, because some abiotic cemented microbial carbonates are essentially indistinguishable even in Holocene reef lithification. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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Full Text from ScienceDirect