Characteristics of Filled Burrows in Carbonates and the Evolution of Burrow-mediated Pores: A case study from the third member of the Ordovician Majiagou Formation, western Henan province
doi: 10.14027/j.issn.1000-0550.2018.172
- Received Date: 2018-07-26
- Rev Recd Date: 2018-09-25
- Publish Date: 2019-08-10
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Key words:
- burrows /
- pore evolution /
- carbonate rocks /
- Majiagou Formation /
- Ordovician
Abstract: Numerous burrows occur in the third member of the Ordovician Majiagou Formation in western Henan Province. A study of the filling characteristics of burrows and the evolution of burrow-mediated pores was conducted on burrow-fills in the research area,based on the observation of outcrops together with polarizing optical microscope, cathodoluminescence microscope and scanning electron microscope. The results showed that macro-scale selective dissolution occurred in four stages. (1) Burrows are almost all either fully filled or semi-filled,mostly with calcite or dolomite;occasional burrows are unfilled. (2) Burrow-mediated pores occur commonly,consisting of dissolution pores and micro-cracks,mainly around the burrow boundary. (3) Burrow-mediated pores were controlled by burial dolomitization and dissolution in the early Hercynian cycle and Indo-Chinese epoch. Most of the dissolution pores were formed in the Hercynian period. (4) Burrow-mediated selective dissolution depends on the degree of crystalliza-tion of the dolomite in the burrow-fills. Micro-dissolution pore formation is influenced by the presence of fluids.
Citation: | HU YaZhou, NIU YongBin, CUI ShengLi, DONG XiaoBo. Characteristics of Filled Burrows in Carbonates and the Evolution of Burrow-mediated Pores: A case study from the third member of the Ordovician Majiagou Formation, western Henan province[J]. Acta Sedimentologica Sinica, 2019, 37(4): 690-701. doi: 10.14027/j.issn.1000-0550.2018.172 |