| 词条 | Pholad borings |
| 释义 |
Pholads are unusual bivalves capable of boring into various kinds of rock, firm clay and peat, and they live permanently in the burrows they create. These clams use a set of ridges or "teeth" on the outer anterior surfaces of their shells to grind into suitable substrate, creating a non-branching burrow. Pholad burrows are typically narrower at the entrance of the burrow than they are across the interior.[2] Ancient, sand-filled pholad borings are a distinctive type of trace fossil known as Gastrochaenolites that are found in some limestones, dolomites and lithified mudstones. They are assigned to the Trypanites ichnofacies,[3] and evidence submarine hardgrounds that formed soon after deposition, typically during episodes of non-sedimentation, with subsequent infilling of the burrow and burial when sedimentation resumed.[5] Pholad burrow trace fossils are not to be confused with specimens of the Trypanites ichnogenus, which are toothpick-sized masses of holes that characterize some hardgrounds. Trypanites probably result from a combination of mechanical abrasion and acid dissolution by the organism, whereas pholad borings are thought to be purely mechanical in origin.[6] See also
References1. ^1 {{cite book |author1=Frey, R.W. |author2=Pemberton, S.G |lastauthoramp=yes |date=1984 |chapter=Trace fossil facies models |editor=Walker, R. |title=Facies Models |publisher=Geological Association of Canada |location=Toronto, Ontario |pages=189–207}} [1][2][3][4][5]2. ^1 {{cite web |author=Hill, Jacqueline |date=2006 |title=Pholas dactylus. Common piddock |website=Marine Life Information Network: Biology and Sensitivity Key Information Sub-programme [on-line] |location= Plymouth |publisher=Marine Biological Association of the United Kingdom |url=http://www.marlin.ac.uk/speciesfullreview.php?speciesID=4102 |accessdate=25 January 2014}} 3. ^1 {{cite journal |author1=Kelly, S.R.A. |author2=Bromley, R.G. |lastauthoramp=yes |year=1984 |title=Ichnological nomenclature of clavate borings |journal=Palaeontology |volume=27 |pages=793–807}} 4. ^1 {{cite book |author=Seilacher, A. |date=2007 |title=Trace Fossil Analysis |publisher=Springer-Verlag |page=204 |isbn=9783540472254 |url= }} 5. ^1 {{cite book |author1=Warme, J.E. |author2=McHuron, E.J. |lastauthoramp=yes |date=1978 |chapter=Marine borers: trace fossils and geological significance |editor=Basan, P.N. |title=Trace fossil concepts - Short Course 5 |publisher=Society Economic Paleontologists and Mineralogists |location=Tulsa, Oklahoma |pages=77–131}} }}{{Commons category|Trace fossils}}{{trace-fossil-stub}} 2 : Boring fossils|Invertebrate paleozoology |
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