Topic
Fissility
About: Fissility is a research topic. Over the lifetime, 105 publications have been published within this topic receiving 2926 citations.
Papers published on a yearly basis
Papers
TL;DR: In this article, the proportions of clay, silt and sand are used to define four major groups: claystone (clay), siltstone (silt), mudstone (mud) and sandstone (sand).
Abstract: Classifications of fine-grained sediments and sedimentary rocks are based on combinations of several criteria. These include: (1) texture, (2) fissility, (3) tectonic association or environment of deposition, (4) mineral composition, (5) color, (6) chemical composition and (7) degree of metamorphism. None of the classifications are generally used, however. For field studies, texture is the most significant property. The proportions of clay, silt and sand are used herein to define four major groups: claystone (clay), siltstone (silt), mudstone (mud) and sandstone (sand). Claystone, siltstone and sandstone are rocks containing more than 50 percent of clay-, silt- or sand-sized material, respectively. Mudstone contains less than 50 percent of clay, slit or sand. Silty and sandy are useful modifiers of claystone when clay-sized material is less than 75 percent but more than 50 percent. Clayey and sandy are used to modify siltstone when silt-sized material is less than 75 percent but more than 50 percent. The expression good sorting is applied to fine-grained clastic rocks that contain more than 90 percent silt or clay-sized material. Fair-sorted rocks contain 75 to 90 percent silt or clay. Poorly sorted siltstone or claystone contains less than 75 percent silt or clay. If fissile, fine-grained clastic rocks are so designated. The mineral composition of most fine-grained clastic rocks can be determined reliably with the petrographic microscope and by X-ray diffraction. Therefore, where possible, they should also be named according to one of the sandstone classifications and on the dominant clay mineral present. Color, bedding types and sedimentary structures, fossil content, type of cement and fissility should be included in complete descriptions. An example of a good field and laboratory description is: clayey siltstone, illite-subarkose, poor sorting, grayish red (5R4/2), dolomite cement, slabby, horizontal lamination, pelecypods.
203 citations
TL;DR: In this article, a simple nomenclature for fine-grained sedimentary rocks is proposed based on sedimentary structures present and abundance of all materials forming more than 10% of rock volume irrespective of their origin.
Abstract: A simple nomenclature for fine-grained sedimentary rocks is proposed based on sedimentary structures present and abundance of all materials forming more than 10% of rock volume irrespective of their origin (allochthonous, autochthonous, and diagenetic). A mudstone (sedimentary rock that comprises > 50% grains 90% clay), "silt- and sand-bearing, clay-rich mudstone" (50 to 90% clay, 10 to 50% sand, 10 to 50% silt), and "calcite ce-ment-, calcareous nannoplankton-, and clay-bearing mudstone" (all components 10 to 50%). Textural information can and should be incorporated into this scheme by prefixing the rock name with descriptions such as "bioturbated," and "thin-bedded." Such a nomenclature is necessary to fully describe variability within fine-grained sedimentary rocks that hitherto have typically been described using selected constituents of varying significance such as total organic carbon, fissility, parting spacing, -ray signature, and lamination. Using the inclusive nomenclature proposed here will improve opportunities to compare all fine-grained sediments, aid interpretation of depositional and diagenetic controls of variability, and enable these rocks to be more easily integrated into basin-scale facies models.
190 citations
Book•
1 Jun 1982
TL;DR: In this paper, the textures of IGENOUS rocks are discussed, including the relationships between crystals and amorphous materials, and the relationships of IGNEOUS this paper.
Abstract: PART ONE: THE TEXTURES OF IGENOUS ROCKS: Crystallinity. Granularity. Crystal shapes. Mutual relations of crystals (and amorphous materials). PART TWO: VARIETIES OF IGNEOUS ROCKS: Ultrabasic rocks. Basic rocks. Intermediate rocks. Acid rocks. Alkaline and miscellaneous rocks.
154 citations
TL;DR: In this paper, the authors show that the property of fissility probably develops only in sediments deposited from anoxic bottom waters, and that carbon and sulphur-rich sediments are formed wherever relatively organic-rich material accumulates at such a rate that intensive diagenetic alteration takes place within the uppermost few metres of the sediment column, but relatively little happens below.
Abstract: To most field geologists 9black shales9 are dark, fissile sedimentary rocks which are rich in both carbon and sulphur. The property of fissility probably develops only in sediments deposited from anoxic bottom waters. Carbon and sulphur-rich sediments are formed wherever relatively organic-rich material accumulates at such a rate that intensive diagenetic alteration takes place within the uppermost few metres of the sediment column, but relatively little happens below. Depositional waters must be marine (or at least sulphate-rich) but not necessarily anoxic.
116 citations
TL;DR: The breaking characteristics of a mudrock can be represented on a triangular diagram with massive, flaky-fissile, and flaggy-fisile as end members.
Abstract: The breaking characteristics of a mudrock can be represented on a triangular diagram with massive, flaky-fissile, and flaggy-fissile as end members Fissility in shales is usually associated with a parallel arrangement of the micaceous clay particles and nonfissility with a random arrangement Experiments and observations indicate that the clay minerals attain a parallel arrangement by gravity settling or by flocculation and compaction, unless the particles are adsorbed on irregularly shaped sesquioxide or silica particles or grow randomly in a gel The nature of the cementing agent determines whether a shale will be flaky or flaggy If the cementing agent can hold the material in a large slab, the shale will be flaggy If the amount or the tenacity of the cementing agent is small, the shale will be flaky Cementing agents other than organic matter tend to hinder cleavage parallel to the clay particles causing a decrease in fissility and an increase in massiveness Moderate weathering increases the fissility of a shale In general the type of fissility does not correlate with the type of clay minerals present in a random collection of mudrocks
95 citations
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| Year | Papers |
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| 2021 | 1 |
| 2020 | 3 |
| 2019 | 1 |
| 2018 | 4 |
| 2017 | 2 |
| 2016 | 1 |