Overview
ISO 710-3:1974 is an international standard published by the International Organization for Standardization (ISO) that establishes a consistent set of graphical symbols for representing magmatic rocks on detailed maps, plans, and geological cross-sections. This standard-Part 3 of a series on geological graphical symbols-focuses specifically on the depiction of various magmatic rock types through a unified system of symbols and ornaments. These symbols are designed to allow clear, precise geological communication, essential for geologists, cartographers, and engineers working with detailed geological data.
Key Topics
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Scope and Purpose
ISO 710-3:1974 provides a logical, expandable system of symbols for magmatic rocks, enabling consistent representation on geological maps and cross-sections. The standard differentiates symbols between principal magmatic rock types and additional varia symbols for special cases, ensuring comprehensive coverage.
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Classification of Symbols
The symbols are divided into two main groups:
- Main Types – Represent principal magmatic rocks such as plutonic and volcanic rocks, classified according to their silica content and texture (coarse-grained, fine-grained, porphyritic, etc.).
- Varia – Includes supplementary symbols for tuffs, lavas, volcanic glasses, dyke rocks, and miscellaneous volcanic rocks that do not fit into the main system.
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Symbol Design Principles
- Plutonic rocks’ symbols derive from crosses (+) or the letter “Y,” modified by line thickness or additional marks for detailed classification.
- Volcanic rocks’ symbols are based on a right angle on its point (v) and are similarly modified to indicate chemical composition or texture.
- Texture and grain-size differences are shown by varying symbol size or by alternation to indicate porphyritic texture.
- Symbol modifications indicate rock acidity/basicity, age variations, and textural properties.
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Specific Symbol Examples
- Alkali granite and trachyte symbols include open spaces at line intersections.
- Ultrabasites use line-length variations to reflect their characteristics.
- Paleo-volcanic and neo-volcanic rocks are distinguished by including a point at the intersection in the symbol.
- Tuffs, pumiceous lava, obsidian, and other volcanic-related materials have unique, specially designated symbols in the varia section.
Applications
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Geological Mapping
ISO 710-3:1974 is fundamental for geologists creating detailed geological maps that include the representation of magmatic rock formations, ensuring standardized and unambiguous communication of rock types.
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Geological Cross-Sections
The symbols facilitate accurate cross-sectional views of subsurface geology, crucial for mining, construction, and petroleum exploration where the identification of igneous bodies is important.
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Educational and Scientific Materials
The standard is useful for textbooks, academic publications, and scientific illustrations requiring standardized graphical representations of magmatic rocks.
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Engineering and Environmental Studies
Engineering geologists and environmental professionals use these symbols in site investigations and risk assessments where magmatic rock identification affects project planning.
Related Standards
ISO 710-3:1974 is part of a broader series on graphical symbols for geological representation:
- ISO 710-1: General Rules – Defines general principles for graphical symbols on maps and plans.
- ISO 710-2: Sedimentary Rocks – Covers symbolization for sedimentary rock types.
- ISO 710-4: Metamorphic Rocks (in preparation) – Will address symbols for metamorphic rocks.
- ISO 710-5: Minerals (in preparation) – Planned standard for mineral representation.
Adhering to all parts of this series ensures comprehensive standardization across geological mapping disciplines.
Keywords: ISO 710-3:1974, graphical symbols, magmatic rocks, geological maps, geological cross-sections, plutonic rocks, volcanic rocks, magmatic rock representation, geological mapping standards, sedimentary rock symbols, geological symbolization, geological cartography, International Organization for Standardization.
Open preview (PDF)Graphical symbols for use on detailed maps, plans and geological cross-sections — Part 3: Representation of magmatic rocks