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The Law of Original Horizontality states that beds are deposited horizontally due to gravity. If the beds are not horizontal, then that is an indication that they have been tilted or warped by geologic processes. [21] The Law of Lateral Continuity states that the bed deposits extend laterally in all directions. This implies that two places ...
This is known as the angle of repose, and a prime example is the surface of sand dunes. Similarly, sediments may drape over a pre-existing inclined surface: these sediments are usually deposited conformably to the pre-existing surface. Also, sedimentary beds may pinch out along strike, implying that slight angles existed during their deposition.
The law of included fragments is a method of relative dating in geology. Essentially, this law states that clasts in a rock are older than the rock itself. [6] One example of this is a xenolith, which is a fragment of country rock that fell into passing magma as a result of stoping.
In geology, strike and dip is a measurement convention used to describe the plane orientation or attitude of a planar geologic feature. A feature's strike is the azimuth of an imagined horizontal line across the plane, and its dip is the angle of inclination (or depression angle) measured downward from horizontal. [1]
Sedimentary structures include all kinds of features in sediments and sedimentary rocks, formed at the time of deposition.. Sediments and sedimentary rocks are characterized by bedding, which occurs when layers of sediment, with different particle sizes are deposited on top of each other. [1]
In geology, a graded bed is a bed characterized by a systematic change in grain or clast size from bottom to top of the bed. Most commonly this takes the form of normal grading, with coarser sediments at the base, which grade upward into progressively finer ones. Such a bed is also described as fining upward. [1]
Sand dune cross-beds can be large, such as in the Jurassic-age erg deposits of Navajo Sandstone in Canyonlands National Park. Aztec Butte shown here Formation of cross-stratification Schematic of eolian cross-bedding Close up of cross-bedding and scour, Logan Formation, Ohio Tabular cross-bedding in the Navajo Sandstone in Zion National Park Tabular cross-bedding in the South Bar Formation in ...
A way up structure, way up criterion, or geopetal indicator is a characteristic relationship observed in a sedimentary or volcanic rock, or sequence of rocks, that makes it possible to determine whether they are the right way up (i.e. in the attitude in which they were originally deposited, also known as "stratigraphic up" or "younging upwards") or have been overturned by subsequent deformation.