these ppt is about hydrodynamic condition

1. Hydrodynamic condition. Paleocurrent and basin analyses
Name: Darji Darshan .R
GEL Paper: 509
Roll No: 3
Guided By: Dr. Rahul Gayakwad Sir
M.G. Science Institute
(Geology Department)
Navrangpura,Ahmedabad,Gujarat 380009
darshandaiya234@gmail.com
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2. content
 What is hydrodynamic condition ?
 What is paleocurrent analysis ?
 Basin Analysis
 References
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3. What is hydrodynamic condition ?
 The hydrodynamic conditions or processes, that come about from waves
transforming over a coastal profile and generating wave set up and longshore
currents, will result in movement and transport of the sediments (e.g. sand) present
in the profile.
 Hydrodynamic sediment environment is an important factor and key problem that
restricts the construction and operation of coastal engineering and marine
engineering. Offshore hydrodynamic factors mainly include tide, tidal current,
wave and sediment transport, which are very important for the study and analysis
of hydrodynamic sediment environment.
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4. EXAMPLE
 The hydrodynamic and sediment conditions in the bay of Bengal are generally
characterized by "strong tide, strong wave and high suspended sediment
concentration". The wave and wind conditions in the bay of Bengal have seasonal
variation characteristics, and the characteristic value of wind and wave during
monsoon (the third quarter) is larger than other quarters. The bay of Bengal is
easily affected by cyclonic storms, which causes a great increase in storm surge.
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5. What is paleocurrent analysis ?
 A paleocurrent or paleocurrent indicator is a geological feature (typically a
sedimentary structure) that helps one determine the direction of flowing water in
the geologic past. This is an invaluable tool in the reconstruction of ancient
depositional environments
 The measurement of palaeocurrents is a vital part of the study of sedimentary
rocks in that they provide information on paleogeography, palaeoslopes, current
and wind directions and they are useful in facies interpretation.
 Of the sedimentary structures commonly seen in the field, cross-stratification and
sole marks have proven to be the most reliable.
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6.  With planar cross-bedding, the palaeocurrent direction is simply the direction of
maximum angle of dip.
 For trough cross-bedding, the palaeocurrent direction is parallel to the trough axis.
Palaeocurrent directions can also be easily determined from groove and flute
casts.
 Palaeocurrent measurements are grouped into classes of 10º, 15º, 20º or 30º
intervals (depending on the number of readings and their variability) and then
plotted on a rose diagram.
Cross Stratification
Sole Mark
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7.  Azimuths are conventionally plotted in the direction to which the current flowed.
There are four types of palaeocurrent patterns, unimodal, bimodal and polymodal,
depicted below:
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8.  As tectonism may have changed the shape and/or orientation of the sedimentary
structure(s), it may be necessary to correct your measurements before plotting.
 The most common correction is for the effects of tilting of the strata of which the
sedimentary structures are a part.
 The following table summarizes the environmental significance of palaeocurrent
patterns:
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9. Basin Analysis
 Sedimentary basin analysis is a geologic method by which the formation and evolution
history of a sedimentary basin is revealed, by analyzing the sediment fill and
subsidence.
 Subsidence of sedimentary basins generates the spatial distribution of accommodation
infilling sediments.
 Aspects of the sediment, namely its composition, primary structures, and internal
architecture, can be synthesized into a history of the basin fill.
 Such a synthesis can reveal how the basin formed, how the sediment fill was
transported or precipitated, and reveal sources of the sediment fill.
 From such syntheses models can be developed to explain broad basin formation
mechanisms.
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10.  Examples of such basin classifications include intracratonic, rift, passive margin,
strike-slip, forearc, backarc-marginal sea, fold and thrust belt, and foreland basins.
 Sedimentary basin analysis is largely conducted by two types of geologists who
have slightly different goals and approaches.
intracratonicpassive
intracratonic passive margin forearc
https://www.sciencedirect.com/
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11.  The petroleum geologist, whose ultimate goal is to determine the possible
presence and extent of hydrocarbons and hydrocarbon-bearing rocks in a basin,
and the academic geologist, who may be concerned with any or all facets of a
basin's evolution.
 Petroleum industry basin analysis is often conducted on subterranean basins
through the use of reflection seismology and data from well logging.
 Academic geologists study subterranean basins as well as those basins which
have been exhumed and dissected by subsequent tectonic events.
 Thus academics sometimes use petroleum industry techniques, but in many cases
they are able to study rocks at the surface. Techniques used to study surficial
sedimentary rocks include: measuring stratigraphic sections, identifying
sedimentary depositional environments and constructing a geologic map.
 An important tool in sedimentary basin analysis is sequence stratigraphy, in which
various sedimentary sequences are related to pervasive changes in sea level and
sediment supply.
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12. References
 https://www.sciencedirect.com/
 https://en.wikipedia.org/
 LAB 5_ SEDIMENTARY STRUCTURES & PALAEOCURRENT ANALYSIS
 Zhong-hua_2021_IOP_Conf._Ser.__Earth_Environ._Sci._621_012081.pdf
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