It provides enough general background, in introductory chapters and appendices, to be easily digestible for sedimentologists and stratigraphers as well as earth scientists at large.
Skip to main content. Search form Search this site. Login Cart. Carbonate Sedimentology and Sequence Stratigraphy. Concepts in Sedimentology and Paleontology 8. Schlager Published Geology Sedimentology and stratigraphy are neighbors yet distinctly separate entities within the earth sciences. Sedimentology searches for the common traits of sedimentary rocks regardless of age as it reconstructs environments and processes of deposition and erosion from the sediment record.
Stratigraphy, by contrast, concentrates on changes with time, on measuring time and correlating coeval events. Sequence stratigraphy straddles the boundary between the two fields. This book, dedicated to… Expand. View via Publisher. Save to Library Save. Create Alert Alert. Share This Paper. Background Citations. Methods Citations. Information about grain types and the manner in which they occur in Rock s can be communicated by means of limestone classifications.
The interpretation of the depositional setting of carbonates is based on grain types, grain packing or fabric, sedimentary structures , and early diagenetic changes. The identification of grain types is commonly used in subsurface studies of depositional setting because, unlike the particles in siliciclastic Rock s, the grains making up carbonates generally formed within the basin of deposition.
This oversimplification or rule of thumb doesn't always apply. For example, ooid sands, which characteristically form on highly-agitated shoals, may also accumulate on beaches, islands, sand flats, deltas and even turbidite fans.
Thus, while most carbonate geologists will use grain types to make an interpretation of depositional setting they should further test their hypothesis using the other criteria listed above. Carbonate sedimentary particles may be subdivided into micrite lime mud and sand-sized grains. The grains can be separated on the basis of their shape and internal structure and can be subdivided into two major groups: skeletal and non-skeletal.
Useful carbonate Texts Most sedimentological texts will help you gain an understanding of carbonates, their depositional system s, facies and diagenesis. Listed below are a few:. Sam Boggs, , Principles of Sedimentology and Stratigraphy , 4th ed. Bathurst, R. The There are some important breaks in sedimen- palaeogeographic importance of these fault sys- tation between some of the Buntsandstein and tems has been described by Arche and L6pez- Muschelkalk facies units, resulting in low-angle G6mez The link between these fault sys- unconformities Arche and L6pez-G6mez, tems represents important points in controlling which can be traced across most of the study the different units described above.
In the eastern part, some of these uncon- formities tend to pass into hiatuses when new 3. The Muschelkalk units stratigraphical units appear Fig. The Iberian Ranges have two main fault sys- The general stratigraphy of the Muschelkalk in tems, a longitudinal NW-SE one Hercynian in the southern part of the Iberian Ranges is shown origin all along the Ranges, and a transversal in Fig. Stratigraphical units of the Middle Triassic SF.
Iberian Ranges and their relation to s y s t e m tracts nomenclature and depositionalsequences. See Fig. Their main features are shown in Table 2 and the lower Muschelkalk and five units members Figs.
Each one of these eleven units 3. Upper Muschelkalk consists of the vertical recurrence of more or less identical shallowing-upward sequences cf. James, The upper Muschelkalk is represented by the , which are usually less than 1. Its thickness ranges from 37 m to 85 m Fig.
Each shallowing-upward sequence consists of a It becomes progressively thinner toward the facies association that is composed of a different northwest, along the basin, although some local number of facies.
It is possible to differentiate a lateral variations are also important. Lower Muschelkalk Ordovician Fig. The upper contact is always with the Keuper Fig. Both pears to the northwest Fig. The maximum lower and upper contacts can sometimes present thickness is m in the southeast, close to problems for their identification due to Alpine Marines Fig.
It overlies the Buntsandstein tectonics, combined with the plastic character of on the Cafiizar Fm. Table 1 Differentiated facies and their main characteristics Facies a b Fig. Sedimentary environments Facies analysis and interpretation of the Lan- dete and Cafiete Fms. This arrangement corresponds to the ramp model of Read Inner ramp and mid ramp environments are well represented in the study area but the outer ramp may be almost totally under the present Mediterranean offshore Valencia.
The sedimentological evolution of both car- bonate formations is similar, although some dif- ferences exist. The lower carbonate formation Landete Fro. Shallowing-upward cycle representing a protected envi- r o n m e n t facies c. This sub- strate was of two types: the Cafiizar Fm. Bunt- sandstein facies or the Marines Fm. R6t facies Fig. The R6t facies covered only part of this area, representing the first incur- sion of the Tethys sea L6pez-G6mez and Arche, b Fig.
The marine transgression started in the east with the Marines Fro. The rest of the basin was subaeriaUy ex- posed at this time, with soil profiles and duri- crusts developing on top of the rocks of the Fig.
Trough-cross stratification. This is the main character- Buntsandstein Fig. As the transgression istic of facies b. Buildups are the main characteristics of facies d which occur only in the upper carbonate unit Cafiete Fm.
Its internal structure is totally blurred by dolomitization. Hammer for scale. Read, higher-energy shoal environments San Martin Although wave energy was not as intense Fm. Wright, This structure is characteristic of facies f and is found at the top of decimetre-scale shallowing-upward sequences.
The Mal Paso and Huelamo Units repre- In this way, the internal geometry of the shoals sent the inner lagoon where in adjacent areas could be mainly controlled by storm activity and tidal channels developed such as in the Vala- tidal currents Gawthorpe and Gutteridge, Almost each sequence culminates in a and Moya Units of both carbonate formations subaerial exposure cf. Gawthorpe and Gut- Figs. In these units, microbial laminae teridge, and the thicker developments of alternated with sediment layers comparable with the oolites represent stacked shallowing-upward modern examples of mixed carbonate-siliciclastic sequences.
Weak transgressions did not extend coasts. Carbonate laminae were later disrupted landwards as far as earlier and later ones. Where by desiccation and growth of evaporite minerals this happened, marked palaeokarstic horizons and polygons developed on the sabkha surface. The subtidal-intertidal environments, including the lagoon, are repre- 5. Vertical facies and Landete Fm. The second corresponds to the changes do not seem to have been frequent in Mas Fm.
The lower bound- this protected area, so fluctuations in the rate of ary SB-1 of the first sequence is an angular sediment supply probably were not important unconformity over various different older units Wright, In the same area, the lateral Buntsandstein or Variscan basement Figs. The shallower and the Mas Fm. The lowstand systems tract and narrower places in the lagoon with higher LST-1 of this sequence is represented by the temperature and salinity would become more re- lower and middle part of the Marines Fm.
In places where the lagoon was wider, G6mez and Arche, b. Pefia Rubia All over the gradual gradual Facies a and f. Evans levels, high-iron , Shinn Cotter Mal Paso All over the sharp gradual Facies c and a. Wright , semiparallel Hardie Unit or un- and planar cross- bivalves, tidal environments.
Ball , Wright with the dissolution-karst , Gawthorpe and Buntsandstein Fig. Serra Only in the gradual with erosive Facies a and g. Gawthorpe Main features of the units members, A to F of the lower carbonate formation Landete Fm.
Each member shows a characteristic shallowing-upward sequence with representative facies see also Table 1. Thickness in metres. Isopachsof the units members included in the lower carbonate formation Landete Fm. Palaeokarst horizon in the lower half of the lower carbonate formation Landete Fm.
Gorgocil Unit, facies b and e Fig. The transgressive surface is thus located Iberian Muschelkalk. Four main units are repre- in the Mas Fm. Buildups domes of cryptalgal lamination with clear convex morphology,but planar or concave in between. These buildups are one of the main characteristics of facies f.
The sequence. Main features of the units members, G to K of the upper carbonate formation Landete Fm. Each member shows its characteristic shallowing-upward sequence with representative facies see also Table 1. Table 3 Main features and interpretation of the units members of the Cafiete Fm. Valacioche Only eastward sharp sharp Facies b and e. Wright
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