Chronohorizons Based on Resistivity Curve Variations - Upper Miocene Sediments of the Ivanić Grad Formation in the Sava Depression (NW Croatia)
<div>Regional definition of chronohorizons represents a fundamental and</div><div>most difficult problem in geology. Adequate precision of dating can</div><div>only be obtained from biological evolution, radioactive decay and</div><div>from the key surfaces...
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| Format: | Article |
| Language: | English |
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Croatian Geological Survey
2002-06-01
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| Series: | Geologia Croatica |
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| Online Access: | http://www.geologia-croatica.hr/ojs/index.php/GC/article/view/240 |
| _version_ | 1818082083594043392 |
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| author | Boris Vrbanac |
| author_facet | Boris Vrbanac |
| author_sort | Boris Vrbanac |
| collection | DOAJ |
| description | <div>Regional definition of chronohorizons represents a fundamental and</div><div>most difficult problem in geology. Adequate precision of dating can</div><div>only be obtained from biological evolution, radioactive decay and</div><div>from the key surfaces of the sequence stratigraphic concept (MFS,</div><div>TSE, and LSE). It is concluded in this paper that the variation of formation</div><div>resistivity values (Ra curve), as measured in wells located in</div><div>the Croatian part of the Pannonian Basin System, is also a criterion</div><div>for the stratigraphic definition of concurrently deposited sediments.</div><div>This enables the construction of a sequence of lithogenetic units relat -</div><div>ed to very small time-intervals.</div><div>The morphology of the resistivity curve measured in well sections</div><div>composed of massive marls (that were deposited in a quiet environment</div><div>of moderate water depth), is regionally exceptionally well</div><div>defined. This pattern consists of a succession of peaks of lower and</div><div>higher resistivity values that are in the same relative position regionally,</div><div>which results in similar form of the resistivity curves of the wells</div><div>in the study area. On the curve, one peak of higher values together</div><div>with the next (overlying) peak of lower ones composes a single cycle</div><div>(SC). Marls of a single cycle were regionally deposited at the same</div><div>time, thus enabling the points of both the maximal and minimal resistivity values of each SC to be considered as time-markers (chronohorizons).</div><div>Variation of the resistivity reflects fine changes of petrographic</div><div>and granulometric composition which can be associated with</div><div>cyclic water-level fluctuations (Milankovitch cycles).</div><div>For future exploration of the remaining, potential hydrocarbon</div><div>accumulations in the sandstone reservoirs of the Ivaniæ Grad Formation</div><div>in the Sava Depression, spatial modelling of the distribution,</div><div>geometry, facies and palaeocurrent structure of separated depositional</div><div>episodes and genetic units is suggested. This should be done with</div><div>special emphasis on the spatial definition of channel sandstones that</div><div>are the most important hydrocarbon reservoirs (according to current interpretations).</div> |
| first_indexed | 2024-12-10T19:16:28Z |
| format | Article |
| id | doaj.art-5e3239cf04654e8fa3914ab82727942b |
| institution | Directory Open Access Journal |
| issn | 1330-030X 1333-4875 |
| language | English |
| last_indexed | 2024-12-10T19:16:28Z |
| publishDate | 2002-06-01 |
| publisher | Croatian Geological Survey |
| record_format | Article |
| series | Geologia Croatica |
| spelling | doaj.art-5e3239cf04654e8fa3914ab82727942b2022-12-22T01:36:35ZengCroatian Geological SurveyGeologia Croatica1330-030X1333-48752002-06-01551112310.4154/GC.2002.02153Chronohorizons Based on Resistivity Curve Variations - Upper Miocene Sediments of the Ivanić Grad Formation in the Sava Depression (NW Croatia)Boris Vrbanac0INA - Naftaplin<div>Regional definition of chronohorizons represents a fundamental and</div><div>most difficult problem in geology. Adequate precision of dating can</div><div>only be obtained from biological evolution, radioactive decay and</div><div>from the key surfaces of the sequence stratigraphic concept (MFS,</div><div>TSE, and LSE). It is concluded in this paper that the variation of formation</div><div>resistivity values (Ra curve), as measured in wells located in</div><div>the Croatian part of the Pannonian Basin System, is also a criterion</div><div>for the stratigraphic definition of concurrently deposited sediments.</div><div>This enables the construction of a sequence of lithogenetic units relat -</div><div>ed to very small time-intervals.</div><div>The morphology of the resistivity curve measured in well sections</div><div>composed of massive marls (that were deposited in a quiet environment</div><div>of moderate water depth), is regionally exceptionally well</div><div>defined. This pattern consists of a succession of peaks of lower and</div><div>higher resistivity values that are in the same relative position regionally,</div><div>which results in similar form of the resistivity curves of the wells</div><div>in the study area. On the curve, one peak of higher values together</div><div>with the next (overlying) peak of lower ones composes a single cycle</div><div>(SC). Marls of a single cycle were regionally deposited at the same</div><div>time, thus enabling the points of both the maximal and minimal resistivity values of each SC to be considered as time-markers (chronohorizons).</div><div>Variation of the resistivity reflects fine changes of petrographic</div><div>and granulometric composition which can be associated with</div><div>cyclic water-level fluctuations (Milankovitch cycles).</div><div>For future exploration of the remaining, potential hydrocarbon</div><div>accumulations in the sandstone reservoirs of the Ivaniæ Grad Formation</div><div>in the Sava Depression, spatial modelling of the distribution,</div><div>geometry, facies and palaeocurrent structure of separated depositional</div><div>episodes and genetic units is suggested. This should be done with</div><div>special emphasis on the spatial definition of channel sandstones that</div><div>are the most important hydrocarbon reservoirs (according to current interpretations).</div>http://www.geologia-croatica.hr/ojs/index.php/GC/article/view/240Resistivity curveChronohorizonsSingle cycleUpper MioceneIvanić Grad FormationSava DepressionCroatia |
| spellingShingle | Boris Vrbanac Chronohorizons Based on Resistivity Curve Variations - Upper Miocene Sediments of the Ivanić Grad Formation in the Sava Depression (NW Croatia) Geologia Croatica Resistivity curve Chronohorizons Single cycle Upper Miocene Ivanić Grad Formation Sava Depression Croatia |
| title | Chronohorizons Based on Resistivity Curve Variations - Upper Miocene Sediments of the Ivanić Grad Formation in the Sava Depression (NW Croatia) |
| title_full | Chronohorizons Based on Resistivity Curve Variations - Upper Miocene Sediments of the Ivanić Grad Formation in the Sava Depression (NW Croatia) |
| title_fullStr | Chronohorizons Based on Resistivity Curve Variations - Upper Miocene Sediments of the Ivanić Grad Formation in the Sava Depression (NW Croatia) |
| title_full_unstemmed | Chronohorizons Based on Resistivity Curve Variations - Upper Miocene Sediments of the Ivanić Grad Formation in the Sava Depression (NW Croatia) |
| title_short | Chronohorizons Based on Resistivity Curve Variations - Upper Miocene Sediments of the Ivanić Grad Formation in the Sava Depression (NW Croatia) |
| title_sort | chronohorizons based on resistivity curve variations upper miocene sediments of the ivanic grad formation in the sava depression nw croatia |
| topic | Resistivity curve Chronohorizons Single cycle Upper Miocene Ivanić Grad Formation Sava Depression Croatia |
| url | http://www.geologia-croatica.hr/ojs/index.php/GC/article/view/240 |
| work_keys_str_mv | AT borisvrbanac chronohorizonsbasedonresistivitycurvevariationsuppermiocenesedimentsoftheivanicgradformationinthesavadepressionnwcroatia |