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Paul M. Harris - One of the best experts on this subject based on the ideXlab platform.
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Statistical pattern analysis of surficial karst in the Pleistocene Miami Oolite of South Florida
Sedimentary Geology, 2018Co-Authors: Paul M. Harris, Samuel J. Purkis, Bella ReyesAbstract:Abstract A robust airborne light detection and ranging digital terrain model (LiDAR DTM) and select outcrops are used to examine the extent and characteristics of the surficial karst overprint of the late Pleistocene Miami Oolite in South Florida. Subaerial exposure of the Miami Oolite barrier bar and shoals to a meteoric diagenetic environment, lasting ca. 120 kyr from the end of the last interglacial highstand MIS 5e until today, has resulted in diagenetic alteration including surface and shallow subsurface dissolution producing extensive dolines and a few small stratiform caves. Analysis of the LiDAR DTM suggests that >50% of the dolines in the Miami Oolite have been obscured/lost to urbanization, though a large number of depressions remain apparent and can be examined for trends and spatial patterns. The verified dolines are analyzed for their size and depth, their lateral distribution and relation to depositional topography, and the separation distance between them. Statistical pattern analysis shows that the average separation distance and average density of dolines on the strike-oriented barrier bar versus dip-oriented shoals is statistically inseparable. Doline distribution on the barrier bar is clustered because of the control exerted on dissolution by the depositional topography of the shoal system, whereas patterning of dolines in the more platform-ward lower-relief shoals is statistically indistinguishable from random. The areal extent and depth of dissolution of the dolines are well described by simple mathematical functions, and the depth of the dolines increases as a function of their size. The separation and density results from the Miami Oolite are compared to results from other carbonate terrains. Near-surface, stratiform caves in the Miami Oolite occur in sites where the largest and deepest dolines are present, and sit at, or near, the top of the present water table.
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quantitative interrogation of a fossilized carbonate sand body the pleistocene miami Oolite of south florida
Sedimentology, 2017Co-Authors: Samuel J. Purkis, Paul M. HarrisAbstract:Exposures of the Pleistocene Miami Oolite in South Florida provide excellent examples of preserved primary sedimentary features and subsequent diagenetic changes of a ‘fossilized’ ooid sand body that has been subaerially exposed in a tropical climate since its deposition during the last interglacial highstand – Marine Isotope Stage 5e. Using a robust airborne light detection and ranging digital terrain model and select outcrops, a detailed analysis of the morphologies and dimensions of the different portions of the Miami Oolite was conducted. The sand body, extending 95 km north to south and approximately 15 km wide, consists of shoals (or bars) separated by tidal channels and is partly bounded on the ocean-facing side by a prograding barrier bar that collectively cover an area of approximately 1000 sq. km. Results of the quantitative interrogation of the Miami Oolite are compared with those of previously published work from modern sand bodies on Great Bahama Bank including the Exumas, Schooners Cays and Tongue of the Ocean. Digital terrain models developed for these modern sand bodies on the Great Bahama Bank and the ancient Miami Oolite were used as the basis for the definition of shoals, shoal crests (peaks) and channels which were examined with respect to their size, shape and orientation. The Exumas sand body is the best morphometric match when analysing the bars and the channels, and the Joulter Cays area is an analogue for the formation of the barrier bar and for burrow reworking of cross-bedding within stabilized sand shoals. The Exumas is a particularly compelling analogue for the Miami Oolite with respect to length and overall visual comparison between the morphologies of the sand bodies, shoal (or bar) shape, number of tidal channels, channel length and width, and high areas parallel to the strike trend of the sand body (islands in the Exumas and possible islands as part of the Miami Oolite barrier bar). Despite ca 115 kyr of subaerial exposure and meteoric diagenesis including karst, the morphology of the Miami Oolite is still relatively intact to the point where it can be easily analysed and meaningful comparisons to modern systems can be made. The Miami Oolite serves as a key reference example for comparison to Holocene sand units in the Bahamas – it validates the concept of comparative sedimentology and in particular emphasizes how results from the modern can improve the interpretation of a fossilized example.
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Quantitative interrogation of a fossilized carbonate sand body – The Pleistocene Miami Oolite of South Florida
Sedimentology, 2017Co-Authors: Samuel J. Purkis, Paul M. HarrisAbstract:Exposures of the Pleistocene Miami Oolite in South Florida provide excellent examples of preserved primary sedimentary features and subsequent diagenetic changes of a ‘fossilized’ ooid sand body that has been subaerially exposed in a tropical climate since its deposition during the last interglacial highstand – Marine Isotope Stage 5e. Using a robust airborne light detection and ranging digital terrain model and select outcrops, a detailed analysis of the morphologies and dimensions of the different portions of the Miami Oolite was conducted. The sand body, extending 95 km north to south and approximately 15 km wide, consists of shoals (or bars) separated by tidal channels and is partly bounded on the ocean-facing side by a prograding barrier bar that collectively cover an area of approximately 1000 sq. km. Results of the quantitative interrogation of the Miami Oolite are compared with those of previously published work from modern sand bodies on Great Bahama Bank including the Exumas, Schooners Cays and Tongue of the Ocean. Digital terrain models developed for these modern sand bodies on the Great Bahama Bank and the ancient Miami Oolite were used as the basis for the definition of shoals, shoal crests (peaks) and channels which were examined with respect to their size, shape and orientation. The Exumas sand body is the best morphometric match when analysing the bars and the channels, and the Joulter Cays area is an analogue for the formation of the barrier bar and for burrow reworking of cross-bedding within stabilized sand shoals. The Exumas is a particularly compelling analogue for the Miami Oolite with respect to length and overall visual comparison between the morphologies of the sand bodies, shoal (or bar) shape, number of tidal channels, channel length and width, and high areas parallel to the strike trend of the sand body (islands in the Exumas and possible islands as part of the Miami Oolite barrier bar). Despite ca 115 kyr of subaerial exposure and meteoric diagenesis including karst, the morphology of the Miami Oolite is still relatively intact to the point where it can be easily analysed and meaningful comparisons to modern systems can be made. The Miami Oolite serves as a key reference example for comparison to Holocene sand units in the Bahamas – it validates the concept of comparative sedimentology and in particular emphasizes how results from the modern can improve the interpretation of a fossilized example.
Samuel J. Purkis - One of the best experts on this subject based on the ideXlab platform.
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Statistical pattern analysis of surficial karst in the Pleistocene Miami Oolite of South Florida
Sedimentary Geology, 2018Co-Authors: Paul M. Harris, Samuel J. Purkis, Bella ReyesAbstract:Abstract A robust airborne light detection and ranging digital terrain model (LiDAR DTM) and select outcrops are used to examine the extent and characteristics of the surficial karst overprint of the late Pleistocene Miami Oolite in South Florida. Subaerial exposure of the Miami Oolite barrier bar and shoals to a meteoric diagenetic environment, lasting ca. 120 kyr from the end of the last interglacial highstand MIS 5e until today, has resulted in diagenetic alteration including surface and shallow subsurface dissolution producing extensive dolines and a few small stratiform caves. Analysis of the LiDAR DTM suggests that >50% of the dolines in the Miami Oolite have been obscured/lost to urbanization, though a large number of depressions remain apparent and can be examined for trends and spatial patterns. The verified dolines are analyzed for their size and depth, their lateral distribution and relation to depositional topography, and the separation distance between them. Statistical pattern analysis shows that the average separation distance and average density of dolines on the strike-oriented barrier bar versus dip-oriented shoals is statistically inseparable. Doline distribution on the barrier bar is clustered because of the control exerted on dissolution by the depositional topography of the shoal system, whereas patterning of dolines in the more platform-ward lower-relief shoals is statistically indistinguishable from random. The areal extent and depth of dissolution of the dolines are well described by simple mathematical functions, and the depth of the dolines increases as a function of their size. The separation and density results from the Miami Oolite are compared to results from other carbonate terrains. Near-surface, stratiform caves in the Miami Oolite occur in sites where the largest and deepest dolines are present, and sit at, or near, the top of the present water table.
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quantitative interrogation of a fossilized carbonate sand body the pleistocene miami Oolite of south florida
Sedimentology, 2017Co-Authors: Samuel J. Purkis, Paul M. HarrisAbstract:Exposures of the Pleistocene Miami Oolite in South Florida provide excellent examples of preserved primary sedimentary features and subsequent diagenetic changes of a ‘fossilized’ ooid sand body that has been subaerially exposed in a tropical climate since its deposition during the last interglacial highstand – Marine Isotope Stage 5e. Using a robust airborne light detection and ranging digital terrain model and select outcrops, a detailed analysis of the morphologies and dimensions of the different portions of the Miami Oolite was conducted. The sand body, extending 95 km north to south and approximately 15 km wide, consists of shoals (or bars) separated by tidal channels and is partly bounded on the ocean-facing side by a prograding barrier bar that collectively cover an area of approximately 1000 sq. km. Results of the quantitative interrogation of the Miami Oolite are compared with those of previously published work from modern sand bodies on Great Bahama Bank including the Exumas, Schooners Cays and Tongue of the Ocean. Digital terrain models developed for these modern sand bodies on the Great Bahama Bank and the ancient Miami Oolite were used as the basis for the definition of shoals, shoal crests (peaks) and channels which were examined with respect to their size, shape and orientation. The Exumas sand body is the best morphometric match when analysing the bars and the channels, and the Joulter Cays area is an analogue for the formation of the barrier bar and for burrow reworking of cross-bedding within stabilized sand shoals. The Exumas is a particularly compelling analogue for the Miami Oolite with respect to length and overall visual comparison between the morphologies of the sand bodies, shoal (or bar) shape, number of tidal channels, channel length and width, and high areas parallel to the strike trend of the sand body (islands in the Exumas and possible islands as part of the Miami Oolite barrier bar). Despite ca 115 kyr of subaerial exposure and meteoric diagenesis including karst, the morphology of the Miami Oolite is still relatively intact to the point where it can be easily analysed and meaningful comparisons to modern systems can be made. The Miami Oolite serves as a key reference example for comparison to Holocene sand units in the Bahamas – it validates the concept of comparative sedimentology and in particular emphasizes how results from the modern can improve the interpretation of a fossilized example.
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Quantitative interrogation of a fossilized carbonate sand body – The Pleistocene Miami Oolite of South Florida
Sedimentology, 2017Co-Authors: Samuel J. Purkis, Paul M. HarrisAbstract:Exposures of the Pleistocene Miami Oolite in South Florida provide excellent examples of preserved primary sedimentary features and subsequent diagenetic changes of a ‘fossilized’ ooid sand body that has been subaerially exposed in a tropical climate since its deposition during the last interglacial highstand – Marine Isotope Stage 5e. Using a robust airborne light detection and ranging digital terrain model and select outcrops, a detailed analysis of the morphologies and dimensions of the different portions of the Miami Oolite was conducted. The sand body, extending 95 km north to south and approximately 15 km wide, consists of shoals (or bars) separated by tidal channels and is partly bounded on the ocean-facing side by a prograding barrier bar that collectively cover an area of approximately 1000 sq. km. Results of the quantitative interrogation of the Miami Oolite are compared with those of previously published work from modern sand bodies on Great Bahama Bank including the Exumas, Schooners Cays and Tongue of the Ocean. Digital terrain models developed for these modern sand bodies on the Great Bahama Bank and the ancient Miami Oolite were used as the basis for the definition of shoals, shoal crests (peaks) and channels which were examined with respect to their size, shape and orientation. The Exumas sand body is the best morphometric match when analysing the bars and the channels, and the Joulter Cays area is an analogue for the formation of the barrier bar and for burrow reworking of cross-bedding within stabilized sand shoals. The Exumas is a particularly compelling analogue for the Miami Oolite with respect to length and overall visual comparison between the morphologies of the sand bodies, shoal (or bar) shape, number of tidal channels, channel length and width, and high areas parallel to the strike trend of the sand body (islands in the Exumas and possible islands as part of the Miami Oolite barrier bar). Despite ca 115 kyr of subaerial exposure and meteoric diagenesis including karst, the morphology of the Miami Oolite is still relatively intact to the point where it can be easily analysed and meaningful comparisons to modern systems can be made. The Miami Oolite serves as a key reference example for comparison to Holocene sand units in the Bahamas – it validates the concept of comparative sedimentology and in particular emphasizes how results from the modern can improve the interpretation of a fossilized example.
Ulf Sturesson - One of the best experts on this subject based on the ideXlab platform.
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Lower Ordovician iron ooids and associated oolitic clays in Russia and Estonia: a clue to the origin of iron Oolites?
Sedimentary Geology, 1999Co-Authors: Ulf Sturesson, Andrei Dronov, Tönis SaadreAbstract:Abstract On the Baltic platform a lower Llanvirn (Ordovician) iron Oolite can be traced for a distance of 1200 km from Norway to the east of Lake Ladoga in Russia. This Oolite is usually thin (seldom exceeding 0.5 m) and is dominated by goethite (limonite) type ooids. The easternmost part of the Oolite, from Tallinn to Ladoga, is examined here. The oolitic limestone is intercalated with oolitic clay beds. The mineralogical, chemical and isotopic composition and other indicators point to volcanic ash being the source for the clay. Similarities in REE distribution patterns and immobile element contents between ooids and the oolitic clay suggest that the ooids were also formed from volcanic ash.
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Llanvirnian (Ord.) iron ooids in Baltoscandia: element mobility, REE distribution patterns, and origin of the REE
Chemical Geology, 1995Co-Authors: Ulf SturessonAbstract:Abstract The chemical and mineralogical compositions of Llanvimian (Ordovician) iron and associated phosphate ooids from Sweden, Estonia and Russia have been examined. The Oolites are generally thin and lean (mud supported), and dominated by Fe-oxyhydroxide (goethite, limonite) ooids. One Swedish Oolite contains a mixture of chamosite, goethite and hematite ooids, and it is suggested that the two latter types were derived from chamosite ooids by early diagenetic alteration. The REE distribution patterns were unaffected by these reactions. All ooids in the area show a typical negative Eu anomaly inherited from the source material. Major-and minor-element contents in limonite and chamosite ooids are similar, whereas their REE patterns are different. Limonite ooids have a LREE/HREE ratio from 1 to 2.4, and chamosite ooids from 3 to 5. The amounts of REE in the ooids are strongly dependent on the amount of phosphate.
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Iron ooids in the lower Ordovician Huk formation, Mj⊘sa district, Norway
GFF, 1994Co-Authors: Ulf SturessonAbstract:Abstract Most ooids in an iron oolitic limestone of Llanvirnian age from the Mj⊘sa district, Norway, have been diagenetically altered, and the original iron silicate (berthierine) has been replaced by carbonate minerals such as calcite, ferroan calcite, and ankerite. Remnants of the original ooid lamination and nuclei show similarities with chamositic iron ooids in Sweden. REE pattern of the ooids shows a pronounced negative Eu anomaly and an enrichment of LREE, similar to most chamosite ooids in Baltoscandia. Low oxygen isotope values of the carbonates indicate low‐temperature interaction with unstable volcanic ash. The Oolite was deposited in a period of iron Oolite formation of short duration, which created coeval Oolites not only in Baltoscandia but also in many places in western and central Europe. It is suggested that the Mj⊘sa Oolite has a volcanic origin. Sturesson, U., 1994: Iron ooids in the Lower Ordovician Huk Formation, Mj⊘sa district, Norway. GFF, Vol. 116 (Pt. 4, December), pp. 249–253. Sto...
Jinhan Gao - One of the best experts on this subject based on the ideXlab platform.
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Giant Induan Oolite: A case study from the Lower Triassic Daye Formation in the western Hubei Province, South China
Geoscience Frontiers, 2012Co-Authors: Mingxiang Mei, Jinhan GaoAbstract:Abstract Most Phanerozoic Oolites are marked by ooids with a diameter less than 2 mm. Observations on a Neoproterozoic Oolite have resulted in a change of concept. The term “pisolite” that traditionally referred to Oolites with a grain size of more than 2 mm, is now restricted to those coated carbonate grains formed by meteoritic freshwater diagenesis; Oolites with a grain size of more than 2 mm are now defined as “giant”. Particular unusual giant Oolites within a set of oolitic-bank limestones with thicknesses of more than 40 m in the top part of the Lower Triassic (Induan) Daye (Ruiping) Formation at the Lichuan section in the western part of Hubei Province in South China, represent an important sedimentological phenomenon in both the specific geological period and the geological setting that is related to the end-Permian biological mass extinction. Like the giant Oolites of the Neoproterozoic that represent deposits where Oolites formed in a vast low-angle carbonate ramp at that special geological period, the Triassic Daye Formation at the study section are significant because they provide a comparative example to help understand the evolving carbonate world reflected by Oolites, the origin of which is still uncertain, and they give insight into the sedimentation pattern of the desolate sea floor, which resulted from the mass extinction at the turn of the Permian into the Triassic.
Tönis Saadre - One of the best experts on this subject based on the ideXlab platform.
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Lower Ordovician iron ooids and associated oolitic clays in Russia and Estonia: a clue to the origin of iron Oolites?
Sedimentary Geology, 1999Co-Authors: Ulf Sturesson, Andrei Dronov, Tönis SaadreAbstract:Abstract On the Baltic platform a lower Llanvirn (Ordovician) iron Oolite can be traced for a distance of 1200 km from Norway to the east of Lake Ladoga in Russia. This Oolite is usually thin (seldom exceeding 0.5 m) and is dominated by goethite (limonite) type ooids. The easternmost part of the Oolite, from Tallinn to Ladoga, is examined here. The oolitic limestone is intercalated with oolitic clay beds. The mineralogical, chemical and isotopic composition and other indicators point to volcanic ash being the source for the clay. Similarities in REE distribution patterns and immobile element contents between ooids and the oolitic clay suggest that the ooids were also formed from volcanic ash.
