Proceedings of the Ocean Drilling Program, Scientific Results, Vol. 165. Caribbean ocean history and the K T boundary event 165

165_map......Page 1 Table 1. Location and water depth of the sites studied.......Page 2 RETURN TO CHAPTER 1......Page 0 Table 2. Ages of calcareous nannofossil events.......Page 8 STRATIGRAPHIC SIGNIFICANCE OF RETICULOFENESTRA COCCOLITHS......Page 13 ACKNOWLEDGMENTS......Page 14 REFERENCES......Page 15 Figure 2. Stratigraphic positions of additional nannofossil datums in Hole 998A. Zonal markers ar.........Page 3 Figure 3. Stratigraphic positions of additional nannofossil datums in Hole 999A. Zonal markers ar.........Page 4 Figure 4. Stratigraphic positions of additional nannofossil datums in Hole 1000A. Zonal markers a.........Page 5 Figure 5. Size distributions of Reticulofenestra specimens at Site 998. Abundance of individual s.........Page 6 Figure 6. Size distributions of Reticulofenestra specimens at Site 999. Abundance of individual s.........Page 7 Table 3. Stratigraphic position of datums in Hole 998A.......Page 9 Table 4. Stratigraphic position of datums in Hole 999A.......Page 10 Table 5. Stratigraphic position of datums in Hole 1000A.......Page 11 Appendix A. Twenty-three genera and 112 species recognized in this investigation of the core samples are listed below.......Page 16 SITE DESCRIPTION......Page 17 Figure 1. Bathymetric map of the western Colombian Basin including the locations of Site 999 and .........Page 18 SEDIMENT ACCUMULATION RATES......Page 20 Figure 3. The age/depth relationship for planktonic foraminifer datums in Hole 999A. Filled circl.........Page 21 TECTONIC AND PALEOCEANOGRAPHIC IMPLICATIONS......Page 27 TAXONOMIC NOTES......Page 28 REFERENCES......Page 35 Figure 2. Planktonic foraminifer and nannofossil biozones are shown with the geopolarity time sca.........Page 19 Table 3. Site 999 and Site 925 datum ages compared.......Page 23 Table 2. Planktonic foraminifer datums used to construct age/depth plot.......Page 22 Table 5. Datums used to construct age model for Hole 999A.......Page 24 Appendix A. Species' ranges, Hole 999A.......Page 38 Appendix A (continued). Pleistocene-late Miocene.......Page 39 Appendix A (continued). Pleistocene-late Miocene.......Page 40 Appendix A (continued). Pleistocene-late Miocene.......Page 41 Appendix A (continued). Pleistocene-late Miocene.......Page 42 Appendix A (continued). Pleistocene-late Miocene.......Page 43 Appendix A (continued). Pleistocene-late Miocene.......Page 44 Appendix A (continued). Late Miocene-early Miocene.......Page 45 Appendix A (continued). Late Miocene-early Miocene.......Page 46 Appendix A (continued). Late Miocene-early Miocene.......Page 47 Appendix A (continued). Late Miocene-early Miocene.......Page 48 Appendix A (continued). Early Miocene......Page 49 Appendix A (continued). Early Miocene......Page 50 Appendix B. Sample Ages, Hole 999A.......Page 51 Plate 1. All specimens are magnified 70X. 1. Truncorotalia truncatulinoides (Sample 165-999A-5H-C.........Page 52 Plate 2. All specimens are magnified 70X. 1. Fohsella fohsi (Sample 165-999A-33X-6, 42–44 cm), um.........Page 54 RADIOLARIAN PRESERVATION......Page 55 Figure 1. Location of Leg 165 sites examined for Paleogene radiolarians. Contours are in meters b.........Page 56 SITE DESCRIPTIONS......Page 58 REFERENCES......Page 68 APPENDIX 1......Page 70 Figure 2. Correlation chart of Paleogene zonal schemes for foraminifers, calcareous nannofossils,.........Page 57 Table 1. Range chart for stratigraphically important radiolarian species, Hole 998A.......Page 59 Table 2. Range chart for stratigraphically important radiolarian species, Hole 998B.......Page 60 Table 2 (continued).......Page 61 Table 3. Range chart for stratigraphically important radiolarian species, Hole 999B.......Page 62 Table 3 (continued).......Page 63 Table 3 (continued).......Page 64 Table 3 (continued).......Page 65 Table 3 (continued).......Page 66 Table 4. Range chart for stratigraphically important radiolarian species, Hole 1001A.......Page 67 Plate 1. Scale bar for fig. 1 = 100 μm; scale bar for figs. 2-17 = 100 μm. Codes after sample des.........Page 74 Plate 2. Scale bar for fig. 12 = 100 μm; scale bar for figs. 1-11, 13-17 = 100 μm. Codes after sa.........Page 76 Plate 3. Scale bar for figs. 1-13 = 100 μm. Codes after sample description are slide description .........Page 78 INTRODUCTION......Page 80 Figure 1. Bathymetric map of Cariaco Basin (in meters) showing the location of ODP Site 1002 on t.........Page 81 RESULTS......Page 82 Figure 6. Comparison between the delta18O record of Hole 1002C and the standard SPECMAP composite rec.........Page 89 REFERENCES......Page 93 Figure 2. Simplified stratigraphic column for ODP Hole 1002C showing the subsurface distribution .........Page 83 Figure 3. Comparison of lithologies recovered at ODP Site 1002 and DSDP Site 147 at approximately.........Page 84 Table 2. Biostratigraphic datums recognized at Site 1002.......Page 87 Figure 5. Expanded detail of the delta18O record of G. ruber for MIS 1 to the top of MIS 6 in Hole 10.........Page 88 Figure 7. Comparison of filtered components of the Site 1002 and SPECMAP delta18O records correspondi.........Page 90 Figure 8. Age-depth function for Hole 1002C derived from the correlation of its delta18O record to th.........Page 91 Figure 9. Downhole variations (wt%) in measured calcium carbonate, total organic carbon (TOC), an.........Page 92 Table 1. Oxygen isotope data from ODP Hole 1002C.......Page 85 Table 1 (continued).......Page 86 BACKGROUND......Page 95 Figure 1. Map showing the major physiographic features of the Caribbean Sea and the location of t.........Page 96 Table 1. Feldspar size measurements of tephra fall layers, Site 998.......Page 97 Figure 5. Cumulative percentage of maximum feldspar size in all measured Miocene tephra fall laye.........Page 99 Table 2. Feldspar size measurements of tephra fall layers, Site 999.......Page 100 Table 3. Feldspar size measurements of tephra fall layers, Site 1000.......Page 102 Figure 12. Vectors of surface winds (1000 mb level) in the Caribbean area. Each barb on the wind .........Page 103 Figure 4. Variation in median size of the 20 largest feldspar crystals vs. thickness of tephra la.........Page 98 Figure 8. Cumulative percentage of maximum feldspar size in all measured Miocene tephra fall laye.........Page 101 Figure 13. Vectors of upper level winds (750 mb level, 11 km height) in the Caribbean area. Each .........Page 104 Figure 15. Reconstruction of the Caribbean area during the mid-Miocene showing the location of Le.........Page 105 Figure 17. Comparison of the maximum feldspar crystal size found in tephra fall layers vs. the nu.........Page 106 Figure 18. Comparison of the ash accumulation rate at Site 999 (right) with the dust grain-size r.........Page 107 INTRODUCTION......Page 108 Figure 1. Location map of sites drilled during Leg 165. Of the sites discussed here, Site 998 is .........Page 109 Figure 2. Absolute concentrations (in weight percent) of CaCO3 (light gray), terrigenous matter (.........Page 112 REFERENCES......Page 116 Figure 4. Terrigenous matter accumulation at Sites 998, 999, and 1001 vs. age, plotted with expan.........Page 113 Figure 6. Dispersed ash accumulation rate at Sites 998 (shaded circles), 999 (solid diamonds), an.........Page 114 Figure 7. Accumulation rate of dispersed ash (open circles) and accumulation of ash layers (solid.........Page 115 Table 1. Composition of Leg 165 sediments, based on shipboard XRF and coulometry.......Page 110 Table 1 (continued).......Page 111 RECENT QUATERNARY OF THE CARIACO BASIN......Page 118 Figure 5. Average duration of dark and light lower order cycles in each core of the virtual serie.........Page 124 Figure 8. Correlation between the sedimentation rate and the number of dark and light alternating.........Page 126 Figure 18. Carbonate concretion, 25 mm long, in a sample from the Querecual Formation, examined .........Page 131 Figure 19. (A) Siliceous and (B) carbonate concretions in an outcrop of the La Luna Formation nea.........Page 132 Figure 1. The Venezuelan areas included in this study. A. Cariaco Basin with bathymetric curves. .........Page 119 Figure 2. Simplified structural map of northern Venezuela showing the Transversale de Barquisimet.........Page 120 Figure 3. Schematic illustration of two orders of dark and light cycles occurring in a thin secti.........Page 121 Figure 4. Process for making the compaction and the sedimentation rates uniform through the Hole .........Page 122 Figure 6. Low-frequency cycles forming the Cariaco succession in Hole 1002C (after Sigurdsson, Le.........Page 125 Figure 10. Rounded sparitic concretion observed in a thin section from Sample 165-1002C-12H-1, 23.........Page 127 Figure 12. Schematic diagram of lamina bundles with their enlargements as appearing in thin secti.........Page 128 Figure 13. Discontinuous and irregular beige micritic layers (BML) in thin sections from the Quer.........Page 129 Figure 16. Light laminae of elementary cycles are deformed against calcitized fillings of forami.........Page 130 Table 1. Cariaco Basin, Hole 1002C.......Page 123 METHODS......Page 134 Figure 2. Zijderveld plots for Sample 165-1001A- 39R-2, 101-103 cm; 353.92 mbsf. A. Horizontal co.........Page 135 Table 1. Magnetostratigraphy and sedimentation rates of the K/T boundary interval.......Page 136 Figure 4. Inclination and magnetization data from Hole 1002C. The gray curve represents NRM data,.........Page 137 Figure 5. Rock-magnetic stratigraphy for Hole 1002C. The first column is the single-sample suscep.........Page 138 INTRODUCTION......Page 139 Figure 1. Location of Leg 165 drill sites (stars) and plate boundaries for the Caribbean plate (b.........Page 140 PALEOMAGNETIC DATA AND ANALYSIS......Page 142 Figure 6. Inclinations from basalt cores from Site 1001. Flow units (53A, 53B, etc.) are labeled .........Page 153 Figure 8. Variation of the precision parameter vs. latitude based on the geomagnetic SV model of .........Page 157 Figure 15. Change in latitude (paleolatitude minus the current latitude) from the paleomagnetic d.........Page 161 Figure 2. AF demagnetization results for Samples 165-998A- 40X-5, 134 cm, and 165-998B-10R-3, 90 .........Page 149 Figure 3. AF demagnetization results from Site 999 for sedimentary Samples 165-999B-11R-4, 89 cm .........Page 150 Figure 4. AF and thermal demagnetization results characteristic of some of the better sedimentary.........Page 151 Figure 5. AF and thermal demagnetization results characteristic of some of the better basalt samp.........Page 152 Figure 10. Site 999 paleolatitudes from discrete samples (open circles). Also shown are the unbia.........Page 158 Figure 12. The interval from Site 1001 in which the magnetostratigraphy could be established. The.........Page 159 Figure 14. Mean paleolatitudes from Sites 999 and 1001. The best-fit line through these (bold sol.........Page 160 Figure 16. Paleogeographic reconstruction of Pindell et al. (1988) with Leg 165 sites (stars) ove.........Page 163 Table 1. Flow unit divisions from this study compared with subdivisions used during Leg 165.......Page 143 Table 5. Split-core (archive half) paleomagnetic data from Hole 999A obtained during Leg 165.......Page 144 Table 9. Split-core (archive half) paleomagnetic data from Hole 1001A obtained during Leg 165.......Page 145 Table 12. Paleomagnetic results from discrete samples from Site 999.......Page 146 Table 15. Basalt split-core inclinations after AF demagnetization and after removing data from ne.........Page 147 Table 18. Inclinations from principal component analysis of discrete samples from ODP Site 1001.......Page 148 Table 19. Expected (observed) paleolatitudes and their relationship to the true paleolatitude.......Page 154 Table 19 (continued).......Page 155 Table 21. Mean paleolatitudes.......Page 156 INTRODUCTION......Page 164 Figure 1. Sonic velocity of discrete freshly recovered (water saturated) samples vs. burial for S.........Page 165 Figure 6. Density downhole logging data (solid line) compared to laboratory wet bulk densities of.........Page 170 Table 5. Occurrence of stylolites and microstylolites, Sites 806, 807, 999, and 1001.......Page 171 Figure 2. Examples of compaction curves. The resulting strain (e) is plotted vs. the uniaxial str.........Page 168 Figure 4. Compaction curves showing uniaxial stress (sigma) vs. porosity (phi) for all samples from Si.........Page 169 Figure 9. Compaction curves showing uniaxial stress (sigma) vs. porosity (phi) for samples from Site 1.........Page 172 Figure 12. Grain-size distribution of samples from Sites 999 and 1001 after compaction experiment.........Page 173 Figure 13. Sonic transit time (the inverse of sonic velocity) vs. porosity for samples from Sites.........Page 174 Table 2. Compaction experiments data, Sites 999 and 1001.......Page 166 Table 4. Specific surface and grain-size data, Leg 130 Site 807.......Page 167 Plate 1. Thin-section photomicrographs of samples from Site 999 subsequent to compaction experime.........Page 175 Plate 2. Thin-section photomicrographs of samples from Site 1001 subsequent to compaction experim.........Page 176 Plate 3. Wispy laminations in Paleocene clayey calcareous mixed sedimentary rock (Sample 165-999B.........Page 177 INTRODUCTION AND BACKGROUND......Page 178 Figure 2. View into the measurement chamber of the XRF core scanner of the Geosciences Department.........Page 180 Figure 5. The upper Paleocene interval drilled in Hole 999B. The section from 974 to 977 mbsf (lo.........Page 183 RESULTS......Page 185 Figure 9. The Paleocene/Eocene boundary as observed in Cores 165-1001A- 27R and 165-1001B-6R. The.........Page 188 CONCLUSIONS......Page 189 REFERENCES......Page 190 Figure 1 (continued). B. The Paleocene Caribbean (tectonic reconstruction from Pindell and Barret.........Page 179 Figure 3. Comparison of calibrated vs. uncalibrated (raw) FMS data from Site 999. Each trace repr.........Page 181 Figure 4. Late Paleocene thermal maximum (LPTM) as observed in a variety of downhole measurements.........Page 182 Figure 6. The composite upper Paleocene interval recovered at Site 1001 as a result of detailed c.........Page 184 Figure 7. Late Paleocene thermal maximum (LPTM) as observed in selected downhole measurements at .........Page 186 Figure 8. The Paleocene/Eocene boundary as observed in Cores 165-1001A- 27R and 165-1001B-6R. Sho.........Page 187 DATA SETS......Page 191 Figure 1. Location map for Sites 998, 1000, and 1001. Contour interval = 1000 m.......Page 192 Figure 7. Uncorrected sonic log and physical properties velocity measurements for Site 1001.......Page 194 Figure 9. Site 998 composite velocity profile containing edited sonic log and physical properties.........Page 195 Figure 15. Site 998 depth-TWT relationship with linear depth scale. Included are the impedance lo.........Page 198 Figure 17. Site 1001 depth-TWT relationship with linear depth scale. Included are the impedance l.........Page 199 Figure 18. Overlay of synthetic seismogram and SCS Line EW9417-13 at Site 998, with depth and age.........Page 200 Figure 19. Correlation of Site 998 lithostratigraphic units and core lithologies with SCS Line EW.........Page 201 Figure 5. Density log and physical properties density measurements for Site 1000.......Page 193 Figure 11. Site 1000 composite velocity profile containing edited sonic log and physical properti.........Page 196 Figure 13. Site 1001 composite velocity profile containing edited sonic log and physical properti.........Page 197 Figure 21. Correlation and noncorrelation of several lithologic events from Site 1000 with SCS Li.........Page 202 Figure 23. Correlation of Site 1001 lithostratigraphic units and core lithologies with SCS Line E.........Page 203 DATA......Page 204 Figure 3. Two-way traveltime vs. depth below seafloor calculated from compressional velocities un.........Page 207 Figure 4. Velocity, density, and resistivity (medium induction resistivity tool) along with calip.........Page 208 Figure 5. Far-field source wavelet as represented by a 10-trace average of the seafloor reflectio.........Page 209 Figure 1. Bathymetric map (1000-m contour interval from ETOPO-5) showing the location of Site 999.........Page 205 Figure 2. An ~4-km portion of IG2901 MCS Line CT1-12a is displayed with a vertical exaggeration o.........Page 206 METHODS......Page 210 Figure 1. General map of the Western Caribbean. The Colombian Basin and the Nicaraguan Rise are c.........Page 211 Figure 3. Paragenesis of cavity fills.......Page 212 Figure 4. Macroscopic fracture-filling carbonate phases. A. Lens of fine- grained carbonate sedim.........Page 213 Figure 5. Optical microphotographs. A. Overview of laminated micrite 2 (m2) and sparry calcite 2 .........Page 214 Figure 6. SEM photomicrographs. A. General aspect of micrite 1 (m1). Note the smooth surfaces of .........Page 215 RESULTS......Page 216 Figure 2. TiO2 vs. MgO diagram comparing the Site 1001 basalt glass reported in this paper and th.........Page 218 Table 2. 40Ar-39Ar plateau and isochron age calculations, Site 1001.......Page 217 HYDROGRAPHIC CONSIDERATIONS......Page 220 Figure 2. Vertical structure of Cariaco Basin upper water column derived from time-series data. T.........Page 221 Table 1 (continued).......Page 223 Figure 4. Alkenone records of concentration (μg/g dry sediment) and temperature estimated from th.........Page 224 REFERENCES......Page 227 Figure 6. Comparison of total organic carbon (TOC) record (Haug et al., 1998) and the alkenone co.........Page 225 Table 1. Results of alkenone analyses of Hole 1002C.......Page 222 INTRODUCTION......Page 229 METHODS AND MATERIALS......Page 231 Table 1. Location, coordinates, and water depth of the cores.......Page 235 Figure 14. Variations of benthic delta13C compared to carbonate mass accumulation rates (CO3 MAR) in .........Page 243 CONCLUSIONS......Page 251 REFERENCES......Page 252 Figure 1. A. Carbonate mass accumulation rates (CO3 MARs) for the eastern equatorial Pacific, ODP.........Page 230 Figure 2. A. Tectonic and paleoceanographic evolution of the Central American Seaway with inferre.........Page 232 Figure 4. Detailed bathymetry in Pedro Channel and Walton Basin (Cunningham, 1998) represents the.........Page 233 Figure 5. Simplified reconstruction sketches of the Caribbean (after Pindell, 1994) illustrating .........Page 234 Table 2. Leg 165 datums for nannostratigraphy, planktonic foraminiferal stratigraphy, and magneto.........Page 236 Figure 8. A. Shipboard datums of planktonic foraminifers, nannofossils, and magnetic reversals (S.........Page 237 Figure 9. Comparison of two carbonate-content data sets derived from Leg 165 shipboard analyses a.........Page 238 Figure 10. Sand-sized fraction, a proxy for carbonate dissolution, compared to carbonate mass acc.........Page 239 Table 3. Correlation coefficient of carbonate content among Sites 998, 999, and 1000.......Page 240 Figure 12. Carbonate mass accumulation rates (CO3 MARs) for (A) Hole 998A, (B) Hole 999A, and (C).........Page 241 Figure 13. Variations of benthic delta18O in Holes (A) 998A, (B) 999A, and (C) 1000A. Bulk sample delta18.........Page 242 Figure 15. Variations of carbonate-content values between 16 and 8 Ma in three different areas of.........Page 245 Figure 16. A. Correlation between fluctuation of North Atlantic Deep Water (NADW) production (fro.........Page 246 Figure 17. Summary chart of paleoceanographic, tectonic, floral, faunal, and sedimentary changes .........Page 248 Figure 18. A. delta13C of the modern equatorial Indian, western Pacific, and western Atlantic oceans .........Page 249 METHODS......Page 254 Table 1. Conversion of Miocene oxygen- and carbon-isotope events from the geomagnetic polarity ti.........Page 255 Figure 2. Lithostratigraphic units in the investigated interval at Site 999 (Subunits IC, IIA, an.........Page 256 Figure 5. Oxygen-isotope data from Site 999 (this study) plotted against carbonate content (Sigur.........Page 258 Figure 9. Oxygen-isotope data for Sites 1000 and 999 plotted against age. The chronologies at bot.........Page 260 Figure 10. Carbon-isotope data for Sites 1000 and 999 plotted against age. The chronologies at bo.........Page 261 Figure 4. Carbon- and oxygen-isotope data from Site 999. Gray and white intervals correspond to l.........Page 257 Figure 7. Carbon- and oxygen-isotope data from Site 1000 smoothed by a 5-running average. Note th.........Page 259 Figure 1. Site locations for ODP Leg 165. Water depths (drill-pipe measurements from sea level) f.........Page 263 Table 1. Representative reactions.......Page 264 Table 3. Geochemical data for discrete ash* layers.......Page 267 Figure 9. Depth profile for total organic carbon (TOC) for Site 1000 reported as weight percent o.........Page 269 Figure 11. Depth profiles for calcium (open and solid circles) and magnesium (open and solid squa.........Page 270 Figure 16. Depth profile for silica in Site 999 interstitial waters. Distribution of discrete ash.........Page 272 Figure 17. Depth profiles for rubidium in Site 999 interstitial waters. Distributions of both dis.........Page 273 Table 2. Modeled sulfate reduction rates.......Page 265 Figure 3. Downcore distribution of total sulfur concentrations at Site 999 reported as weight per.........Page 266 Figure 7. Depth profile for total alkalinity in Site 1000 interstitial waters. Bulk sediment calc.........Page 268 Figure 14. Depth profile for total alkalinity in Site 998 interstitial waters. Distribution of di.........Page 271 ANALYTICAL METHODS......Page 275 Figure 1. Location of sites drilled during Leg 165, discussed in the text.......Page 276 Figure 2. The accumulation rate of tephra layers at sites drilled during Leg 165, expressed as as.........Page 277 Figure 6. Photograph of a typical Miocene silicic tephra fall layer in a Leg 165 sediment core, s.........Page 286 REFERENCES......Page 289 Table 1: 40Ar/39Ar Dating of biotites from Leg 165 tephra layers.......Page 278 Figure 4. Comparison of radiometric dates of Caribbean tephra layers and the Neogene biostratigra.........Page 283 Figure 5. The plate tectonic configuration of the volcanic arc that comprised the Cayman Rise and.........Page 285 Figure 7. The relationship between Miocene Central American ignimbrite volcanism (Tertiary volcan.........Page 287 Figure 8. A comparison of the Caribbean record of explosive volcanism (tephra accumulation rate a.........Page 288 Table 1 (continued).......Page 279 Table 1 (continued).......Page 280 Table 2. Comparison of Leg 165 40Ar/39Ar radiometric dates of tephra layers vs. biostratigraphic .........Page 281 Table 3: 40Ar/39Ar Dating of feldspars in Leg 165 tephra layer.......Page 282 INDEX TO VOLUME 165......Page 291 VOLUME 165 SUBJECT INDEX......Page 292 Campanian (cont.)......Page 293 dissolution......Page 294 dissolution (cont.)......Page 295 lithostratigraphy......Page 296 lithostratigraphy (cont.)......Page 297 Panama, Isthmus of......Page 298 Panama, Isthmus of (cont.)......Page 299 Site 998......Page 300 Site 998 (cont.)......Page 301 well-log Unit 1......Page 302 VOLUME 165 TAXONOMIC INDEX......Page 303 Discoaster berggrenii......Page 304 Discoaster berggrenii (cont.)......Page 305 insueta s. l., Globigerinatella......Page 306 insueta s. l., Globigerinatella (cont.)......Page 307 rugosus, Ceratolithus......Page 308 rugosus, Ceratolithus (cont.)......Page 309 Zygrhablithus bijugatus......Page 310 Appendix B. Stratigraphic distribution of calcareous nannofossils, Hole 998A.......Page 311 Part 1......Page 312 Part 2......Page 313 Part 3......Page 314 Part 4......Page 315 Part 5......Page 316