1120


Journal of Paleontology 91(6):1102–1122


Figure 12. Down-core variations of main species and assemblages of benthic foraminifers in Core CSJA6.


(Min and Wang, 1979), which documented the post-glacial transgresstion-regression history, referred to as the “Ammonia transgression” during the Holocene (Wang et al., 1981). The Ammonia beccarii-Florilus decorus assemblage points


to a weak marine transgression during the early post-glacial period. The Ammoina beccarii-Elphidium advenum assem- blage, however, suggests the strongest transgression during the early–middle Holocene, when the warm and relatively deep sea water invaded this region. The Ammoina beccarii-Elphidium magellanicum assemblage corresponds to the late Holocene marine regression, an episode of global sea level drop. Due to the difference in the locations of the studied cores, the results suggest that CoreZKA4 is first out of the influence of the marine water during the late middle Holocene, when the other two cores were still of marine environment during the late Holocene.


Conclusions


The occurrence of abundant foraminifers in three cores drilled in the incised Yangtze paleo-valley revealed post-glacial environmental changes. Three benthic foraminiferal assemblages are present, including the Ammonia beccari-Florilus decorus assemblage dur- ing the early post-glacial period, the Ammoina beccarii-Elphidium advenum assemblage during the early-middle Holocene, and the Ammoina beccarii-Elphidiummagellanicumassemblage in the late Holocene. The assemblages can be correlated with the “Ammonia marine transgression” during theHolocene (Wang et al., 1981).The early–middle Holocene benthic foraminiferal assemblage also


implies a warm environment because of the occurrence of abundant Cavarotalia annectens and Pararotalia nipponica, and porcel- laneous forms. The difference in foraminiferal abundance and diversity suggests that the cores in the modern coastal area are influenced by ocean water since the early post-glacial period, while the upstream core witnessed the transgression only during the middle Holocene.With the global sea level drop, the ocean water retreated from the west since the late middle Holocene and gradu- ally formed the estuary environment in the Yangtze Delta.


Acknowledgments


We thank Dr. S. Stukins for arranging the observation on the foraminiferal collections at the Natural HistoryMuseum (London). We also thank two anonymous reviewers for their detailed and constructive reviews, which considerably improved themanuscript. This study was supported by the NSFC (Grant No. 41276044), CAS Strategic Priority Project (Grant No. XDPB05), and the Foundation of Geological Survey of China (Nos. GZH201200506, 1212011120173, and 121201004000150021).


References


Andersen, H.V., 1952, Buccella, a new genus of the rotailed Foraminifera: Journal of the Washington Academy of Sciences, v. 42, p. 143–151.


Asano, K., 1950–1953, in Stach, L.W., compl. & ed., Illustrated Catalogue of Japanese Tertiary Smaller Foraminifera, Parts 1–15, Suppl. 1: Tokyo, Kurogane Printing Co. & Hosokawa Printing Co., 183 p.


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56  |  Page 57  |  Page 58  |  Page 59  |  Page 60  |  Page 61  |  Page 62  |  Page 63  |  Page 64  |  Page 65  |  Page 66  |  Page 67  |  Page 68  |  Page 69  |  Page 70  |  Page 71  |  Page 72  |  Page 73  |  Page 74  |  Page 75  |  Page 76  |  Page 77  |  Page 78  |  Page 79  |  Page 80  |  Page 81  |  Page 82  |  Page 83  |  Page 84  |  Page 85  |  Page 86  |  Page 87  |  Page 88  |  Page 89  |  Page 90  |  Page 91  |  Page 92  |  Page 93  |  Page 94  |  Page 95  |  Page 96  |  Page 97  |  Page 98  |  Page 99  |  Page 100  |  Page 101  |  Page 102  |  Page 103  |  Page 104  |  Page 105  |  Page 106  |  Page 107  |  Page 108  |  Page 109  |  Page 110  |  Page 111  |  Page 112  |  Page 113  |  Page 114  |  Page 115  |  Page 116  |  Page 117  |  Page 118  |  Page 119  |  Page 120  |  Page 121  |  Page 122  |  Page 123  |  Page 124  |  Page 125  |  Page 126  |  Page 127  |  Page 128  |  Page 129  |  Page 130  |  Page 131  |  Page 132  |  Page 133  |  Page 134  |  Page 135  |  Page 136  |  Page 137  |  Page 138  |  Page 139  |  Page 140  |  Page 141  |  Page 142  |  Page 143  |  Page 144  |  Page 145  |  Page 146  |  Page 147  |  Page 148  |  Page 149  |  Page 150  |  Page 151  |  Page 152  |  Page 153  |  Page 154  |  Page 155  |  Page 156  |  Page 157  |  Page 158  |  Page 159  |  Page 160  |  Page 161  |  Page 162  |  Page 163  |  Page 164  |  Page 165  |  Page 166  |  Page 167  |  Page 168  |  Page 169  |  Page 170  |  Page 171  |  Page 172  |  Page 173  |  Page 174  |  Page 175  |  Page 176  |  Page 177  |  Page 178  |  Page 179  |  Page 180  |  Page 181  |  Page 182  |  Page 183  |  Page 184  |  Page 185  |  Page 186  |  Page 187  |  Page 188  |  Page 189  |  Page 190  |  Page 191  |  Page 192  |  Page 193  |  Page 194  |  Page 195  |  Page 196  |  Page 197  |  Page 198  |  Page 199  |  Page 200  |  Page 201  |  Page 202  |  Page 203  |  Page 204  |  Page 205  |  Page 206  |  Page 207  |  Page 208  |  Page 209  |  Page 210  |  Page 211  |  Page 212  |  Page 213  |  Page 214  |  Page 215  |  Page 216  |  Page 217  |  Page 218  |  Page 219  |  Page 220  |  Page 221  |  Page 222  |  Page 223  |  Page 224  |  Page 225  |  Page 226  |  Page 227  |  Page 228  |  Page 229  |  Page 230  |  Page 231  |  Page 232  |  Page 233  |  Page 234  |  Page 235  |  Page 236  |  Page 237  |  Page 238  |  Page 239  |  Page 240  |  Page 241  |  Page 242  |  Page 243  |  Page 244  |  Page 245  |  Page 246  |  Page 247  |  Page 248  |  Page 249  |  Page 250  |  Page 251  |  Page 252  |  Page 253  |  Page 254  |  Page 255  |  Page 256  |  Page 257  |  Page 258  |  Page 259  |  Page 260  |  Page 261  |  Page 262  |  Page 263  |  Page 264  |  Page 265  |  Page 266  |  Page 267  |  Page 268  |  Page 269  |  Page 270  |  Page 271  |  Page 272  |  Page 273  |  Page 274  |  Page 275  |  Page 276