R. Dunay, W. Braham, M. K. E. Cooper, Martin Lester, F. Tremolada
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引用次数: 3
摘要
摘要构造模型表明,在新新时代早期,莫桑比克海脊上没有深水连接。这些模型暗示了在巴雷米亚-最早阿普提时代形成的南大西洋和印度洋之间的深水连接的开始。然而,先前对莫桑比克海脊最早的深水沉积物的生物地层学研究表明,基底部分的年龄为新新纪。在这里,我们提出了一种新的生物地层学分析方法来测试这个构造模型,并确定莫桑比克海岭深水沉积的最早年龄。采集了25 Leg 249号DSDP站点222.05 - 406.32 m白垩纪(19-32)岩心样品,进行了钙质纳米浮游生物和孢粉学分析。大部分采样集中在294 m以下的下白垩统层段。研究结果表明,下沉积剖面比巴雷米亚期更早,因此为构造模型提出的年龄提供了支持。
Micropalaeontological dating of the basal Cretaceous section of DSDP Site 249, Leg 25, Mozambique Ridge: implications for the timing of the southern Atlantic–Indian Ocean connection
Abstract. Tectonic models suggest the absence of a deep water connection on the
Mozambique Ridge during early Neocomian time. These models imply the
initiation of a deep water connection between the southern Atlantic and
Indian oceans formed during Barremian–earliest Aptian times. However,
previous biostratigraphic studies of the earliest deep water sediments on the
Mozambique Ridge suggest that the basal section is Neocomian in age. Here, we
present a new biostratigraphic analysis undertaken to test this tectonic
model and determine the earliest age of deep water sedimentation on the
Mozambique Ridge. Core samples from the Cretaceous interval
222.05–406.32 m (Cores 19–32) of DSDP Site 249, Leg 25, were
sampled for calcareous nannoplankton and palynological analysis. Most of the
sampling was concentrated on the Lower Cretaceous interval below
294 m . Our results indicate that the lower sedimentary section is no
older than Barremian and therefore provides support for the age proposed by
the tectonic models.
期刊介绍:
The Journal of Micropalaeontology (JM) is an established international journal covering all aspects of microfossils and their application to both applied studies and basic research. In particular we welcome submissions relating to microfossils and their application to palaeoceanography, palaeoclimatology, palaeobiology, evolution, taxonomy, environmental change and molecular phylogeny.