Palaeoclimate evolution across the Cretaceous–Palaeogene boundary in the Nanxiong Basin (SE China) recorded by red strata and its correlation with marine records
The climate during the Cretaceous Period represented one of the <q>greenhouse states</q> of Earth's history. Significant transformation of climate patterns and a mass extinction event characterised by the disappearance of dinosaurs occurred across the Cretaceous–Palaeogene bounda...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2018-03-01
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| Series: | Climate of the Past |
| Online Access: | https://www.clim-past.net/14/287/2018/cp-14-287-2018.pdf |
| Summary: | The climate during the Cretaceous Period represented one of the <q>greenhouse
states</q> of Earth's history. Significant transformation of climate patterns
and a mass extinction event characterised by the disappearance of dinosaurs
occurred across the Cretaceous–Palaeogene boundary. However, most records of
this interval are derived from marine sediments. The continuous and
well-exposed red strata of the Nanxiong Basin (SE China) provide ideal
material to develop continental records. Considerable research into
stratigraphic, palaeontological, chronologic, palaeoclimatic, and tectonic
aspects has been carried out for the Datang profile, which is a type section
of a non-marine Cretaceous–Palaeogene stratigraphic division in China. For
this study, we reviewed previous work and found that (1) the existing
chronological framework of the Datang profile is flawed; (2) precise
palaeoclimatic reconstruction is lacking because of the limitations of
sampling resolution (e.g. carbonate samples) and/or the lack of efficient
proxies; and (3) comparisons of climate changes between marine and continental
records are lacking. To resolve these problems, detailed field observations
and sampling, as well as environmental magnetic and rare earth element (REE)
measurements, were carried out. The results show that (1) more accurate ages
of the Datang profile range from 72 to 62.8 Ma based on a combination of
the most recently published radiometric, palaeontological, and palaeomagnetic
ages; (2) there is considerable evidence of palaeosol generation, which
indicates that the red strata formed in a long-term hot, oxidising
environment that lacked underwater conditions; (3) haematite was the
dominant magnetic mineral in the red strata, and the variation trend of
magnetic susceptibility was consistent with the oxygen isotope records from
deep-sea sediments, which indicates that the content of haematite was
controlled by the global climate; and (4) the palaeoclimate changes from 72 to
62.8 Ma in the Nanxiong Basin were consistent with global patterns and can
be divided into three stages: a relatively hot and wet stage during 72–71.5 Ma,
a cool and arid stage during 71.5–66 Ma, and a relatively hot and wet
stage again during 66–62.8 Ma with a notable drying and cooling event at
64.7–63.4 Ma. Moreover, there are several sub-fluctuations during each
stage. This work provides basic information for further palaeoclimate
reconstructions with a higher resolution and longer timescales for the
Cretaceous to Palaeocene in the Nanxiong Basin and may even help to test
ocean–land climate interactions in the future. |
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| ISSN: | 1814-9324 1814-9332 |