Abstract
Abstract. The climate during the Cretaceous Period represented one of the greenhouse states 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.
Highlights
The Earth existed in a greenhouse state during the Late Cretaceous (Hay, 2011; Friedrich et al, 2012; Wang et al, 2014); palaeoclimate studies show that based on marine records, the seawater surface temperature near the Equator reached up to 36 ◦C during the Late Cretaceous (Linnert et al, 2014), and reconstructed CO2 concentrations reach up to 837 ppm across the Cretaceous–Tertiary boundary, as recorded in palaeosol carbonates in NE China (Huang et al, 2013)
The results show that the upper 465 m of the Datang profile has five well-defined polarity zones (30N, 29R, 29N, 28R, and 28N), whereas the DT05 section is characterised by a single long, reversed-polarity zone (26R), which has been confirmed by the U–Pb ages of the tephra layer from the www.clim-past.net/14/287/2018/
Combined with the most recently published isotopic ages of volcanic ash and biostratigraphic dating, a new chronological framework has been proposed; the results show that the age of the Datang profile is between 72 and 62.8 Ma
Summary
The Earth existed in a greenhouse state during the Late Cretaceous (Hay, 2011; Friedrich et al, 2012; Wang et al, 2014); palaeoclimate studies show that based on marine records, the seawater surface temperature near the Equator reached up to 36 ◦C during the Late Cretaceous (Linnert et al, 2014), and reconstructed CO2 concentrations reach up to 837 ppm across the Cretaceous–Tertiary boundary, as recorded in palaeosol carbonates in NE China (Huang et al, 2013). The palaeotemperature decreased significantly from the Mesozoic Era to the Cenozoic (Zachos et al, 2001; Hay, 2011), and a mass extinction event occurred across the Cretaceous–Palaeogene boundary (Schulte et al, 2010; Renne et al, 2013); climate changes and biological evolution during this interval have become a research hot spot. Terrestrial palaeoclimate records are few, and published comparisons and correlations between marine and terrestrial palaeoclimate records are even fewer (Wang et al, 2013b)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
