Astronomical Pacing of Third-Order Sea-Level Sequences During the Middle Miocene in the Northern South China Sea
MARINE AND PETROLEUM GEOLOGY（2023）
China Univ Geosci
Abstract
The Miocene Hanjiang Formation of the Pearl River Mouth Basin (PRMB) forms one of the most productive hydrocarbon reservoirs in China. Sparse biostratigraphic age control and limited dating hinder a thorough un-derstanding of sea-level change and its sedimentary expression through this formation. To establish the rela-tionship between third-order sea-level changes, their expression in the lithological record and astronomical forcing, a sequence stratigraphic and cyclostratigraphic analysis has been conducted through the Hanjiang Formation in the LF14 borehole. One second-order sequence and six third-order sequences are recognized based on gamma ray (GR) data, vertical lithofacies changes and sedimentary stacking patterns. Time series analysis of the GR data and subsequent interpretation allows recognition of approximately eighteen 405 kyr long eccen-tricity cycles. Based on this cyclostratigraphy, we constructed a-7.22-Myr floating astronomical time scale (ATS) for the Hanjiang Formation. We anchored this timescale to globally significant biostratigraphic events preserved in the basin to build an absolute ATS spanning 17.423 +/- 0.4 to 10.221 +/- 0.4 Ma. A prominent -1.2-Myr periodicity is identified in the amplitude modulation (AM) envelope curves of-41-kyr obliquity cycles preserved in the record. This-1.2-Myr periodicity shows good agreement with our sequence stratigraphic analysis and global eustatic curves. Our results suggest that-1.2-Myr obliquity AM was the main driver of third-order sea-level change and sequence development in the PRMB. Combined application of cyclostratigraphic and sequence stratigraphic analysis (utilizing INPEFA and wavelet transform methods) are demonstrated to be useful for understanding the drivers and subdivisions of third-order sequence evolution on a regional scale.
MoreTranslated text
Key words
Astronomical forcing,Long-period-1,2-Myr cycles,Third-order sequence,Eustasy
求助PDF
上传PDF
View via Publisher
AI Read Science
AI Summary
AI Summary is the key point extracted automatically understanding the full text of the paper, including the background, methods, results, conclusions, icons and other key content, so that you can get the outline of the paper at a glance.
Example
Background
Key content
Introduction
Methods
Results
Related work
Fund
Key content
- Pretraining has recently greatly promoted the development of natural language processing (NLP)
- We show that M6 outperforms the baselines in multimodal downstream tasks, and the large M6 with 10 parameters can reach a better performance
- We propose a method called M6 that is able to process information of multiple modalities and perform both single-modal and cross-modal understanding and generation
- The model is scaled to large model with 10 billion parameters with sophisticated deployment, and the 10 -parameter M6-large is the largest pretrained model in Chinese
- Experimental results show that our proposed M6 outperforms the baseline in a number of downstream tasks concerning both single modality and multiple modalities We will continue the pretraining of extremely large models by increasing data to explore the limit of its performance
Upload PDF to Generate Summary
Must-Reading Tree
Example
Generate MRT to find the research sequence of this paper
Data Disclaimer
The page data are from open Internet sources, cooperative publishers and automatic analysis results through AI technology. We do not make any commitments and guarantees for the validity, accuracy, correctness, reliability, completeness and timeliness of the page data. If you have any questions, please contact us by email: report@aminer.cn
Chat Paper
Summary is being generated by the instructions you defined