3 research outputs found
Processing methods for enrichment of diatoms in sediment samples
No full textBased on the existing guide-documentation and practical experiences of author, the paper presents the processing methods for enrichment of diatoms in sediment samples for classification and research in biostratigraphy. Processing samples must be performed by five stages as: 1. sample preparation; 2. cleaning and preliminary enrichment; 3- enrichment by heavy solution; 4. creating hard specimen; 5.recovering and recycling heavy solution. Depending on the kind of processed samples, the operations need to be adjusted accordingly. For the stage of enrichment by heavy solution, the result is influenced greatly by all three factors such as: density of solution, centrifugal speed and time. Under the condition of humid climate, the preliminary enriched samples are difficult to keep dry absolutely. Therefore, the standard solution density of 2.6 prepared from the proportional weight: H2O: CdI2: KI = 1: 2.5: 2.25 may be reduced slightly when mixed with the samples for centrifugation. For this reason, it needs to make the appropriate adjustments conditions such as: increasing heavy solution density or decreasing centrifugal speed. Recovering and recycling heavy solution are particularly necessary, and the recovery rate can reach up 75-80%. The formulas given in this article could make recycling heavy solution fast and accurately.ReferencesĐào Thị Miên, Nguyễn Ngọc, Nguyễn Thị Thu Cúc, 2006: Ý nghĩa của các phức hệ Diatomeae trong việc xác định nguồn gốc trầm tích cuối Holocen giữa - Holocen muộn ở một số đồng bằng ven biển Việt Nam. Tạp chí Địa chất, số 295 (7-8), tr.1-14. Juse, A.P.; Proschkina-Laverenko, A.I.; Sheshykova, V.C., 1949: Phân tích tảo Silics (Diatoms). Tập I. Địa chất. Nhà xuất bản Văn liệu Quốc gia. Leningrad, 339tr (tiếng Nga). Juze A.P., 1963: Ngành Bacillariophyta, tảo Diatomeae. Trong: “Cơ sở cổ sinh”. T.15. Nhà xuất bản Viện Hàn lâm Khoa học Liên Xô, Mascơva (tiếng Nga). Đặng Đức Nga, Trần Đức Thạnh, 1982: Các phức hệ tảo Silic (Diatomeae) Pliocen Tây Nguyên và ý nghĩa của chúng. Tạp chí Các Khoa học về Trái Đất. T.4, 1, tr.27-30. Tạ Thị kim Oanh, Nguyễn Văn Lập, 2000: Diatom - chỉ thị môi trường trầm tích và dao động mực nước biển trong Pleistocen muộn- Holocen. Tạp chí Các Khoa học về Trái Đất, T.22, 3, tr.226-233. Trần Đức Thạnh, 1991: Phân bố của tảo silic trong trầm tích bề mặt vùng ven biển từ cửa Văn Úc tới cửa Ba Lạt. Tuyển tập Tài nguyên và Môi trường biển. Tập I. Nxb. Khoa học và Kỹ thuật, Hà Nội, tr.67-72.
The Sedimentary geochemistry and paleoenvironments project phase 2 data release: An open data resource for the study of Earth's environmental history
No full textGeochemical data from sedimentary rocks are the primary source of information regarding Earth's surface evolution through time, including its air and water envelopes and interactions with life and deep Earth processes. The Sedimentary Geochemistry and Paleoenvironments Project (SGP) is a scientific consortium centered around open data and community-driven development of cyberinfrastructure tools and resources for sedimentary geochemistry and Earth history. Here we describe the SGP Phase 2 data release, which focused on incorporating Paleoproterozoic and Mesoproterozoic (2500–1000 million years ago) data and better accommodating carbonate data. This data release was built through the involvement of >200 researchers worldwide in academia, government, and industry, and provides the largest available public data resource for our user community in the academic fields of geochemistry, sedimentology, tectonics, paleontology, Earth history, and paleoclimate, as well as the petroleum and minerals industries. The dataset now encompasses 126,006 samples and 4,132,371 geochemical analyses. In addition to direct entry by SGP Team Members, we have ingested and incorporated datasets from the Geoscience Australia OZCHEM database, the Alberta Geological Survey, and the Deep-Time Marine Sedimentary Element Database (DM-SED) compilation. This paper details sampling in the Phase 2 dataset with respect to age, geography, lithology, and other geological characteristics, documents access via our search website and API, discusses possible issues and/or biases in the dataset that could impact analyses, describes plans for governance and stewardship of data from Indigenous lands, and serves as the citable reference paper for the data release
The Sedimentary Geochemistry and Paleoenvironments project
No full textAuthors thank the donors of The American Chemical Society Petroleum Research Fund for partial support of SGP website development (61017-ND2). EAS is funded by National Science Foundation grant (NSF) EAR-1922966. BGS authors (JE, PW) publish with permission of the Executive Director of the British Geological Survey, UKRI.Peer reviewe
