Table T1. Definition of lithostratigraphic and lithologic units, descriptive intervals, and domains, Expedition 350.
| JOIDES Resolution |
Typical thickness range (m) |
JOIDES Resolution data logging spreadsheet context |
Traditional sediment drilling | Traditional igneous rock drilling |
Comparable nondrilling terminology |
|---|---|---|---|---|---|
| Lithostratigraphic unit | 101~103 | One row per unit in “lithostrat” summary tab; numbered I, II, IIa, IIb, III, etc. | Used as specified; however, often referred to as lithologic unit in the past. | Typically not used when only igneous rocks are drilled. | Not specified during field campaign. Formal names need to be approved by stratigraphic commission. |
| Lithologic unit | 10−1~101 | One row per unit in “lith_unit” summary tab; numbered 1, 2, 3, 4, etc. | Typically not used because descriptive intervals correspond to beds, which are directly summarized in lithostratigraphic units. Similar concept: facies type; however, those are not contiguous. | Often defined previously as lava flows, etc., and used in the sense of a descriptive interval. Enumerated contiguously as Unit 1, 2, 3, etc. As defined here, units may correspond to one or more description intervals. | Sedimentology: group of beds. |
| Descriptive interval | 10−1~101 | Primary descriptive entity that can be readily differentiated during time available. One row per interval in principal logging tab (lithology specific) | Typically corresponds to beds. If beds are too thin, a thicker interval of “intercalated…” is created, and 2−3 domains describe the characteristics of the different types of thin beds. | Typically corresponds to the lithologic unit. As defined here, a lithologic unit may correspond to one or more description intervals. | Sedimentology: thinnest bed to be measured individually within a preset interval (e.g., 0.2 m, 1 m, 5 m, etc.), which is determined based on time available. |
| Domain | Same as parent descriptive interval | Additional rows per interval in principal logging tab, below the primary description interval row; numbered 1, 2, etc. (with description interval numbered 0) | Describes types of beds in an intercalated sequence can be specified in detail as a group. | Describes multiple lithologies in a thin section or textural domains in a macroscopic description. | Feature description within descriptive interval, as needed. |
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