Rare Earth Partition Characteristics and Sedimentary Diagenetic Response in Layered Argillaceous Limestone: Taking the Shale of Upper Es4 in the Nx55 Well Area as an Example

Table 1

Th and U contents of the four components.

Component	Th content (ppm)	Th average content (ppm)	U content (ppm)	U average content (ppm)	Content level
Calcite vein	0.003–3.99	0.873	0.004~3.14	0.70	Low
Interface between argillaceous lamina and sparry calcite	0.80~1.57	1.15	0.72~1.61	1.14	Low
Clay	4.88~6.71	5.27	3.92~6.69	4.71	High
Micrite calcite	2.38~5.16	3.79	1.89~5.14	3.26	High