diff --git a/src/datatypes/mod.rs b/src/datatypes/mod.rs
index 4be369da0a2..658ca67aef9 100644
--- a/src/datatypes/mod.rs
+++ b/src/datatypes/mod.rs
@@ -191,6 +191,11 @@ impl UnionMode {
 }
 
 /// The time units defined in Arrow.
+///
+/// # Parquet Compatibility
+/// As of [parquet-format v2.9](https://github.com/apache/parquet-format/blob/master/LogicalTypes.md)
+/// `TimeUnit::Second`' is not a defined parquet logical type. The use of `TimeUnit::Second` will
+/// result in no logical type being stored within a parquet file.
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 #[cfg_attr(feature = "serde_types", derive(Serialize, Deserialize))]
 pub enum TimeUnit {