coerce to ns resolution only if time unit, not date unit

Author: cmeeren

pandas/io/parsers.py

@@ -2153,8 +2153,12 @@ def _try_convert_dates(parser, colspec, data_dict, columns):
 
     new_name = '_'.join([str(x) for x in colnames])
     to_parse = [data_dict[c] for c in colnames if c in data_dict]
-
-    new_col = parser(*to_parse).astype('datetime64[ns]')
+    new_col = parser(*to_parse)
+    if hasattr(new_col, 'dtype') and any(r in str(new_col.dtype) for r in
+                                         ['[h]', '[m]', '[s]',
+                                          '[ms]', '[us]', '[ns]',
+                                          '[ps]', '[fs]', '[as]']):
+        new_col = new_col.astype('datetime64[ns]')
     return new_name, new_col, colnames