What field names default to "Date or Date Time" during an import from Excel

What field names default to "Date or Date Time" during an import from Excel

  
I've been reviewing Outsystems for about a month.  I am having an issue with using the Import from Excel with the data type for certain columns.  As an example, I have a column called StartDate and another called CreatedDate.  The StartDate column has an attribute data type of Date when imported.  The CreatedDate column has an attribute data type of Text. 

If I allow this type of thing to happen during import and then change the data type after importing, it creates an error that I need to resolve.

What is the algorithm used to determine the data type of an Excel column during import?
Or,asked another way, what name should I give columns in Excel if I want them to be interpeted as a Date attribute when I import the file as an entity?