The Archives, available at the footer menu, starts with a calendar, that provides a concise view. Years and months are both links to periodic archives. In the pelicanconf.py file, the two following variables should be defined, for instance as:

YEAR_ARCHIVE_SAVE_AS  = 'archive_{date:%Y}.html'
MONTH_ARCHIVE_SAVE_AS = 'archive_{date:%Y}_{date:%m}.html'

The calendar view do not refer to any pelican plugin: this is an original functionality of the Lepagito theme. If you don't want the calendar to appear on the archives page, you could either not define at least one of these variable, or set:

ARCHIVES_CALENDAR = False

By default, this variable is True.