Dissolved Thorium and Protactinium Isotopes U.S. GEOTRACES Arctic Cruise (HLY1502, GN01) PIs: Robert F. Anderson (LDEO) & R. Lawrence Edwards (UMTC) Co-PIs: Martin Q. Fleisher (LDEO) & Hai Cheng (UMTC) Contact/Analyst: Sebastian M. Vivancos (LDEO) Version history: 2021-08-25 (v3) - version 3 published; includes corrections to dates, times, latitudes, longitudes, cast numbers, & sample depths (refer to metadata for complete list of changes); file submitted to BCO-DMO on 2021-08-01. 2021-02-23 (v2) - version 2 published; includes changes to some data values; file submitted to BCO-DMO on 2021-01-28. 2020-12-29 (v1) - version 1 published; file submitted to BCO-DMO on 2020-12-21.