Revision History for Scientific Investigations Map 3291

Warren C. Day,1 J. Michael O’Neill,1 Cynthia Dusel-Bacon,1 John N. Aleinikoff,1 and Christopher R. Siron2

GEOLOGIC MAP OF THE KECHUMSTUK FAULT ZONE IN THE MOUNT VETA AREA, FORTYMILE MINING DISTRICT, EAST-CENTRAL ALASKA

-----------------------------------------------------
Posted online March 10, 2014

-----------------------------------------------------
Revised and reposted March 12, 2014, version 1.1

The changes that were made in version 1.1 were as follows:

1. Unit Kqfp was changed from Early Cretaceous to Late Cretaceous, and moved up in the Description of Map units, right under unit Kdm. 

2. In the Correlation of map units, the unit Kqfp was moved up right under unit Kr.

2. In the ArcMap files, (Geology_area) the age of the unit Kqfp was changed to Late Cretaceous. The gdb and shapefiles were updated to reflect
this change. The metadata had the correction for the date of the unit made as well.

3. Some minor changes were made to the wording in the Introduction. Reference to unit Kqfp changed to “earliest Late Cretaceous” and 1886 gold
rush changed to 1896-1898 gold rush. Some other minor changes were made, as per the following statement:

“…least since the earliest Late Cretaceous (Cenomanian), during which a series of about 96–94 Ma quartz-feldspar porphyry intrusions (Kqfp) were
emplaced in the zone (Kqf). Subsequent brittle deformation has brecciated the mid-Cretaceous intrusions…”  

4. The reference to the age dating using the Geologic Society of America was added to the references and a note was added to the Description of Map Units.