100 Snowballs, Unconformities, BIFs and Beyond: Navigating the Neoproterozoic Rock and Climate Records Using Geochronology

The Neoproterozoic comprised periods of upheaval in Earth’s climate which changed the course of life and resulted in unique geologic features and formations. We welcome contributions applying geochronometers to investigate the timing of events and processes which shaped the Neoproterozoic.

Monday, 20 October 2025
8:00 AM - 12:00 PM
HBGCC, 304C

Tava: U-Pb Dating of Cryogenian Snowball Earth Meltwater Events in Colorado

Paper number: 100-8
Program: Technical Sessions
Time: 10:10 AM – 10:25 AM

Authors

Abstract

Terrestrial records of the Cryogenian (720-635 Ma) ice sheets are rare, and until recently were unknown from low paleolatitudes within interior continental settings.  Here, we document a terrestrial Sturtian glacial record in the Colorado Front Range referred to as ‘Tava’, after the ancestral Ute name for Pikes Peak where many outcrops are found. Tava is composed of meter scale sandstone/quartzite dikes (injectites) and ridges hundreds of meters in length, which preserve features characteristic of fluidization and deformation in a subglacial environment. We use in-situ hematite U-Pb geochronology to date injectite formation via veinlet age bracketing, providing constraints on glacial meltwater events associated with rifting and deglaciation (~690-660 Ma). The chemically weathered crystalline rock associated with the Tava dikes lacks evidence of mechanical abrasion and glacial scouring, suggesting that erosion at the adjacent Great Unconformity predates the Sturtian glaciation.

Geological Society of America Abstracts with Programs. Vol. 57, No. 6

doi: 10.1130/abs/2025AM-412408

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