A slippery slope for Cryogenian diamictites? / Daniel Paul, Le Heron ; Vandyk, Thomas.

In: The Depositional Record, 12.03.2019, p. 1-16.

Research output: Contribution to journalArticle

E-pub ahead of print

Abstract

The Death Valley region has previously been claimed to preserve the sedimentary records of both the Sturtian and Marinoan snowball Earth events. A more complete sedimentary record has been alleged to be preserved in the west, although it is intensely metamorphosed, whereas in the east there is excellent preservation, with lower metamorphic grade, but perhaps a less complete record of events. In spite of this, units of widespread regional extent and purported global significance have been recognised in the high quality exposures of the eastern Death Valley areas. In the Saddle Peak Hills, a unit named “KP4” was correlated by Macdonald et al. (2013) to the Wildrose diamictite of the northern Panamints, and interpreted as Death Valley’s record of the Marinoan glaciation. In the Alexander Hills, a unit named pꞒk4 was mapped by Wright (1974) and later assigned to KP4 (Mrofka and Kennedy 2011). In this paper, we present new sedimentary logs and detailed clast textural analyses which allow diamictites of the Alexander Hills and the Saddle Peak Hills to be compared in detail for the first time, and contrasted with rocks of established glaciogenic origin elsewhere in Death Valley from the southern Kingston Range. Notably, in the Saddle Peak Hills, clasts identical in composition and facies to that of the Noonday Dolomite- previously interpreted as the post-Marinoan cap carbonate- are incorporated into diamictites at the top of the Kingston Peak Formation. Combined with the carbonate-rich composition of rocks at the top of the KPF, these observations lead us to propose that the uppermost diamictites of the Saddle Peak Hills and Alexander Hills are genetically related to cap carbonates of the Noonday Dolomite cap carbonates and are unrelated to glacial processes. We propose that both the KP4 and pꞒk4 diamictites formed through local slope foundering and basinward collapse of the adjacent carbonate platform, a model which substantiates recent interpretations of Noonday carbonate platform dynamics (Creveling et al., 2016) demonstrates that they are genetically unrelated to Cryogenian glaciation. By comparing this new data to those published data for the Wildrose diamictite of Panamint Valley, we explore whether the Marinoan glaciation can be discerned in the Death valley region at all.
Original languageEnglish
Pages (from-to)1-16
Number of pages16
JournalThe Depositional Record
Early online date12 Mar 2019
DOIs
Publication statusE-pub ahead of print - 12 Mar 2019
This open access research output is licenced under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.

ID: 30782219