Geologic map of the Chulitna region, southcentral Alaska

Abstract

This publication released by the Division of Geological & Geophysical Surveys was produced and printed in Fairbanks, Alaska at a cost of $16 per copy. Publication is required by Alaska Statute 4 1, "to determine the potential of Alaskan land for production of metals, minerals, fuels, and geothermal resources; the location and supplies of groundwater and construction materials; the potential geologic hazards to buildings, roads, bridges, and other installations and structures; and shall conduct such other surveys and investigations as will advance knowledge of the geology of Alaska."

The Crustal Magmatic Structure Beneath the Denali Volcanic Gap Imaged by a Dense Linear Seismic Array

“…The fast velocity area bounded by the BPF to the north and the HF to the south could be related to the mafic and ultramafic rocks of the BPT underlining the Chulitna terrane (Jones et al., 1980) and corresponds with a positive magnetic anomaly (Burns et al., 2020). The BPF and the HF played an important role during the formation of the SZ in the Late Cretaceous with inferred strike‐slip or thrust displacements (Clautice, Newberry, Blodgett, et al., 2001; Clautice, Newberry, Pinney, et al., 2001; Jones et al., 1980). They have been reactivated during the Holocene with a few kilometers of thrust displacement (Haeussler, Saltus, et al., 2017).…”

“…They have been reactivated during the Holocene with a few kilometers of thrust displacement (Haeussler, Saltus, et al., 2017). The relationship between the terranes and the faults in the Broad Pass area is not fully understood (Clautice, Newberry, Blodgett, et al., 2001; Clautice, Newberry, Pinney, et al., 2001).…”

“…The metamorphic and sedimentary rocks of the SZ in Central Alaska, known as the Kahiltna assemblage, can be divided into northern and southern succession, with affinity to the Yukon Composite Terrane (YCT) (continental crust) and Wrangelia composite terrane (oceanic crust), respectively (Clautice, Newberry, Blodgett, et al., 2001; Clautice, Newberry, Pinney, et al., 2001; Hampton et al., 2010) (Figure 1). Both Kahlitna successions have rocks from volcanism and intrusions from the subduction‐related arc and collisional magmatism (Romero et al., 2020); some of these rocks form the Broad Pass Terrane (BPT) (Clautice, Newberry, Blodgett, et al., 2001; Clautice, Newberry, Pinney, et al., 2001). The terranes north of the SZ are commonly referred to as the YCT, consisting of metamorphosed rocks of the former continental margin (Ridgway et al., 2002).…”

“…(Figure 1). Both Kahlitna successions have rocks from volcanism and intrusions from the subduction-related arc and collisional magmatism (Romero et al, 2020); some of these rocks form the Broad Pass Terrane (BPT) Clautice, Newberry, Pinney, et al, 2001). The terranes north of the SZ are commonly referred to as the YCT, consisting of metamorphosed rocks of the former continental margin (Ridgway et al, 2002).…”

Suture Reactivation, Slip Partitioning, and a Protracted Strike‐Slip Rate Gradient in the Denali Fault System, Southern Alaska, USA

“…Farther west, the Colorado Creek and Broad Pass faults cut through cover strata along the geophysically inferred boundaries of the allochthonous Chulitna terrane exposed at the base of the Denali massif (cf. Clautice et al., 2001; Gilman et al., 2009; Haeussler, Saltus, et al., 2017; Trop et al., 2019). The transition to a thin‐skinned fold‐and‐thrust belt structural style to the north of the Denali fault coincides with a decrease in depth of Cenozoic exhumation, despite the thrust belt accommodating the bulk of the Quaternary shortening across the Alaska Range (Bemis et al., 2015).…”