Freshwater plumes and brackish lakes: Integrated microfossil and O-C-Sr isotopic evidence from the late Miocene and early Pliocene Bouse Formation (California-Arizona) supports a lake overflow model for the integration of the lower Colorado River corridor

Abstract

This paper is published under the terms of the CC-BY-NC license.

Mixed carbonate–siliciclastic tidal sedimentation in the Miocene to Pliocene Bouse Formation, palaeo‐Gulf of California

“…The Bouse Formation deposits display tidal cyclicity similar to that of the modern Gulf of California (Marinone, 1997;O'Connell et al, 2017), and the tectonic setting and basin geometries are well-constrained (Dorsey et al, 2018;Gardner & Dorsey, 2021). Published analyses, however, are incomplete, and some studies favour a lacustrine origin for the Bouse Formation in its southern exposures along the lower Colorado River region (Spencer & Jonathan Patchett, 1997;House et al, 2008;Spencer et al, 2013;Bright et al, 2016Bright et al, , 2018a.…”

Mixed carbonate-siliciclastic tidal sedimentation in the Miocene to Pliocene Bouse Formation, palaeo-Gulf of California

“…The Bouse Formation in the studied area formed at the margin of a tidal strait near the north end of the Gulf of California oblique rift as indicated by marine and brackish-water fossils and a wide range of tidal sedimentary structures (e.g., Buising, 1990;Turak, 2000;McDougall, 2008;McDougall & Miranda-Martinez, 2014;Dorsey et al, 2018;Garnder & Dorsey, in press). Although some authors favour an isolated inland-lake model for the Bouse Formation in the study area (Spencer & Patchett, 1997;House et al, 2008;Spencer et al, 2008Spencer et al, , 2013Bright et al, 2016Bright et al, , 2018a2018b), the lacustrine model is incompatible with abundant evidence for intertidal, marine to brackish-water fossils and trace fossils, and widespread tideinfluenced sedimentary structures (Buising, 1990;Turak, 2000;O'Connell et al, 2017;Dorsey et al, 2018;Garnder & Dorsey, in press).…”

“…The Bouse Formation deposits display tidal cyclicity similar to that of the modern Gulf of California (Marinone, 1997;O'Connell et al, 2017), and the tectonic setting and basin geometries are well constrained (Dorsey et al, 2018;Garnder & Dorsey, in press). Published analyses, however, are incomplete, and some studies favour a lacustrine origin for the Bouse Formation in its southern exposures along the lower Colorado River region (e.g., Spencer & Patchett, 1997;House et al, 2008;Spencer et al, 2013;Bright et al, 2016Bright et al, , 2018aBright et al, , 2018b. Spencer et al (2008) (grey).…”

The Bouse Formation, a controversial Neogene archive of the evolving Colorado River: a scientific drilling workshop report (28 February–3 March 2019 – BlueWater Resort & Casino, Parker, AZ, USA)

“…3). The fossil record of the lower Bouse Formation includes a bewildering mixture of apparently marine or estuarine (e.g., planktic foraminiferans, barnacles, and Thalassinoides trace fossils) and lacustrine (ostracodes, Chara, molluscs) fossils (Bright et al, 2018b). Sigmoidal bedding and other depositional features interpreted to be of marine tidal origin (O'Connell et al, 2017) were also interpreted by Spencer et al (2018) to indicate a lacustrine origin.…”