Work

Global distribution, hierarchical clustering classification, and significance of Holocene braid deltas

Year: 2025

Type: article

Abstract: Braid deltas, environments that form where braided rivers meet base level, are more abundant on Holocene Earth than previously appreciated. A worldwide survey identified 786 braid deltas with feeder systems >500 m wide. Braid deltas occur at all latitudes north of the Antarctic Circle and are most abundant by land area in the 45°S–60°S and 60°N–90°N latitude bands. Marine-associated braid deltas compose 71% of the dataset, with the remainder in marginal lacustrine settings. Half of the observed braid deltas do not form radial terminal delta-plain geometry. Hierarchical clustering analysis separates braid deltas into nine clusters that define a classification scheme. Drivers of differentiation include basin type, embayment, sediment supply, and flow intermittence. The classified dataset provides analogues to ancient, nonvegetated deltaic environments and the essential framework for development of braid-delta facies models.

Source: Geology

DOI: 10.1130/g53851.1

Authors: Jason G. Muhlbauer, Christopher M. Fedo

Institutions: Boise State University, University of Tennessee at Knoxville

Language: English

Topic: Geological formations and processes

Subfield: Earth-Surface Processes

Field: Earth and Planetary Sciences

Domain: Physical Sciences

Open Access status: bronze

Funders: National Aeronautics and Space Administration, Nuclear Safety and Security Commission

Award: THE PROPOSED STUDY WILL FOCUS ON DEVELOPING THREE CENTRAL OBJECTIVES. (1) THE PROPOSAL WILL FOCUS ON THE MINERALOGY GEOCHEMISTRY AND TEXTURAL CHARACTERISTICS OF PALEOSOLS BECAUSE SOIL DEVELOPMENT IS GREATLY CATALYZED BY MICROBIAL PROCESSING. A PRIME TARGET WILL BE THE BEDROCK PALEOSOL UPON WHICH THE TERRESTRIAL MMWCF RESTS BUT RESEARCH WILL ALSO BE AIMED AT IDENTIFYING INTRAFORMATIONAL WEATHERING PROFILES DEVELOPED ON SEDIMENTARY STRATA. RESEARCH WILL REQUIRE FIELD WORK MICROSCOPIC ANALYSIS AND GEOCHEMICAL ANALYSIS. (2) THE DETAILED INNER WORKINGS OF FLUVIAL TRANSPORT PROCESSES AND RECOGNITION OF ASSOCIATED TERRESTRIAL FACIES WILL BE EXAMINED IN BED-BY-BED DETAIL BY COMBINING CONVENTIONAL FIELD TECHNIQUES AND POTENTIAL MODERN ANALOG SITES WITH THE DEVELOPMENT OF THREE-DIMENSIONAL SUBCENTIMETER SCALE DIGITAL OUTCROP MODELS. IN A PILOT STUDY WE HAVE CONDUCTED TO DEMONSTRATE THIS APPROACH THOUSANDS OF LOW-ALTITUDE HIGH-RESOLUTION IMAGES WERE TAKEN USING AN UNMANNED AERIAL VEHICLE AND THEN TRANSFORMED INTO A MODEL USING PIX4D PHOTOGRAMMETRY SOFTWARE. WE ARE PRESENTLY ANALYZING THE MODEL USING 3D VISUALIZATION SOFTWARE. (3) GIVEN THE ENVIRONMENTS OF DEPOSITION WE PLAN TO COMPLETE AN EXHAUSTIVE SEARCH IN THE FIELD FOR MACROSCOPIC EVIDENCE OF TERRESTRIAL LIFE FROM BOTH MICROBIOLOGICAL (E.G. MICROBIALLY INDUCED SEDIMENTARY STRUCTURES) AND MACROBIOLOGICAL (TRACE FOSSILS) PERSPECTIVES.