Constraining the Duration and Ages of Stratigraphic Unconformities on Mars Using Exhumed Craters
Year: 2024
Type: article
Abstract: Crater counting is a widely applied methodology for dating large areas of planetary surfaces, but is difficult to apply the method to constrain the durations of stratigraphic unconformities. Unconformities with exhumed craters are thought to indicate long hiatuses that can only be indirectly dated through stratigraphic relationships with other surfaces with uniform exposure ages. On Mars, sedimentary deposits with prominent unconformities with exhumed craters are found in layered deposits in the Arabia Terra region as well as Gale crater within Mount Sharp. In this work, we present a Linear Crater Counting methodology and apply it to constrain these unconformities observed in Arabia Terra and in Mount Sharp. The method applies a linear sampling domain correction to conventional two‐dimensional crater size frequency distributions and Bayesian Poisson process statistics in order to constrain the likely durations of these unconformities. We found that unconformities in Arabia Terra were on the order of 0.1–1 Gyr in length and that the unconformity preserved at Mount Sharp is at least 0.2 Gyr in length given estimates of the ages of the host craters. Hiatuses of these lengths constrain the age of the overlying deposits to be Late Hesperian or Amazonian in age. Two utility plots are also provided, along with the derivation, for researchers to apply this method to dating arbitrary geologic contacts on Mars and to adapt it to other bodies.
DOI: 10.1029/2023je008073
Authors: A. M. Annex, K. W. Lewis
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $3,880
Awards: SCIENCE GOALS AND OBJECTIVES: THE OBJECTIVES OF THIS PROPOSAL ARE TO WORK TOWARD THE FIRST REGIONAL FRAMEWORK FOR EQUATORIAL LAYERED DEPOSITS ON MARS BY IDENTIFYING SPECIFIC STRATIGRAPHIC TIEPOINTS VIA PHYSICAL SPECTROSCOPIC AND THERMOPHYSICAL PROPERTIES. ON THE EARTH THE ADVENT OF BIOSTRATIGRAPHY WAS REVOLUTIONARY IN THE TEMPORAL CORRELATION OF DISPARATE SEDIMENTARY UNITS ACROSS THE GLOBE. ON MARS NO CLEAR STRATIGRAPHIC FRAMEWORK CURRENTLY EXISTS TO RELATE WIDESPREAD LAYERED DEPOSITS MANY OF WHICH ARE ISOLATED WITHIN SEPARATE SEDIMENTARY BASINS PROVIDED BY IMPACT CRATERS. LEWIS AND AHARONSON (2014) HAVE DEMONSTRATED THE ABILITY TO CORRELATE INDIVIDUAL SECTIONS (WITHIN ONE UNIT) BY USING DETAILED LAYER-BY-LAYER BEDDING THICKNESS MEASUREMENTS FROM HIGH-RESOLUTION TOPOGRAPHIC DATA THAT FORM A UNIQUE FINGERPRINT WITHIN THE STRATIGRAPHY. FURTHERMORE THIS STUDY SHOWED BROAD SIMILARITIES IN BOTH THE STYLE AND SCALE OF LAYERING AMONG SEVERAL DEPOSITS PARTICULARLY IN WESTERN ARABIA TERRA. WE PLAN TO EXPAND UPON THIS WORK BY SEARCHING FOR THE FIRST TIME FOR CONCRETE LINKS BETWEEN WIDELY SEPARATED SEDIMENTARY DEPOSITS. THIS WORK HAS TWO GOALS INCLUDING: 1) IDENTIFYING TEMPORAL RELATIONSHIPS BETWEEN MULTIPLE SEDIMENTARY UNITS ON MARS AND 2) CONSTRAINING THE CLIMATIC AND DEPOSITIONAL CONDITIONS DURING THEIR FORMATION. WE WILL COMBINE VISUAL SPECTRAL AND THERMOPHYSICAL STRATIGRAPHIC PROXIES OF THE UNITS TO BE STUDIED ALONGSIDE PHYSICAL STRATIGRAPHIC MEASUREMENTS. OUR PRIMARY FOCUS AREA WILL BE IN ARABIA TERRA WHERE THE MOST PROMISING CANDIDATES EXIST FOR THIS STUDY. THE SUCCESSFUL CORRELATION OF THESE DEPOSITS WOULD POINT STRONGLY TOWARD A REGIONAL DEPOSITIONAL MECHANISM DICTATED BY LARGE-SCALE CLIMATE CONTROLS RATHER THAN THOSE UNIQUE TO INDIVIDUAL CRATERS OR BASINS., G8889537449
OpenAlex ID: W4404325939