TY - JOUR

T1 - Stratigraphic Relationships in Jezero Crater, Mars

T2 - Constraints on the Timing of Fluvial-Lacustrine Activity From Orbital Observations

AU - Holm-Alwmark, S.

AU - Kinch, K. M.

AU - Hansen, M. D.

AU - Shahrzad, S.

AU - Svennevig, K.

AU - Abbey, W. J.

AU - Anderson, R. B.

AU - Calef, F. J.

AU - Gupta, S.

AU - Hauber, E.

AU - Horgan, B. H. N.

AU - Kah, L. C.

AU - Knade, J.

AU - Miklusicak, N. B.

AU - Stack, K. M.

AU - Sun, V. Z.

AU - Tarnas, J. D.

AU - Quantin-Nataf, C.

PY - 2021/7/8

Y1 - 2021/7/8

N2 - On February 18, 2021 NASA's Perseverance rover landed in Jezero crater, located at the northwestern edge of the Isidis basin on Mars. The uppermost surface of the present-day crater floor is dominated by a distinct geologic assemblage previously referred to as the dark-toned floor. It consists of a smooth, dark-toned unit overlying and variably covering light-toned, roughly eroded deposits showing evidence of discrete layers. In this study, we investigated the stratigraphic relations between materials that comprise this assemblage, the main western delta deposit, as well as isolated mesas located east of the main delta body that potentially represent delta remnants. A more detailed classification and differentiation of crater floor units in Jezero and determination of their relative ages is vital for the understanding of the geologic evolution of the crater system, and determination of the potential timeline and environments of habitability. We have investigated unit contacts using topographic profiles and DEMs as well as the distribution of small craters and fractures on the youngest portions of the crater floor. Our results indicate that at least some of the deltaic deposition in Jezero postdates emplacement of the uppermost surface of the crater floor assemblage. The inferred age of the floor assemblage can therefore help to constrain the timing of the Jezero fluviolacustrine system, wherein at least some lake activity postdates the age of the uppermost crater floor. We present hypotheses that can be tested by Perseverance and can be used to advance our knowledge of the geologic evolution of the area.

AB - On February 18, 2021 NASA's Perseverance rover landed in Jezero crater, located at the northwestern edge of the Isidis basin on Mars. The uppermost surface of the present-day crater floor is dominated by a distinct geologic assemblage previously referred to as the dark-toned floor. It consists of a smooth, dark-toned unit overlying and variably covering light-toned, roughly eroded deposits showing evidence of discrete layers. In this study, we investigated the stratigraphic relations between materials that comprise this assemblage, the main western delta deposit, as well as isolated mesas located east of the main delta body that potentially represent delta remnants. A more detailed classification and differentiation of crater floor units in Jezero and determination of their relative ages is vital for the understanding of the geologic evolution of the crater system, and determination of the potential timeline and environments of habitability. We have investigated unit contacts using topographic profiles and DEMs as well as the distribution of small craters and fractures on the youngest portions of the crater floor. Our results indicate that at least some of the deltaic deposition in Jezero postdates emplacement of the uppermost surface of the crater floor assemblage. The inferred age of the floor assemblage can therefore help to constrain the timing of the Jezero fluviolacustrine system, wherein at least some lake activity postdates the age of the uppermost crater floor. We present hypotheses that can be tested by Perseverance and can be used to advance our knowledge of the geologic evolution of the area.

KW - Jezero crater

KW - Mars

KW - stratigraphy

KW - FLUID TRANSPORT

KW - EROSION RATES

KW - ROCKS

KW - BASIN

KW - DEPOSITS

KW - SURFACE

KW - ORIGIN

KW - NETWORK

KW - VALLEYS

KW - DELTA

U2 - 10.1029/2021JE006840

DO - 10.1029/2021JE006840

M3 - Journal article

VL - 126

JO - Journal of Geophysical Research: Solid Earth

JF - Journal of Geophysical Research: Solid Earth

SN - 0148-0227

IS - 7

M1 - e2021JE006840

ER -