Data from Perseverance suggests the delta in Jezero Crater was formed by a wide variety of different “fluvial” events
Jezero Crater delta
Using data from the Perseverance rover in Jezero crater, scientists now conclude that the delta that poured through a gap in the crater’s rim was formed by a wide variety of different “fluvial” events, not a steady flow as previously assumed.
From the paper’s conclusions:
The origin of this variability as well as that of the high discharge represented by the boulder conglomerate is still unknown. Realistic hypotheses include seasonal variations due to melting of snow, glacial input with possible episodic surges punctuating more regular fluvial input, or arid climate type of flows with intense storms and related flash floods.
We do not speculate further about the nature of fluvial activity in this study. However, the variability and the presence of high discharge rates have important implications on the lake evolution. Firstly, previous modeling of Jezero delta formation used steady-state discharge rates to estimate the time required to form the delta, an assumption that we can no longer justify according to our observations. Secondly, estimates of discharge rates … may be used as upper limits for some of the peak discharge rates, although the number of flood events is still difficult to determine from the sparse outcrops and the ubiquitous presence of scree.
In other words, the delta was not formed by a single event or a long stream of liquid flowing into the crater to form the lake that scientists believe once filled the crater. Instead, that flow varied, involved numerous distinct and different events over time, and likely included glacial ice transport as well.
Not that this is a surprise, but as always, the closer we get to a planet and the more detailed our data about it, the more complicated we find its nature and origins.
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
The print edition can be purchased at Amazon. from any other book seller, or direct from my ebook publisher, ebookit.
The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News
Jezero Crater delta
Using data from the Perseverance rover in Jezero crater, scientists now conclude that the delta that poured through a gap in the crater’s rim was formed by a wide variety of different “fluvial” events, not a steady flow as previously assumed.
From the paper’s conclusions:
The origin of this variability as well as that of the high discharge represented by the boulder conglomerate is still unknown. Realistic hypotheses include seasonal variations due to melting of snow, glacial input with possible episodic surges punctuating more regular fluvial input, or arid climate type of flows with intense storms and related flash floods.
We do not speculate further about the nature of fluvial activity in this study. However, the variability and the presence of high discharge rates have important implications on the lake evolution. Firstly, previous modeling of Jezero delta formation used steady-state discharge rates to estimate the time required to form the delta, an assumption that we can no longer justify according to our observations. Secondly, estimates of discharge rates … may be used as upper limits for some of the peak discharge rates, although the number of flood events is still difficult to determine from the sparse outcrops and the ubiquitous presence of scree.
In other words, the delta was not formed by a single event or a long stream of liquid flowing into the crater to form the lake that scientists believe once filled the crater. Instead, that flow varied, involved numerous distinct and different events over time, and likely included glacial ice transport as well.
Not that this is a surprise, but as always, the closer we get to a planet and the more detailed our data about it, the more complicated we find its nature and origins.
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
The print edition can be purchased at Amazon. from any other book seller, or direct from my ebook publisher, ebookit. The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News
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