#tillite — Public Fediverse posts
Live and recent posts from across the Fediverse tagged #tillite, aggregated by home.social.
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A bizarre #sedimentary feature
Some layers in the #Neoproterozoic #Squantum Member of the #Roxbury #Conglomerate have been rolled up like a pie crust, into a tube. If this were a #tillite, as it once was thought to be, then it could have been caused by the drag of a #Gaskiers #glacier over the till. These rocks are mostly interpreted as deposited by submarine debris flows these days, in which case they could’ve been deformed during a slump and flow. Site of a field trip for #UMassBoston.
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A bizarre #sedimentary feature
Some layers in the #Neoproterozoic #Squantum Member of the #Roxbury #Conglomerate have been rolled up like a pie crust, into a tube. If this were a #tillite, as it once was thought to be, then it could have been caused by the drag of a #Gaskiers #glacier over the till. These rocks are mostly interpreted as deposited by submarine debris flows these days, in which case they could’ve been deformed during a slump and flow. Site of a field trip for #UMassBoston.
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A small #outcrop of the #Squantum Member of the #Roxbury #Conglomerate
These #rocks are in the #BostonBay Group, which is currently dated to #Neoproterozoic. The Squantum Member was interpreted as a #tillite, possibly associated with the #Gaskiers #glaciation, although there a scant signs like scratched pebbles or faceted cobbles. It is currently commonly interpreted as a #debrite (debris flow). Details in captions.
#geology #glacier #turbidite #Quincy #Boston #Massachusetts #NewEngland -
A small #outcrop of the #Squantum Member of the #Roxbury #Conglomerate
These #rocks are in the #BostonBay Group, which is currently dated to #Neoproterozoic. The Squantum Member was interpreted as a #tillite, possibly associated with the #Gaskiers #glaciation, although there a scant signs like scratched pebbles or faceted cobbles. It is currently commonly interpreted as a #debrite (debris flow). Details in captions.
#geology #glacier #turbidite #Quincy #Boston #Massachusetts #NewEngland -
The #glacier went that-a-way
The #striations on this face of the #Ediacaran (ca. 560 Ma) #Squantum Member of the #Roxbury #Conglomerate were probably left by the #Pleistocene #Laurentide ice sheet, which retreated ca. 12 ka. The striations have the right orientation, from northwest to southeast.
The Squantum Member was once interpreted as a (#glacial) #tillite. The most common contemporary model is a peri-#Gondwana #debrite (#turbidite).
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The #glacier went that-a-way
The #striations on this face of the #Ediacaran (ca. 560 Ma) #Squantum Member of the #Roxbury #Conglomerate were probably left by the #Pleistocene #Laurentide ice sheet, which retreated ca. 12 ka. The striations have the right orientation, from northwest to southeast.
The Squantum Member was once interpreted as a (#glacial) #tillite. The most common contemporary model is a peri-#Gondwana #debrite (#turbidite).