Puddingstone, also known as either pudding stone or plum-pudding stone, is a popular name applied to a

conglomerate Conglomerate or conglomeration may refer to: * Conglomerate (company) * Conglomerate (geology) * Conglomerate (mathematics) In popular culture: * The Conglomerate (American group), a production crew and musical group founded by Busta Rhymes ** ...

that consists of distinctly rounded pebbles whose colours contrast sharply with the colour of the finer-grained, often sandy, matrix or cement surrounding them. The rounded pebbles and the sharp contrast in colour gives this type of conglomerate the appearance of a raisin or Christmas pudding.Neuendorf, K.E.K., J.P. Mehl, Jr., and J.A. Jackson (2005) ''Glossary of Geology.'' Springer-Verlag, New York, 779 pp., The McGraw-Hill Companies (2003) ''McGraw-Hill dictionary of geology and mineralogy'', 2nd ed. The McGraw-Hill Companies, Inc, New York, 420 pp., There are different types of puddingstone, with different composition, origin, and geographical distribution. Examples of different types of puddingstones include the Hertfordshire, Schunemunk, Roxbury, and St. Joseph Island (Drummond Island) puddingstones.

Hertfordshire puddingstone

Hertfordshire puddingstone is a

silica Silicon dioxide, also known as silica, is an oxide of silicon with the chemical formula , most commonly found in nature as quartz and in various living organisms. In many parts of the world, silica is the major constituent of sand. Silica is ...

-cemented

composed of rounded

flint Flint, occasionally flintstone, is a sedimentary cryptocrystalline form of the mineral quartz, categorized as the variety of chert that occurs in chalk or marly limestone. Flint was widely used historically to make stone tools and start ...

pebbles and cobbles with matrix of fine

sand Sand is a granular material composed of finely divided mineral particles. Sand has various compositions but is defined by its grain size. Sand grains are smaller than gravel and coarser than silt. Sand can also refer to a textural class ...

and silica cement. The Hertfordshire Puddingstone is characterized by silica-cemented flint gravel that is brown to deep red in colour and often exhibits black exteriors and thin rinds on cut or polished surfaces. It typically occurs scattered across the land surface as isolated concretion-like masses in the areas of

Hertfordshire Hertfordshire ( or ; often abbreviated Herts) is one of the home counties in southern England. It borders Bedfordshire and Cambridgeshire to the north, Essex to the east, Greater London to the south, and Buckinghamshire to the west. For gov ...

and Plumstead Common,

England England is a country that is part of the United Kingdom. It shares land borders with Wales to its west and Scotland to its north. The Irish Sea lies northwest and the Celtic Sea to the southwest. It is separated from continental Europe ...

. Large masses of Hertfordshire Puddingstone often occur within local

Pleistocene The Pleistocene ( , often referred to as the ''Ice age'') is the geological Epoch (geology), epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fina ...

glacial tills. More than a dozen large blocks of this puddingstone were recovered from

Paleogene The Paleogene ( ; also spelled Palaeogene or Palæogene; informally Lower Tertiary or Early Tertiary) is a geologic period and system that spans 43 million years from the end of the Cretaceous Period million years ago ( Mya) to the beginning o ...

sediments during recent construction of the A10 bypass from Thundridge to Puckeridge. This indicates that the loose blocks of Hertfordshire Puddingstone were probably eroded out of these sediments. Although it is hypothesized that it is groundwater silcrete, its origin remains unresolved.Lovell, B., and J. Tubb (2006
''Ancient Quarrying of Rare in situ Palaeogene Hertfordshire Puddingstone.''
Mercian Geologist. 16(3):185-189.Perkins, S. (2005
''Hertfordshire Puddingstone.''East Herts Rock Club
Ware, England.

Schunemunk puddingstone

The Schunemunk puddingstone, which is exposed extensively on Bearfort Mountain,

Boonton Boonton is a town in Morris County, New Jersey, United States. As of the 2020 United States census, the town's population was 8,815, an increase of 468 (+5.6%) from the 2010 census count of 8,347, which in turn reflected a decline of 149 (− ...

Rockaway Township Rockaway Township is a township in Morris County, New Jersey, United States. As of the 2020 United States Census, the township's population was 25,341, reflecting an increase of 1,185 (+4.9%) from the 24,156 counted in the 2010 Census. Rockaw ...

and Schunemunk Mountain, is a conglomerate in New York and New Jersey that is part of a thick

geologic formation A geological formation, or simply formation, is a body of rock having a consistent set of physical characteristics (lithology) that distinguishes it from adjacent bodies of rock, and which occupies a particular position in the layers of rock expo ...

formally known as the

Skunnemunk Conglomerate The Skunnemunk Conglomerate (also spelled Schunemunk) is a mapped bedrock unit in New Jersey and New York from the Middle Devonian period. It forms the resistant ridge of Schunemunk Mountain in New York and Bearfort Mountain in New Jersey. Descri ...

. This puddingstone is a distinctive, Late

Devonian The Devonian ( ) is a geologic period and system of the Paleozoic era, spanning 60.3 million years from the end of the Silurian, million years ago (Mya), to the beginning of the Carboniferous, Mya. It is named after Devon, England, wh ...

, grayish-purple to grayish-red, thin to very thick-bedded, cross–bedded, conglomerate. Within the Skunnemunk Conglomerate, it is interbedded with grayish-purple to grayish-red

sandstone Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks. Most sandstone is composed of quartz or feldspar (both silicat ...

, thin-bedded, medium-gray sandstone, and greenish-gray and grayish-red shale with

mudcrack Mudcracks (also known as mud cracks, desiccation cracks or cracked mud) are sedimentary structures formed as muddy sediment dries and contracts.Jackson, J.A., 1997, ''Glossary of Geology'' (4th ed.), American Geological Institute, Alexandria, VA, ...

s. This conglomerate consists of pebbles and cobbles of white vein

quartz Quartz is a hard, crystalline mineral composed of silica ( silicon dioxide). The atoms are linked in a continuous framework of SiO4 silicon-oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall chemical f ...

, red and green

quartzite Quartzite is a hard, non- foliated metamorphic rock which was originally pure quartz sandstone.Essentials of Geology, 3rd Edition, Stephen Marshak, p 182 Sandstone is converted into quartzite through heating and pressure usually related to tec ...

, sandstone, red and gray

chert Chert () is a hard, fine-grained sedimentary rock composed of microcrystalline or cryptocrystalline quartz, the mineral form of silicon dioxide (SiO2). Chert is characteristically of biological origin, but may also occur inorganically as a ...

, and red shale. The grayish-purple to grayish-red conglomerate and sandstone is cemented largely by

hematite Hematite (), also spelled as haematite, is a common iron oxide compound with the formula, Fe2O3 and is widely found in rocks and soils. Hematite crystals belong to the rhombohedral lattice system which is designated the alpha polymorph of . ...

and microcrystalline quartz. The cobbles that it contains range in size from to .Herman, G.C., and J.P. Mitchell (1991) ''Bedrock Geologic Map of the Green Pond Mountain Region from Dover to Greenwood Lake, New Jersey.'' Geological Map Series no. 91-2. New Jersey Geological and Water Survey, Trenton, New Jersey.Merguerian, C., and J.E. Sanders (1992) ''Guide 17: Delaware Water Gap and Vicinity, New Jersey and Pennsylvania, Trip 23: 20 June 1992.'' Duke Geological Laboratory, Westbury, New York. Pieces of Skunnemunk Conglomerate are easy to recognize and have been found in glacial deposits throughout the lower Hudson Valley region.Anonymous (2013a
''The Green Pond Outlier.''
Geology of National Parks, United States Geological Survey, Reston, Virginia.

Roxbury puddingstone

The Roxbury puddingstone is a massive, Ediacaran, clast-supported pebble and cobble conglomerate that occurs within the Brookline Member of the Roxbury Conglomerate that is exposed around

Boston Boston (), officially the City of Boston, is the state capital and most populous city of the Commonwealth of Massachusetts, as well as the cultural and financial center of the New England region of the United States. It is the 24th- mo ...

Massachusetts Massachusetts (Massachusett: ''Muhsachuweesut Massachusett_writing_systems.html" ;"title="nowiki/> məhswatʃəwiːsət.html" ;"title="Massachusett writing systems">məhswatʃəwiːsət">Massachusett writing systems">məhswatʃəwiːsət'' En ...

region. This conglomerate is composed of a grey feldspathic sand matrix and well-rounded pebbles and cobbles of quartzite,

granite Granite () is a coarse-grained ( phaneritic) intrusive igneous rock composed mostly of quartz, alkali feldspar, and plagioclase. It forms from magma with a high content of silica and alkali metal oxides that slowly cools and solidifies un ...

, felsite, and

quartz monzonite Quartz monzonite is an intrusive, felsic, igneous rock that has an approximately equal proportion of orthoclase and plagioclase feldspars. It is typically a light colored phaneritic (coarse-grained) to porphyritic granitic rock. The plagio ...

. The beds of ‘puddingstone’ are complexly interbedded with layers of massive diamictite and laminated and graded argillite and sandstone. It likely accumulated as turbidites and submarine slumps within a

submarine fan Abyssal fans, also known as deep-sea fans, underwater deltas, and submarine fans, are underwater geological structures associated with large-scale sediment deposition and formed by turbidity currents. They can be thought of as an underwater ver ...

or outer slope environment within a deep rift basin submerged by marine waters.Carto, S.L., and N. Eyles (2011) ''Chapter 43 The Squantum Member of the Boston Basin, Massachusetts, USA'' In: E. Arnaud, G.P. Halverson, and G. Shields-Zhou, eds. pp. 475-480, The Geological Record of Neoproterozoic Glaciations. Memoirs no. 36. Geological Society, London, England.Passchier, S., and E. Erukanure (2010) ''Palaeoenvironments and weathering regime of the Neoproterozoic Squantum ‘Tillite’, Boston Basin: no evidence of a snowball Earth.'' Sedimentology. 57(6):1526–1544.

Jasper conglomerate

Jasper conglomerate Jasper conglomerate is an informal term for a very distinctive Paleoproterozoic quartz and jasper pebble conglomerate that occurs within the middle part of the Lorrain Formation of the Cobalt Group of the Huronian Supergroup. It is also known b ...

, which is also denominated "pebble jasper conglomerate", "Saint Joseph Island puddingstone", "Drummond Island puddingstone", or "Michigan(ian) puddingstone", occurs in Saint Joseph Island and the vicinity of the Saint Mary's River, north and northwest of the

Bruce Mines Bruce Mines is a town in the Canadian province of Ontario, located on the north shore of Lake Huron in the Algoma District along Highway 17. The town of Bruce Mines had a population of 582 residents in 2016. The current mayor of Bruce Mines is L ...

Northern Ontario Northern Ontario is a primary geographic and quasi-administrative region of the Canadian province of Ontario, the other primary region being Southern Ontario. Most of the core geographic region is located on part of the Superior Geological Pro ...

Canada Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by to ...

, circa east of

Sault Sainte Marie, Ontario Sault Ste. Marie ( ) is a city in Ontario, Canada. It is at the St. Mary's River on the Canada–US border. It is the third largest city in Northern Ontario, after Sudbury and Thunder Bay. The Ojibwe, the indigenous Anishinaabe inhabitants ...

. In these locales, it occurs as thick beds of Paleoproterozoic pebble conglomerate within the medial part of a

that is named the Lorrain Formation of the Cobalt Group. The jasper conglomerate consists of subrounded pebbles of red jasper, black chert, white quartzite, hematite, and semi-transparent quartz in a matrix of coarsely grained quartzite. It contains circa 30% to 90% of pebbles. Within the deposits of Lorrain Formation, the jasper conglomerates occur principally as the sedimentary fills of erosional troughs and channels of what are interpreted to be either alluvial fans or deposits of

braided river A braided river, or braided channel, consists of a network of river channels separated by small, often temporary, islands called braid bars or, in English usage, ''aits'' or ''eyots''. Braided streams tend to occur in rivers with high sediment ...

.Lowey, G.W. (1985) ''Stratigraphy and Sedimentology of the Lorrain Formation, Huronian Supergroup (Aphebian), Between Sault Ste. Marie and Elliot Lake, Ontario, and Implications For Stratiform Gold Mineralization.'' Open File Report no. 1154. Geological Survey of Canada, Ottawa, Canada.Baumann, S. D. J., T. Arrospide, and A. E. Wolosyzn (2011) ''Preliminary Redefinition of the Cobalt Group (Huronian Supergroup), in the Southern Geologic Province, Ontario, Canada.'' Midwest Institute of Geosciences and Engineering, Chicago, Illinois, USA. These deposits are inferred to be nonglacial in origin and immediately postdate the Paleoproterozoic Makganyene glaciation.Kopp R. E., J. L. Kirschvink, I. A. Hilburn, and C. Z. Nash. (2005) ''The Paleoproterozoic snowball Earth: a climate disaster triggered by the evolution of oxygenic photosynthesis.'' Proceedings of the National Academy of Sciences. 102(32): 11131–6. Elsewhere, e. g. in Drummond Island,

Michigan Michigan () is a state in the Great Lakes region of the upper Midwestern United States. With a population of nearly 10.12 million and an area of nearly , Michigan is the 10th-largest state by population, the 11th-largest by area, and t ...

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country Continental United States, primarily located in North America. It consists of 50 U.S. state, states, a Washington, D.C., ...

, jasper conglomerate, there denominated "Drummond Island puddingstone", occurs as loose gravel within

glacial drift In geology, drift is a name for all sediment (clay, silt, sand, gravel, boulders) transported by a glacier and deposited directly by or from the ice, or by glacial meltwater. Drift is often subdivided into (unsorted and) unstratified drift (gla ...

. These fragments of jasper conglomerate are

glacial erratic A glacial erratic is glacially deposited rock differing from the type of rock native to the area in which it rests. Erratics, which take their name from the Latin word ' ("to wander"), are carried by glacial ice, often over distances of hundred ...

s that continental ice sheets from Northern Ontario eroded and then spread throughout Michigan, including in Drummond Island, and as far south as

Ohio Ohio () is a U.S. state, state in the Midwestern United States, Midwestern region of the United States. Of the List of states and territories of the United States, fifty U.S. states, it is the List of U.S. states and territories by area, 34th-l ...

and

Kentucky Kentucky ( , ), officially the Commonwealth of Kentucky, is a state in the Southeastern region of the United States and one of the states of the Upper South. It borders Illinois, Indiana, and Ohio to the north; West Virginia and Virginia ...

during repeated glacial advances and retreats.Slawson, C. B. (1933) ''The Jasper Conglomerate, an Index of Drift Dispersion.'' The Journal of Geology. 41(5): 546–52.

References

{{reflist

External links

*Anonymous (nd
''Hertfordshire Puddingstone.''East Herts Rock Club
Ware, England. *Kelley, J.G., (2009
''Drummond Island Puddingstone.''
Drummond Island Tourism Association, Drummond Island, Michigan. *Share, J. (2011a

ttp://written-in-stone-seen-through-my-lens.blogspot.com/ Written In Stone...seen through my lens *Share, J. (2011a
''Architectural Geology of Boston: The Roxbury Conglomerate (Puddingstone) Part II - Quarries and Building Stone.''Written In Stone...seen through my lens
*Tubb, J. (2009
''Ancient Quarrying of Rare in situ Palaeogene Hertfordshire Puddingstone (Lovell and Tubb Mercian Geologist August 2006). An update.''East Herts Rock Club
Ware, England. Sedimentary rocks Conglomerates (geology)