Dangosir y 250 milltir o arfordir Sir Benfro, mwy o amrywiaeth o greigiau a golygfeydd, na unrhyw ardal arall o’r un maint, ym Mhrydain.

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Mae’r tirlun hynafol, gyda’r rhan fwyaf o’i chreigiau wedi eu ffurfio cyn diwedd cyfnod Carbonifferaidd, tua 290 miliwn o flynyddoedd yn ôl.

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Mae Penrhyn Teginnis, un o’r enghreifftiau hynaf, i’r de-orllewin o Dŷ Ddewi, yn dyddio nôl 600 miliwn o flynyddoedd. Mae’r creigiau sy’n ifancach na 290 miliwn o flynyddoedd wedi’u colli, dan ddylanwad y tywydd ac erydiad y môr.

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Yn fras, yn nhermau daearegol, gallwch rhannu’r sir yn ddwy, y gogledd a’r de. Mae creigiau’r gogledd o oes cyn-Gambriaidd a Paleosõig Isaf, wedi’u creu gan gwaddodion o waelod y môr, er bod hefyd rhai creigiau igneaidd.

Ffurfiwyd hwy i gyd cyn y cyfnod Caledonian, a ddaeth i ben tua 400 miliwn o flynyddoedd yn ôl. Oherwydd hyn, maent yn dangos graen de-orllewin i ogledd-ddwyrain.

Mae’r plygion a’r thoriadau a welir er engraifft yn y creigiau ym Mae Ceibwr yn y gogledd, wedi’u ffurfio yn ystod yr amser hyn.

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Gwelir creigiau ifancach yn Ne Sir Benfro, yn perthyn i oes hwyrach y Paleosõig Uchaf .

Y creigiau mwyaf cyffredin yw Old Red Tywodfaen a Carreg galch formation Carbonifferaidd, gan gynnwys glo o byllau glo De Sir Benfro. Mae’r rhan fwyaf yn sedimentary, ond mae rhai creigiau igneaidd i’w gweld ar hyd arfordir y de,yn ardal Bae San Ffraid.

Creuwyd y plygion a’r toriadau a welir yn y creigiau yn y de, fel Cobbler’s Hole a Penrhyn St Ann, ar ddiwedd cyfnod creu’r mynyddoedd o’r enw Hercynian Orogeny. Yn y fan yma mae’r graen bron yn ddwyrain-orllewin.

Mae’r amrywiaeth tirwedd arfordirol a welir heddiw yn ganlynial o effaith a phroses daearegol fel rhewlifiant, afonydd, y tywydd ac erydiad y môr, ar yr amrywiaeth eang o’r creigiau yma.

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Mae’r tirlun hynafol, gyda’r rhan fwyaf o’i chreigiau wedi eu ffurfio cyn diwedd cyfnod Carbonifferaidd, tua 290 miliwn o flynyddoedd yn ôl.

Mae Penrhyn Teginnis, un o’r enghreifftiau hynaf, i’r de-orllewin o Dŷ Ddewi, yn dyddio nôl 600 miliwn o flynyddoedd. Mae’r creigiau sy’n ifancach na 290 miliwn o flynyddoedd wedi’u colli, dan ddylanwad y tywydd ac erydiad y môr.

Yn fras, yn nhermau daearegol, gallwch rhannu’r sir yn ddwy, y gogledd a’r de. Mae creigiau’r gogledd o oes cyn-Gambriaidd a Paleosõig Isaf, wedi’u creu gan gwaddodion o waelod y môr, er bod hefyd rhai creigiau igneaidd.

Ffurfiwyd hwy i gyd cyn y cyfnod Caledonian, a ddaeth i ben tua 400 miliwn o flynyddoedd yn ôl. Oherwydd hyn, maent yn dangos graen de-orllewin i ogledd-ddwyrain.

Mae’r plygion a’r thoriadau a welir er engraifft yn y creigiau ym Mae Ceibwr yn y gogledd, wedi’u ffurfio yn ystod yr amser hyn.

Ceibwr Bay

Gwelir creigiau ifancach yn Ne Sir Benfro, yn perthyn i oes hwyrach y Paleosõig Uchaf .

Y creigiau mwyaf cyffredin yw Old Red Tywodfaen a Carreg galch formation Carbonifferaidd, gan gynnwys glo o byllau glo De Sir Benfro. Mae’r rhan fwyaf yn sedimentary, ond mae rhai creigiau igneaidd i’w gweld ar hyd arfordir y de,yn ardal Bae San Ffraid.

Creuwyd y plygion a’r toriadau a welir yn y creigiau yn y de, fel Cobbler’s Hole a Penrhyn St Ann, ar ddiwedd cyfnod creu’r mynyddoedd o’r enw Hercynian Orogeny. Yn y fan yma mae’r graen bron yn ddwyrain-orllewin.

Mae’r amrywiaeth tirwedd arfordirol a welir heddiw yn ganlynial o effaith a phroses daearegol fel rhewlifiant, afonydd, y tywydd ac erydiad y môr, ar yr amrywiaeth eang o’r creigiau yma.

Limeston
Castlemartin Range

Darganfyddwch fwy am Lwybr yr Arfordir