Sedimentary features and penecontemporaneous slumping in the Waitemata Group, Whangaparaoa Peninsula, North Auckland, New Zealand

Abstract

Rocks belonging to a turbidite facies of the Lower Miocene Waitemata Group are exposed extensively about Whangaparaoa Peninsula. Interbedded with this sequence are a number of thick, distinctive, volcaniclastic grits believed to have been emplaced by submarine lahars. These sediments accumulated towards the axial parts of a marine basin within a continental borderland. The turbidites were deposited by predominantly south-east -flowing currents. Directions of weak bottom (traction) currents were more variable. Deformation and contortion of strata occur on a grand scale and are attributed to the penecontemporaneous slumping of poorly consolidated sediments in response to tilting of the sea floor. Injection of clastic dikes accompanied later stages of movement in slumped sequences. Evidence suggests that one great slump sheet extends over a distance of at least 10 miles from near Red Beach in the west to Whangaparaoa Head and possibly Tiritiri Matangi in the east.

Paleoenvironmental implications of stormscoured, ichnofossiliferous mid-tertiary limestones, Waihao district, south Canterbury, New Zealand

“…11; also see Fig. 14) is identified by comparison to the description and figures published by Gregory (1969;also via pers. comm.…”

“…They were first recorded from Waihao Forks by Wild & Speight (1919, p. 86), who considered them to be "casts of fish intestines". Ghent & Henderson (1966) tentatively suggested holothurians as the progenitors of their Laminites (a form-genus name preempted by Scolicia, see Gregory 1969). In the Arno Limestone, the structures conform to the cross-sectional geometry of spatangoid echinoids (e.g., No te intraclasts below hammer head and others left of hammer handl e. Rapid depos ition and bur ial accounts for the absence of bioturbation, which abounds in the sur rounding calcarenites.…”

“…Long meandering, subhorizontal, smooth cylindrical tubes, 5 to 10 mm in diameter, can be referred to ichnogenus Planolites (e .g., see Frey & Howard 1970;Gregory 1969 ) . They are abundant and widespread in the Arno Limestone, but often obscure.…”

Lithostratigraphy of the basal Waitemata Group, Kawau Subgroup (new), Auckland, New Zealand

“…Most significant have been theses on rocks in the north around Cape Rodney and Kawau Island (Hopgood 1961;Wood 1976), on Tiritiri, Motutapu, and Waiheke Islands (Halcrow 1956;Mayer 1965;Gregory 1966), in the northern Hunua Ranges (Firth 1930;Laws 1931;Healy 1935;Brown 1942), at Cape Colville (Skinner 1969), and in South Auckland (Gilbert 1921;Purser 1961;Weigel 197 6).…”

The turbidite problem: A reply to Kuenen

“…The number of occurrences and the range of depths covered by deep-sea photography are still too limited to be conclusive. A recently published paper by Gregory (1969) describes trace fossils from the Waitemata flysch-type deposits in New Zealand. These belong to what Seilacher (1967) calls the Nereites faci,es, thought characteristic for a geosynclinal, deep-water environment.…”